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"source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_54.pdf?download=true", "local_path": "_source-pdfs/2025-May-June/qp/9701_s25_qp_54.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "41", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "42", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "43", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "44", "paper": 4, "question_count": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "51", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_51.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_51.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "52", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_52.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_52.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "53", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_53.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_53.pdf" }, { "year": 2025, "session": "Oct/Nov", "session_code": "on", "variant": "54", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_54.pdf?download=true", "local_path": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_54.pdf" }, { "year": 2026, "session": "March", "session_code": "m", "variant": "42", "paper": 4, "question_count": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "local_path": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf" }, { "year": 2026, "session": "March", "session_code": "m", "variant": "52", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-52.pdf?download=true", "local_path": "_source-pdfs/2026-March/qp/9701_m26_qp_52.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "41", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "42", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "43", "paper": 4, "question_count": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "44", "paper": 4, "question_count": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "51", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-51.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_51.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "52", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-52.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_52.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "53", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-53.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_53.pdf" }, { "year": 2026, "session": "May/June", "session_code": "mj", "variant": "54", "paper": 5, "question_count": 2, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-54.pdf?download=true", "local_path": "_source-pdfs/2026-May-June/qp/9701_s26_qp_54.pdf" } ], "records": [ { "id": "9701-2021-m-42-q01", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-m-42-q01-p01-b3232abcb6.png", "9701-topic-27-group-2/assets/9701-2021-m-42-q01-p02-bfbdbe7b24.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "The most common oxidation states of cobalt are +2 and +3. 1 (a)\nComplete the electronic configurations of the following free ions.\nCo2+ ● [Ar] ............................................................................................................................\nCo3+ ● [Ar] ............................................................................................................................\n[1]\nCo2+ Co3+ edta4–. and both form complexes with (b)\no half-equation E / V\nCo3+ e– Co2+ +1.82 +\n4H+ 4e– +1.23 + + 2H O O\n2 2\n[Co(edta)]– e– [Co(edta)]2– +0.38 +\nCo2+ 2e– –0.28 + Co\nUse the data in the table to predict what happens, if anything, when separate aqueous solutions\nCo3+ [Co(edta)]– and are left to stand in the air. of\nCo3+ a queous solution of\n....................................................................................................................................................\n....................................................................................................................................................\n[Co(edta)]– a queous solution of\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\ncobalt(II) Hydrated nitrate, Co(NO ) •6H O, is a red solid that behaves like hydrated (c)\n3 2 2\nmagnesium nitrate, Mg(NO ) •6H O, when heated.\n3 2 2\nD escribe in detail what you would expect to observe when crystals of Co(NO ) •6H O are\n3 2 2\nheated in a boiling tube, gently at first and then more strongly.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nExplain why the thermal stability of the Group 2 nitrates increases down the group. (d)\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 8]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-m-42-q01-772de2f226.pdf" }, { "id": "9701-2021-m-42-q02", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-m-42-q02-p01-a9a8eab1f0.png", "9701-topic-24-electrochemistry/assets/9701-2021-m-42-q02-p02-940054f15e.png", "9701-topic-24-electrochemistry/assets/9701-2021-m-42-q02-p03-00f0910e13.png", "9701-topic-24-electrochemistry/assets/9701-2021-m-42-q02-p04-9ddb6a89b3.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q02", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Iron(II) compounds are generally only stable in neutral, non-oxidising conditions. 2 (a)\nIt is difficult to determine the lattice energy of FeO experimentally.\nUse data from the Data Booklet and this Born–Haber cycle to calculate the lattice energy, (i)\n∆H mol–1. , of FeO(s) in kJ\nlatt\nFe2+(g) O2–(g) +\nFe2+(g) 2e– + O(g) +\nmol–1 +798 kJ\nmol–1 –141 kJ\nFe2+(g) O–(g) e– + +\nFe+(g) e– + O(g) +\nFe(g) + O(g)\n(cid:31)H\nlatt\n1 Fe(g) + O (g)\n2 2\nmol–1 +416 kJ 1 Fe(s) + O (g)\n2 2\nmol–1 –272 kJ\nFeO(s)\n∆H mol–1 FeO(s) = .............................. kJ [2]\nlatt\niron(II) Most naturally occurring samples of oxide are found as the mineral wüstite. (ii)\nFe2+ Fe3+ O . It contains both and ions. Wüstite has formula Fe\n20 x\nFe2+ Fe3+. and 10% is present as 90% of the iron is present as\nDeduce the value of x.\nx = .............................. [1]\nState and explain how the lattice energy of FeO(s) compares to the lattice energy of (iii)\nCaO(s).\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nHeating of FeO results in the formation of Fe O , as shown. (b)\n3 4\n→ O 4FeO Fe + Fe reaction 1\n3 4\nFe2+ Fe3+ Each formula unit of Fe O contains one and two ions.\n3 4\nShow how reaction 1 can be described as a disproportionation reaction. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nFeO (l) can be electrolysed using inert electrodes to form Fe.\n3 4\nWrite the half-equation for the reaction that occurs at the anode during the electrolysis of (ii)\nO (l). Fe\n3 4\n....................................................................................................................................... [1]\nO (l) is electrolysed for Calculate the maximum mass of iron metal formed when Fe (iii)\n3 4\nsix hours using a current of 50 A.\nFe2+ Fe3+ and two ions are discharged at the same rate. Assume the one\nmass of iron = .............................. g [3]\nLiFePO can be used in lithium-ion rechargeable batteries. (c)\n4\n. When the cell is charging, lithium reacts with a gr", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-m-42-q02-db334c1d45.pdf" }, { "id": "9701-2021-m-42-q03", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2021-m-42-q03-p01-6b76ac3f55.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-m-42-q03-p02-a2c3586b7f.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-m-42-q03-p03-b116becfd9.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-m-42-q03-p04-2566c4822e.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-m-42-q03-p05-7c0c16550d.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "– IO Iodates are compounds that contain the anion. 3\n3\n– IO anion is shown. The (a)\n3\nO– O\nI\nO\n– IO anion E xplain, with reference to the qualitative model of electron-pair repulsion, why the\n3\nhas a pyramidal shape.\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe reaction of iodine and hot aqueous sodium hydroxide is similar to that of chlorine and (b)\nNaIO , is formed as one of the products. hot aqueous sodium hydroxide. Sodium iodate,\n3\nSuggest an equation for the reaction of iodine and hot aqueous sodium hydroxide.\n.............................................................................................................................................. [1]\n–. IO The decomposition of hydrogen peroxide, H O , is catalysed by acidified (c)\n2 2 3\n– IO O reduces acidified as shown. H\n2 2 3\n→ 2H+ – 2IO I O + + + 5O + 6H O 5H\n2 2 3 2 2 2\nI by H O . T his reaction is followed by the oxidation of\n2 2 2\no half-equation E / V\n2H+ 2e– +1.77 O + + 2H O H\n2 2 2\n1 6H+ 5e– – +1.19 I IO + + + 3H O\n2 3 2 2\n2H+ 2e– +0.68 O + + H O\n2 2 2\n– IO I O with and with are both Use the data to show that the separate reactions of H (i)\n2 2 3 2\nfeasible under standard conditions.\nI O with . In your answer, give the equation for the reaction of H\n2 2 2\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\n–. IO O catalysed by acidified W rite the overall equation for the decomposition of H (ii)\n2 2 3\n....................................................................................................................................... [1]\n–, IO A student collects some data for the reaction of H O with acidified as shown in the table. (d)\n2 2 3\n[H+] –] [IO [H O ] initial rate of reaction\n2 2 3 experiment\ndm–3 dm–3 dm–3 s–1 dm–3 / mol / mol / mol / mol\n× 10–5 1 0.0500 0.0700 0.025 1.47\n× 10–5 2 0.100", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2021-m-42-q03-fc1742f883.pdf" }, { "id": "9701-2021-m-42-q04", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-m-42-q04-p01-4919070e10.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-m-42-q04-p02-073e5da388.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-m-42-q04-p03-d5e49ddfa6.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "The transition elements are able to form stable complexes with a wide range of molecules and ions. 4\nState the meaning of transition element. (a)\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe d orbitals in an isolated transition metal ion are degenerate. In complexes, the d orbitals (b)\noccupy two energy levels.\nComplete the diagram to show the arrangement of d orbital energy levels in octahedral (i)\nand in tetrahedral complexes.\nenergy\ndegenerate\nd orbitals\noctahedral isolated transition tetrahedral\ncomplex metal ion complex\n[1]\nS ketch the shape of d orbitals: (ii) two\n● one d orbital from the lower energy level in an octahedral complex\n● one d orbital from the higher energy level in an octahedral complex.\nUse the axes below.\nlower energy level higher energy level\nz z\nx x\ny y\n[2]\nEdds4– edta4– Fe3+(aq). and are polydentate ligands that form octahedral complexes with (c)\nedds4– edta4–\n– – CO CO\n2 2 – CO\n2\nH\n–O – N C CO N\n2 2\n– N N CO\n2\nH\n– – CO CO\n2 2\n[Fe(edds)]– [Fe(edta)]– The formulae of the complexes are and respectively.\nedds4–, Fe3+ [Fe(edds)]–. circle each atom that forms a bond to the ion in On the diagram of (i)\n[1]\n[Fe(edds)]– [Fe(edta)]– is red and is yellow. (ii)\nExplain why the two complexes have different colours.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nedds4–(aq) Fe3+(aq), is added to the following reaction occurs. When (iii)\n]3+(aq) edds4–(aq) [Fe(edds)]–(aq) O) + + 6H O(l) [Fe(H\n2 6 2\nState the type of reaction that occurs.\n....................................................................................................................................... [1]\n[Fe(edds)]–(aq). Write an expression for the stability constant, K , of (iv)\nstab\nK =\nstab\n[1]\n, of both complexes. The table shows the values for the stability constants, K (v)\nstab\nmol–1 dm3 complex K /\nstab\n× [Fe(edds)]– 1020 3.98\n× [Fe(edta)]– 1025 1.26\n[Fe(edds)]– [Fe(edta)]– Predict which of the and complexes is mor", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-m-42-q04-403d9719ee.pdf" }, { "id": "9701-2021-m-42-q05", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-m-42-q05-p01-5d0c82703d.png", "9701-topic-36-organic-synthesis/assets/9701-2021-m-42-q05-p02-3761b76181.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q05", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Carboplatin and satraplatin are used as anticancer drugs instead of cisplatin. 5 (a)\ncarboplatin satraplatin\nO\nO\nO\nNH O\n3 NH Cl\n3\nPt Pt\nCl N\nO NH\nO H 3\n2\nO\nO\nDescribe the action of cisplatin as an anticancer drug. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nSuggest the geometry of the platinum centre in the carboplatin complex. (ii)\n....................................................................................................................................... [1]\nSuggest why carboplatin does show cis-trans isomerism. (iii) not\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n– –, Cl CO C H NH , and NH . Satraplatin is a neutral complex, containing the ligands CH (iv)\n3 2 6 11 2 3\nDeduce the oxidation state of platinum in satraplatin.\n....................................................................................................................................... [1]\nCompound is made from 1,3-dimethylbenzene in a two-step synthesis. (b) M\n1,3-dimethylbenzene L M\nO O\nstep 1 step 2\nC H O\nCl Cl 8 6 4\nDraw the structure of L. (i)\n[1]\nSuggest reactants and conditions for each step of this synthesis. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nWrite an equation for step 2. (iii)\n....................................................................................................................................... [1]\nCOCl A student investigates a possible synthesis of directly from benzene using in the (iv) M\n2\nAl Cl catalyst. presence of an\n3\nCOCl Benzene initially reacts with as shown.\n2\n+\n→ – COCl Al Cl Al Cl Cl + + C O reaction 1\n2 3 4\n+\n→ H+ Cl COCl H + C O C H + C reaction 2\n6 6 6 5\n+\nH+ Cl Reaction 2 is the electrophilic substitution of C O for in benzene.\nSuggest a mechanism for reaction 2.\n[3]\n[Total: 12]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-m-42-q05-9a7a19ec02.pdf" }, { "id": "9701-2021-m-42-q06", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 18, 19, 20 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2021-m-42-q06-p01-4123bc20c7.png", "9701-topic-35-polymerisation/assets/9701-2021-m-42-q06-p02-97adf5d005.png", "9701-topic-35-polymerisation/assets/9701-2021-m-42-q06-p03-a5e95ace95.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q06", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "Fumaric acid is a naturally occurring dicarboxylic acid. 6\nfumaric acid\nCO H\n2\nHO C\n2\nIdentify the products of the reaction between fumaric acid and an excess of hot, concentrated, (a)\nmanganate(VII). acidified\n.............................................................................................................................................. [1]\nFumaric acid can form addition and condensation polymers. (b)\nDraw the repeat unit of the addition polymer poly(fumaric acid). (i)\n[1]\nD raw the repeat unit of the polyester formed when fumaric acid reacts with ethane-1,2-diol, (ii)\nOH) . (CH\n2 2\nThe ester bond should be shown fully displayed.\n[2]\nExplain why polyesters normally biodegrade more readily than polyalkenes. (iii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nmanganate(VII) Fumaric acid reacts with cold, dilute, acidified to form compound P. (c)\nP\nOH\nCO H\n2\nHO C\n2\nOH\nO nly three stereoisomers of exist. One of the stereoisomers is shown. P\nOH\nH\nCO H\n2\nHO C\n2\nH\nOH\nComplete the three-dimensional diagrams in the boxes to show the two stereoisomers other\nof P.\nHO C HO C\n2 2\n[2]\n2–, The enzyme fumarase catalyses the reaction of fumarate ions, C H O with water to form (d)\n4 2 4\n2–. H O malate ions, C\n4 4 5\n2– 2– H O + H O C H O C\n4 2 4 2 4 4 5\nDescribe, with the aid of a suitably labelled diagram, how an enzyme such as fumarase can\ncatalyse a reaction.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\n[Total: 10]", "pdf_path": "9701-topic-35-polymerisation/print/9701-2021-m-42-q06-3a14422f43.pdf" }, { "id": "9701-2021-m-42-q07", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 28, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_42.pdf?download=true", "source_pages": [ 21, 22, 23, 24, 25, 26, 27 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p01-a8a35ab4fc.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p02-b91c247196.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p03-0a1f490748.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p04-c998c153a0.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p05-d10c85f37d.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p06-dce0d1f10e.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-m-42-q07-p07-ceb2d0e488.png" ], "answer": { "status": "pending", "id": "9701-2021-m-42-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Proline (Pro) is a naturally occurring amino acid. 7\nproline\nO\nOH\nN\nH\nProline is often found bonded to glycine (Gly) in a protein. (a)\nDraw the dipeptide Pro-Gly. (i)\nThe peptide bond must be shown fully displayed.\n[2]\nN ame the type of reaction that forms a dipeptide from two amino acids. (ii)\n....................................................................................................................................... [1]\nProline is able to form a poly(proline) peptide chain. (iii)\nA section of a poly(proline) chain is shown.\nN N N\nO O O\nSuggest why the secondary structure of poly(proline) be stabilised by hydrogen cannot\nbonding.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe reaction scheme shows several reactions of proline. (b)\nproline\nO\nreaction 1\nQ\nOH NaOH(aq)\nN\nH\nreaction 3\nreaction 2\nCOCl CH\n3\nprolinol\nR\nH NO C\n7 11 3 OH\nN\nH\nWrite an equation for the reaction of proline with NaOH(aq) in reaction 1. (i)\nH NHCO H + ........................................................................................................... [1] C\n4 7 2\nProline has a secondary amine functional group. (ii)\nSecondary amines react with acyl chlorides. For example, dimethylamine reacts with\nRCOCl according to the following equation.\ndimethylamine\nH C H C\n3 3\nHCl RCOCl NCOR + NH +\nH H C C\n3 3\nSuggest the skeletal structure of R, C H NO , the product of reaction 2.\n7 11 3\n[1]\nSuggest the reagent required for reaction 3. (iii)\n....................................................................................................................................... [1]\nProline was first synthesised in the laboratory using a multi-stage synthetic route. (c)\n(CO C H ) and CH =CHCN react to form a single product U. In stage 1, CH\n2 2 2 5 2 2\nU\nCO C H\n2 2 5\nCH (CO C H ) + CH CHCN H C CO C H stage 1\n2 2 2 5 2 2 2 2 5\nCH CH CN\n2 2\nName the functional groups present in the reactants of stage 1. (i) all\n(CO C H ) .................................................................................................................... CH\n2 2 2 5 2\n=CHCN ......................................................................................................................... CH\n2\n[2]\nSuggest the type of reaction that occurs in stage 1. (ii)\n....................................................................................................................................... [1]\nIn stage 2, reacts with reagent to form W. U V\nU W\nCO C H CO C H\n2 2 5 2 2 5\nreagent V\nH C CO C H H C CO C H stage 2\n2 2 5 2 2 5\nCH CH CN CH CH CH NH\n2 2 2 2 2 2\nSuggest a suitable reagent V. (iii)\n....................................................................................................................................... [1]\nStage 3 takes place in the presence ", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-m-42-q07-fcea8eba04.pdf" }, { "id": "9701-2021-m-52-q01", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-m-52-q01-p01-efccbda54d.png", "9701-experimental-skills/assets/9701-2021-m-52-q01-p02-98d01b22b1.png", "9701-experimental-skills/assets/9701-2021-m-52-q01-p03-d00dc07d19.png" ], "answer": { "status": "pending", "id": "9701-2021-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "copper(II) Zinc metal reacts with aqueous sulfate. 1\n→ (aq) Cu(s) + ZnSO (aq) Zn(s) + CuSO\n4 4\n∆H, The enthalpy change of this reaction, can be determined by adding excess zinc powder to a\ncopper(II) dm–3 aqueous sulfate. measured volume of 0.500 mol\ncopper(II) cm3 dm–3 of 0.500 mol aqueous sulfate is recorded for three The temperature of 25.0\nminutes. At four minutes 3 g, an excess, of zinc powder is added and the mixture is continuously\nstirred. The temperature is recorded at times shown in the table.\n41 51 61 time / min 0 1 2 3 5 6 7 8 9 10\n2 2 2\ntemperature\n18 19.5 19.5 19.5 32.5 38 36 34 33 32.5 31.5 31 31\n°C /\nUse the results table to deduce the graduations on the thermometer that is used to record (a)\nthese temperature readings.\n.............................................................................................................................................. [1]\nDraw a labelled diagram of the apparatus set up at one minute. (b)\n[2]\n(××) Plot a graph of temperature (y-axis) against time (x-axis). Use a cross to plot each data (c)\npoint. Draw a line of best fit during cooling.\nE xtrapolate the cooling curve back to four minutes and determine the temperature change\nduring the reaction.\n50\n45\n40\n35\ntemperature\n/ °C\n30\n25\n20\n15\n10\n10 0 2 4 6 8\ntime / min\n°C temperature change = .............................. [2]\n∆H –mc∆T ∆H, mol–1. Use the formula = to determine the enthalpy change of reaction, in kJ (d)\nA ssume:\ncm3 of solution = 1.00 g ● mass of 1.00\ng–1 K–1. ● c = 4.18 J\n∆H mol–1 = .............................. kJ [2]\nHeat loss is a major source of error in the results of this experiment. (e)\nS uggest how the following changes would affect the amount of heat loss, if at all.\nE xplain your answer in each case.\nThe mass of zinc is doubled. (i)\neffect on heat loss ...............................................................................................................\nexplanation .........................................................................................................................\n....................................................................................................................................... [1]\ncopper(II) cm3 of aqueous sulfate is doubled. The amount of T he concentration of 25.0 (ii)\nzinc used is still an excess.\neffect on heat loss ...............................................................................................................\nexplanation .........................................................................................................................\n....................................................................................................................................... [1]\ncopper(II) dm–3 aqueous sulfate is doubled. The amount of zinc The volume of 0.500 mol (iii)\nused is still an excess.\neffect on heat loss ...............................................................................................................\nexplanation ...............", "pdf_path": "9701-experimental-skills/print/9701-2021-m-52-q01-5af46b20a0.pdf" }, { "id": "9701-2021-m-52-q02", "subject": "9701", "year": 2021, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 20, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-march/9701_m21_qp_52.pdf?download=true", "source_pages": [ 5, 6, 7, 8 ], "local_pdf": "_source-pdfs/2021-March/qp/9701_m21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-m-52-q02-p01-9007f7c521.png", "9701-experimental-skills/assets/9701-2021-m-52-q02-p02-fb240ae575.png", "9701-experimental-skills/assets/9701-2021-m-52-q02-p03-ed653cf312.png", "9701-experimental-skills/assets/9701-2021-m-52-q02-p04-4106380763.png" ], "answer": { "status": "pending", "id": "9701-2021-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Ethanedioic acid is a white crystalline solid. 2\nC O (aq), If excess aqueous potassium hydroxide, KOH(aq), is added to dilute ethanedioic acid, H\n2 2 4\nC O (aq), forms. full neutralisation occurs and potassium ethanedioate, K\n2 2 4\n→ C O (aq) + 2KOH(aq) K C O (aq) + 2H O(l) H\n2 2 4 2 2 4 2\nIf a small amount of potassium hydroxide is added, neutralisation takes place and not all partial\nH+ K+ ions in the acid are replaced by ions.\nH (C O ) •d H O. Instead an acid salt forms, which crystallises to form a solid with the formula K\na b 2 4 c 2\nThe letters a, b and c represent a ratio of the numbers of species present in the compound and may\nnot necessarily be whole numbers. The relative number of water molecules associated with one\nformula of the compound is represented by d.\nA student attempted to determine the values of a, b, c and d in a sample of an acid salt,\nH (C O ) •d H O. K\na b 2 4 c 2\ncm3 aqueous solution of K H (C O ) •d H O, solution A. The student wants to make a 250.0 (a)\na b 2 4 c 2\ncm3 H (C O ) •d H O into a 100 beaker. T he student adds 1.89 g of K\na b 2 4 c 2\nD escribe the next steps the student should take to make solution A, containing exactly 1.89 g\nH (C O ) •d H O. of K\na b 2 4 c 2\nG ive the name and capacity of the apparatus which should be used and describe how the\ncm3. student should ensure the volume is exactly 250.0\nW rite your answer using a series of numbered steps.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\n2– (b) Determining the number of moles of C O present\n2 4\nmanganate(VII) 2–(aq), –(aq), O react with ions, MnO in acidified E thanedioate ions, C\n2 4 4\nconditions, as shown.\n→ 16H+(aq) 2Mn2+(aq) 2–(aq) –(aq) O + + 2MnO + 8H O(l) + 10CO (g) 5C\n2 4 4 2 2\n–(aq) ions are a very deep purple in colour. All other species appear colourless. M nO\n4\n°C. T he reaction takes place above a temperature of 70", "pdf_path": "9701-experimental-skills/print/9701-2021-m-52-q02-a08dbc1a1e.pdf" }, { "id": "9701-2021-mj-41-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 3 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-mj-41-q01-p01-0139431f11.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "T he carbonates and hydroxides of Group 2 elements show similar trends in thermal stability. 1 (a)\nS uggest and explain the variation in the trend in the thermal stability of the Group 2 hydroxides.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nCalcium hydroxide is slightly soluble in water. (b)\n(s), in aqueous Write an equation to show the dissociation of calcium hydroxide, Ca(OH) (i)\n2\nsolution. Include state symbols.\n............................................................... [1] ...............................................................\ndm–3, of Ca(OH) . C alculate the solubility, in mol (ii)\n2\n× 10–6 mol3 dm–9] : Ca(OH) , 5.02 [K\nsp 2\ndm–3 [2] solubility = .............................. mol\nin aqueous NaOH compares to its solubility in Suggest how the solubility of Ca(OH) (iii)\n2\nwater.\nExplain your reasoning.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 7]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-mj-41-q01-748b334cdc.pdf" }, { "id": "9701-2021-mj-41-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-41-q02-p01-d86a5ba7aa.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-41-q02-p02-4a464099da.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Explain why chromium complexes are coloured. 2 (a)\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nchromium(III) chloride reacts with Four different compounds can be obtained when anhydrous (b)\nwater under various conditions. When samples of each compound are reacted separately with\naqueous silver nitrate, different amounts of silver chloride are precipitated. The precipitation\nleaves the complex ions P, Q, and in solution. R S\nAgCl formula of moles of precipitated property of\ncomplex ion\ncompound per mole of complex ion complex ion\nCrCl (H O) 3 non-polar P\n3 2 6\nCrCl (H O) 2 polar Q\n3 2 5\nCrCl (H O) 1 polar R\n3 2 4\nCrCl (H O) 1 non-polar S\n3 2 4\nDraw three-dimensional diagrams for the structures of complex ions P, Q, and S. (i) R\nInclude the charges for each complex ion.\nP Q\nCr Cr\nR S\nCr Cr\n[4]\nS uggest why complex ion is non-polar. (ii) S\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe structure of picolinic acid is shown. (c)\npicolinic acid\nCO H\n2\nN\nT he conjugate base of picolinic acid is a bidentate ligand, Z.\nDefine the term bidentate ligand. (i)\n.............................................................................................................................................\n....................................................................................................................................... [2]\nD raw the structure of Z. (ii)\n[1]\nchromium(III) ]3+, ions, [Cr(H O) in a 3 : 1 ratio to form a new neutral reacts with aqueous (iii) Z\n2 6\ncomplex.\nchromium(III) centre in the State the coordination number and the geometry of the\ncomplex.\ncoordination number ......................................... geometry ......................................... [1]\n) Cr O decomposes readily on heating to form Cr O , steam and an inert colourless gas. (NH (d)\n4 2 2 7 2 3\n) Cr O and in Cr O . Deduce the oxidation numbers of chromium in (NH (i)\n4 2 2 7 2 3\n) Cr O ................................................... Cr O ................................................... [1] (NH\n4 2 2 7 2 3\n) Cr O . C onstruct an equation", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-mj-41-q02-eb99ae6e94.pdf" }, { "id": "9701-2021-mj-41-q03", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 6, 7, 8 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-mj-41-q03-p01-4be4e08ba4.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-41-q03-p02-cae61cca6a.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-41-q03-p03-995132d79a.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Define the term transition element. 3 (a) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nS tate how the melting point and density of iron compare to those of calcium. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n. Define the term standard cell potential, (b) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nD raw a fully labelled diagram of the apparatus that can be used to measure the cell potential (ii)\nCu(II)/Cu Fe(III)/Fe(II) electrode and an electrode. Include all of a cell composed of a\nnecessary reactants.\n[3]\n–(aq) Fe3+(aq). 2–(aq) I The reaction between S O and is catalysed by adding a few drops of (c)\n2 8\nFe3+ in this reaction. Use equations to show the catalytic role of (i)\n[2]\nFe3+(aq) –(aq), ]3–(aq) –(aq). I I can oxidise whereas [Fe(CN) cannot oxidise (ii)\n6\no values to explain these observations. Use E\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n2– O and tartrate ions are mixed the reaction proceeds very When aqueous solutions of S (d)\n2 8\nFe3+(aq) catalyst. slowly. However, this reaction proceeds quickly in the presence of an\nT he overall equation for this reaction is shown.\ntartrate ions\nOH\n– CO\n2– – 6H+ 2– (cid:31) + 3S O + 2H O 2CO + 2HCO + + 6SO 2\n–O C 2 8 2 2 2 4\n2\nOH\nFe3+ catalyst. Suggest why this reaction is slow without the (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nU se the overall equation to deduce the half-equation for the ox", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-mj-41-q03-c703bb27a7.pdf" }, { "id": "9701-2021-mj-41-q04", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 9 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-41-q04-p01-1d8b44cb34.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "]2+ S amples of [Cu(H O) are reacted separately with an excess of aqueous sodium hydroxide 4 (a)\n2 6\nor with an excess of aqueous ammonia.\nG ive the following information about these reactions.\n]2+ O) with an excess of aqueous of sodium hydroxide reaction 1: [Cu(H (i)\n2 6\ncolour and state of the copper-containing species .............................................................\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[3]\n]2+ O) with an excess of aqueous ammonia r eaction 2: [Cu(H (ii)\n2 6\ncolour and state of the copper-containing species .............................................................\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[3]\nCopper(I) oxide is added to hot dilute sulfuric acid. A blue solution, X, and a red-brown solid, (b)\nY, form.\nS uggest the identities of and Y. Name the type of reaction. X\n................................................................................................................................................ X\n................................................................................................................................................ Y\ntype of reaction ..........................................................................................................................\n[2]\n[Total: 8]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-mj-41-q04-ef3f43ccdb.pdf" }, { "id": "9701-2021-mj-41-q05", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-41-q05-p01-d153133496.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-41-q05-p02-3d3319cba5.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Dinitrogen pentoxide, N O , is dissolved in an inert solvent (solv) and the rate of decomposition 5\n2 5\nO is investigated. This reaction produces nitrogen dioxide, which remains in solution, and of N\n2 5\noxygen gas.\n1 → O (solv) 2NO (solv) + O (g) N\n2 2 5 2 2\nS uggest what measurements could be used to follow the rate of this reaction from the given (a)\ninformation.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nO (g) is investigated. In a separate experiment, the rate of the decomposition of N (b)\n2 5\n1 → O (g) 2NO (g) + O (g) N\n2 2 5 2 2\nT he graph shows the results obtained.\n0.30\n0.25\n0.20\n[N O ]\n0.15 2 5\ndm–3 / mol\n0.10\n0.05\n0\n0 100 200 300 400 500 600 700\ntime / s\nThe reaction is first order with respect to N O . This can be confirmed from the graph using\n2 5\nhalf-lives.\nExplain the term half-life of a reaction. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD etermine the half-life of this reaction. Show your working on the graph. (ii)\nhalf-life = .............................. s [1]\nO is Suggest the effect on the half-life of this reaction if the initial concentration of N (iii)\n2 5\nhalved.\n....................................................................................................................................... [1]\nU se the graph in to determine the rate of reaction at 200 s. Show your working. (c) (i) 5(b)\nrate = ..............................\nunits = ..............................\n[2]\nT he rate equation for this reaction is shown.\nO ] rate = k [N\n2 5\nU se your answer to to calculate the value of the rate constant, k, for this reaction and (ii) (c)(i)\nstate its units.\nk = .............................. units .............................. [1]\nNitrogen dioxide reacts with ozone, O , as shown. (d)\n3\n→ + O N O + O 2NO\n2 3 2 5 2\nT he rate equation for this reaction is rate = k [NO ][O ].\n2 3\nS uggest a possible two-step mechanism for this reaction.\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 9]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2021-mj-41-q05-da5225bedf.pdf" }, { "id": "9701-2021-mj-41-q06", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 12, 13, 14, 15 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-41-q06-p01-f1872c2092.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-41-q06-p02-ad9cde7734.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-41-q06-p03-88088760bc.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-41-q06-p04-8200fe0c91.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q06", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "C ompare and explain the relative acidities of butanoic acid, ethanol, ethanoic acid and water. 6 (a)\n................................. > ................................. > ................................ > ................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nH, ethanedioic acid, HO CCO H, and Three carboxylic acids, methanoic acid, HCO (b)\n2 2 2\nCCH CH CO H, are compared. Two tests were carried out on separate butanedioic acid, HO\n2 2 2 2\nsamples of each organic acid, as shown.\n  T he following results were obtained. = observed change = no observed reaction\nreagents and\ntest H HO CCO H HO CCH CH CO H observed change HCO\n2 2 2 2 2 2 2 conditions\n   1\n   2\nComplete the table with the reagents and conditions and the observed change for a (i)\npositive test.\nAssume these organic acids all have a similar acid strength. [3]\nE ach compound, HCO H, HO CCO H and HO CCH CH CO H, is dissolved seperately in (ii)\n2 2 2 2 2 2 2\n(1H) (13C) CDCl . Proton NMR and carbon-13 NMR spectra are then obtained.\n3\nComplete the table.\nnumber of peaks number of peaks\ncompound\nin proton NMR in carbon-13 NMR\nH HCO\n2\nCCO H HO\n2 2\nCCH CH CO H HO\n2 2 2 2\n[2]\nH in D O is obtained. The proton NMR spectrum of HCO (iii)\n2 2\nDescribe and explain the difference observed between this spectrum and the proton NMR\nH in (b)(ii). spectrum of HCO\n2\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n1,4-dibromobutane, Br(CH ) Br, is used in the synthesis of the dicarboxylic acid and diamine (c) J K\n2 4\nas shown.\nBrCH CH CH CH Br\n2 2 2 2\nstep 1 step 3\nG H\nstep 2 step 4\nJ K\nHO CCH CH CO H H NCH CH CH CH CH CH NH\n2 2 2 2 2 2 2 2 2 2 2 2\nDraw the structures of and in the boxes. [2] (i) G H\nS uggest reagents and conditions for each of steps 1", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2021-mj-41-q06-1e39c2da7c.pdf" }, { "id": "9701-2021-mj-41-q07", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-41-q07-p01-dcde0f3397.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-41-q07-p02-d0e7a0cb7c.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-41-q07-p03-3699497008.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "3-aminobenzoic acid can be synthesised from methylbenzene in three steps. 7 (a)\nmethylbenzene\nM N\nstep 1 step 2\nstep 3\n3-aminobenzoic acid\nCO H\n2\nNH\n2\nDraw the structures of and in the boxes. [2] (i) M N\nS uggest reagents and conditions for each step of the synthesis. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\nstep 3 ..................................................................................................................................\n[3]\nA mixture of serine, HOCH CH(NH )CO H, and lysine, H N(CH ) CH(NH )CO H, reacts to form (b)\n2 2 2 2 2 4 2 2\nseveral different products.\nH N O Draw the structures of the two structural isomers with the molecular formula C (i)\n6 12 2 5\nthat could be present in the product mixture.\nThe functional group formed in each case should be displayed.\n[3]\nH N O Predict the number of different structural isomers with the molecular formula C (ii)\n9 19 3 4\nthat could be present in the product mixture.\nmolecular formula number of structural isomers formed\nC H N O\n9 19 3 4\n[1]\nGlutathione is a naturally occurring compound found in plants. (c)\nglutathione\nSH\nO O H O\nN\nN HO OH\nNH H O\n2\nOn the diagram of glutathione, label each chiral centre with an asterisk (*). [1] (i)\nD raw the structures of the three products formed after complete acid hydrolysis of (ii)\nglutathione. Assume the thiol group, –SH, does not react.\n[2]\nGlutathione is soluble in water. (iii)\nBy referring to the structure of glutathione, explain why glutathione is soluble in water.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 13]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-mj-41-q07-90c7e3dbc8.pdf" }, { "id": "9701-2021-mj-41-q08", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 19, 20 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2021-mj-41-q08-p01-cb3819d8de.png", "9701-topic-25-equilibria/assets/9701-2021-mj-41-q08-p02-4bc2a57fd6.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q08", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "T he sketch graph for the titration of ethanoic acid, CH CO H, with sodium hydroxide is shown. 8 (a)\n3 2\n14\n12\n10\nequivalence point\n8\npH\n6\n4\n2\n0\ncm3 volume of sodium hydroxide /\nIn the region circled on the graph, identify the organic species that are present in (i) two\nthe solution. Explain why the pH of the mixture only changes slowly and gradually in this\nregion when sodium hydroxide is being added.\ntwo species present ............................................... ...............................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nT he equivalence point in this acid-base titration is where the two solutions have been (ii)\nmixed in exactly equal molar proportion.\nSuggest why the pH is greater than 7 at the equivalence point in this titration.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nvanadate(V), An impure sample of ammonium NH VO , with mass 0.150 g, is dissolved in an (b)\n4 3\nexcess of dilute acid.\n+ ions. An excess of zinc powder is added to the I n this solution all vanadium is present as VO\n2\nV2+ + ions are reduced to ions. The mixture is filtered to remove any solution and all the VO\n2\nremaining zinc powder.\n→ 4H+ 3e– V2+ + + + + 2H O VO\n2 2\ncm3 dm–3 – of 0.0250 mol acidified MnO oxidises all W hen the resulting solution is titrated, 20.10\n4\nV2+ + ions back to VO ions.\n2\n8H+ 5e– Mn2+ – + + + 4H O MnO\n4 2\nVO in the 0.150 g impure sample of NH VO . C alculate the percentage by mass of NH\n4 3 4 3\nG ive your answer to significant figures. three\n: NH VO , 116.9] [M\nr 4 3\npercentage by mass of NH VO = .............................. % [3]\n4 3\n[Total: 7]", "pdf_path": "9701-topic-25-equilibria/print/9701-2021-mj-41-q08-d14f052c6b.pdf" }, { "id": "9701-2021-mj-41-q09", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_41.pdf?download=true", "source_pages": [ 21 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-mj-41-q09-p01-fa6e5691ca.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-41-q09", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "(13C) The carbon-13 NMR spectrum of compound A, C H O , contains six peaks. 9\n8 8 2\nH Br O . Compound reacts with an excess of bromine water to give compound B, C A\n8 6 2 2\nCompound reacts with alkaline aqueous iodine to form a yellow precipitate and compound D. A C\nCl. PCl to form compound E, C H O Compound reacts with D\n5 7 5 2\nCompound reacts with propan-2-ol to form compound F. E\nDraw the structures of compounds A, B, C, D, and in the boxes. E F\nC H O yellow ppt. A C D\n8 8 2\nI alkaline (aq)\n2\n+\nBr (aq) PCl\n2 5\nC H Br O B Cl C H O E\n8 6 2 2 7 5 2\npropan-2-ol\nF\n[6]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-mj-41-q09-6907d70cf2.pdf" }, { "id": "9701-2021-mj-42-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-42-q01-p01-d853db2b0b.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-42-q01-p02-99ef9d26b1.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "chromium(III) ]3+ A n aqueous solution of contains the green [Cr(H O) complex ion. 1 (a)\n2 6\nCr3+ ion. Complete the electronic configuration of an isolated, gaseous (i)\n1s2 ................................................................................................................................. [1]\nDefine the term complex ion. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]3+(aq) ]2+(aq). O) shows some similar chemical properties to [Co(H O) [Cr(H (b)\n2 6 2 6\n]3+ O) are reacted separately with either NaOH(aq), H O (aq), or excess S amples of [Cr(H\n2 6 2 2\n(aq). NH\n3\nU se this information and the Data Booklet to suggest the formula of the chromium species\nformed. State the type of reaction taking place in each case.\nformula of chromium reagent added to\ntype of reaction\n]3+(aq) O) species formed [Cr(H\n2 6\nNaOH(aq)\nO (aq) H\n2 2\n(aq) an excess of NH\n3\n[5]\nchromium(II) ]2+ [Cr(H O) and [Cr (O CCH ) (H O) ] are both complexes of and have different (c)\n2 6 2 2 3 4 2 2\ncolours.\nExplain why the colours of these complexes are different.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nThe structure of [Cr (O CCH ) (H O) ] is shown. Ethanoate ions act as ligands in this complex. (d)\n2 2 3 4 2 2\n–, CO is shown as . The ethanoate ligand, CH\nO O 3 2\nO O\nO O\nO Cr Cr OH H\n2 2\nO O\nO O\nWater and ethanoate ions behave as different types of ligand in this complex. (i)\nSuggest an explanation for this statement.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD educe the coordination number of Cr and the geometry around each Cr atom in this (ii)\nstructure.\ncoordination number ...........................................................................................................\ngeometry around Cr atom ...................................................................................................\n[1]\nState the type of bond between the two atoms in the Cr–Cr bond. (iii)\n......................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-mj-42-q01-62594fc69a.pdf" }, { "id": "9701-2021-mj-42-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-mj-42-q02-p01-7d2eacc3dd.png", "9701-topic-27-group-2/assets/9701-2021-mj-42-q02-p02-7147ec4b18.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q02", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "State and explain the trend observed in the thermal stability of the Group 2 nitrates. 2 (a)\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nLead(II) nitrate, Pb(NO ) , decomposes on heating in a similar manner to the Group 2 (b) (i)\n3 2\nnitrates.\nlead(II) nitrate. Write an equation for the decomposition of\n....................................................................................................................................... [1]\n) would compare to that of Ba(NO ) . Suggest how the ease of decomposition of Pb(NO (ii)\n3 2 3 2\nExplain your answer. You may find it useful to refer to the Data Booklet.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nO , decomposes on heating to produce barium oxide and a Barium ethanedioate, BaC (c) (i)\n2 4\nmixture of two different gases.\nConstruct an equation for the decomposition of barium ethanedioate.\n....................................................................................................................................... [1]\ncm3 dm–3 A n impure sample of BaC O , of mass 0.500 g, is added to 50.0 of 0.0200 mol (ii)\n2 4\n–(aq), an excess. A redox reaction takes place and all the BaC O reacts. acidified MnO\n4 2 4\ndm–3 –, is titrated with 0.0500 mol The resulting solution, containing unreacted acidified MnO\n4\nFe2+(aq).\ncm3 dm–3 Fe2+(aq) of 0.0500 mol has been added. The end-point is reached when 30.40\n2e– 2– O 2CO + C\n2 4 2\n8H+ 5e– Mn2+ – MnO + + + 4H O\n4 2\nFe2+ Fe3+ e– +\nCalculate the percentage by mass of BaC O in the 0.500 g impure sample. Show your\n2 4\nworking.\n: BaC O , 225.3] [M\nr 2 4\nO = .............................. [4] percentage by mass of BaC\n2 4\nBarium hydroxide, Ba(OH) , is completely dissociated in aqueous solution. (d)\n2\ndm–3 Ba(OH) (aq) at 298 K. Calculate the pH of 0.120 mol\n2\npH = .............................. [2]\n[Total: 12]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-mj-42-q02-081a13dfba.pdf" }, { "id": "9701-2021-mj-42-q03", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 6, 7, 8 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-mj-42-q03-p01-377adca402.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-42-q03-p02-3f7aab5f9d.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-42-q03-p03-f20c495e04.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Define the term standard electrode potential. 3 (a) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nNCH CH NH , Three redox systems, A, and C, are shown. The ligand 1,2-diaminoethane, H B\n2 2 2 2\nis represented by en.\n]3+ e– ]2+ [Ru(H O) + [Ru(H O) A\n2 6 2 6\n]3+ e– ]2+ [Ru(NH ) + [Ru(NH ) B\n3 6 3 6\n]3+ e– ]2+ [Ru(en) + [Ru(en) C\n3 3\no, Two electrochemical cells are set up to compare the standard electrode potentials, E of three\nhalf-cells. The diagrams show the relative potential of each electrode.\n– – + + V V\nsalt bridge salt bridge\nPt Pt Pt Pt\n]3+ ]3+ ]3+ ]3+ [Ru(en) [Ru(en) [Ru(NH ) [Ru(H O)\n3 3 6 2 6 3\n]2+ ]2+ ]2+ ]2+ [Ru(en) [Ru(NH ) [Ru(H O) [Ru(en)\n3 3 6 2 6 3\nU se this information to complete the table by adding the labels A, and to deduce the (ii) B C\no for the three half-cells. order of E\no E redox system\nmost negative\nleast negative\n[1]\n]3+ The complex [Ru(en) shows stereoisomerism. The ligand en is bidentate. (iii)\n3\n]3+. Represent the Draw three-dimensional diagrams to show the two isomers of [Ru(en)\n3\nligand en by using .\nN N\nName the type of stereoisomerism.\nisomer 1 isomer 2\nRu Ru\ntype of stereoisomerism .....................................................................................................\n[3]\n– Ag+/Ag A n electrochemical cell consists of a Br /Br half-cell and a half-cell, under standard (b) (i)\n2\nconditions.\n. Deduce the direction of electron flow in the wire Use the Data Booklet to calculate the\nthrough the voltmeter between these two half-cells.\n= .............................. V\ndirection of electron flow from ....................................... to ......................................... [1]\nAg+/Ag half-cell in (b)(i). W ater is added to the (ii)\n( . Place a tick ) in the appropriate box. Suggest the effect of this addition on the E\ncell\nless positive no change more positive\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n2– Silver bromide, AgBr, dissolves in an aqueous solution of S O ions to form the complex ion (c)\n2 3\n]3–. 2– O ) The S O ions act as monodentate ligands. [Ag(S\n2 3 2 2 3\n]3–(aq) –(aq) 2–(aq) equilibrium 1 AgBr(s) + 2S O [Ag(S O ) + Br\n2 3 2 3 2\nDefine the term ligand. (i)\n....................................................", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-mj-42-q03-7151ec4aae.pdf" }, { "id": "9701-2021-mj-42-q04", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 9, 10 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2021-mj-42-q04-p01-04ddb0aa35.png", "9701-topic-23-chemical-energetics/assets/9701-2021-mj-42-q04-p02-5c6e29b95c.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Define the term lattice energy. 4 (a) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nU se the following data to calculate a value for the enthalpy change of solution of (ii)\ncopper(II) CuCl chloride, (s). You might find it helpful to construct an energy cycle.\n2\n– mol–1 Cl = –378 kJ enthalpy change of hydration of\nCu2+ mol–1 enthalpy change of hydration of = –2099 kJ\nmol–1 CuCl lattice energy of (s) = –2824 kJ\n2\nmol–1 CuCl enthalpy change of solution of (s) = .............................. kJ [2]\n2\nCa2+ mol–1. is –1579 kJ The enthalpy change of hydration of (iii)\n∆H Ca2+ for Use the Data Booklet to suggest why there is a big difference in the values of\nhyd\nCu2+. and\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nI dentify the substances formed at the anode and at the cathode during the electrolysis of (b) (i)\nCaCl (aq). saturated\n2\nat the anode ........................................................................................................................\nat the cathode .....................................................................................................................\n[1]\nCaCl (l). Calcium can be produced by the electrolysis of molten calcium chloride, (ii)\n2\nCaCl (l) Calculate the mass, in g, of Ca formed when a current of 0.75 A passes through\n2\nfor 60 minutes.\n: Ca, 40.1] [A\nr\nmass of Ca = .............................. g [2]\nE xplain what is meant by the term entropy of a system. (c) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n( ∆S. Place one tick ) in each row of the table to show the sign of each entropy change, (ii)\n∆S ∆S ∆S process is negative is zero is positive\nNaCl dissolving in water\nwater solidifying to ice\n[1]\n∆G o, The evaporation of one mole of water has a standard Gibbs free energy change, of (iii)\n°C. +8.6 kJ at 25\n°C ∆G o changes for this process between 25 and Sketch a graph on the axes to show how\n°C 150 at 101 kPa.\npositive\no (cid:31)G\n(cid:30)C temperature / 0\n50 75 100 125 150 25\nnegative\n[2]\nThe reaction between A ", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2021-mj-42-q04-4d6418fbc3.pdf" }, { "id": "9701-2021-mj-42-q05", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 11, 12 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-mj-42-q05-p01-b14e9be1de.png", "9701-topic-36-organic-synthesis/assets/9701-2021-mj-42-q05-p02-346e23eea6.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q05", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Describe and explain the relative basicities of phenylamine, ethylamine and 4-nitrophenylamine. 5 (a)\n................................. > ................................. > ................................\nmost basic least basic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nThe dye can be synthesised from 4-nitrophenylamine in two steps. (b) R\nQ 4-nitrophenylamine\nstep 1\nNH O N\n2 2\nstep 2\nR\nOH\nO N N N\n2\nDeduce and draw the structure of the organic salt in the box. [1] (i) Q\nS uggest reagents and conditions for step 1 and 2 in (b). (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nCompound can be synthesised from methylbenzene in three steps. (c) G\nE F\nCH\n3\nstep 1 step 2\nstep 3\nG\nCO H\n2\nNO\n2\nBr\nGive the systematic name of compound G. (i)\n....................................................................................................................................... [1]\nD educe the identities of and and draw their structures in the boxes. [2] (ii) E F\nSuggest reagents and conditions for each of steps 1 to 3 in (c). (iii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\nstep 3 ..................................................................................................................................\n[3]\n[Total: 13]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-mj-42-q05-4e1b8d0617.pdf" }, { "id": "9701-2021-mj-42-q06", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2021-mj-42-q06-p01-802fd21d17.png", "9701-topic-30-hydrocarbons/assets/9701-2021-mj-42-q06-p02-3c1a110235.png", "9701-topic-30-hydrocarbons/assets/9701-2021-mj-42-q06-p03-34a44da748.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q06", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "T here are four possible structural isomers of C H that contain a benzene ring. 6 (a)\n8 10\nD raw the formulae of the four structural isomers in the appropriate boxes. The number skeletal\n(13C) NMR spectrum of each compound is given. of peaks observed in the carbon-13\nisomer 2 isomer 1\n13C 13C three peaks in NMR four peaks in NMR\nisomer 3 isomer 4\n13C 13C five peaks in NMR six peaks in NMR\n[4]\nA three-step synthesis of (C H O) from benzene is suggested as shown. (b) X\n10 10\nW\nCl (CH ) CO H\n2 3 2\nAl Cl\n3\nstep 1\nstep 2\nCl\nO\nAl Cl step 3\n3\n(C H O) X\n10 10\nStep 1 is the alkylation of benzene by electrophilic substitution. (i)\nR–Cl Cl ) CO H. Use to represent (CH\n2 3 2\nR–Cl Al Cl . Write an equation for the formation of an electrophile from and\n3\n....................................................................................................................................... [1]\nD educe and draw the structures of and in the boxes. [2] (ii) W X\nSuggest the reagents and conditions for step 2. (iii)\n....................................................................................................................................... [1]\nComplete the mechanism for the reaction of benzene with the electrophile formed (iv)\nin (b)(i).\nInclude all relevant charges and curly arrows showing the movement of electron pairs.\nDraw the structure of the intermediate.\nintermediate\nR\n[3]\n[Total: 11]", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2021-mj-42-q06-a20de2ed38.pdf" }, { "id": "9701-2021-mj-42-q07", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 16, 18, 19 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-42-q07-p01-b5dedd0d3a.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-42-q07-p02-ab0b7a7f5a.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-42-q07-p03-2d8324a384.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q07", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Cl In aqueous solution, chlorine dioxide, O , reacts with hydroxide ions as shown. 7 (a)\n2\n→ 2OH– – – Cl Cl 2Cl + O + O + H O O\n2 3 2 2\nOH–. Cl and The A series of experiments is carried out using different concentrations of O\n2\ntable shows the results obtained.\n[OH–] [Cl O ] initial rate\n2 experiment\ndm–3 dm–3 dm–3 min–1 / mol / mol / mol\n× 10–4 1 0.020 0.030 7.20\n× 10–3 2 0.020 0.120 2.88\n× 10–3 3 0.050 0.030 4.50\nExplain the term order of reaction. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nUse the data in the table to determine the order of reaction with respect to each reactant, (ii)\nOH–. Cl and O\n2\nExplain your reasoning.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nUse your answer to to construct the rate equation for this reaction. (iii) (a)(ii)\nrate = ............................................................................................................................ [1]\nUse your rate equation and the data from experiment 1 to calculate the rate constant, k, (iv)\nfor this reaction.\nInclude the units of k.\nk = .............................. units .............................. [2]\n+, The decomposition of benzenediazonium ions, C H N using a large excess of water, is a (b)\n6 5 2\nfirst-order reaction.\nT he graph shows the results obtained.\n0.025\n0.020\n0.015\n+] [C H N\n6 5 2\ndm–3 / mol\n0.010\n0.005\n0\n0 100 200 300 400 500 600\ntime / s\nDraw the structure of the organic product formed in this reaction. (i)\n[1]\nUse the graph to determine the rate of reaction at 100 s. Show your working. (ii)\ndm–3 s–1 [1] rate = .............................. mol\nSketch a concentration–time graph for a reaction. (c) zero-order\nU se your graph to suggest how successive half-lives for a zero-order reaction vary as the\n( concentration of a reactant decreases. Indicate this by placing a tick ) in the appropriate box\nin the table.\nconcentration\ntime\nsuccessive half-lives no change in successive half-lives\ndecrease successive half-liv", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2021-mj-42-q07-da474ddd7d.pdf" }, { "id": "9701-2021-mj-42-q08", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_42.pdf?download=true", "source_pages": [ 20, 21, 22 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_42.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-42-q08-p01-8b218166cf.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-42-q08-p02-8e74092f5a.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-42-q08-p03-563219e893.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-42-q08", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "State and explain the relative rate of hydrolysis of acyl chlorides, alkyl chlorides and 8 (a)\naryl chlorides.\n................................. > ................................. > ................................\nfastest slowest\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nThe drug remifentanil is shown. (b)\nremifentanil\nO O\nO\nN O\nN\nO\nR emifentanil is hydrolysed under acidic conditions. Three different organic completely\ncompounds are formed.\nD raw the structures for these organic compounds in the boxes.\n[3]\n(1H) Compound Y, C H O , reacts with Na CO (aq) to evolve bubbles of gas. The proton NMR (c)\n5 10 2 2 3\nO is shown. spectrum of compound in D Y\n2\n2 1 0\n(cid:31) / ppm\nUse this information to suggest a structure for Y. (i)\n[1]\n(1H) NMR spectrum and your answer to to complete Use the Data Booklet, the proton (c)(i) (ii)\nthe table.\n1H chemical atoms number of\nenvironment of proton splitting pattern\n(δ) shift responsible for the peak\n0.95\n1.90\n2.20\n[3]\n[Total: 10]", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2021-mj-42-q08-98cde35a38.pdf" }, { "id": "9701-2021-mj-43-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 3 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-mj-43-q01-p01-0139431f11.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "T he carbonates and hydroxides of Group 2 elements show similar trends in thermal stability. 1 (a)\nS uggest and explain the variation in the trend in the thermal stability of the Group 2 hydroxides.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nCalcium hydroxide is slightly soluble in water. (b)\n(s), in aqueous Write an equation to show the dissociation of calcium hydroxide, Ca(OH) (i)\n2\nsolution. Include state symbols.\n............................................................... [1] ...............................................................\ndm–3, of Ca(OH) . C alculate the solubility, in mol (ii)\n2\n× 10–6 mol3 dm–9] : Ca(OH) , 5.02 [K\nsp 2\ndm–3 [2] solubility = .............................. mol\nin aqueous NaOH compares to its solubility in Suggest how the solubility of Ca(OH) (iii)\n2\nwater.\nExplain your reasoning.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 7]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-mj-43-q01-b1231887af.pdf" }, { "id": "9701-2021-mj-43-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-43-q02-p01-d86a5ba7aa.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-43-q02-p02-4a464099da.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Explain why chromium complexes are coloured. 2 (a)\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nchromium(III) chloride reacts with Four different compounds can be obtained when anhydrous (b)\nwater under various conditions. When samples of each compound are reacted separately with\naqueous silver nitrate, different amounts of silver chloride are precipitated. The precipitation\nleaves the complex ions P, Q, and in solution. R S\nAgCl formula of moles of precipitated property of\ncomplex ion\ncompound per mole of complex ion complex ion\nCrCl (H O) 3 non-polar P\n3 2 6\nCrCl (H O) 2 polar Q\n3 2 5\nCrCl (H O) 1 polar R\n3 2 4\nCrCl (H O) 1 non-polar S\n3 2 4\nDraw three-dimensional diagrams for the structures of complex ions P, Q, and S. (i) R\nInclude the charges for each complex ion.\nP Q\nCr Cr\nR S\nCr Cr\n[4]\nS uggest why complex ion is non-polar. (ii) S\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe structure of picolinic acid is shown. (c)\npicolinic acid\nCO H\n2\nN\nT he conjugate base of picolinic acid is a bidentate ligand, Z.\nDefine the term bidentate ligand. (i)\n.............................................................................................................................................\n....................................................................................................................................... [2]\nD raw the structure of Z. (ii)\n[1]\nchromium(III) ]3+, ions, [Cr(H O) in a 3 : 1 ratio to form a new neutral reacts with aqueous (iii) Z\n2 6\ncomplex.\nchromium(III) centre in the State the coordination number and the geometry of the\ncomplex.\ncoordination number ......................................... geometry ......................................... [1]\n) Cr O decomposes readily on heating to form Cr O , steam and an inert colourless gas. (NH (d)\n4 2 2 7 2 3\n) Cr O and in Cr O . Deduce the oxidation numbers of chromium in (NH (i)\n4 2 2 7 2 3\n) Cr O ................................................... Cr O ................................................... [1] (NH\n4 2 2 7 2 3\n) Cr O . C onstruct an equation", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-mj-43-q02-e499c3a235.pdf" }, { "id": "9701-2021-mj-43-q03", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 6, 7, 8 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-mj-43-q03-p01-4be4e08ba4.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-43-q03-p02-cae61cca6a.png", "9701-topic-24-electrochemistry/assets/9701-2021-mj-43-q03-p03-995132d79a.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Define the term transition element. 3 (a) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nS tate how the melting point and density of iron compare to those of calcium. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n. Define the term standard cell potential, (b) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nD raw a fully labelled diagram of the apparatus that can be used to measure the cell potential (ii)\nCu(II)/Cu Fe(III)/Fe(II) electrode and an electrode. Include all of a cell composed of a\nnecessary reactants.\n[3]\n–(aq) Fe3+(aq). 2–(aq) I The reaction between S O and is catalysed by adding a few drops of (c)\n2 8\nFe3+ in this reaction. Use equations to show the catalytic role of (i)\n[2]\nFe3+(aq) –(aq), ]3–(aq) –(aq). I I can oxidise whereas [Fe(CN) cannot oxidise (ii)\n6\no values to explain these observations. Use E\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n2– O and tartrate ions are mixed the reaction proceeds very When aqueous solutions of S (d)\n2 8\nFe3+(aq) catalyst. slowly. However, this reaction proceeds quickly in the presence of an\nT he overall equation for this reaction is shown.\ntartrate ions\nOH\n– CO\n2– – 6H+ 2– (cid:31) + 3S O + 2H O 2CO + 2HCO + + 6SO 2\n–O C 2 8 2 2 2 4\n2\nOH\nFe3+ catalyst. Suggest why this reaction is slow without the (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nU se the overall equation to deduce the half-equation for the ox", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-mj-43-q03-0046f77bcf.pdf" }, { "id": "9701-2021-mj-43-q04", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 9 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-mj-43-q04-p01-1d8b44cb34.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "]2+ S amples of [Cu(H O) are reacted separately with an excess of aqueous sodium hydroxide 4 (a)\n2 6\nor with an excess of aqueous ammonia.\nG ive the following information about these reactions.\n]2+ O) with an excess of aqueous of sodium hydroxide reaction 1: [Cu(H (i)\n2 6\ncolour and state of the copper-containing species .............................................................\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[3]\n]2+ O) with an excess of aqueous ammonia r eaction 2: [Cu(H (ii)\n2 6\ncolour and state of the copper-containing species .............................................................\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[3]\nCopper(I) oxide is added to hot dilute sulfuric acid. A blue solution, X, and a red-brown solid, (b)\nY, form.\nS uggest the identities of and Y. Name the type of reaction. X\n................................................................................................................................................ X\n................................................................................................................................................ Y\ntype of reaction ..........................................................................................................................\n[2]\n[Total: 8]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-mj-43-q04-763bd571d7.pdf" }, { "id": "9701-2021-mj-43-q05", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-43-q05-p01-d153133496.png", "9701-topic-26-reaction-kinetics/assets/9701-2021-mj-43-q05-p02-3d3319cba5.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Dinitrogen pentoxide, N O , is dissolved in an inert solvent (solv) and the rate of decomposition 5\n2 5\nO is investigated. This reaction produces nitrogen dioxide, which remains in solution, and of N\n2 5\noxygen gas.\n1 → O (solv) 2NO (solv) + O (g) N\n2 2 5 2 2\nS uggest what measurements could be used to follow the rate of this reaction from the given (a)\ninformation.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nO (g) is investigated. In a separate experiment, the rate of the decomposition of N (b)\n2 5\n1 → O (g) 2NO (g) + O (g) N\n2 2 5 2 2\nT he graph shows the results obtained.\n0.30\n0.25\n0.20\n[N O ]\n0.15 2 5\ndm–3 / mol\n0.10\n0.05\n0\n0 100 200 300 400 500 600 700\ntime / s\nThe reaction is first order with respect to N O . This can be confirmed from the graph using\n2 5\nhalf-lives.\nExplain the term half-life of a reaction. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD etermine the half-life of this reaction. Show your working on the graph. (ii)\nhalf-life = .............................. s [1]\nO is Suggest the effect on the half-life of this reaction if the initial concentration of N (iii)\n2 5\nhalved.\n....................................................................................................................................... [1]\nU se the graph in to determine the rate of reaction at 200 s. Show your working. (c) (i) 5(b)\nrate = ..............................\nunits = ..............................\n[2]\nT he rate equation for this reaction is shown.\nO ] rate = k [N\n2 5\nU se your answer to to calculate the value of the rate constant, k, for this reaction and (ii) (c)(i)\nstate its units.\nk = .............................. units .............................. [1]\nNitrogen dioxide reacts with ozone, O , as shown. (d)\n3\n→ + O N O + O 2NO\n2 3 2 5 2\nT he rate equation for this reaction is rate = k [NO ][O ].\n2 3\nS uggest a possible two-step mechanism for this reaction.\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 9]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2021-mj-43-q05-7d3a06c862.pdf" }, { "id": "9701-2021-mj-43-q06", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 12, 13, 14, 15 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-43-q06-p01-f1872c2092.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-43-q06-p02-ad9cde7734.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-43-q06-p03-88088760bc.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2021-mj-43-q06-p04-8200fe0c91.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q06", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "C ompare and explain the relative acidities of butanoic acid, ethanol, ethanoic acid and water. 6 (a)\n................................. > ................................. > ................................ > ................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nH, ethanedioic acid, HO CCO H, and Three carboxylic acids, methanoic acid, HCO (b)\n2 2 2\nCCH CH CO H, are compared. Two tests were carried out on separate butanedioic acid, HO\n2 2 2 2\nsamples of each organic acid, as shown.\n  T he following results were obtained. = observed change = no observed reaction\nreagents and\ntest H HO CCO H HO CCH CH CO H observed change HCO\n2 2 2 2 2 2 2 conditions\n   1\n   2\nComplete the table with the reagents and conditions and the observed change for a (i)\npositive test.\nAssume these organic acids all have a similar acid strength. [3]\nE ach compound, HCO H, HO CCO H and HO CCH CH CO H, is dissolved seperately in (ii)\n2 2 2 2 2 2 2\n(1H) (13C) CDCl . Proton NMR and carbon-13 NMR spectra are then obtained.\n3\nComplete the table.\nnumber of peaks number of peaks\ncompound\nin proton NMR in carbon-13 NMR\nH HCO\n2\nCCO H HO\n2 2\nCCH CH CO H HO\n2 2 2 2\n[2]\nH in D O is obtained. The proton NMR spectrum of HCO (iii)\n2 2\nDescribe and explain the difference observed between this spectrum and the proton NMR\nH in (b)(ii). spectrum of HCO\n2\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n1,4-dibromobutane, Br(CH ) Br, is used in the synthesis of the dicarboxylic acid and diamine (c) J K\n2 4\nas shown.\nBrCH CH CH CH Br\n2 2 2 2\nstep 1 step 3\nG H\nstep 2 step 4\nJ K\nHO CCH CH CO H H NCH CH CH CH CH CH NH\n2 2 2 2 2 2 2 2 2 2 2 2\nDraw the structures of and in the boxes. [2] (i) G H\nS uggest reagents and conditions for each of steps 1", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2021-mj-43-q06-ae58a28d1f.pdf" }, { "id": "9701-2021-mj-43-q07", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-43-q07-p01-dcde0f3397.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-43-q07-p02-d0e7a0cb7c.png", "9701-topic-34-nitrogen-compounds/assets/9701-2021-mj-43-q07-p03-3699497008.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "3-aminobenzoic acid can be synthesised from methylbenzene in three steps. 7 (a)\nmethylbenzene\nM N\nstep 1 step 2\nstep 3\n3-aminobenzoic acid\nCO H\n2\nNH\n2\nDraw the structures of and in the boxes. [2] (i) M N\nS uggest reagents and conditions for each step of the synthesis. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\nstep 3 ..................................................................................................................................\n[3]\nA mixture of serine, HOCH CH(NH )CO H, and lysine, H N(CH ) CH(NH )CO H, reacts to form (b)\n2 2 2 2 2 4 2 2\nseveral different products.\nH N O Draw the structures of the two structural isomers with the molecular formula C (i)\n6 12 2 5\nthat could be present in the product mixture.\nThe functional group formed in each case should be displayed.\n[3]\nH N O Predict the number of different structural isomers with the molecular formula C (ii)\n9 19 3 4\nthat could be present in the product mixture.\nmolecular formula number of structural isomers formed\nC H N O\n9 19 3 4\n[1]\nGlutathione is a naturally occurring compound found in plants. (c)\nglutathione\nSH\nO O H O\nN\nN HO OH\nNH H O\n2\nOn the diagram of glutathione, label each chiral centre with an asterisk (*). [1] (i)\nD raw the structures of the three products formed after complete acid hydrolysis of (ii)\nglutathione. Assume the thiol group, –SH, does not react.\n[2]\nGlutathione is soluble in water. (iii)\nBy referring to the structure of glutathione, explain why glutathione is soluble in water.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 13]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-mj-43-q07-aa6048079c.pdf" }, { "id": "9701-2021-mj-43-q08", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 19, 20 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2021-mj-43-q08-p01-cb3819d8de.png", "9701-topic-25-equilibria/assets/9701-2021-mj-43-q08-p02-4bc2a57fd6.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q08", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "T he sketch graph for the titration of ethanoic acid, CH CO H, with sodium hydroxide is shown. 8 (a)\n3 2\n14\n12\n10\nequivalence point\n8\npH\n6\n4\n2\n0\ncm3 volume of sodium hydroxide /\nIn the region circled on the graph, identify the organic species that are present in (i) two\nthe solution. Explain why the pH of the mixture only changes slowly and gradually in this\nregion when sodium hydroxide is being added.\ntwo species present ............................................... ...............................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nT he equivalence point in this acid-base titration is where the two solutions have been (ii)\nmixed in exactly equal molar proportion.\nSuggest why the pH is greater than 7 at the equivalence point in this titration.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nvanadate(V), An impure sample of ammonium NH VO , with mass 0.150 g, is dissolved in an (b)\n4 3\nexcess of dilute acid.\n+ ions. An excess of zinc powder is added to the I n this solution all vanadium is present as VO\n2\nV2+ + ions are reduced to ions. The mixture is filtered to remove any solution and all the VO\n2\nremaining zinc powder.\n→ 4H+ 3e– V2+ + + + + 2H O VO\n2 2\ncm3 dm–3 – of 0.0250 mol acidified MnO oxidises all W hen the resulting solution is titrated, 20.10\n4\nV2+ + ions back to VO ions.\n2\n8H+ 5e– Mn2+ – + + + 4H O MnO\n4 2\nVO in the 0.150 g impure sample of NH VO . C alculate the percentage by mass of NH\n4 3 4 3\nG ive your answer to significant figures. three\n: NH VO , 116.9] [M\nr 4 3\npercentage by mass of NH VO = .............................. % [3]\n4 3\n[Total: 7]", "pdf_path": "9701-topic-25-equilibria/print/9701-2021-mj-43-q08-8513910d39.pdf" }, { "id": "9701-2021-mj-43-q09", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_43.pdf?download=true", "source_pages": [ 21 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-mj-43-q09-p01-fa6e5691ca.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-43-q09", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "(13C) The carbon-13 NMR spectrum of compound A, C H O , contains six peaks. 9\n8 8 2\nH Br O . Compound reacts with an excess of bromine water to give compound B, C A\n8 6 2 2\nCompound reacts with alkaline aqueous iodine to form a yellow precipitate and compound D. A C\nCl. PCl to form compound E, C H O Compound reacts with D\n5 7 5 2\nCompound reacts with propan-2-ol to form compound F. E\nDraw the structures of compounds A, B, C, D, and in the boxes. E F\nC H O yellow ppt. A C D\n8 8 2\nI alkaline (aq)\n2\n+\nBr (aq) PCl\n2 5\nC H Br O B Cl C H O E\n8 6 2 2 7 5 2\npropan-2-ol\nF\n[6]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-mj-43-q09-2ad47679a6.pdf" }, { "id": "9701-2021-mj-51-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_51.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-51-q01-p01-b8e7bcf0ec.png", "9701-experimental-skills/assets/9701-2021-mj-51-q01-p02-dce35c2da0.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Hydrogen peroxide decomposes slowly at room temperature to give water and oxygen. 1\n→ O (aq) 2H O(l) + O (g) 2H\n2 2 2 2\nThe rate of this reaction can be increased by the addition of a metal oxide catalyst. initial\nA student is asked to investigate which metal oxide catalyst is best at increasing the rate of initial\nthis reaction by using a method which involves the collection of oxygen.\ncopper(II) iron(III) oxide, oxide, The student is provided with the following metal oxides:\nmanganese(IV) nickel(II) titanium(IV) oxide, oxide and oxide.\nThe student is also provided with an excess volume, of a known concentration, of aqueous hydrogen\nperoxide and any laboratory equipment needed.\nS tate the independent variable. (a) (i)\n....................................................................................................................................... [1]\nS tate the dependent variable. (ii)\n....................................................................................................................................... [1]\nState two variables that would need to be controlled. (b)\n1 .................................................................................................................................................\n2 .................................................................................................................................................\n[2]\nDraw a labelled diagram of the assembled apparatus that could be used to carry out these (c)\nexperiments. The apparatus should allow the accurate recording of the oxygen produced.\n[3]\nW hat measurements need to be recorded during the course of each experiment to allow (d) (i)\nthe rate to be determined? initial\n....................................................................................................................................... [1]\nH ow is the rate determined using these measurements? (ii) initial\n.............................................................................................................................................\n....................................................................................................................................... [1]\nHow can the student ensure that the results are reliable? (e)\n.............................................................................................................................................. [1]\nSuggest an alternative method to investigate these reactions which does not include the (f)\ncollection of gas.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nOnce the reaction has finished, how can the student demonstrate that the metal oxide has not (g)\nbeen affected by the reaction?\n....................................................", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-51-q01-b06da147e9.pdf" }, { "id": "9701-2021-mj-51-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_51.pdf?download=true", "source_pages": [ 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-51-q02-p01-78aa95db37.png", "9701-experimental-skills/assets/9701-2021-mj-51-q02-p02-98db2e82ce.png", "9701-experimental-skills/assets/9701-2021-mj-51-q02-p03-9ebe6af501.png", "9701-experimental-skills/assets/9701-2021-mj-51-q02-p04-366bcaf5e4.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "cm3 Fe2+ Fe3+ A student is given 250.0 of solution containing a mixture of and ions. The student 2\nFe3+ in the solution by is asked to find the total mass of iron ions and the percentage by mass of\nmanganate(VII), KMnO . performing titrations with aqueous potassium\n4\nFe3+(aq) Fe2+(aq) ions can be reduced to ions by reaction with zinc. The student is told that the\nThe student is given the following instructions.\ncm3 dm–3 needed to make 500.0 of 0.0200 mol KMnO (aq). ● Calculate the mass of KMnO\n4 4\n● Record the mass of an empty plastic weighing boat (a small container used to hold solid\nsamples).\nto the weighing boat. ● Add the calculated mass of KMnO\n4\ncm3 from the weighing boat into a 100 beaker. ● Transfer the KMnO\n4\ncm3 of distilled water to the beaker. ● Add 50\ncm3 volumetric flask. ● Transfer the mixture from the beaker into a 500.0\n● Make up to the graduation mark, dropwise, with distilled water.\ncm3 dm–3 needed to make 500.0 of 0.0200 mol KMnO (aq). C alculate the mass of KMnO (a) (i)\n4 4\n: K, 39.1; Mn, 54.9; O, 16.0] [A\nr\nneeded = .............................. g [1] mass of KMnO\n4\nT he student used a balance accurate to two decimal places. (ii)\nby difference. Calculate the percentage error in weighing the mass of the KMnO\n4\nIf you were unable to calculate a value for use the mass 1.75 g. This is the 2(a)(i) not\ncorrect answer to 2(a)(i). Show your working.\npercentage error = .............................. % [1]\nwere stuck to the weighing boat after The student noticed that some crystals of KMnO (iii)\n4\nsolid to the beaker. adding the KMnO\n4\nState how the student should modify the instructions to ensure that the measured mass of\nwas accurate. KMnO\n4\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nGive two additional instructions that should be given to the student to ensure that the (iv)\nsolution is prepared as accurately as possible.\n1 ..........................................................................................................................................\n.............................................................................................................................................\n2 ..........................................................................................................................................\n.............................................................................................................................................\n[2]\n(aq) is ready for use, the student is given additional instructions. When the KMnO (b)\n4\ndm–3 KMnO (aq). Fill a burette with 0.0200 mol step 1\n4\ncm3 Fe2+(aq) Fe3+(aq) of / solutio", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-51-q02-85f36b8183.pdf" }, { "id": "9701-2021-mj-52-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-52-q01-p01-767d2b2cc7.png", "9701-experimental-skills/assets/9701-2021-mj-52-q01-p02-fe0f814285.png", "9701-experimental-skills/assets/9701-2021-mj-52-q01-p03-ee0f10645e.png", "9701-experimental-skills/assets/9701-2021-mj-52-q01-p04-c94cd4c49c.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student is asked to find the enthalpy change for the reaction between anhydrous 1\nmagnesium sulfate and water.\n→ (s) + 7H O(l) MgSO •7H O(s) MgSO\n4 2 4 2\nThis enthalpy change cannot be measured directly.\nPredict whether the enthalpy change for this reaction is positive or negative. Explain the reason (a)\nfor your prediction.\nprediction ...................................................................................................................................\nexplanation ................................................................................................................................\n....................................................................................................................................................\n[1]\nThe student decided to do two separate experiments. (b)\nE xperiment 1\n(s), To find the enthalpy change of solution of anhydrous magnesium sulfate, MgSO\n4\ncm3 (s) are dissolved in 50.0 distilled water. 0.0250 moles of MgSO\n4\nE xperiment 2\n•7H O(s), To find the enthalpy change of solution of hydrated magnesium sulfate, MgSO\n4 2\ncm3 •7H O(s) are dissolved in 50.0 distilled water. 0.0250 moles of MgSO\n4 2\nThe results for are shown in the graph of temperature against time on page 3. Experiment 1\nDraw and extrapolate the cooling curve back to 180 seconds. Determine the temperature (i)\nchange during the reaction.\n°C temperature change = .............................. [1]\nThe anhydrous magnesium sulfate was not added when the timing started. (ii)\nExplain why.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n29.0\n28.0\n27.0\n26.0\n25.0\nC°\n/\nerutarepmet\n24.0\n23.0\n22.0\n21.0\n20.0\n19.0\n0 60 120 180 240 300 360 420 480\ntime / s\n3.01 g (0.0250 mol) of anhydrous magnesium sulfate is weighed. (iii)\nOutline the next steps that should be taken in order to obtain the results in 1. Experiment\nWrite your answer using a series of numbered steps.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n...........", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-52-q01-9cafddc10f.pdf" }, { "id": "9701-2021-mj-52-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-52-q02-p01-fd79f2dd8b.png", "9701-experimental-skills/assets/9701-2021-mj-52-q02-p02-e31ffb254d.png", "9701-experimental-skills/assets/9701-2021-mj-52-q02-p03-d4aefe6fdf.png", "9701-experimental-skills/assets/9701-2021-mj-52-q02-p04-01b4ad1718.png", "9701-experimental-skills/assets/9701-2021-mj-52-q02-p05-3c8438741d.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student is asked to determine the acid dissociation constant, K , for butanoic acid, 2\na\nCH CH COOH. CH\n3 2 2\nCOO–][H+] [CH CH CH\n3 2 2 K =\na [CH CH CH COOH]\n3 2 2\nCH CH COOH and the The student is told to measure the pH of eight buffer solutions containing CH\n3 2 2\nCOO–Na+. COO–, CH CH The salt provides butanoate ions, CH CH CH salt sodium butanoate, CH\n3 2 2 3 2 2\nas the base.\nCOO–]. CH CH COOH] to [CH CH CH Each buffer solution contains a different ratio of [CH\n3 2 2 3 2 2\nEach buffer solution is prepared by mixing different volumes of distilled water,\ndm–3 dm–3 COO–Na+. CH CH CH COOH and 2.00 mol CH CH CH 2.00 mol\n3 2 2 3 2 2\nPure butanoic acid must be kept away from naked flames. (a)\nExplain why.\n.............................................................................................................................................. [1]\ndm–3 solution that can be prepared using 55.0 g What is the maximum volume of a 2.00 mol (b) (i)\nCOO–Na+(s)? CH CH of CH\n3 2 2\n: Na, 23.0; O, 16.0; C, 12.0; H, 1.0] [A\nr\ncm3 volume = .............................. [1]\nCOO–Na+(s) A student is given 55.0 g of CH CH CH in a beaker. (ii)\n3 2 2\ndm–3 solution of the Describe the next steps the student should take to make a 2.00 mol\nvolume calculated in (b)(i).\nGive the name and capacity of any key apparatus which should be used.\nWrite your answer as a series of numbered steps.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nCOO–Na+(aq) CH CH and distilled water Complete the table to show the volumes of CH (iii)\n3 2 2\nCH CH COOH and that would be needed to provide the stated number of moles of CH\n3 2 2\nCOO– cm3 CH CH for a 50.0 buffer solution. CH\n3 2 2\nvolume of volume of\nvolume of\ndm–3 dm–3 2.00 mol moles of moles of 2.00 mol\ndistilled water\nCOO– COO–Na+", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-52-q02-e3397ee453.pdf" }, { "id": "9701-2021-mj-53-q01", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_53.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-53-q01-p01-b8e7bcf0ec.png", "9701-experimental-skills/assets/9701-2021-mj-53-q01-p02-dce35c2da0.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Hydrogen peroxide decomposes slowly at room temperature to give water and oxygen. 1\n→ O (aq) 2H O(l) + O (g) 2H\n2 2 2 2\nThe rate of this reaction can be increased by the addition of a metal oxide catalyst. initial\nA student is asked to investigate which metal oxide catalyst is best at increasing the rate of initial\nthis reaction by using a method which involves the collection of oxygen.\ncopper(II) iron(III) oxide, oxide, The student is provided with the following metal oxides:\nmanganese(IV) nickel(II) titanium(IV) oxide, oxide and oxide.\nThe student is also provided with an excess volume, of a known concentration, of aqueous hydrogen\nperoxide and any laboratory equipment needed.\nS tate the independent variable. (a) (i)\n....................................................................................................................................... [1]\nS tate the dependent variable. (ii)\n....................................................................................................................................... [1]\nState two variables that would need to be controlled. (b)\n1 .................................................................................................................................................\n2 .................................................................................................................................................\n[2]\nDraw a labelled diagram of the assembled apparatus that could be used to carry out these (c)\nexperiments. The apparatus should allow the accurate recording of the oxygen produced.\n[3]\nW hat measurements need to be recorded during the course of each experiment to allow (d) (i)\nthe rate to be determined? initial\n....................................................................................................................................... [1]\nH ow is the rate determined using these measurements? (ii) initial\n.............................................................................................................................................\n....................................................................................................................................... [1]\nHow can the student ensure that the results are reliable? (e)\n.............................................................................................................................................. [1]\nSuggest an alternative method to investigate these reactions which does not include the (f)\ncollection of gas.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nOnce the reaction has finished, how can the student demonstrate that the metal oxide has not (g)\nbeen affected by the reaction?\n....................................................", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-53-q01-58d810eff7.pdf" }, { "id": "9701-2021-mj-53-q02", "subject": "9701", "year": 2021, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-may-june/9701_s21_qp_53.pdf?download=true", "source_pages": [ 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2021-May-June/qp/9701_s21_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-mj-53-q02-p01-78aa95db37.png", "9701-experimental-skills/assets/9701-2021-mj-53-q02-p02-98db2e82ce.png", "9701-experimental-skills/assets/9701-2021-mj-53-q02-p03-9ebe6af501.png", "9701-experimental-skills/assets/9701-2021-mj-53-q02-p04-366bcaf5e4.png" ], "answer": { "status": "pending", "id": "9701-2021-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "cm3 Fe2+ Fe3+ A student is given 250.0 of solution containing a mixture of and ions. The student 2\nFe3+ in the solution by is asked to find the total mass of iron ions and the percentage by mass of\nmanganate(VII), KMnO . performing titrations with aqueous potassium\n4\nFe3+(aq) Fe2+(aq) ions can be reduced to ions by reaction with zinc. The student is told that the\nThe student is given the following instructions.\ncm3 dm–3 needed to make 500.0 of 0.0200 mol KMnO (aq). ● Calculate the mass of KMnO\n4 4\n● Record the mass of an empty plastic weighing boat (a small container used to hold solid\nsamples).\nto the weighing boat. ● Add the calculated mass of KMnO\n4\ncm3 from the weighing boat into a 100 beaker. ● Transfer the KMnO\n4\ncm3 of distilled water to the beaker. ● Add 50\ncm3 volumetric flask. ● Transfer the mixture from the beaker into a 500.0\n● Make up to the graduation mark, dropwise, with distilled water.\ncm3 dm–3 needed to make 500.0 of 0.0200 mol KMnO (aq). C alculate the mass of KMnO (a) (i)\n4 4\n: K, 39.1; Mn, 54.9; O, 16.0] [A\nr\nneeded = .............................. g [1] mass of KMnO\n4\nT he student used a balance accurate to two decimal places. (ii)\nby difference. Calculate the percentage error in weighing the mass of the KMnO\n4\nIf you were unable to calculate a value for use the mass 1.75 g. This is the 2(a)(i) not\ncorrect answer to 2(a)(i). Show your working.\npercentage error = .............................. % [1]\nwere stuck to the weighing boat after The student noticed that some crystals of KMnO (iii)\n4\nsolid to the beaker. adding the KMnO\n4\nState how the student should modify the instructions to ensure that the measured mass of\nwas accurate. KMnO\n4\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nGive two additional instructions that should be given to the student to ensure that the (iv)\nsolution is prepared as accurately as possible.\n1 ..........................................................................................................................................\n.............................................................................................................................................\n2 ..........................................................................................................................................\n.............................................................................................................................................\n[2]\n(aq) is ready for use, the student is given additional instructions. When the KMnO (b)\n4\ndm–3 KMnO (aq). Fill a burette with 0.0200 mol step 1\n4\ncm3 Fe2+(aq) Fe3+(aq) of / solutio", "pdf_path": "9701-experimental-skills/print/9701-2021-mj-53-q02-d2e57e285b.pdf" }, { "id": "9701-2021-on-41-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-on-41-q01-p01-6b207c6a8b.png", "9701-topic-24-electrochemistry/assets/9701-2021-on-41-q01-p02-0039659012.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q01", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "When dilute sulfuric acid is electrolysed, water is split into hydrogen and oxygen. 1\n→ 2H O(l) 2H (g) + O (g)\n2 2 2\ncm3 of hydrogen are produced A current of A is passed through the solution for 14.0 minutes. 462 x\nat the cathode, measured under room conditions.\nCalculate the number of hydrogen molecules produced during the electrolysis. (a)\nnumber of hydrogen molecules = .............................. [2]\nCalculate the total number of electrons transferred to produce this number of hydrogen (b)\nmolecules.\ntotal number of electrons = .............................. [1]\nCalculate the quantity of charge, in coulombs, of the total number of electrons calculated in (b). (c)\nquantity of charge = .............................. C [1]\nCalculate the current, x, passed during this experiment. (d)\n= .............................. A [1] x\no, The standard entropies, S of three species are given in the table. (e)\no K–1 mol–1 species S / J\nH O(l) +70\n2\n(g) +131 H\n2\n(g) +205 O\n2\n→ ∆S o for the reaction 2H O(l) 2H (g) + O (g). Calculate (i)\n2 2 2\n\b ∆S o K–1 mol–1 = .............................. J [1]\n→ ∆ o mol–1. for the reaction 2H O(l) 2H (g) + O (g) is +572 kJ H (ii)\n2 2 2\n∆G o for this reaction at 298 K. Calculate\n\b ∆G o mol–1 = .............................. kJ [2]\nPredict the effect of increasing temperature on the spontaneity of this reaction. (iii)\nExplain your answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 9]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-on-41-q01-93a4a8ca7e.pdf" }, { "id": "9701-2021-on-41-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2021-on-41-q02-p01-ca41d86638.png", "9701-topic-25-equilibria/assets/9701-2021-on-41-q02-p02-5548a74cf3.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "HCl Solution is hydrochloric acid, (aq). Solution is aqueous 4-chlorobutanoic acid, 2 Y Z\nCl Cl ) CO H(aq). The pK of (CH ) CO H(aq) is 4.52. The pH of both solutions is 4.00. (CH\n2 3 2 a 2 3 2\nCl of (CH ) CO H(aq). W rite an expression for the K (a) (i)\na 2 3 2\nK =\na\n[1]\nW rite a mathematical expression to describe the relationship between K and pK . (ii)\na a\n....................................................................................................................................... [1]\n[H+] in solutions and Z. Calculate Y (iii)\n[H+] dm–3 = .............................. mol [1]\n[HCl ] dissolved in solution Y\nCalculate the ratio . (iv)\n[Cl (CH ) CO H] dissolved in solution Z\n2 3 2\n[HCl ] dissolved in solution Y\n= .............................. [2]\n[Cl (CH ) CO H] dissolved in solution Z\n2 3 2\nA buffer solution of pH 5.00 is produced by adding sodium propanoate to 5.00 g of propanoic acid (b)\ncm3 in 100 of distilled water.\nCalculate the mass of sodium propanoate that must be used to produce this buffer solution.\n× 10–5 dm–3. of propanoic acid is 1.35 mol The K\na\n: propanoic acid, 74.0; sodium propanoate, 96.0] [ M\nr\nmass of sodium propanoate = .............................. g [3]\nSome dilute sulfuric acid is mixed with a small sample of the buffer solution described in (b). (c)\nThe final pH of the mixture is close to 1.\nE xplain this observation.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 10]", "pdf_path": "9701-topic-25-equilibria/print/9701-2021-on-41-q02-a3be42ae01.pdf" }, { "id": "9701-2021-on-41-q03", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2021-on-41-q03-p01-71f7bb769e.png", "9701-topic-23-chemical-energetics/assets/9701-2021-on-41-q03-p02-e10152c129.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Define the term electron affinity. 3 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nWrite an equation for the process corresponding to the ionisation energy of calcium. (b) second\nInclude state symbols.\n.............................................................................................................................................. [1]\nSome data relating to calcium and oxygen are listed. Select relevant data from this list for your\nanswers to parts (c), and (e). (d)\nmol–1 process value / kJ\nfirst ionisation energy of oxygen +1310\nsecond ionisation energy of oxygen +3390\nfirst electron affinity of oxygen –142\nsecond electron affinity of oxygen +844\n1 → 2e– O2–(g) +951 enthalpy change for O (g) +\n2 2\n→ Ca2+(g) 2e– enthalpy change for Ca(s) + +1933\nlattice energy of CaO(s) –3517\nmolecules. Oxygen exists as O (c)\n2\nU se the data in this question to calculate a value for the bond energy of the O=O bond.\nS how all your working.\nmol–1 [3] bond energy = .............................. kJ\nSuggest why the first electron affinity of oxygen is negative. (d) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nSuggest why the second electron affinity of oxygen is positive. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCalculate the enthalpy of formation of calcium oxide, CaO(s). (e)\nmol–1 [2] enthalpy of formation = .............................. kJ\nmol–1. The lattice energy of lithium fluoride, LiF(s), is –1022 kJ (f)\nI dentify the factor that causes the lattice energy of calcium oxide to be more exothermic than\nthat of lithium fluoride. Explain why this factor causes the difference in lattice energies.\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 12]", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2021-on-41-q03-a3383cc2e1.pdf" }, { "id": "9701-2021-on-41-q04", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 8 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-on-41-q04-p01-bffdd18f99.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q04", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Separate samples of 0.02 mol of calcium carbonate and 0.02 mol of barium carbonate are heated 4\nuntil completely decomposed to the metal oxide and carbon dioxide.\nState which of these two Group 2 carbonates requires the temperature before it begins (a) higher\nto decompose. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nAfter decomposition is complete, the 0.02 mol sample of calcium oxide is taken and added to (b)\ndm3 of water. A solution is formed with no solid present. Dilute sulfuric acid is then added 2.00\ndropwise until a precipitate is seen.\nT he same procedure is repeated with the 0.02 mol sample of barium oxide, using the same\nconcentration solution of dilute sulfuric acid.\nI dentify the sample to which sulfuric acid must be added to cause a precipitate to appear. most\nE xplain your answer. You should refer to the solubilities of the precipitates and relevant energy\nterms in your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nproduced by the decomposition of 0.020 moles of C alculate the mass, in g, of CO (c) (i)\n2\ncalcium carbonate.\nmass of CO = .............................. g [1]\n2\nC alculate the minimum mass, in g, of propane that would, on complete combustion, (ii)\ncalculated in (c)(i). produce the same mass of CO\n2\nGive your answer to three significant figures.\nmass of propane = .............................. g [2]\n[Total: 8]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-on-41-q04-1ef9e0f756.pdf" }, { "id": "9701-2021-on-41-q05", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 9, 10 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-41-q05-p01-1cd8075900.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-41-q05-p02-d6670658c2.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "]2– [MnCl is a complex ion. 5 (a)\n4\n]2–. [MnCl Deduce the oxidation state of manganese in (i)\n4\noxidation state = .............................. [1]\n180° ]2– [MnCl The complex does contain any bond angles. (ii) not\n4\n]2– [MnCl Draw a three-dimensional diagram to show the shape of the complex.\n4\nState one bond angle on your diagram.\nMn\n[2]\ncobalt(II) ]2+. A solution of sulfate contains the complex ion [Co(H O) (b)\n2 6\n]2+ A solution containing [Co(H O) is reacted separately with an excess of each of NaOH(aq),\n2 6\nNaCl NH (aq) and (aq).\n3\nW rite an equation for each of these reactions. State observation that can be made one\nimmediately after the reaction, include the colour and state of the cobalt-containing product.\n]2+ [Co(H O) and an excess of NaOH(aq) (i)\n2 6\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\n]2+ [Co(H O) and an excess of NH (aq) (ii)\n2 6 3\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\n]2+ NaCl [Co(H O) and an excess of (aq) (iii)\n2 6\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\nName the type of reaction that occurs in (b)(iii). (iv)\n....................................................................................................................................... [1]\n]2+. ) (en) The abbreviation en is used for the bidentate Cobalt forms the complex ion [Co(NH (c)\n3 2 2\nNCH CH NH . The complex ion shows both geometrical and ligand 1,2-diaminoethane, H\n2 2 2 2\noptical isomerism.\nDefine the term bidentate ligand. (i)\n.............................................................................................................................................\n....................................................................................................................................... [2]\n]2+. ) (en) D raw three-dimensional diagrams for the two isomers of [Co(NH (ii) optical\n3 2 2\nEach en ligand can be represented using .\nN N\nCo Co\n[2]\n[Total: 14]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-41-q05-0fdc44d85b.pdf" }, { "id": "9701-2021-on-41-q06", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 11 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-41-q06-p01-0bea26eb6e.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "copper(II) An excess of sodium iodide is added to a solution of sulfate. Iodine and a white precipitate 6\ncopper(I) iodide are formed. of\nWrite an equation for the reaction that occurs. (a)\n.............................................................................................................................................. [1]\ncopper(II) sulfate solution is coloured. Explain why the (b) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\ncopper(I) iodide is white. S uggest why the precipitate of (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\no Cu2+ values from the Data Booklet to predict whether iodide ions can reduce Use suitable E (c)\nCu+ under standard conditions. Explain your answer. to\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\ncopper(II) Copper(I) sulfate solution. iodide forms as An excess of sodium iodide is added to (d)\n[Cu+] dm–3. is much lower than 1.0 mol a precipitate. After precipitation,\nU se this information and your answer to to explain how the relevant electrode potentials (c)\nI– Cu2+ ions can reduce ions. change and hence why\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-41-q06-492c40ea7b.pdf" }, { "id": "9701-2021-on-41-q07", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-on-41-q07-p01-82563dd9b9.png", "9701-topic-36-organic-synthesis/assets/9701-2021-on-41-q07-p02-7d6fd54a52.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "The structure of phenylethanoic acid is shown. 7\nOH\nO\n(13C) Give the number of different peaks in the carbon-13 NMR spectrum of phenylethanoic (a)\nacid.\nnumber of peaks = .............................. [1]\nPhenylethanoic acid, ethanol and phenol can all behave as acids. (b)\nC ompare and explain the relative acidities of these three compounds.\n............................................ > ............................................ > ............................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nPhenylethanoic acid can be synthesised using benzene as the starting material. (c)\nIn the first stage of this synthesis, benzene reacts with chloromethane in the presence of an\nAl Cl catalyst to form methylbenzene.\n3\n+CH Al Cl C hloromethane reacts with to form two ions. One of these is the carbocation .\n3 3\nAl Cl Write an equation for the reaction between chloromethane and . (i)\n3\n....................................................................................................................................... [1]\n+CH D raw the mechanism of the reaction between benzene and . Include all relevant curly (ii)\n3\narrows, charges and the structure of the intermediate.\n+CH intermediate\n3\nCH\n3\n(cid:31) (cid:31)\n[3]\nA three-step synthesis of phenylethanoic acid from methylbenzene is shown. (d)\nBr\nOH\nstep 1 step 2 step 3\ncompound\nQ O\nState reagents and conditions for step 1. (i)\n....................................................................................................................................... [1]\nS uggest the structure of compound Q. (ii)\n[1]\nState reagents and conditions for steps 2 and 3. (iii)\nstep 2 ..................................................................................................................................\nstep 3 ..................................................................................................................................\n[2]\nDraw the structure of an organic by-product that forms in step 1. (iv)\n[1]\n[Total: 14]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-on-41-q07-4d3e37ed5e.pdf" }, { "id": "9701-2021-on-41-q08", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 5, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 14 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-on-41-q08-p01-4dbf64fe1c.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Phenylamine, C H NH , and ethylamine, C H NH , can be distinguished by adding aqueous 8\n6 5 2 2 5 2\nbromine.\nState what is seen when aqueous bromine is added to phenylamine. (a)\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nSuggest what is seen when aqueous bromine is added to ethylamine. (b)\n.............................................................................................................................................. [1]\nDraw the structure of the organic product formed when an excess of aqueous bromine is (c)\nadded to phenylamine.\n[1]\nName the product you have drawn in (c). (d)\n.............................................................................................................................................. [1]\n[Total: 5]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-on-41-q08-8da1f780f5.pdf" }, { "id": "9701-2021-on-41-q09", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 15, 16, 17 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2021-on-41-q09-p01-25a5cba3bf.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-41-q09-p02-d42d909d3b.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-41-q09-p03-7ab908e76a.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q09", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Compound is made by a three-stage synthesis. 9 T\nIn stage 1, phenylethanoic acid reacts with a suitable reagent to form compound R. (a)\nphenylethanoic acid R\nCl OH\n(cid:31) stage 1\nO O\nS uggest a suitable reagent for stage 1.\n.............................................................................................................................................. [1]\nIn stage 2, compound reacts with ethylamine to form compound S. (b) R\nR S\nH\nCl\nN\n(cid:31) stage 2 + C H NH\n2 5 2\nO\nO\nName the functional group formed in stage 2. (i)\n....................................................................................................................................... [1]\nI dentify the other product formed in stage 2. (ii)\n....................................................................................................................................... [1]\nIn stage 3, compound reacts with a suitable reagent to form compound T. (c) S\nS T\nH H\nN N\n(cid:31) stage 3\nO\nState the formula of a suitable reagent for stage 3. (i)\n....................................................................................................................................... [1]\nN ame the type of reaction that occurs in stage 3. (ii)\n....................................................................................................................................... [1]\nThe relative abundance of the molecular ion peak in the mass spectrum of ethylamine is 62. (d)\nCalculate the relative abundance of the M+1 peak in the mass spectrum of ethylamine. (i)\nrelative abundance = .............................. [1]\nT he mass spectrum of compound contains several fragments. The m/e values of two of (ii) T\nthese fragments are 29 and 91.\nDraw the structures of the ions responsible for these peaks.\nm/e structure of ion\n29\n91\n[2]\n(1H) NMR spectrum of compound shows hydrogen atoms in different environments. The proton T (e)\nSix of these environments are shown on the structure using letters a, b, c, d, e and f.\nd\nH\nf b\nN\nc e\na\nU se the letters a, b, c, d, e and f to answer the questions that follow. The questions relate to\n(1H) the proton NMR spectrum of T.\nP roton d does not cause splitting of the peaks for protons c or e under the conditions used.\nE ach answer may be one, or more than one, of the letters a, b, c, d, e and f.\n(δ) Identify the proton or protons with a chemical shift in the range 6.0 to 9.0. (i)\n.............................. [1]\nI dentify the proton or protons whose peak will disappear if D O is added. (ii)\n2\n.............................. [1]\nIdentify the proton or protons whose peak is a triplet. (iii)\n.............................. [1]\n(δ). Identify the proton or protons with the lowest chemical shift (iv)\n.............................. [1]\n[Total: 12]", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2021-on-41-q09-f5883e4985.pdf" }, { "id": "9701-2021-on-41-q10", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 10, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_41.pdf?download=true", "source_pages": [ 18 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-on-41-q10-p01-0c36ea7d6f.png" ], "answer": { "status": "pending", "id": "9701-2021-on-41-q10", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Valine (Val) and lysine (Lys) are amino acids. The structures of these amino acids can be found in 10\nthe Data Booklet.\nThe isoelectric point of an amino acid is the pH at which it exists as a zwitterion. The isoelectric\npoint of valine is 6.0. The isoelectric point of lysine is 9.7.\nDraw the structure of valine at pH 6.0. (a)\n[1]\nA solution of lysine is produced with pH 9.7. Dilute sulfuric acid is added slowly until the pH of (b)\nthe solution is 1.0. The sulfuric acid reacts with lysine to produce different organic ions that are\nnot present in significant concentrations at pH 9.7.\nD raw the structures of three of the organic ions that form during the addition of sulfuric acid in\nthe boxes. Draw the organic ion present at pH 1.0 in box C.\nA B C (pH 1.0)\n[3]\nDraw the structure of the dipeptide Val-Lys. The peptide bond should be shown fully displayed. (c)\n[2]\n[Total: 6]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-on-41-q10-09bfecb305.pdf" }, { "id": "9701-2021-on-42-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2021-on-42-q01-p01-e517eafd81.png", "9701-topic-23-chemical-energetics/assets/9701-2021-on-42-q01-p02-3782b759f2.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Radium is a Group 2 element. 1\nmol–1. The predicted lattice energy, , of radium sulfide, RaS, is –2612 kJ\n. Define (a)\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nSome data relating to radium and sulfur are listed. Select relevant data from this list for use in your\nanswers to parts to (e). (b)\nmol–1 process value / kJ\n→ Ra2+(g) 2e– enthalpy change for Ra(s) + +1619\nfirst ionisation energy of sulfur +1000\nsecond ionisation energy of sulfur +2260\nfirst electron affinity of sulfur –200\nsecond electron affinity of sulfur +532\n→ 2e– S2–(g) +555 S (s) + enthalpy change for\n8\nlattice energy of RaS(s) –2612\nWrite an equation for the process corresponding to the electron affinity of sulfur. (b) second\nInclude state symbols.\n.............................................................................................................................................. [1]\nmolecules in the solid state. Sulfur exists as S (c)\n8\n→ (s) 8S(g). U se the data in this question to calculate the enthalpy change for the reaction S\n8\nkJmol–1 enthalpy change = .............................. [3]\nCalculate the standard enthalpy change of formation, , of radium sulfide. (d)\nmol–1 standard enthalpy change, = .............................. kJ [2]\nState the major factors that affect the numerical magnitude of a lattice energy. (e) (i) two\n.............................................................................................................................................\n....................................................................................................................................... [2]\nFor factor you have identified in (e)(i), state whether it tends to make the lattice (ii) each\nenergy of radium sulfide more or less exothermic than that of sodium chloride.\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nmol–1 NaCl, The lattice energies of sodium chloride, and radium sulfide, RaS, are –771 kJ (iii)\nmol–1, respectively. and –2612 kJ\nIdentify the factor in determining the relative numerical magnitudes of the lattice dominant\nenergies of radium sulfide and sodium chloride.\nExplain your answer.\n...................................................................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2021-on-42-q01-b4a6f787f9.pdf" }, { "id": "9701-2021-on-42-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2021-on-42-q02-p01-53958908d2.png", "9701-topic-25-equilibria/assets/9701-2021-on-42-q02-p02-620641e257.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Ethoxyethane, C H OC H , can dissolve both in water and in octan-1-ol. The expression and 2\n2 5 2 5\nnumerical value for the partition coefficient of ethoxyethane between water and octan-1-ol are\ngiven. Water and octan-1-ol are immiscible.\nconcentration of C H OC H in octan-1-ol\n2 5 2 5 °C K = = 6.760 at 20\npc H OC H in water concentration of C\n2 5 2 5\n°C °C. In an experiment, octan-1-ol at 20 is added to a solution of ethoxyethane in water at 20 (a)\nis calculated. The mixture is analysed immediately and a value of K\npc\nT he calculation is performed correctly; the value calculated is 5.625.\nE xplain why the value calculated is than 6.760. less\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nis found to be 6.760. The concentration A second experiment is performed and the value of K (b)\npc\ndm–3. of ethoxyethane in the octan-1-ol layer is 7.62 g\ndm–3, of ethoxyethane in the aqueous layer. Calculate the concentration, in g (i)\ndm–3 [1] .............................. g\ncm3 cm3 of the octan-1-ol layer is taken and shaken with 100 of water. 1 00 (ii)\nCalculate the maximum amount, in mol, of ethoxyethane that can be extracted into the\nwater.\n.............................. mol [3]\nlead(II) An aqueous solution of nitrate is mixed with an aqueous solution of sodium iodide. A (c)\nlead(II) iodide is formed and is filtered out, leaving solution X. yellow precipitate of\n× Pb2+ 10–3 dm–3. in solution is 5.68 mol T he concentration of X\n× I– 10–4 dm–3. in solution is 4.20 mol T he concentration of X\nlead(II) , of iodide. Use these data to calculate a value for the solubility product, K (i)\nsp\n. State the units of K\nsp\n= .............................. K\nsp\nunits = ..............................\n[2]\nP otassium iodide is very soluble in water. (ii)\nDescribe and explain what is seen if a few drops of saturated potassium iodide solution\nare added to a portion of solution X.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n[Total: 10]", "pdf_path": "9701-topic-25-equilibria/print/9701-2021-on-42-q02-a963d0b520.pdf" }, { "id": "9701-2021-on-42-q03", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-on-42-q03-p01-6b851a5e94.png", "9701-topic-24-electrochemistry/assets/9701-2021-on-42-q03-p02-e4793a03c1.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Pure water is a very poor conductor of electricity. However, when hydrogen chloride gas is dissolved 3\nin water, ions are formed and a current flows during electrolysis.\n→ H+(aq) –(aq) Cl HCl + (g) + aq\nThe overall change after electrolysis is that hydrogen chloride gas is converted into hydrogen and\nchlorine.\n→ Cl 2HCl (g) + (g) (g) H\n2 2\ncm3 of chlorine are When a current of 3.10 A is passed through the solution for Y minutes, 351\nproduced at the anode, measured under room conditions.\nCalculate the number of chlorine molecules produced during the electrolysis. (a)\nnumber of chlorine molecules = .............................. [2]\nCalculate the total number of electrons transferred to produce this number of chlorine molecules. (b)\ntotal number of electrons = .............................. [1]\nCalculate the quantity of charge, in coulombs, of the total number of electrons calculated in (b). (c)\nquantity of charge = .............................. C [1]\nCalculate the time, Y, in minutes, for which the current flows. (d)\nY = .............................. minutes [1]\no, The standard entropies, S of three species are given in the table. (e)\no K–1 mol–1 species S / J\nHCl(g) +187\n(g) +131 H\n2\nCl (g) +223\n2\n→ ∆S o 2HCl Cl for the reaction (g) H (g) + (g). C alculate (i)\n2 2\n\b ∆S o K–1 mol–1 = .............................. J [1]\n→ ∆ o mol–1. 2HCl Cl for the reaction (g) H (g) + (g) is +185 kJ H (ii)\n2 2\n∆G o for this reaction at 298 K. Calculate\n\b ∆G o mol–1 = .............................. kJ [2]\nPredict the effect of increasing temperature on the spontaneity of this reaction. Explain (iii)\nyour answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 9]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-on-42-q03-23f9a3ebb1.pdf" }, { "id": "9701-2021-on-42-q04", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-on-42-q04-p01-d5e6f9f4e4.png", "9701-topic-27-group-2/assets/9701-2021-on-42-q04-p02-d1e01460bc.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q04", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Separate samples of 0.01 mol of magnesium nitrate and 0.01 mol of strontium nitrate are heated 4\nuntil completely decomposed to the metal oxide, nitrogen dioxide and oxygen.\nState which of these two Group 2 nitrates requires the temperature before it begins to (a) higher\ndecompose. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nAfter decomposition is complete the 0.01 mol sample of magnesium oxide is taken and (b)\nincreasing amounts of water are added to it, with stirring, until no solid remains.\nT his procedure is repeated with the 0.01 mol sample of strontium oxide.\nI dentify the sample to which most water must be added to cause all the solid to dissolve.\nExplain your answer by reference to the solubilities of the products formed when water is\nadded to the oxides. You should refer to relevant energy terms in your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nThe nitrogen dioxide given off by the decomposition of 0.0100 mol of strontium nitrate is (c)\ncm3 O (aq) is then added to give 150.0 of a solution dissolved in water. The oxidising agent H\n2 2\n, is the only nitrogen-containing product. in which nitric acid, HNO\n3\ndm–3, cm3 of HNO in the 150.0 of solution. Calculate the concentration, in mol (i)\n3\ndm–3 [1] concentration = .............................. mol\ncm3 dm–3 The HNO present in 25.0 of this solution is neutralised using 0.125 mol NaOH(aq). (ii)\n3\ncm3, of NaOH(aq) needed. Give your answer to three Calculate the minimum volume, in\nsignificant figures.\ncm3 [1] volume = ..............................\n[Total: 7]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-on-42-q04-e6d127f47a.pdf" }, { "id": "9701-2021-on-42-q05", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-42-q05-p01-13c0237e9e.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-42-q05-p02-04369ba78a.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Transition elements form complexes. 5\nMolybdenum, Mo, forms an octahedral complex consisting of one Mo atom surrounded by (a)\ncarbon monoxide, CO, molecules. CO is a monodentate ligand. Iron forms an octahedral\nFe3+ CN–, CN– and a number of cyanide, ions. is a monodentate complex consisting of one\nligand.\nDefine the term monodentate ligand. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nC omplete the table by stating the formulae and charges of the complexes described. (ii)\nformula charge\nmolybdenum complex\niron(III) complex\n[2]\niron(III) complex. Draw a three-dimensional diagram to show the shape of this (iii)\n180° Label one bond angle on your diagram.\nFe\n[1]\ncopper(II) An excess of aqueous ammonia is added to dilute sulfate solution. A dark blue (b)\n]2+, ) (H O) is formed. complex, [Cu(NH\n3 4 2 2\nWrite an ionic equation for this reaction. (i)\n....................................................................................................................................... [1]\ncopper(II) E xplain the origin of colour in complexes. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\nAn excess of concentrated hydrochloric acid is added to the dark blue solution of (c)\n]2+. ) (H O) A new complex, Z, is formed. The colour of the solution changes. [Cu(NH\n3 4 2 2\n]2+. ) (H O) Include the Write an equation for the formation of from the solution of [Cu(NH (i) Z\n3 4 2 2\nformula and charge of Z.\n....................................................................................................................................... [2]\n]2+. ) (H O) N ame the type of reaction when forms from [Cu(NH (ii) Z\n3 4 2 2\n....................................................................................................................................... [1]\nState the geometry of Z. (iii)\n....................................................................................................................................... [1]\nState the colou", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-42-q05-36a16f7e48.pdf" }, { "id": "9701-2021-on-42-q06", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 12 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-42-q06-p01-65ff4425c1.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "]2+. An excess of aqueous ammonia is added to a solution containing the complex ion [Co(H O) 6\n2 6\n]2+ ]2+ O) + 6NH [Co(NH ) + 6H O [Co(H\n2 6 3 3 6 2\nComplete the sentence to describe the colour change that will be seen during this reaction. (a)\nT he colour changes from ................................................ to .............................................. . [1]\n]2+. , of [Co(NH ) Write an expression for the stability constant, K (b)\nstab 3 6\nK =\nstab\n[1]\n× ]2+ 104. The numerical value of K of [Co(NH ) is 7.7 (c)\nstab 3 6\n]2+ ]2+ ) and [Co(H O) can be made from this W hat deduction about the properties of [Co(NH\n3 6 2 6\nvalue? K\nstab\n.............................................................................................................................................. [1]\n]2+ ]3+ Oxygen can oxidise [Co(NH ) to [Co(NH ) under standard conditions in alkaline solutions. (d)\n3 6 3 6\n]3+ e– ]2+ o ) + [Co(NH ) E = +0.10 V [Co(NH\n3 6 3 6\nvalue for this oxidation of Use this information and the Data Booklet to calculate the (i)\n]2+. ) [Co(NH\n3 6\n.............................................................................................................................................\n.............................................................................................................................................\n= .............................. V\n[1]\n]2+. ) W rite an ionic equation for this oxidation of [Co(NH (ii)\n3 6\n....................................................................................................................................... [1]\nPredict, by selecting suitable data from the Data Booklet, whether oxygen can oxidise (iii)\nCo2+(aq) in solution, in the absence of ammonia. Explain your answer. acidic\n.............................................................................................................................................\n....................................................................................................................................... [2]\n[Total: 7]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-42-q06-6848356bbe.pdf" }, { "id": "9701-2021-on-42-q07", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 13, 14 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2021-on-42-q07-p01-355450e8db.png", "9701-topic-30-hydrocarbons/assets/9701-2021-on-42-q07-p02-6c7dc059d5.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q07", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "The structure of benzene-1,3-dicarboxylic acid is shown. 7\nbenzene-1,3-dicarboxylic acid\nO\nHO\nOH\nO\nState the empirical formula of benzene-1,3-dicarboxylic acid. (a)\n.............................................................................................................................................. [1]\nBenzene-1,3-dicarboxylic acid is an isomer of benzene-1,4-dicarboxylic acid. These two (b)\n(13C) NMR spectroscopy. isomers can be distinguished by carbon-13\n(13C) NMR spectrum of each compound. S tate the number of peaks in the carbon-13\nbenzene-1,3-dicarboxylic acid\nbenzene-1,4-dicarboxylic acid\n[2]\nBenzene-1,3-dicarboxylic acid can be made by the two-step synthesis shown below. (c)\nbenzene-1,3-dicarboxylic acid\nO compound compound P Q\nO\nstep 1 step 2\nC H O HO\n9 8 3\nOH HO\nO\nName compound P. (i)\n....................................................................................................................................... [1]\nE xplain why the major product of this two-step synthesis is benzene-1,3-dicarboxylic acid (ii)\nand benzene-1,4-dicarboxylic acid. not\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCOCl Al Cl The reagents used for step 1 are CH and . These reagents give rise to (iii)\n3 3\n+\nions which react with compound P. CH C=O\n3\nName the mechanism of this reaction.\n....................................................................................................................................... [1]\n+\nCH C=O ions with compound P. Include all Draw the mechanism of the reaction of (iv)\n3\nrelevant curly arrows and charges, the structure of the intermediate and the structure of\ncompound Q.\nintermediate compound Q\n+\nCH C=O\n3\nO\nHO\n[3]\nSuggest a reagent and conditions to convert compound into benzene-1,3-dicarboxylic (v) Q\nacid, in step 2.\n....................................................................................................................................... [1]\n[Total: 10]", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2021-on-42-q07-dd4f331854.pdf" }, { "id": "9701-2021-on-42-q08", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 15, 16, 17 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2021-on-42-q08-p01-593033eb8d.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-42-q08-p02-d8ad38ab60.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-42-q08-p03-2adbe9aee1.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Alanine, H NCH(CH )CO H, and glutamic acid, H NCH(CH CH CO H)CO H, are two naturally 8\n2 3 2 2 2 2 2 2\noccurring amino acids.\nH NCH(CH )CO H exists as two optical isomers. (a)\n2 3 2\nD raw three-dimensional structures of these two optical isomers.\n[2]\n(1H) NMR spectrum of alanine in D O or glutamic acid in D O is shown. The proton either (b)\n2 2\n9 8 7 6 5 4 3 2 1 0\n(cid:31) / ppm\nS tate whether this is the spectrum of alanine in D O or the spectrum of glutamic acid in D O.\n2 2\nE xplain your answer by reference to the number of peaks and splitting patterns.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nThe mass spectrum of glutamic acid, H NCH(CH CH CO H)CO H, is obtained. (c)\n2 2 2 2 2\nState the m/e value of the molecular ion peak in this spectrum. (i)\n....................................................................................................................................... [1]\nT he spectrum has peaks with m/e values of 88 and 131. (ii)\nDraw the structures of the ions responsible for these peaks.\nm/e structure of ion\n88\n131\n[2]\n– At pH 11 alanine exists as H NCH(CH )CO ions and glutamic acid exists as (d)\n2 3 2\n–)CO – NCH(CH CH CO ions. A mixture of alanine and glutamic acid at pH 11 is subjected H\n2 2 2 2 2\nto electrophoresis.\nState how the mixture can be maintained at pH 11 during electrophoresis. (i)\n....................................................................................................................................... [1]\nD raw a fully labelled diagram for the apparatus that would be used to carry out this (ii)\nelectrophoresis. Your diagram should include the position of the mixture of alanine and\nglutamic acid at the start of the electrophoresis experiment.\n[2]\nIdentify the electrode that each amino acid travels towards during electrophoresis at pH 11. (iii)\nalanine ................................................................................................................................\nglutamic acid .......................................................................................................................\n[1]\nIn a particular electrophoresis experiment at pH 11, the glutamic acid travels 3.4 cm. (iv)\nAlanine travels a shorter distance.\nExplain the factors that account for the difference in the distances travelled.\n.............................................................................................................................................\n.......", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2021-on-42-q08-dfef7d9e20.pdf" }, { "id": "9701-2021-on-42-q09", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 18 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-on-42-q09-p01-d7072d67a5.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Butylamine, CH CH CH CH NH , can be synthesised from different organic compounds by using 9\n3 2 2 2 2\nsuitable reagents. Each reaction involves one step.\nComplete the table to describe three different syntheses. (a)\n● One of the three syntheses should involve a nucleophilic substitution reaction.\n● The starting organic compound for each synthesis should contain a different functional\ngroup.\n● A different reagent should be used for each synthesis.\nstarting organic compound reagent and conditions\n[6]\nCompare and explain the relative basicities of ammonia, butylamine and phenylamine. (b)\n.............................................. > ............................................. > .............................................\nmost basic least basic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\n[Total: 10]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-on-42-q09-55ae202c40.pdf" }, { "id": "9701-2021-on-42-q10", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 10, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 5, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_42.pdf?download=true", "source_pages": [ 19 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2021-on-42-q10-p01-c0e890ee8e.png" ], "answer": { "status": "pending", "id": "9701-2021-on-42-q10", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Complete the table to show the structure of the organic product from each reaction of phenol, 10 (a)\nH OH. C\n6 5\nreaction reaction mixture structure of organic product\n1 phenol + NaOH(aq)\n2 phenol + Na(s)\nN\n+\nN\nphenol + (aq) 3\n°C + NaOH, at 4\nan excess of phenol +\nO O\n4\nC C\nCl Cl\n[4]\nIdentify reactions from the table in which ethanol would behave in a similar way to phenol. (b) two\n.............................................................................................................................................. [1]\n[Total: 5]", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2021-on-42-q10-5c79ef4866.pdf" }, { "id": "9701-2021-on-43-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2021-on-43-q01-p01-6b207c6a8b.png", "9701-topic-24-electrochemistry/assets/9701-2021-on-43-q01-p02-0039659012.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q01", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "When dilute sulfuric acid is electrolysed, water is split into hydrogen and oxygen. 1\n→ 2H O(l) 2H (g) + O (g)\n2 2 2\ncm3 of hydrogen are produced A current of A is passed through the solution for 14.0 minutes. 462 x\nat the cathode, measured under room conditions.\nCalculate the number of hydrogen molecules produced during the electrolysis. (a)\nnumber of hydrogen molecules = .............................. [2]\nCalculate the total number of electrons transferred to produce this number of hydrogen (b)\nmolecules.\ntotal number of electrons = .............................. [1]\nCalculate the quantity of charge, in coulombs, of the total number of electrons calculated in (b). (c)\nquantity of charge = .............................. C [1]\nCalculate the current, x, passed during this experiment. (d)\n= .............................. A [1] x\no, The standard entropies, S of three species are given in the table. (e)\no K–1 mol–1 species S / J\nH O(l) +70\n2\n(g) +131 H\n2\n(g) +205 O\n2\n→ ∆S o for the reaction 2H O(l) 2H (g) + O (g). Calculate (i)\n2 2 2\n\b ∆S o K–1 mol–1 = .............................. J [1]\n→ ∆ o mol–1. for the reaction 2H O(l) 2H (g) + O (g) is +572 kJ H (ii)\n2 2 2\n∆G o for this reaction at 298 K. Calculate\n\b ∆G o mol–1 = .............................. kJ [2]\nPredict the effect of increasing temperature on the spontaneity of this reaction. (iii)\nExplain your answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 9]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2021-on-43-q01-2c72d400b3.pdf" }, { "id": "9701-2021-on-43-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2021-on-43-q02-p01-ca41d86638.png", "9701-topic-25-equilibria/assets/9701-2021-on-43-q02-p02-5548a74cf3.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "HCl Solution is hydrochloric acid, (aq). Solution is aqueous 4-chlorobutanoic acid, 2 Y Z\nCl Cl ) CO H(aq). The pK of (CH ) CO H(aq) is 4.52. The pH of both solutions is 4.00. (CH\n2 3 2 a 2 3 2\nCl of (CH ) CO H(aq). W rite an expression for the K (a) (i)\na 2 3 2\nK =\na\n[1]\nW rite a mathematical expression to describe the relationship between K and pK . (ii)\na a\n....................................................................................................................................... [1]\n[H+] in solutions and Z. Calculate Y (iii)\n[H+] dm–3 = .............................. mol [1]\n[HCl ] dissolved in solution Y\nCalculate the ratio . (iv)\n[Cl (CH ) CO H] dissolved in solution Z\n2 3 2\n[HCl ] dissolved in solution Y\n= .............................. [2]\n[Cl (CH ) CO H] dissolved in solution Z\n2 3 2\nA buffer solution of pH 5.00 is produced by adding sodium propanoate to 5.00 g of propanoic acid (b)\ncm3 in 100 of distilled water.\nCalculate the mass of sodium propanoate that must be used to produce this buffer solution.\n× 10–5 dm–3. of propanoic acid is 1.35 mol The K\na\n: propanoic acid, 74.0; sodium propanoate, 96.0] [ M\nr\nmass of sodium propanoate = .............................. g [3]\nSome dilute sulfuric acid is mixed with a small sample of the buffer solution described in (b). (c)\nThe final pH of the mixture is close to 1.\nE xplain this observation.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 10]", "pdf_path": "9701-topic-25-equilibria/print/9701-2021-on-43-q02-6dbff90113.pdf" }, { "id": "9701-2021-on-43-q03", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2021-on-43-q03-p01-71f7bb769e.png", "9701-topic-23-chemical-energetics/assets/9701-2021-on-43-q03-p02-e10152c129.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Define the term electron affinity. 3 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nWrite an equation for the process corresponding to the ionisation energy of calcium. (b) second\nInclude state symbols.\n.............................................................................................................................................. [1]\nSome data relating to calcium and oxygen are listed. Select relevant data from this list for your\nanswers to parts (c), and (e). (d)\nmol–1 process value / kJ\nfirst ionisation energy of oxygen +1310\nsecond ionisation energy of oxygen +3390\nfirst electron affinity of oxygen –142\nsecond electron affinity of oxygen +844\n1 → 2e– O2–(g) +951 enthalpy change for O (g) +\n2 2\n→ Ca2+(g) 2e– enthalpy change for Ca(s) + +1933\nlattice energy of CaO(s) –3517\nmolecules. Oxygen exists as O (c)\n2\nU se the data in this question to calculate a value for the bond energy of the O=O bond.\nS how all your working.\nmol–1 [3] bond energy = .............................. kJ\nSuggest why the first electron affinity of oxygen is negative. (d) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nSuggest why the second electron affinity of oxygen is positive. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCalculate the enthalpy of formation of calcium oxide, CaO(s). (e)\nmol–1 [2] enthalpy of formation = .............................. kJ\nmol–1. The lattice energy of lithium fluoride, LiF(s), is –1022 kJ (f)\nI dentify the factor that causes the lattice energy of calcium oxide to be more exothermic than\nthat of lithium fluoride. Explain why this factor causes the difference in lattice energies.\n....................................................................................................................................................\n.............................................................................................................................................. [2]\n[Total: 12]", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2021-on-43-q03-8e1b143829.pdf" }, { "id": "9701-2021-on-43-q04", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 8 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2021-on-43-q04-p01-bffdd18f99.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q04", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Separate samples of 0.02 mol of calcium carbonate and 0.02 mol of barium carbonate are heated 4\nuntil completely decomposed to the metal oxide and carbon dioxide.\nState which of these two Group 2 carbonates requires the temperature before it begins (a) higher\nto decompose. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nAfter decomposition is complete, the 0.02 mol sample of calcium oxide is taken and added to (b)\ndm3 of water. A solution is formed with no solid present. Dilute sulfuric acid is then added 2.00\ndropwise until a precipitate is seen.\nT he same procedure is repeated with the 0.02 mol sample of barium oxide, using the same\nconcentration solution of dilute sulfuric acid.\nI dentify the sample to which sulfuric acid must be added to cause a precipitate to appear. most\nE xplain your answer. You should refer to the solubilities of the precipitates and relevant energy\nterms in your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nproduced by the decomposition of 0.020 moles of C alculate the mass, in g, of CO (c) (i)\n2\ncalcium carbonate.\nmass of CO = .............................. g [1]\n2\nC alculate the minimum mass, in g, of propane that would, on complete combustion, (ii)\ncalculated in (c)(i). produce the same mass of CO\n2\nGive your answer to three significant figures.\nmass of propane = .............................. g [2]\n[Total: 8]", "pdf_path": "9701-topic-27-group-2/print/9701-2021-on-43-q04-2c213b5ff3.pdf" }, { "id": "9701-2021-on-43-q05", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 9, 10 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-43-q05-p01-1cd8075900.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-43-q05-p02-d6670658c2.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "]2– [MnCl is a complex ion. 5 (a)\n4\n]2–. [MnCl Deduce the oxidation state of manganese in (i)\n4\noxidation state = .............................. [1]\n180° ]2– [MnCl The complex does contain any bond angles. (ii) not\n4\n]2– [MnCl Draw a three-dimensional diagram to show the shape of the complex.\n4\nState one bond angle on your diagram.\nMn\n[2]\ncobalt(II) ]2+. A solution of sulfate contains the complex ion [Co(H O) (b)\n2 6\n]2+ A solution containing [Co(H O) is reacted separately with an excess of each of NaOH(aq),\n2 6\nNaCl NH (aq) and (aq).\n3\nW rite an equation for each of these reactions. State observation that can be made one\nimmediately after the reaction, include the colour and state of the cobalt-containing product.\n]2+ [Co(H O) and an excess of NaOH(aq) (i)\n2 6\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\n]2+ [Co(H O) and an excess of NH (aq) (ii)\n2 6 3\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\n]2+ NaCl [Co(H O) and an excess of (aq) (iii)\n2 6\nequation ..............................................................................................................................\nobservation .........................................................................................................................\n[2]\nName the type of reaction that occurs in (b)(iii). (iv)\n....................................................................................................................................... [1]\n]2+. ) (en) The abbreviation en is used for the bidentate Cobalt forms the complex ion [Co(NH (c)\n3 2 2\nNCH CH NH . The complex ion shows both geometrical and ligand 1,2-diaminoethane, H\n2 2 2 2\noptical isomerism.\nDefine the term bidentate ligand. (i)\n.............................................................................................................................................\n....................................................................................................................................... [2]\n]2+. ) (en) D raw three-dimensional diagrams for the two isomers of [Co(NH (ii) optical\n3 2 2\nEach en ligand can be represented using .\nN N\nCo Co\n[2]\n[Total: 14]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-43-q05-58f42c1a7f.pdf" }, { "id": "9701-2021-on-43-q06", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 11 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2021-on-43-q06-p01-0bea26eb6e.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "copper(II) An excess of sodium iodide is added to a solution of sulfate. Iodine and a white precipitate 6\ncopper(I) iodide are formed. of\nWrite an equation for the reaction that occurs. (a)\n.............................................................................................................................................. [1]\ncopper(II) sulfate solution is coloured. Explain why the (b) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\ncopper(I) iodide is white. S uggest why the precipitate of (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\no Cu2+ values from the Data Booklet to predict whether iodide ions can reduce Use suitable E (c)\nCu+ under standard conditions. Explain your answer. to\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\ncopper(II) Copper(I) sulfate solution. iodide forms as An excess of sodium iodide is added to (d)\n[Cu+] dm–3. is much lower than 1.0 mol a precipitate. After precipitation,\nU se this information and your answer to to explain how the relevant electrode potentials (c)\nI– Cu2+ ions can reduce ions. change and hence why\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2021-on-43-q06-5887ee6965.pdf" }, { "id": "9701-2021-on-43-q07", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2021-on-43-q07-p01-82563dd9b9.png", "9701-topic-36-organic-synthesis/assets/9701-2021-on-43-q07-p02-7d6fd54a52.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "The structure of phenylethanoic acid is shown. 7\nOH\nO\n(13C) Give the number of different peaks in the carbon-13 NMR spectrum of phenylethanoic (a)\nacid.\nnumber of peaks = .............................. [1]\nPhenylethanoic acid, ethanol and phenol can all behave as acids. (b)\nC ompare and explain the relative acidities of these three compounds.\n............................................ > ............................................ > ............................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [4]\nPhenylethanoic acid can be synthesised using benzene as the starting material. (c)\nIn the first stage of this synthesis, benzene reacts with chloromethane in the presence of an\nAl Cl catalyst to form methylbenzene.\n3\n+CH Al Cl C hloromethane reacts with to form two ions. One of these is the carbocation .\n3 3\nAl Cl Write an equation for the reaction between chloromethane and . (i)\n3\n....................................................................................................................................... [1]\n+CH D raw the mechanism of the reaction between benzene and . Include all relevant curly (ii)\n3\narrows, charges and the structure of the intermediate.\n+CH intermediate\n3\nCH\n3\n(cid:31) (cid:31)\n[3]\nA three-step synthesis of phenylethanoic acid from methylbenzene is shown. (d)\nBr\nOH\nstep 1 step 2 step 3\ncompound\nQ O\nState reagents and conditions for step 1. (i)\n....................................................................................................................................... [1]\nS uggest the structure of compound Q. (ii)\n[1]\nState reagents and conditions for steps 2 and 3. (iii)\nstep 2 ..................................................................................................................................\nstep 3 ..................................................................................................................................\n[2]\nDraw the structure of an organic by-product that forms in step 1. (iv)\n[1]\n[Total: 14]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2021-on-43-q07-0dddb97ab7.pdf" }, { "id": "9701-2021-on-43-q08", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 5, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 14 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-on-43-q08-p01-4dbf64fe1c.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Phenylamine, C H NH , and ethylamine, C H NH , can be distinguished by adding aqueous 8\n6 5 2 2 5 2\nbromine.\nState what is seen when aqueous bromine is added to phenylamine. (a)\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nSuggest what is seen when aqueous bromine is added to ethylamine. (b)\n.............................................................................................................................................. [1]\nDraw the structure of the organic product formed when an excess of aqueous bromine is (c)\nadded to phenylamine.\n[1]\nName the product you have drawn in (c). (d)\n.............................................................................................................................................. [1]\n[Total: 5]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-on-43-q08-b873937803.pdf" }, { "id": "9701-2021-on-43-q09", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 15, 16, 17 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2021-on-43-q09-p01-25a5cba3bf.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-43-q09-p02-d42d909d3b.png", "9701-topic-37-analytical-techniques/assets/9701-2021-on-43-q09-p03-7ab908e76a.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q09", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Compound is made by a three-stage synthesis. 9 T\nIn stage 1, phenylethanoic acid reacts with a suitable reagent to form compound R. (a)\nphenylethanoic acid R\nCl OH\n(cid:31) stage 1\nO O\nS uggest a suitable reagent for stage 1.\n.............................................................................................................................................. [1]\nIn stage 2, compound reacts with ethylamine to form compound S. (b) R\nR S\nH\nCl\nN\n(cid:31) stage 2 + C H NH\n2 5 2\nO\nO\nName the functional group formed in stage 2. (i)\n....................................................................................................................................... [1]\nI dentify the other product formed in stage 2. (ii)\n....................................................................................................................................... [1]\nIn stage 3, compound reacts with a suitable reagent to form compound T. (c) S\nS T\nH H\nN N\n(cid:31) stage 3\nO\nState the formula of a suitable reagent for stage 3. (i)\n....................................................................................................................................... [1]\nN ame the type of reaction that occurs in stage 3. (ii)\n....................................................................................................................................... [1]\nThe relative abundance of the molecular ion peak in the mass spectrum of ethylamine is 62. (d)\nCalculate the relative abundance of the M+1 peak in the mass spectrum of ethylamine. (i)\nrelative abundance = .............................. [1]\nT he mass spectrum of compound contains several fragments. The m/e values of two of (ii) T\nthese fragments are 29 and 91.\nDraw the structures of the ions responsible for these peaks.\nm/e structure of ion\n29\n91\n[2]\n(1H) NMR spectrum of compound shows hydrogen atoms in different environments. The proton T (e)\nSix of these environments are shown on the structure using letters a, b, c, d, e and f.\nd\nH\nf b\nN\nc e\na\nU se the letters a, b, c, d, e and f to answer the questions that follow. The questions relate to\n(1H) the proton NMR spectrum of T.\nP roton d does not cause splitting of the peaks for protons c or e under the conditions used.\nE ach answer may be one, or more than one, of the letters a, b, c, d, e and f.\n(δ) Identify the proton or protons with a chemical shift in the range 6.0 to 9.0. (i)\n.............................. [1]\nI dentify the proton or protons whose peak will disappear if D O is added. (ii)\n2\n.............................. [1]\nIdentify the proton or protons whose peak is a triplet. (iii)\n.............................. [1]\n(δ). Identify the proton or protons with the lowest chemical shift (iv)\n.............................. [1]\n[Total: 12]", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2021-on-43-q09-02589a0594.pdf" }, { "id": "9701-2021-on-43-q10", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 10, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_43.pdf?download=true", "source_pages": [ 18 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2021-on-43-q10-p01-0c36ea7d6f.png" ], "answer": { "status": "pending", "id": "9701-2021-on-43-q10", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Valine (Val) and lysine (Lys) are amino acids. The structures of these amino acids can be found in 10\nthe Data Booklet.\nThe isoelectric point of an amino acid is the pH at which it exists as a zwitterion. The isoelectric\npoint of valine is 6.0. The isoelectric point of lysine is 9.7.\nDraw the structure of valine at pH 6.0. (a)\n[1]\nA solution of lysine is produced with pH 9.7. Dilute sulfuric acid is added slowly until the pH of (b)\nthe solution is 1.0. The sulfuric acid reacts with lysine to produce different organic ions that are\nnot present in significant concentrations at pH 9.7.\nD raw the structures of three of the organic ions that form during the addition of sulfuric acid in\nthe boxes. Draw the organic ion present at pH 1.0 in box C.\nA B C (pH 1.0)\n[3]\nDraw the structure of the dipeptide Val-Lys. The peptide bond should be shown fully displayed. (c)\n[2]\n[Total: 6]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2021-on-43-q10-21078d840e.pdf" }, { "id": "9701-2021-on-51-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-51-q01-p01-37147350db.png", "9701-experimental-skills/assets/9701-2021-on-51-q01-p02-02f3970c4f.png", "9701-experimental-skills/assets/9701-2021-on-51-q01-p03-24fd6d56f4.png", "9701-experimental-skills/assets/9701-2021-on-51-q01-p04-1973e36940.png" ], "answer": { "status": "pending", "id": "9701-2021-on-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Potassium hydrogencarbonate, KHCO , decomposes when strongly heated to form 1\n3\nCO . potassium carbonate, K\n2 3\n→ (s) K CO (s) + CO (g) + H O(l) 2KHCO\n3 2 3 2 2\n∆H, which cannot A student plans to determine the value for the enthalpy change for this reaction,\nr\nbe determined directly. The student carries out two separate experiments using the following\napparatus.\nthermometer\ncup polystyrene\ndm–3 mol 2.0\nhydrochloric acid\nsolid\n. uses solid KHCO Experiment 1\n3\nCO . uses solid K Experiment 2\n2 3\nThe following method is used for both experiments:\ncm3, dm–3 an excess, of 2 mol hydrochloric acid into a cup. ● Transfer 50.00\n● After 2 minutes, record the temperature of the acid.\n● Weigh approximately 0.0250 moles of solid.\n● Add the solid to the acid, stir the mixture using a thermometer and record the temperature\nthroughout the reaction.\ndm–3 hydrochloric acid is irritant, solid potassium hydrogencarbonate and Hazard information: 2 mol\nsolid potassium carbonate may cause irritation to the skin and eyes.\nThe equations for the two reactions are:\n→ HCl KCl (s) + (aq) (aq) + CO (g) + H O(l) reaction 1 KHCO\n3 2 2\n→ 2HCl 2KCl CO (s) + (aq) (aq) + CO (g) + H O(l) reaction 2 K\n2 3 2 2\nfor the decomposition reaction directly. Suggest why it is not possible to measure ∆H (a)\nr\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nC alculate the mass of 0.0250 moles of each solid. Give your answers to decimal (b) (i) three\nplaces.\n: K, 39.1; H, 1.0; C, 12.0; O, 16.0] [A\nr\n= .............................. g mass of KHCO\n3\nCO = .............................. g mass of K\n2 3\n[1]\nT he masses of solid are measured using a three decimal place balance. (ii)\n. Calculate the percentage error in the measurement of the mass of KHCO\n3\nShow your working.\npercentage error = .............................. [1]\nThe student obtained the following results. (c)\ninitial maximum / minimum temperature\nsolid\n°C °C °C temperature / temperature / change, ∆T /\n17.5 14.0 KHCO\n3\nCO 19.0 20.5 K\n2 3\nComplete the table by calculating temperature change. (i)\nmc∆T Use the formula q = to determine the energy change, q, that took place during\n∆H mol–1. , in kJ 1. Use q to calculate the enthalpy change of reaction 1, experiment\n1\nInclude a sign in your answer.\ncm3 of solution has a mass of 1.00 g. Assume 1.00\ng–1 K–1 c = 4.18 J\n\b ∆H mol–1 = .............................. kJ [2]\n1\nU se the formula q = mc∆T to determine the energy change, q, that took place during (ii)\n∆H mol–1. , in kJ 2. Use q to calculate the enthalpy change of reaction 2, experiment\n2\nInclude a sign in your answer.\ncm3 of solution has a mass of 1.00 g. Assume 1.00\ng–1 K–1 c = 4.18 J\n\b ∆H mol–1 = .............................. kJ [2]\n2\nUse the following cycle to calculate ∆H. (d)\nr\n∆H\nr\n2KHCO ", "pdf_path": "9701-experimental-skills/print/9701-2021-on-51-q01-5e92066be9.pdf" }, { "id": "9701-2021-on-51-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_51.pdf?download=true", "source_pages": [ 6, 8, 9, 10, 11 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-51-q02-p01-7ba1db3f63.png", "9701-experimental-skills/assets/9701-2021-on-51-q02-p02-ffa001b074.png", "9701-experimental-skills/assets/9701-2021-on-51-q02-p03-34687a9a1f.png", "9701-experimental-skills/assets/9701-2021-on-51-q02-p04-33ca70cc6d.png", "9701-experimental-skills/assets/9701-2021-on-51-q02-p05-2afbb30e14.png" ], "answer": { "status": "pending", "id": "9701-2021-on-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "HCl, The rate of reaction between calcium carbonate, CaCO , and hydrochloric acid, can be followed 2\n3\nby collecting and measuring the volume of carbon dioxide produced at 30-second intervals.\nThe equation for the reaction is:\n→ 2HCl CaCl (s) + (aq) (aq) + CO (g) + H O(l) CaCO\n3 2 2 2\nA student plans to collect the carbon dioxide by displacement of water. (a)\nD raw a labelled diagram of the apparatus that could be used to carry out this experiment.\nT he apparatus should allow the accurate recording of the volume of carbon dioxide produced.\n[3]\nThe student carried out the investigation using an excess of calcium carbonate with dilute (b)\nhydrochloric acid. The student stopped timing after 330 seconds had passed. The volume of\ncm3. carbon dioxide produced was 93\nis the final volume of carbon dioxide collected at 330 seconds. V\nfinal\nis the volume of carbon dioxide collected at each interval of time, t. V\nt\n–V is proportional to the concentration of hydrochloric acid at a given time. V\nfinal t\nvolume of carbon dioxide\ncm3 time, t / s V –V /\ncm3 final t collected /\n0 0\n30 22\n60 37\n90 50\n120 61\n150 68\n180 75\n210 78\n240 79\n270 87\n300 90\n330 93\nComplete the table. [1] (i)\nP lot a graph of V –V (y-axis) against time, t (x-axis). (ii)\nfinal t\n(××) to plot each data point. Draw a curved line of best fit. Use a cross\n–V V\nfinal t\ncm3 /\ntime, t / s\n[2]\nCircle the point which you consider to be most anomalous. [1] (iii)\nSuggest reason for this anomalous point. (iv) one\n.............................................................................................................................................\n....................................................................................................................................... [1]\nDraw construction lines on the graph to calculate two consecutive half-lives for this (v)\nt . reaction. Use these half-lives to determine the mean half-life,\n1\n2\nfirst half-life = .............................. s\nsecond half-life = .............................. s\nt = .............................. s mean half-life,\n1\n2\n[2]\nThe rate constant, k, for this reaction can be calculated using the following expression. (vi)\n0.693\nt =\n1 k\n2\nCalculate k.\nt in you may use 95 seconds. This is the correct If you did not obtain a value for (v) not\n1\n2\nanswer.\ns–1 [1] k = ..............................\nState how an increase in temperature would affect the value of k for this reaction. Explain your (c)\nanswer.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nCalcium carbonate is a component of antacid tablets. (d)\nA n alternative method of studying the rate of reaction between calcium carbonate and\nhydrochloric acid is:\n● Place one antacid tablet into a beaker.\ncm3, dm–3 excess, of 2.0 mol ", "pdf_path": "9701-experimental-skills/print/9701-2021-on-51-q02-4913ca939b.pdf" }, { "id": "9701-2021-on-52-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-52-q01-p01-06e07bbd6a.png", "9701-experimental-skills/assets/9701-2021-on-52-q01-p02-3550ba9b81.png", "9701-experimental-skills/assets/9701-2021-on-52-q01-p03-0ecc84e1da.png" ], "answer": { "status": "pending", "id": "9701-2021-on-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "∆H It is possible to measure the enthalpy change of combustion, , of ethanol, C H OH, using the 1\nc 2 5\nfollowing apparatus.\nthermometer\nmetal can\nwater\nlid\ntripod\nwick\nspirit burner\ncontaining ethanol\nwooden blocks\nA student carries out an experiment to determine the value for ∆H of ethanol using the following\nc\ninstructions:\n● Weigh the spirit burner with ethanol and lid, record the starting mass to two decimal places.\ncm3 of water and place it into the metal can. ● Measure 100.00\n°C ● Place a thermometer, with 0.1 graduations, into the water and stir it, wait for 2 minutes.\n● Record the temperature of the water.\n● Light the wick and allow the flame to heat the water.\n● Continue to stir the water using the thermometer.\n°C A fter the temperature has risen by approximately 20 place the lid on the flame to extinguish it. ●\n● Record the maximum temperature of the water.\n● Weigh the spirit burner and record the final mass.\nThe student obtained the following results.\ninitial maximum change in mass of\ninitial mass of final mass of\ntemperature temperature temperature of ethanol\nspirit burner / g spirit burner / g\n°C °C °C of water / of water / water, ∆T / burned / g\n18.1 38.2 153.29 152.76\nComplete the table. Record your answers to the correct number of decimal places. [1] (a)\nCalculate the number of moles of ethanol burned. Give your answer to significant figures. (b) three\n: C, 12.0; H, 1.0; O, 16.0] [A\nr\nmoles of ethanol = .............................. [1]\nUse the formula q = mc∆T to determine the energy change, q, that took place during the (c)\nexperiment. Use q and your answer to to calculate the enthalpy change of combustion of (b)\n∆H mol–1. , in kJ ethanol,\nc\nI nclude a sign in your answer.\ncm3 of water has a mass of 1.00 g 1 .00\ng–1 K–1 c = 4.18 J\n∆H mol–1 = .............................. kJ [2]\nc\nCalculate the percentage error of the temperature change recorded in the table in (a). (d)\nS how your working.\npercentage error = .............................. [1]\nState the effect, if any at all, on the accuracy of the experiment if the spirit burner was allowed (e)\nto burn for longer. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe flame was extinguished, but the lid of the spirit burner was not replaced immediately. (f)\n∆H . Explain your answer. Predict how this would affect the value of\nc\n..................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2021-on-52-q01-688f207e1b.pdf" }, { "id": "9701-2021-on-52-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_52.pdf?download=true", "source_pages": [ 5, 6, 8, 9, 10 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-52-q02-p01-d2bddac380.png", "9701-experimental-skills/assets/9701-2021-on-52-q02-p02-c83be219d2.png", "9701-experimental-skills/assets/9701-2021-on-52-q02-p03-076c75f47d.png", "9701-experimental-skills/assets/9701-2021-on-52-q02-p04-93d7b2646e.png", "9701-experimental-skills/assets/9701-2021-on-52-q02-p05-f078232564.png" ], "answer": { "status": "pending", "id": "9701-2021-on-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Halogenoalkanes undergo hydrolysis with aqueous sodium hydroxide to form alcohols. 2\n→ CH CH CH Br(l) + NaOH(aq) CH CH CH CH OH(l) + NaBr(aq) e.g. CH\n3 2 2 2 3 2 2 2\nA student carried out an experiment to compare the rate at which three halogenoalkanes,\nCl, CH CH CH 1-bromobutane, CH CH CH CH Br, and 1-iodobutane, 1-chlorobutane, CH\n3 2 2 2 3 2 2 2\nI, CH CH CH undergo hydrolysis. The method used was as follows: CH\n3 2 2 2\ncm3 sample of each halogenoalkane into separate test-tubes. ● Place a 5\ncm3 of organic solvent to each test-tube. ● Add 1\ncm3 aqueous sodium hydroxide to each test-tube. ● Add 2\n● Add 3 drops of acid–base indicator to the mixture.\n● Heat the test-tubes in a thermostatically controlled, electrically heated water bath.\n● Record the time taken for the indicator to change colour.\nGive reasons why the experiment was carried out using an electrically heated water bath. (a) two\n1 .................................................................................................................................................\n....................................................................................................................................................\n2 .................................................................................................................................................\n....................................................................................................................................................\n[2]\nSodium hydroxide is corrosive. (b)\nA part from wearing safety glasses and a lab coat, state safety precaution which must be one\ntaken when handling sodium hydroxide.\n.............................................................................................................................................. [1]\nSuggest why an organic solvent must be used in this experiment. (c)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nWhy is acid–base indicator added to the reaction mixture? (d)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe student obtained the following results. (e)\ntime taken for indicator 1\ns–1 / halogenoalkane\ntime to change colour / s\n1-chlorobutane 417\n1-bromobutane 238\n1-iodobutane 135\n1\nComplete the table to show . [1] (i)\ntime\n1\ncan be used to represent rate of reaction. (ii)\ntime\n1\nvalues tell you about the trend in carbon-halogen bond enthalpies. Suggest what the\ntime\n...................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2021-on-52-q02-2bc6dcf95f.pdf" }, { "id": "9701-2021-on-53-q01", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-53-q01-p01-37147350db.png", "9701-experimental-skills/assets/9701-2021-on-53-q01-p02-02f3970c4f.png", "9701-experimental-skills/assets/9701-2021-on-53-q01-p03-24fd6d56f4.png", "9701-experimental-skills/assets/9701-2021-on-53-q01-p04-1973e36940.png" ], "answer": { "status": "pending", "id": "9701-2021-on-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Potassium hydrogencarbonate, KHCO , decomposes when strongly heated to form 1\n3\nCO . potassium carbonate, K\n2 3\n→ (s) K CO (s) + CO (g) + H O(l) 2KHCO\n3 2 3 2 2\n∆H, which cannot A student plans to determine the value for the enthalpy change for this reaction,\nr\nbe determined directly. The student carries out two separate experiments using the following\napparatus.\nthermometer\ncup polystyrene\ndm–3 mol 2.0\nhydrochloric acid\nsolid\n. uses solid KHCO Experiment 1\n3\nCO . uses solid K Experiment 2\n2 3\nThe following method is used for both experiments:\ncm3, dm–3 an excess, of 2 mol hydrochloric acid into a cup. ● Transfer 50.00\n● After 2 minutes, record the temperature of the acid.\n● Weigh approximately 0.0250 moles of solid.\n● Add the solid to the acid, stir the mixture using a thermometer and record the temperature\nthroughout the reaction.\ndm–3 hydrochloric acid is irritant, solid potassium hydrogencarbonate and Hazard information: 2 mol\nsolid potassium carbonate may cause irritation to the skin and eyes.\nThe equations for the two reactions are:\n→ HCl KCl (s) + (aq) (aq) + CO (g) + H O(l) reaction 1 KHCO\n3 2 2\n→ 2HCl 2KCl CO (s) + (aq) (aq) + CO (g) + H O(l) reaction 2 K\n2 3 2 2\nfor the decomposition reaction directly. Suggest why it is not possible to measure ∆H (a)\nr\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nC alculate the mass of 0.0250 moles of each solid. Give your answers to decimal (b) (i) three\nplaces.\n: K, 39.1; H, 1.0; C, 12.0; O, 16.0] [A\nr\n= .............................. g mass of KHCO\n3\nCO = .............................. g mass of K\n2 3\n[1]\nT he masses of solid are measured using a three decimal place balance. (ii)\n. Calculate the percentage error in the measurement of the mass of KHCO\n3\nShow your working.\npercentage error = .............................. [1]\nThe student obtained the following results. (c)\ninitial maximum / minimum temperature\nsolid\n°C °C °C temperature / temperature / change, ∆T /\n17.5 14.0 KHCO\n3\nCO 19.0 20.5 K\n2 3\nComplete the table by calculating temperature change. (i)\nmc∆T Use the formula q = to determine the energy change, q, that took place during\n∆H mol–1. , in kJ 1. Use q to calculate the enthalpy change of reaction 1, experiment\n1\nInclude a sign in your answer.\ncm3 of solution has a mass of 1.00 g. Assume 1.00\ng–1 K–1 c = 4.18 J\n\b ∆H mol–1 = .............................. kJ [2]\n1\nU se the formula q = mc∆T to determine the energy change, q, that took place during (ii)\n∆H mol–1. , in kJ 2. Use q to calculate the enthalpy change of reaction 2, experiment\n2\nInclude a sign in your answer.\ncm3 of solution has a mass of 1.00 g. Assume 1.00\ng–1 K–1 c = 4.18 J\n\b ∆H mol–1 = .............................. kJ [2]\n2\nUse the following cycle to calculate ∆H. (d)\nr\n∆H\nr\n2KHCO ", "pdf_path": "9701-experimental-skills/print/9701-2021-on-53-q01-064bb57d70.pdf" }, { "id": "9701-2021-on-53-q02", "subject": "9701", "year": 2021, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2021-oct-nov/9701_w21_qp_53.pdf?download=true", "source_pages": [ 6, 8, 9, 10, 11 ], "local_pdf": "_source-pdfs/2021-Oct-Nov/qp/9701_w21_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2021-on-53-q02-p01-7ba1db3f63.png", "9701-experimental-skills/assets/9701-2021-on-53-q02-p02-ffa001b074.png", "9701-experimental-skills/assets/9701-2021-on-53-q02-p03-34687a9a1f.png", "9701-experimental-skills/assets/9701-2021-on-53-q02-p04-33ca70cc6d.png", "9701-experimental-skills/assets/9701-2021-on-53-q02-p05-2afbb30e14.png" ], "answer": { "status": "pending", "id": "9701-2021-on-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "HCl, The rate of reaction between calcium carbonate, CaCO , and hydrochloric acid, can be followed 2\n3\nby collecting and measuring the volume of carbon dioxide produced at 30-second intervals.\nThe equation for the reaction is:\n→ 2HCl CaCl (s) + (aq) (aq) + CO (g) + H O(l) CaCO\n3 2 2 2\nA student plans to collect the carbon dioxide by displacement of water. (a)\nD raw a labelled diagram of the apparatus that could be used to carry out this experiment.\nT he apparatus should allow the accurate recording of the volume of carbon dioxide produced.\n[3]\nThe student carried out the investigation using an excess of calcium carbonate with dilute (b)\nhydrochloric acid. The student stopped timing after 330 seconds had passed. The volume of\ncm3. carbon dioxide produced was 93\nis the final volume of carbon dioxide collected at 330 seconds. V\nfinal\nis the volume of carbon dioxide collected at each interval of time, t. V\nt\n–V is proportional to the concentration of hydrochloric acid at a given time. V\nfinal t\nvolume of carbon dioxide\ncm3 time, t / s V –V /\ncm3 final t collected /\n0 0\n30 22\n60 37\n90 50\n120 61\n150 68\n180 75\n210 78\n240 79\n270 87\n300 90\n330 93\nComplete the table. [1] (i)\nP lot a graph of V –V (y-axis) against time, t (x-axis). (ii)\nfinal t\n(××) to plot each data point. Draw a curved line of best fit. Use a cross\n–V V\nfinal t\ncm3 /\ntime, t / s\n[2]\nCircle the point which you consider to be most anomalous. [1] (iii)\nSuggest reason for this anomalous point. (iv) one\n.............................................................................................................................................\n....................................................................................................................................... [1]\nDraw construction lines on the graph to calculate two consecutive half-lives for this (v)\nt . reaction. Use these half-lives to determine the mean half-life,\n1\n2\nfirst half-life = .............................. s\nsecond half-life = .............................. s\nt = .............................. s mean half-life,\n1\n2\n[2]\nThe rate constant, k, for this reaction can be calculated using the following expression. (vi)\n0.693\nt =\n1 k\n2\nCalculate k.\nt in you may use 95 seconds. This is the correct If you did not obtain a value for (v) not\n1\n2\nanswer.\ns–1 [1] k = ..............................\nState how an increase in temperature would affect the value of k for this reaction. Explain your (c)\nanswer.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nCalcium carbonate is a component of antacid tablets. (d)\nA n alternative method of studying the rate of reaction between calcium carbonate and\nhydrochloric acid is:\n● Place one antacid tablet into a beaker.\ncm3, dm–3 excess, of 2.0 mol ", "pdf_path": "9701-experimental-skills/print/9701-2021-on-53-q02-853c2ca3e3.pdf" }, { "id": "9701-2022-m-42-q01", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2022-m-42-q01-p01-a2abb24bd3.png", "9701-topic-25-equilibria/assets/9701-2022-m-42-q01-p02-8694fdf706.png", "9701-topic-25-equilibria/assets/9701-2022-m-42-q01-p03-be671ca6ad.png", "9701-topic-25-equilibria/assets/9701-2022-m-42-q01-p04-c05492bf15.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q01", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Iodine is found naturally in compounds in many different oxidation states. 1\nI–, I react with acidified H O (aq) to form iodine, , and water. Iodide ions, (a)\n2 2 2\nI H , to extract the . This reaction mixture is shaken with cyclohexane, C\n6 12 2\nCyclohexane is immiscible with water.\nI– O (aq) in its reaction with ions in acidic conditions. Identify the role of H (i)\n2 2\nWrite an ionic equation for the reaction.\nrole ......................................................................................................................................\nionic equation .....................................................................................................................\n.............................................................................................................................................\n[2]\ncm3 cm3 I of C H is shaken with 20.0 of an aqueous solution containing until no 15.0 (ii)\n6 12 2\nfurther change is seen.\nI is extracted into the C H . It is found that 0.390 g of\n2 6 12\nI between C H and water, K , is 93.8. The partition coefficient of\n2 6 12 pc\nI that remains in the aqueous layer. Calculate the mass of\n2\nShow your working.\nI in aqueous layer = .............................. g [2] mass of\n2\nI of between hexan-2-one, CH (CH ) COCH , and water Suggest how the value of K (iii)\npc 2 3 2 3 3\ncompares to the value given in (a)(ii).\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nThe Group 1 iodides all form stable ionic lattices and are soluble in water. (b)\nDefine enthalpy change of solution. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nUse the data in Table 1.1 to calculate the enthalpy change of solution of potassium iodide, (ii)\nKI.\nTable 1.1\n∆H mol–1 process enthalpy change, / kJ\n→ K+(g) I–(g) KI(s) –629 +\n→ K+(g) K+(aq) –322\n→ I–(g) I–(aq) –293\nmol–1 [1] enthalpy change of solution = .............................. kJ\nLiI, NaI, Suggest the trend in the magnitude of the lattice energies of the Group 1 iodides, (iii)\nKI.\nExplain your answer.\n.....................................................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2022-m-42-q01-659895bee6.pdf" }, { "id": "9701-2022-m-42-q02", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-m-42-q02-p01-2a883c3631.png", "9701-topic-23-chemical-energetics/assets/9701-2022-m-42-q02-p02-001fed86a6.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Silicon is the second most abundant element by mass in the Earth’s crust. 2\n°C. by reaction with carbon at over 2000 In industry, silicon is extracted from SiO (a)\n2\n→ (s) + 2C(s) Si(l) + 2CO(g) reaction 1 SiO\n2\n∆S, Explain why the entropy change, of reaction 1 is positive. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nReaction 1 is highly endothermic. (ii)\nSuggest the effect of an increase in temperature on the feasibility of this reaction.\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nSiHCl HCl SiHCl . The formed is Silicon is purified by first heating it in a stream of (g) to form (b)\n3 3\nthen distilled to remove other impurities.\n→ 3HCl SiHCl (g) + H (g) reaction 2 Si(s) + (g)\n3 2\nTable 2.1 shows some standard entropy data. (i)\nTable 2.1\no K–1 mol–1 compound standard entropy, S / J\nSi(s) 19\nHCl (g) 187\nSiHCl (g) 314\n3\n(g) 131 H\n2\n∆S o for reaction 2. Use the data in Table 2.1 to calculate\n∆ o K–1 mol–1 S = .............................. J [2]\nReaction 3 is the reverse of reaction 2 and is used to obtain pure silicon. (ii)\n→ ∆H mol–1 3HCl SiHCl (g) + H (g) Si(s) + (g) = +219.3 kJ reaction 3\n3 2\nUse this information and your answer to to calculate the temperature, in K, at which (b)(i)\nreaction 3 becomes feasible.\nShow your working.\n∆S o K–1 mol–1 = –150 J for reaction 2. [If you were unable to answer (b)(i), you should use\nThis is not the correct answer to (b)(i).]\ntemperature = .............................. K [2]\nCaCl Silicon can also be produced by electrolysis of SiO dissolved in molten . (c)\n2 2\nThe relevant half-equation for the cathode is shown.\n→ 4e– 2O2– + Si + SiO\n2\nCalculate the time, in seconds, required to produce 1.00 g of Si by this electrolysis, using a\ncurrent of 6.00 A.\nAssume no other substances are produced at the cathode.\ntime = .............................. s [2]\n[Total: 9]", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-m-42-q02-e12f99a655.pdf" }, { "id": "9701-2022-m-42-q03", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 8, 9, 10, 11 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-m-42-q03-p01-04cbb12818.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-m-42-q03-p02-68eb63b475.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-m-42-q03-p03-9dbbec3fcc.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-m-42-q03-p04-ab12c6831e.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Titanium is a transition element in Period 4. It is commonly found as TiO in minerals. 3\n2\nDefine transition element. (a) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nIdentify typical properties of transition elements. (ii) two\n1 ..........................................................................................................................................\n2 ..........................................................................................................................................\n[1]\nTiO2+ ion forms when TiO reacts with an excess of sulfuric acid. The (b)\n2\nTiO2+ can be reduced by zinc metal in acidic conditions to form a purple solution containing\nTi3+(aq).\nTiO2+(aq) is a colourless ion. (i)\nSuggest why.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nTi3+ ion. Give the electronic configuration of an isolated (ii)\n1s2 ................................................................................................................................. [1]\nTiO2+ by zinc metal in acidic conditions. Write an ionic equation for the reduction of (iii)\n....................................................................................................................................... [1]\nTi3+(aq) Acidified reacts with oxygen dissolved in water as shown. (c)\n→ ∆G 4Ti3+ 4TiO2+ 4H+ o mol–1 + O + 2H O + = –436.1 kJ\n2 2\no, 4H+ 4e– T he standard reduction potential, E of O + + 2H O is +1.23 V.\n2 2\no, TiO2+(aq) Ti3+(aq) in V, of the / half-cell. Calculate the standard reduction potential, E (i)\nShow your working.\no = .............................. V [3] E\nTi3+(aq), ]3–(aq) 3–, H O are added to the [Ti(C H O ) complex When aqueous citrate ions, C (ii)\n6 5 7 6 5 7 2\nforms.\nTi3+ is able to form complex ions. Explain, in terms of d-orbitals, why\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]3–(aq) H O ) does not react with oxygen dissolved in water, unlike acidified Acidified [Ti(C (iii)\n6 5 7 2\nTi3+(aq).\no, of the Suggest what this means for the value of the stand", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-m-42-q03-8c64cdfc39.pdf" }, { "id": "9701-2022-m-42-q04", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 12, 13, 14, 15 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2022-m-42-q04-p01-8bc0b388ca.png", "9701-topic-32-hydroxy-compounds/assets/9701-2022-m-42-q04-p02-eaa9b41e1e.png", "9701-topic-32-hydroxy-compounds/assets/9701-2022-m-42-q04-p03-72d57c0a59.png", "9701-topic-32-hydroxy-compounds/assets/9701-2022-m-42-q04-p04-119897f969.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q04", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Compounds and are shown in Fig. 4.1. 4 F J\nF J\nOH O\nO OH\nO H N\n2\nFig. 4.1\nand both contain the arene functional group. (a) F J\nIdentify the other functional groups in and J. (i) F\nF: ........................................................................................................................................\nJ: .........................................................................................................................................\n[2]\nState the number of chiral centres in a molecule of and in a molecule of J. (ii) F\nnumber of chiral centres in: = ......................................... = ........................................ F J\n[1]\nA student proposes a multi-step synthesis of from benzene, as shown in Table 4.1. (b) F\nComplete Table 4.1 by providing relevant details of the reagents and conditions for steps 1 (i)\nand 4, and the structure of product D.\nTable 4.1\nstep organic reactant reagent(s) and conditions organic product\n1\n.........................................\nD\nand concentrated HNO\n3 2\nconcentrated H SO\n2 4\nE\nCOOH\nhot alkaline KMnO\n4 3 D\nthen dilute H SO\n2 4\nO N\n2\nF\nCOOH\nCOOH\n4\nO N\n......................................... 2 H N\n2\n[3]\nIn a second multi-step synthesis, the student changes the order in which the reagents and (ii)\nconditions are used.\nThe reaction scheme is shown in Fig. 4.2.\nis the major product of this synthesis. G\nconcentrated\nHNO and\n3\nhot alkaline concentrated COOH\nSO H KMnO step 1\n2 4 4\nG\nthen dilute\nSO H\n2 4\nFig. 4.2\nDraw the structure of G.\nExplain why is the major product of the synthesis rather than E. G\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n[2]\nreacts under suitable conditions with NaOH(aq). (c) J\nAfter acidification of the reaction mixture, compounds and form. K L\nJ K\nOH OH\nO 1. NaOH(aq) OH + L\nHCl 2. (aq)\nO O\nFig. 4.3\nGive the molecular formula of L. (i)\n....................................................................................................................................... [1]\nState the types of reaction that occur when reacts with NaOH(aq). (ii) two J\n1 ..........................................................................................................................................\n2 ..........................................................................................................................................\n[2]\nH OH. can also be synthesised from phenol, C (d) K\n6 5\nFig. 4.4 shows several reactions of phenol.\nM\nreaction 1\nphenol\nNa(s)\nOH\nreaction 2\nreaction 3 excess Br (aq)\n2\nN\nNaOH(aq) followed\nby CO (g) and H SO\n2 2 4\nK\nOH\nOH\nO\nFig. 4.4\nWrite an equation for the f", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2022-m-42-q04-6c6a21e152.pdf" }, { "id": "9701-2022-m-42-q05", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 21, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 16, 17, 18, 19, 20 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2022-m-42-q05-p01-b61329cbb6.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-m-42-q05-p02-367c3c27cc.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-m-42-q05-p03-ca61ba8f04.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-m-42-q05-p04-eae5e342d2.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-m-42-q05-p05-5b3f1f36d7.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "CHCl 2-Chloropropanoic acid, CH COOH, is used in many chemical syntheses. 5\n3\nCHCl COOH is added to water. An equilibrium is set up when CH (a) (i)\n3\nWrite the equation for this equilibrium.\n....................................................................................................................................... [1]\ncm3 CHCl COOH dissolves in 250 of distilled water to produce a solution 0.150 mol of CH (ii)\n3\nof pH 1.51.\nCHCl of CH COOH. Calculate the pK\na 3\n= .............................. [2] pK\na\nAn equal concentration of aqueous propanoic acid has pH 2.55. (iii)\nCHCl COOH and Explain the difference in the pH of solutions of equal concentration of CH\n3\npropanoic acid.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nCHCl COOH reacts with aqueous NH , alanine forms. When CH (b)\n3 3\nalanine\nCH\n3\nC COOH H N\n2\nH\nFig. 5.1\nAlanine is an amino acid. Its isoelectric point is 6.1.\nState what is meant by isoelectric point. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nGive the structural formula of alanine at pH 2. (ii)\n....................................................................................................................................... [1]\nAlanine exists as a pair of optical isomers. The structure of one optical isomer is shown in (iii)\nFig. 5.2.\nDraw the three-dimensional structure of the other optical isomer of alanine.\noptical isomer 1 optical isomer 2\nCH\n3\nC\nH\nH N\n2\nCOOH\nFig. 5.2\n[1]\nPolymer forms from the reaction between alanine and 4-aminobutanoic acid, (iv) C\nN(CH ) COOH. H\n2 2 3\nDraw a repeat unit of C. The functional group formed should be displayed.\n[2]\nState the type of polymerisation shown in (b)(iv). (v)\n....................................................................................................................................... [1]\nScientists are investigating as a replacement for poly(propene) in packaging. (vi) C\nSuggest an advantage of using instead of poly(propene). C\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCHCl A s", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2022-m-42-q05-31cee7a67f.pdf" }, { "id": "9701-2022-m-42-q06", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_42.pdf?download=true", "source_pages": [ 21, 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p01-f322e570c2.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p02-232e1a5e23.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p03-1b2e3eb17b.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p04-8fb83b3b51.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p05-b61ecdd3cd.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p06-84ad6bf493.png", "9701-topic-37-analytical-techniques/assets/9701-2022-m-42-q06-p07-b676007870.png" ], "answer": { "status": "pending", "id": "9701-2022-m-42-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Lidocaine is used as an anaesthetic. A synthesis of lidocaine is shown in Fig. 6.1. 6\nY W X\nO\nNH\n2\nO\nCl\nHN\n+ Cl\nreaction 1\nCl\nreaction 2 (C H ) NH\n2 5 2\nlidocaine\nO\nN(C H )\n2 5 2\nHN\nFig. 6.1\nSOCl COOH with an excess of . can be formed by reacting HOCH (a) W\n2 2\nWrite an equation for this reaction.\n.............................................................................................................................................. [1]\nCOONa(aq) is added to the reaction After and have reacted together, an excess of CH (b) W X\n3\nmixture.\nSuggest why.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe reaction of with X, reaction 1, follows an addition–elimination mechanism. (c) W\nComplete the mechanism for the reaction of with X. W\nInclude all relevant curly arrows, lone pairs of electrons, charges and partial charges.\nto represent X. Use Ar–NH\n2\nO\nCl\nCl\nAr NH\n2\n[4]\n(CH ) NH reacts with in reaction 2. (d) Y\n2 5 2\nH ) NH can act as a nucleophile. Explain why (C\n2 5 2\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe purity of lidocaine can be checked using thin-layer chromatography. (e)\nEthyl ethanoate is used as the solvent.\nvalues of and lidocaine are given in Table 6.1. T he R X\nf\nTable 6.1\ncompound R\nf\n0.49 X\nlidocaine 0.71\nIdentify the substances used as the mobile and stationary phases in this thin-layer (i)\nchromatography experiment.\nmobile phase ......................................................................................................................\nstationary phase .................................................................................................................\n[1]\nvalue can be calculated. Describe how an R (ii)\nf\n.............................................................................................................................................\n....................................................................................................................................... [1]\nvalue for is less than that for lidocaine. Suggest why the R X (iii)\nf\n.............................................................................................................................................\n....................................................................................................................................... [1]\n(1H) The proton NMR spectrum of lidocaine is shown in Fig. 6.2. (f)\nlidocaine (cid:31)(cid:30)2.3\nO\nN(C H )\n2 5 2\nHN\n(cid:31)(cid:30)3.0\n(cid:31)(cid:30)1.1\n(cid:31)(cid:30)2.6\n(cid:", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2022-m-42-q06-78c14054b6.pdf" }, { "id": "9701-2022-m-52-q01", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_52.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-m-52-q01-p01-930807d750.png", "9701-experimental-skills/assets/9701-2022-m-52-q01-p02-745d16ab0d.png" ], "answer": { "status": "pending", "id": "9701-2022-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "copper(II) A student has a sample of sulfate crystals, CuSO •xH O. The student wants to show that 1\n4 2\nthe value of x is 5.\nThe student uses the following method.\nW eigh a clean crucible on a balance reading to two decimal places. Record the mass. step 1\n•xH O into the crucible. Record the mass. P lace the sample of CuSO step 2\n4 2\nH eat the crucible gently for about 1 minute then strongly for about 4 minutes. step 3\nW eigh the crucible and contents. Record the mass. step 4\nIdentify the instruction that is missing between and 4. (a) step 3 step\n.............................................................................................................................................. [1]\nExplain why gentle heating takes place in 3. (b) step\n.............................................................................................................................................. [1]\nName the apparatus that should be used to hold the crucible during heating. (c)\n.............................................................................................................................................. [1]\nThe method is incomplete. (d)\nS tate the step(s) that should be carried out to complete the method.\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nThe student records their results in Table 1.1. (e)\nTable 1.1\nmass / g\nmass of crucible 13.60\nmass of crucible + contents before heating 21.09\nmass of crucible + contents at the end of experiment 17.94\nCalculate the experimental value of x from these results. (i)\nexperimental value of x = .............................. [3]\nS uggest why the experimental value of x varies from the expected value of 5. (ii)\nIf you were unable to obtain an answer to (e)(i), use the experimental value x = 6.9. This\nis the correct answer. not\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe empty crucible weighs 13.60 g. (f)\nC alculate the percentage error in this measurement.\nS how your working.\npercentage error = .............................. [1]\n[Total: 9]", "pdf_path": "9701-experimental-skills/print/9701-2022-m-52-q01-9be4888cef.pdf" }, { "id": "9701-2022-m-52-q02", "subject": "9701", "year": 2022, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 21, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-feb-march/9701_m22_qp_52.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 11, 12 ], "local_pdf": "_source-pdfs/2022-March/qp/9701_m22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-m-52-q02-p01-018e8979b4.png", "9701-experimental-skills/assets/9701-2022-m-52-q02-p02-d144b308e9.png", "9701-experimental-skills/assets/9701-2022-m-52-q02-p03-ff46c66d8c.png", "9701-experimental-skills/assets/9701-2022-m-52-q02-p04-38cf6522d9.png", "9701-experimental-skills/assets/9701-2022-m-52-q02-p05-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-m-52-q02-p06-d0c2dab4ef.png" ], "answer": { "status": "pending", "id": "9701-2022-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "The conductivity of an ionic solution can be determined by passing an electric current through the 2\nsolution and measuring the conductivity using a conductivity meter.\nA student carries out an experiment to measure the conductivity of different solutions of (a)\nCOOH, which is a weak acid. ethanoic acid, CH\n3\n, can be determined from this experiment. T he acid dissociation constant, K\na\ncm3 dm–3 of 2.00 mol CH COOH(aq). T he student makes standard solution A, 250.0\n3\nState what is meant by a standard solution. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD escribe how the student should make standard solution from pure ethanoic acid. (ii) A\ndm–3 to the nearest The concentration of standard solution should be 2.00 mol three A\nsignificant figures.\nYour answer should state the name and capacity of any apparatus that the student should\nuse. A balance is not available.\ncm–3 at room temperature. Pure ethanoic acid is a liquid with a density of 1.05 g\nYou may wish to write your answer using a series of numbered steps.\n: CH COOH, 60.0] [M\nr 3\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\nThe student wears chemically resistant gloves throughout this procedure. (b)\nSuggest why.\n.............................................................................................................................................. [1]\nThe student dilutes standard solution with distilled water to make solutions of different (c) A\nconcentrations. The conductivity of these solutions is measured.\nT able 2.1 shows the results.\nTabl", "pdf_path": "9701-experimental-skills/print/9701-2022-m-52-q02-5981ce05c3.pdf" }, { "id": "9701-2022-mj-41-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-mj-41-q01-p01-8456dff16b.png", "9701-topic-23-chemical-energetics/assets/9701-2022-mj-41-q01-p02-b4220d1595.png", "9701-topic-23-chemical-energetics/assets/9701-2022-mj-41-q01-p03-0a25f3da34.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "T he solubility of the Group 2 sulfates decreases down the group. 1 (a)\nE xplain this trend.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nDescribe what is observed when magnesium and barium are reacted separately with an (b)\nexcess of dilute sulfuric acid.\nmagnesium ................................................................................................................................\nbarium ........................................................................................................................................\n[1]\n× 10–10 mol2 dm–6 , of BaSO is 1.08 at 298 K. The solubility product, K (c)\nsp 4\ncm3 in g per 100 of solution. C alculate the solubility of BaSO\n4\ncm3 = .............................. g per 100 of solution solubility of BaSO\n4\n[2]\nT he equation for the formation of a gaseous sulfate ion is shown. (d) (i)\n→ ∆H 2e– 2–(g) 2–(g) (g) + SO = of SO S(s) + 2O\n2 4 4\n2–(g). , of SO It may be helpful Calculate the standard enthalpy change of formation,\n4\nto draw a labelled energy cycle. Use relevant data from Table 1.1 in your calculations.\nTable 1.1\nmol–1 energy change value / kJ\nlattice energy of barium sulfate, BaSO (s) –2469\n4\nstandard enthalpy change of formation of barium sulfate –1473\nstandard enthalpy change of atomisation of barium +180\nfirst ionisation energy of barium +503\nsecond ionisation energy of barium +965\nstandard enthalpy change of atomisation of sulfur +279\n→ S2–(g) +440 standard enthalpy change for S(g)\n→ O2–(g) +657 standard enthalpy change for O(g)\nO=O bond energy +496\nmol–1 2–(g) of SO = .............................. kJ [3]\n4\nS uggest how the lattice energy of BaSO (s) differs from the lattice energy of Cs SO (s). (ii)\n4 2 4\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n•8H O, with ammonium salts is The reaction of solid hydrated barium hydroxide, Ba(OH) (e)\n2 2\nendothermic.\n•8H O with NH NO C alculate the temperature at wh", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-mj-41-q01-155131390a.pdf" }, { "id": "9701-2022-mj-41-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 5, 6 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-41-q02-p01-067afd596e.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-41-q02-p02-20f6b98253.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Define transition element. 2 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\norbital. Sketch the shape of a 3d (b)\nz2\nz\ny x\n[1]\nManganese(IV) oxide, MnO , acts as a heterogeneous catalyst in the decomposition of (c)\n2\nO . hydrogen peroxide, H\n2 2\nExplain what is meant by a heterogeneous catalyst. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD escribe the mode of action of a heterogeneous catalyst in a reaction. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nManganese(VII) oxide, Mn O , can be made by treatment of KMnO with concentrated (d)\n2 7 4\nsulfuric acid (reaction 1).\nmanganese(IV) O readily decomposes at room temperature to form oxide and a colourless Mn\n2 7\ndiatomic gas (reaction 2).\nC onstruct equations for the reactions described. both\nreaction 1 ...................................................................................................................................\nreaction 2 ...................................................................................................................................\n[2]\nmanganese(II) copper(II) Aqueous ions show similar chemical properties to aqueous ions (e)\nHCl. when reacted separately with NaOH(aq) and with concentrated\n]2+ O) with Write the ionic equation, and state the type of reaction, for the reaction of [Mn(H (i)\n2 6\nNaOH(aq).\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[2]\n]2+ O) with W rite the ionic equation, and state the type of reaction, for the reaction of [Mn(H (ii)\n2 6\nHCl. concentrated\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[2]\nTabl", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-41-q02-eff4f32c83.pdf" }, { "id": "9701-2022-mj-41-q03", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-mj-41-q03-p01-1451b1272e.png", "9701-topic-24-electrochemistry/assets/9701-2022-mj-41-q03-p02-2fc4613f71.png", "9701-topic-24-electrochemistry/assets/9701-2022-mj-41-q03-p03-7a5e5ffbe7.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "CCl, The rate of reaction between 2-chloro-2-methylpropane, (CH ) and methanol is 3 (a)\n3 3\ninvestigated. When a large excess of methanol is used, the overall reaction is first order.\n→ CCl HCl ) + CH OH (CH ) COCH + (CH\n3 3 3 3 3 3\nF ig. 3.1 shows the results obtained.\n0.0200\n0.0175\n0.0150\n0.0125\nCCl [(CH ) ]\n3 3 0.0100\ndm–3 / mol\n0.0075\n0.0050\n0.0025\n0.0000\n125 150 175 200 0 25 50 75 100\ntime / s\nFig. 3.1\nUse the graph to determine the rate of reaction at 40 s. Show all your working. (i)\ndm–3 s–1 rate = .............................. mol [1]\nU se the graph to show that the overall reaction is first order. Explain your answer. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nIn a different reaction, which is also a first order reaction, 75% of the reactant is consumed in (b)\n320 s.\nC alculate the rate constant, k, for this reaction. State the units for k.\nk = .............................. units = .............................. [2]\no. D efine standard electrode potential, E (c) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nA salt bridge is used in an electrochemical cell. (ii)\nState the function of the salt bridge. Explain your answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\no of the Complete the diagram of the apparatus that can be used to measure the E (iii)\nH+(aq)/Cr3+(aq) 2–(aq), O electrode against the standard hydrogen electrode. Cr\n2 7\nYour diagram should be fully labelled to identify all apparatus, substances and conditions.\nsalt bridge\n[3]\no H+(aq)/Cr3+(aq) 2–(aq), of the Cr O electrode is +1.33 V. The E (iv)\n2 7\nLabel the negative electrode and the direction of electron flow in the external circuit when\nthe current flows in your diagram in (c)(iii). [1]\nTable 3.1 lists relevant electrode potentials for some electrode reactions for use in and (d) (d)(i)\n(d)(ii).\nTable 3.1\no electrode reaction E / V\n14H+ 6e– 2Cr3+ 2– +1.33 O + + + 7H O Cr\n2 7 2\n2H+ 2e– –0.61 CHO + + CH CH OH CH\n3 3 2\n2H+ 2e– –0.94 COOH + + CH CHO + H O CH\n3 3 2\n4H+ 4e– +1.23 + + 2H O O\n", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-mj-41-q03-1836b9652a.pdf" }, { "id": "9701-2022-mj-41-q04", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-41-q04-p01-003ab88d1d.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-41-q04-p02-d119535bc7.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-41-q04-p03-be9cf5f47c.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Fe2+ T he 3d orbitals in an isolated ion are degenerate. 4 (a)\nFe2+ C omplete the diagram to show the splitting of the 3d orbital energy levels in an isolated\nFe2+ forms an octahedral complex. ion and when\nenergy\nFe2+ Fe2+ isolated ion in an octahedral complex\n[2]\nBipyridine, bipy, is a bidentate ligand. (b) (i)\nbipy\nN N\nFig. 4.1\nExplain what is meant by bidentate ligand.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n]2+ T he complex [Fe(bipy) exists as two stereoisomers. (ii)\n3\n]2+. Complete the three-dimensional diagrams to show the two stereoisomers of [Fe(bipy)\n3\nState the type of stereoisomerism shown.\nto represent bipy in your diagrams. Use\nN N\nFe Fe\ntype of stereoisomerism .....................................................................................................\n[3]\nStandard electrode potentials can be used to compare the stability of different complex ions for (c)\na given transition element.\nFe3+ Fe2+ / systems. T able 4.1 lists electrode potentials for some electrode reactions for\nTable 4.1\no electrode reaction E / V\n]3+ e– ]2+ +0.77 O) + [Fe(H O) [Fe(H\n2 6 2 6\n]3– e– ]4– +0.36 + [Fe(CN) [Fe(CN)\n6 6\n]3+ e– ]2+ +0.96 + [Fe(bipy) [Fe(bipy)\n3 3\niron(III) complex is hardest to reduce. U se relevant data from Table 4.1 to state which\nE xplain your choice.\niron(III) complex ...........................................\nexplanation ................................................................................................................................\n....................................................................................................................................................\n[1]\nThe ligand bipyridine consists of two pyridine rings. (d)\nH N, and benzene, C H , have similar planar, cyclic structures. P yridine, C\n5 5 6 6\npyridine\nN\nFig. 4.2\nB y reference to the hybridisation of the carbon atoms and the nitrogen atom, and orbital\nσ π overlap, suggest how the and bonds are formed in a pyridine molecule.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-41-q04-bcaa9b543b.pdf" }, { "id": "9701-2022-mj-41-q05", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-41-q05-p01-d31b585a47.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-41-q05-p02-1d5d0b7f60.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-41-q05-p03-4653bb3712.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q05", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "C ompare the relative acidities of benzoic acid (C H COOH), phenylmethanol (C H CH OH), 5 (a)\n6 5 6 5 2\nH OH). and phenol (C\n6 5\nE xplain your reasoning.\n........................................... > ........................................... > ...........................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\nA series of nine separate experiments is carried out as shown in Table 5.1. (b)\n(✓) C omplete the table by placing a tick in the relevant box if a reaction occurs. Place a\n(✗) cross in the box if no reaction occurs.\nTable 5.1\nbenzoic acid phenylmethanol phenol\nNa(s)\nNaOH(aq)\nNa CO (aq)\n2 3\n[3]\nCOCl, B enzoyl chloride, C H can be synthesised by the reaction of benzoic acid with (c) (i)\n6 5\nSOCl PCl or . either\n5 2\nComplete the equations for these reactions.\n→ PCl COCl H COOH + C H + ........................ + ........................ reaction 1 C\n6 5 5 6 5\n→ SOCl COCl H COOH + C H + ........................ + ........................ reaction 2 C\n6 5 2 6 5\n[1]\nCOCl H U se your answer to to suggest why it is easier to isolate, in a pure form, the C (ii) (c)(i)\n6 5\nfrom reaction 2 compared to reaction 1.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nBenzoyl chloride is hydrolysed by water at room temperature to form benzoic acid. (d)\nCOCl H and Complete the diagram to show the mechanism for the reaction between C (i)\n6 5\nO. H\n2\nInclude charges, dipoles, lone pairs of electrons and curly arrows as appropriate.\nO\nC products\nCl\nH O\n2\n[4]\nN ame the type of mechanism you showed in (d)(i). (ii)\n....................................................................................................................................... [1]\nAcyl chlorides react with sodium carboxylates to form acid anhydrides as shown in Fig. 5.1. (e)\nacyl chloride sodium carboxylate acid anhydride\nO O O O\nNaCl + +\nC C C C\nCl R R' ONa R O R'\nFig. 5.1\nT he condensation polymers, polyanhydride and polyester, are formed by similar methods.\nT he repeat unit for a polyanhydride is shown in Fig. 5.2.\npolyanhydri", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2022-mj-41-q05-f2b690e209.pdf" }, { "id": "9701-2022-mj-41-q06", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 16, 17, 18, 19 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-41-q06-p01-a81281f955.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-41-q06-p02-50a2f16757.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-41-q06-p03-10bbc687dd.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-41-q06-p04-64bd07cbb2.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q06", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Describe what is meant by a racemic mixture. 6 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nAsparagine is an amino acid that contains a chiral carbon atom and displays stereoisomerism. (b)\nCDCl and analysed using carbon-13 and S eparate samples of asparagine are dissolved in\n3\n(1H) NMR spectroscopy. proton\nasparagine\nO\nC H N CH\n2 2\nC C OH\nH NH\nO 2\nFig. 6.1\n(1H) NMR spectra of asparagine. P redict the number of peaks seen in the carbon-13 and proton\n(1H) carbon-13 NMR proton NMR\nnumber of peaks\n[1]\nThe isoelectric point of asparagine, asn, is at pH 5.4. (c)\nDescribe the meaning of the term isoelectric point. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD raw the structure of asparagine at pH 1.0. (ii)\n[1]\nAsparagine can polymerise to form poly(asparagine). (d)\nD raw the structure of poly(asparagine), showing repeat units. The peptide linkage should two\nbe shown displayed.\n[2]\nThe isoelectric point of lysine, lys, is at pH 9.8. (e)\nlysine\nNH\n2\n(CH )\n2 4\nH N C COOH\n2\nH\nFig. 6.2\nA mixture of the dipeptide lys-asn and its two constituent amino acids, asparagine and lysine,\nis analysed by electrophoresis using a buffer at pH 5.0. The results obtained are shown in\nFig. 6.3.\nmixture applied here E F G\n– +\nFig. 6.3\nS uggest identities for the species responsible for spots E, and G. Explain your answers. F\nspot identity\nE\nF\nG\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\nThin-layer and gas-liquid chromatography can be used to analyse mixtures of substances. (f)\nE ach type of chromatography makes use of a stationary phase and a mobile phase.\nComplete Table 6.1 with an example of each of these. (i)\nTable 6.1\nstationary phase mobile phase\nthin-layer chromatography\ngas-liquid chromatography\n[1]\nA n unknown amino acid is analysed using thin-layer chromatography. Two chromatographs (ii)\nof the unknown amino acid and four reference amino acids, P, Q, and S, are obtained R\nusing two different solvents.\n5\n4\n3\n2\n1\ncm\n0\nP Q R S P Q R S\nunknown unknown\namino acid amino acid\nsolvent 1 solvent 2\nFig. 6.4\nIdentify the unknown amino acid. Justify your answer.\n.............................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-mj-41-q06-0a889d59ce.pdf" }, { "id": "9701-2022-mj-41-q07", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_41.pdf?download=true", "source_pages": [ 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2022-mj-41-q07-p01-d8f9455430.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-41-q07-p02-0d9ee6c76b.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-41-q07-p03-84ad6bf493.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-41-q07-p04-62e1bb3019.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-41-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Procaine is used as an anaesthetic in medicine. It can be synthesised from methylbenzene in 7\nfive steps as shown in Fig. 7.1.\nmethylbenzene X\nCOCl CH COOH\n3\nsteps 1 and 2 step 3\nSOCl\n2\nNO NO\n2 2\nstep 4\nprocaine\nCH N(CH CH ) CH N(CH CH ) O O CH O O CH\n2 2 2 3 2 2 2 2 3 2\nC C\nstep 5\nNH NO\n2 2\nFig. 7.1\nN ame all the functional groups present in procaine. (a) (i)\n....................................................................................................................................... [1]\nA molecule of procaine has 13 carbon atoms. (ii)\nsp2 sp3 and hybridised in procaine. State the number of carbon atoms that are sp,\nsp2 sp3 carbons = ..................... carbons = ..................... [1] sp carbons = .....................\n(1H) The proton NMR spectrum of procaine dissolved in D O is recorded. (b)\n2\nP redict the number of peaks observed.\n.............................................................................................................................................. [1]\nState why procaine can act as a base. (c)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nCompound can be synthesised in two steps from methylbenzene. (d) X\nW\nmethylbenzene X\nCH COOH\n3\nstep 1 step 2\nNO\n2\nFig. 7.2\nDraw the structure of compound in the box provided. [1] (i) W\nS tate the reagents and conditions for step 1 and step 2. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nProcaine is synthesised in three steps from X. (e)\nS uggest the reagents and conditions for step 4 and for step 5 in Fig. 7.1.\nstep 4 .........................................................................................................................................\nstep 5 .........................................................................................................................................\n[3]\n. E xplain what is meant by partition coefficient, K (f) (i)\npc\n.............................................................................................................................................\n....................................................................................................................................... [2]\nT he partition coefficient of procaine between octan-1-ol and water is 1.77. (ii)\ncm3 Octan-1-ol and water are immiscible. A solution containing 0.500 g of procaine in 75.0\ncm3 of octan-1-ol. of water is shaken with 50.0\nCalculate the mass of procaine that is extracted into the octan-1-ol.\nmass of procaine extracted = .............................. g [2]\n[T", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2022-mj-41-q07-03eb65cc2a.pdf" }, { "id": "9701-2022-mj-42-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-42-q01-p01-ce6dea287c.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-42-q01-p02-642f582128.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "T he solubility of the Group 2 hydroxides increases down the group. 1 (a)\nE xplain this trend.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\n× 10–6 dm–3 in water is 2.40 g at 298 K. The solubility of Be(OH) (b)\n2\n, of Be(OH) and state its units. Write an expression for the solubility product, K (i)\nsp 2\n= K\nsp\nunits = ..............................\n[2]\nfor Be(OH) at 298 K. C alculate the numerical value of K (ii)\nsp 2\n= .............................. [2] K\nsp\nBe(OH) is soluble in aqueous solutions containing an excess of hydroxide ions and forms the (c)\n2\n]2–. ]2–. [CuCl This complex ion has a similar shape to that of complex ion [Be(OH)\n4 4\nDefine the term complex ion. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2–. D raw a three-dimensional diagram to show the structure of the complex ion [Be(OH) (ii)\n4\n]2– complex ion. Name the shape of the [Be(OH)\n4\nshape ..................................................................................................................................\n[1]\nE xplain why transition elements can form complex ions. (d) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nC omplete Table 1.1 to show the coordination number of each metal ion, and the shapes (ii)\nand overall polarities of the complex ions listed.\nTable 1.1\ncoordination polar or\ncomplex ion shape\nnumber non-polar\n)Cl NCH CH NH ] square planar cis-[Pt(H\n2 2 2 2 2\n]+ ) non-polar [Ag(NH\n3 2\n]3– O ) 6 [Fe(C\n2 4 3\n[2]\n. Define stability constant, K (e) (i)\nstab\n.............................................................................................................................................\n....................................................................................................................................... [1]\nNCH CH NH , and tn, H NCH CH CH NH , N ickel can form complexes with t", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-42-q01-1f3cc53e34.pdf" }, { "id": "9701-2022-mj-42-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-42-q02-p01-ba885dbe11.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-42-q02-p02-460ca54174.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "E xplain why transition elements have variable oxidation states. 2 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\norbital. Sketch the shape of a 3d (b)\nxy\nz\ny x\n[1]\nExplain why transition elements form coloured compounds. (c)\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\ncopper(II) ]2+ Aqueous solutions of salts contain [Cu(H O) ions. (d)\n2 6\nE quilibrium and equilibrium show two reactions of these ions. 3 4\n]2+(aq) 2OH–(aq) O) + Cu(OH) (s) + 6H O(l) equilibrium [Cu(H 3\n2 6 2 2\n]2+(aq) ]2+(aq) O) + 4NH (aq) [Cu(NH ) (H O) + 4H O(l) equilibrium [Cu(H 4\n2 6 3 3 4 2 2 2\n]2+(aq). (s) and [Cu(NH ) (H O) State the colour of Cu(OH) (i)\n2 3 4 2 2\n(s) ........................................................................................................... colour of Cu(OH)\n2\n]2+(aq) ) (H O) ......................................................................................... colour of [Cu(NH\n3 4 2 2\n[1]\nU se Le Chatelier’s principle to explain why a precipitate is formed when NaOH(aq) is (ii)\n]2+(aq). O) added dropwise to [Cu(H\n2 6\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+. ) (H O) There are two possible stereoisomers with the formula [Cu(NH (e)\n3 4 2 2\nD raw three-dimensional diagrams to show the two stereoisomers.\nCu Cu\n[2]\n[Total: 9]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-42-q02-6875d60188.pdf" }, { "id": "9701-2022-mj-42-q03", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-mj-42-q03-p01-02a6d20c9e.png", "9701-topic-23-chemical-energetics/assets/9701-2022-mj-42-q03-p02-be1c972ddf.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Define first electron affinity. 3 (a) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nThe first electron affinity of an atom is usually an exothermic process, whereas the second (ii)\nelectron affinity is an endothermic process.\nSuggest why.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nI. Cl, Describe the general trend in first electron affinities for Br and Explain your answer. (iii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nTable 3.1 shows energy changes to be used in this question and in (c). (b)\nTable 3.1\nmol–1 energy change value / kJ\nstandard enthalpy change of atomisation of zinc +131\nfirst ionisation energy of zinc +906\nsecond ionisation energy of zinc +1733\nZnI –208 (s) standard enthalpy change of formation of\n2\nZnI –2605 , of zinc iodide, (s) lattice energy,\n2\nfirst ionisation energy of iodine +1008\nsecond ionisation energy of iodine +1846\nI–I +151 bond energy\n→ I I +62 (s) (g) enthalpy change of sublimation of iodine,\n2 2\nCalculate the first electron affinity for iodine. Use relevant data from Table 3.1 in your working.\nI t may be helpful to draw a labelled energy cycle.\nS how all working.\nmol–1 [3] first electron affinity for iodine = .............................. kJ\nCdI ZnI Predict how of (s) differs from of (s). (c)\n2 2\n(✓) P lace a tick in the appropriate box in Table 3.2.\nTable 3.2\nCdI CdI CdI of (s) is less of (s) is the of (s) is more\n2 2 2\nZnI ZnI ZnI of (s) of (s) of (s) negative than same as negative than\n2 2 2\nE xplain your answer.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\n[Total: 9]", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-mj-42-q03-c260fb7951.pdf" }, { "id": "9701-2022-mj-42-q04", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2022-mj-42-q04-p01-93ae258530.png", "9701-topic-25-equilibria/assets/9701-2022-mj-42-q04-p02-f0ce20300d.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q04", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "C alcium carbonate decomposes on heating. 4 (a)\n→ (s) CaO(s) + CO (g) CaCO\n3 2\n∆G o, for this reaction at various T able 4.1 shows the values of the Gibbs free energy change,\ntemperatures.\nTable 4.1\n∆G o mol–1 T / K / kJ\n1050 9.9\n1085 4.3\n1120 –1.3\n1148 –5.8\n1176 –10.3\n∆S ∆H o, o, and the standard entropy change, for this A ssume the standard enthalpy change,\nreaction remain constant over this temperature range.\n∆G o against T on the grid. Use the data in Table 4.1 to plot a graph of (i)\n12.5\n10.0\n7.5\n5.0\n2.5 (cid:31)Go mol–1 / kJ\n/ K T 0.0\n1040 1060 1080 1100 1120 1140 1160 1180 1200\n–2.5\n–5.0\n–7.5\n–10.0\n–12.5\n[2]\n∆S o K–1 mol–1 in J for this reaction. C alculate the gradient of your graph. Determine the (ii)\nShow all working.\n\b ∆S o K–1 mol–1 = .............................. J [2]\nGroup 1 hydrogencarbonates, MHCO , decompose on gentle heating to give the corresponding (b)\n3\nmetal carbonate, carbon dioxide and water vapour.\nWrite an ionic equation for the decomposition of the hydrogencarbonate ion. (i)\n....................................................................................................................................... [1]\nT he thermal stability of Group 1 hydrogencarbonates increases down the group. (ii)\nSuggest an explanation for the trend in thermal stability of the Group 1 hydrogencarbonates.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n– and H CO . The buffer system in seawater contains a mixture of HCO (c)\n3 2 3\nO+ – CO + H O HCO + H equilibrium H 5\n2 3 2 3 3\nDefine a buffer solution. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nConstruct equations to show how equilibrium acts as a buffer solution. (ii) two 5\n.............................................................................................................................................\n....................................................................................................................................... [2]\n–] / [H CO ] ratio in a sample of seawater is 14.1. The [HCO (iii)\n3 2 3\nCalculate the pH of this sample.\n: H CO , 6.35] [pK\na 2 3\npH = .................", "pdf_path": "9701-topic-25-equilibria/print/9701-2022-mj-42-q04-b0fcb99032.pdf" }, { "id": "9701-2022-mj-42-q05", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 10 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-mj-42-q05-p01-16f0be7597.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q05", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Complete Table 5.1 to predict the substance liberated at each electrode during electrolysis of 5 (a)\nthe indicated electrolyte with inert electrodes.\nTable 5.1\nsubstance liberated substance liberated\nelectrolyte\nat the anode at the cathode\n(l) PbBr\n2\nNaCl concentrated (aq)\n) (aq) Cu(NO\n3 2\n[3]\nAn electrolytic cell is set up to determine a value for the Avogadro constant, L. The electrolyte (b)\nis dilute sulfuric acid and both electrodes are copper.\nW hen a current of 0.600 A is passed through the acid for 30.0 minutes, the anode decreases\nin mass by 0.350 g.\nState the relationship between the Faraday constant, F, and the Avogadro constant, L. (i)\n....................................................................................................................................... [1]\nU se the experimental information in and data from the table on page 23 to calculate a (ii) (b)\nvalue for the Avogadro constant, L.\nShow all working.\nAvogadro constant, L = .............................. [4]\n[Total: 8]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-mj-42-q05-2df2b93dcc.pdf" }, { "id": "9701-2022-mj-42-q06", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 11, 12, 13 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2022-mj-42-q06-p01-2c3d3bce26.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-42-q06-p02-a175c0e236.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-42-q06-p03-69b66415c4.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q06", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "T he reagent and conditions required for the nitration of benzene, benzoic acid and phenol are 6 (a)\nshown in Table 6.1.\nTable 6.1\ncompound reagents and conditions for nitration\n°C, , 50 concentrated H SO catalyst benzene concentrated HNO\n3 2 4\n°C, , 100 concentrated H SO catalyst benzoic acid concentrated HNO\n3 2 4\n°C (aq), 20 phenol dilute HNO\n3\n+. reacts with concentrated H SO to generate the electrophile NO C oncentrated HNO\n3 2 4 2\n+. Complete Fig. 6.1 to show the mechanism of the reaction between benzene and NO (i)\n2\nInclude all relevant curly arrows and charges.\n+ NO\n2\nFig. 6.1\n[3]\nSO is regenerated. W rite an equation to show how H (ii)\n2 4\n....................................................................................................................................... [1]\nDraw the major products from the mononitration of benzoic acid and of phenol. (b)\nmajor product from benzoic acid major product from phenol\n[2]\nCompare the relative ease of nitration of benzene, benzoic acid and phenol. (c)\nE xplain your reasoning; include reference to the structures of the three compounds in your\nanswer.\n............................................... > ............................................... > ..............................................\neasiest least easy\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[4]\nThe azo compound Congo Red is used as an acid–base indicator and can be made by the (d)\nroute shown in Fig. 6.2.\nI n step 3 of this synthesis, compound reacts with compound Z. Compound is made from Y Z\nNa+ – compound X. Assume that the –SO groups do not react.\n3\nC H N X\n12 12 2\nstep 1\nO N NO\n2 2\nstep 2\nC H NO SNa Y Z\n10 8 3\n+\nNaOH(aq) step 3\nCongo Red\nNH\n2\nNa+ – N SO\n3\nN N\n– Na+ N SO\n3\nNH\n2\nFig. 6.2\nSuggest structures for compounds X, and and draw them in the boxes in Fig. 6.2. [3] (i) Y Z\nG ive the reagents and conditions for step 1 and step 2. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[3]\n[Total: 16]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2022-mj-42-q06-14a215e355.pdf" }, { "id": "9701-2022-mj-42-q07", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2022-mj-42-q07-p01-6b41285c41.png", "9701-topic-37-analytical-techniques/assets/9701-2022-mj-42-q07-p02-ce5b7b33a8.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q07", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "S tate the uses of TMS and D O in NMR spectroscopy. 7 (a)\n2\nTMS ...........................................................................................................................................\nO ............................................................................................................................................ D\n2\n[1]\nThe three isomeric ketones with molecular formula C H O are: (b)\n5 10\n● pentan-2-one\n● pentan-3-one\n● 3-methylbutanone.\n(1H) NMR Complete Table 7.1 to show the number of peaks observed in the proton (i)\nspectrum and in the carbon-13 NMR spectrum for each compound listed.\nTable 7.1\nnumber of peaks observed in number of peaks observed in\nketone\n(1H) NMR spectrum the carbon-13 NMR spectrum the proton\npentan-2-one\npentan-3-one\n3-methylbutanone\n[2]\nH O that have: State the ketones with molecular formula C (ii) all\n5 10\n(1H) NMR spectrum a doublet in their proton\n.............................................................................................................................................\n(1H) NMR spectrum. a singlet in their proton\n.............................................................................................................................................\n[2]\nCortisone, C H O , is a naturally occurring chemical that contains chiral carbon atoms. (c)\n21 28 5\ncortisone\nOH\nO\nCH\n3\nO OH\nCH\n3\nO\nFig. 7.1\nDeduce the number of chiral carbon atoms in one molecule of cortisone. (i)\n....................................................................................................................................... [1]\n. C ortisone is reacted with an excess of NaBH (ii)\n4\nState the molecular formula of the organic compound formed.\n....................................................................................................................................... [1]\nCortisone is an optically active molecule. (iii)\nExplain what is meant by optically active.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 8]", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2022-mj-42-q07-7fa54592ab.pdf" }, { "id": "9701-2022-mj-42-q08", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2022-mj-42-q08-p01-cfc0007a39.png", "9701-topic-35-polymerisation/assets/9701-2022-mj-42-q08-p02-d8222fc535.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q08", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "Compare the relative acidities of ethanol, ethanoic acid, chloroethanoic acid and phenol. 8 (a)\nE xplain your reasoning.\n.................................. > .................................. > .................................. > ..................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[4]\n(aq). An excess of ethanedioic acid, HOOCCOOH(aq), is reacted with warm acidified KMnO (b)\n4\nS tate the type of reaction undergone by ethanedioic acid.\nD escribe what you would observe.\nW rite an equation for this reaction.\nY our equation can use [O] or [H] as necessary.\ntype of reaction ..........................................................................................................................\nobservations ..............................................................................................................................\nequation .....................................................................................................................................\n[2]\nA section of a polyester is shown. (c)\npolyester\nO O O O\nO CH C O CH C O CH C O CH C\n2 2\nCH CH\n3 3\nFig. 8.1\nD raw the structures of the two monomers that form this polyester.\n[2]\nSerine can polymerise to form two different types of condensation polymer; a polyester and a (d)\npolypeptide.\nserine\nOH\nH C\nO 2\nH N C C\n2\nOH\nH\nFig. 8.2\nD raw the structure of the polypeptide showing repeat units. The peptide linkage should be two\nshown displayed.\n[2]\nExplain why condensation polymers normally biodegrade more readily than addition polymers. (e)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\n[Total: 11]", "pdf_path": "9701-topic-35-polymerisation/print/9701-2022-mj-42-q08-2610e493a7.pdf" }, { "id": "9701-2022-mj-42-q09", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_42.pdf?download=true", "source_pages": [ 18, 19, 23, 24 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-42-q09-p01-fea3ff2449.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-42-q09-p02-771d137b75.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-42-q09-p03-84ad6bf493.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-42-q09-p04-b676007870.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "The structure of cyclohexylamine is shown in Fig. 9.1. 9\ncyclohexylamine\nNH\n2\nFig. 9.1\nCompare the relative basicities of ammonia, cyclohexylamine and phenylamine. (a)\nE xplain your reasoning.\n............................................... > ............................................... > ..............................................\nmost basic least basic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\nCyclohexylamine reacts with ethanoyl chloride to form the corresponding amide, L. (b)\nL\nO\nC\nCH NH HN\n2 3\nCOCl CH\n3\nFig. 9.2\nName the mechanism for the reaction shown in Fig. 9.2. (i)\n....................................................................................................................................... [1]\nCOCl. C omplete the mechanism of the reaction between cyclohexylamine and CH (ii)\n3\nis used to represent cyclohexylamine. R–NH\n2\nInclude all relevant lone pairs of electrons, curly arrows, charges and partial charges.\nO\nH C C products\n3\nCl\nR NH\n2\n[4]\nCOCl forms compound M. The reaction between cyclohexylamine and an excess of CH (iii)\n3\nH NO . Compound has the molecular formula C M\n10 17 2\nSuggest and draw the structure of M.\n[1]\n[Total: 9]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n× 104 mol–1 Faraday constant F = 9.65 C\n× 1023 mol–1 Avogadro constant L = 6.022\n× 10–19 electronic charge e = –1.60 C\ndm3 mol–1 molar volume of gas V = 22.4 at s.t.p. (101 kPa and 273 K)\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n× °C)) 10–14 mol2 dm–6 ionic product of water K = 1.00 (at 298 K (25\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eH eN nR eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nmuicnerwal enissennet enimorb enirolhc enitatsa muitetul eniroulf 9.621 0.571 enidoi 0.91 5.53 9.97 uL 71 lC 301 sT rB 711 tA rL 71 53 35 58 17 F I – – – 9\nmuiromrevil muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib cinesra muiluht 8.121 0.902 9.861 mT dM cM bS 0.41 0.13 9.47 sA 51 101 511 iB N P 51 33 15 38 96 – – 7\nmuinamreg muivorelf muimref nobrac muibre 2.702 3.761 7.811 mF nocilis ", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-mj-42-q09-9b559cf5f0.pdf" }, { "id": "9701-2022-mj-43-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-mj-43-q01-p01-8456dff16b.png", "9701-topic-23-chemical-energetics/assets/9701-2022-mj-43-q01-p02-b4220d1595.png", "9701-topic-23-chemical-energetics/assets/9701-2022-mj-43-q01-p03-0a25f3da34.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "T he solubility of the Group 2 sulfates decreases down the group. 1 (a)\nE xplain this trend.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nDescribe what is observed when magnesium and barium are reacted separately with an (b)\nexcess of dilute sulfuric acid.\nmagnesium ................................................................................................................................\nbarium ........................................................................................................................................\n[1]\n× 10–10 mol2 dm–6 , of BaSO is 1.08 at 298 K. The solubility product, K (c)\nsp 4\ncm3 in g per 100 of solution. C alculate the solubility of BaSO\n4\ncm3 = .............................. g per 100 of solution solubility of BaSO\n4\n[2]\nT he equation for the formation of a gaseous sulfate ion is shown. (d) (i)\n→ ∆H 2e– 2–(g) 2–(g) (g) + SO = of SO S(s) + 2O\n2 4 4\n2–(g). , of SO It may be helpful Calculate the standard enthalpy change of formation,\n4\nto draw a labelled energy cycle. Use relevant data from Table 1.1 in your calculations.\nTable 1.1\nmol–1 energy change value / kJ\nlattice energy of barium sulfate, BaSO (s) –2469\n4\nstandard enthalpy change of formation of barium sulfate –1473\nstandard enthalpy change of atomisation of barium +180\nfirst ionisation energy of barium +503\nsecond ionisation energy of barium +965\nstandard enthalpy change of atomisation of sulfur +279\n→ S2–(g) +440 standard enthalpy change for S(g)\n→ O2–(g) +657 standard enthalpy change for O(g)\nO=O bond energy +496\nmol–1 2–(g) of SO = .............................. kJ [3]\n4\nS uggest how the lattice energy of BaSO (s) differs from the lattice energy of Cs SO (s). (ii)\n4 2 4\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n•8H O, with ammonium salts is The reaction of solid hydrated barium hydroxide, Ba(OH) (e)\n2 2\nendothermic.\n•8H O with NH NO C alculate the temperature at wh", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-mj-43-q01-9e3629f5ef.pdf" }, { "id": "9701-2022-mj-43-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 5, 6 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-43-q02-p01-067afd596e.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-43-q02-p02-20f6b98253.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Define transition element. 2 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\norbital. Sketch the shape of a 3d (b)\nz2\nz\ny x\n[1]\nManganese(IV) oxide, MnO , acts as a heterogeneous catalyst in the decomposition of (c)\n2\nO . hydrogen peroxide, H\n2 2\nExplain what is meant by a heterogeneous catalyst. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD escribe the mode of action of a heterogeneous catalyst in a reaction. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nManganese(VII) oxide, Mn O , can be made by treatment of KMnO with concentrated (d)\n2 7 4\nsulfuric acid (reaction 1).\nmanganese(IV) O readily decomposes at room temperature to form oxide and a colourless Mn\n2 7\ndiatomic gas (reaction 2).\nC onstruct equations for the reactions described. both\nreaction 1 ...................................................................................................................................\nreaction 2 ...................................................................................................................................\n[2]\nmanganese(II) copper(II) Aqueous ions show similar chemical properties to aqueous ions (e)\nHCl. when reacted separately with NaOH(aq) and with concentrated\n]2+ O) with Write the ionic equation, and state the type of reaction, for the reaction of [Mn(H (i)\n2 6\nNaOH(aq).\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[2]\n]2+ O) with W rite the ionic equation, and state the type of reaction, for the reaction of [Mn(H (ii)\n2 6\nHCl. concentrated\nionic equation .....................................................................................................................\ntype of reaction ...................................................................................................................\n[2]\nTabl", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-43-q02-8c3f4e233a.pdf" }, { "id": "9701-2022-mj-43-q03", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-mj-43-q03-p01-1451b1272e.png", "9701-topic-24-electrochemistry/assets/9701-2022-mj-43-q03-p02-2fc4613f71.png", "9701-topic-24-electrochemistry/assets/9701-2022-mj-43-q03-p03-7a5e5ffbe7.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "CCl, The rate of reaction between 2-chloro-2-methylpropane, (CH ) and methanol is 3 (a)\n3 3\ninvestigated. When a large excess of methanol is used, the overall reaction is first order.\n→ CCl HCl ) + CH OH (CH ) COCH + (CH\n3 3 3 3 3 3\nF ig. 3.1 shows the results obtained.\n0.0200\n0.0175\n0.0150\n0.0125\nCCl [(CH ) ]\n3 3 0.0100\ndm–3 / mol\n0.0075\n0.0050\n0.0025\n0.0000\n125 150 175 200 0 25 50 75 100\ntime / s\nFig. 3.1\nUse the graph to determine the rate of reaction at 40 s. Show all your working. (i)\ndm–3 s–1 rate = .............................. mol [1]\nU se the graph to show that the overall reaction is first order. Explain your answer. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nIn a different reaction, which is also a first order reaction, 75% of the reactant is consumed in (b)\n320 s.\nC alculate the rate constant, k, for this reaction. State the units for k.\nk = .............................. units = .............................. [2]\no. D efine standard electrode potential, E (c) (i)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nA salt bridge is used in an electrochemical cell. (ii)\nState the function of the salt bridge. Explain your answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\no of the Complete the diagram of the apparatus that can be used to measure the E (iii)\nH+(aq)/Cr3+(aq) 2–(aq), O electrode against the standard hydrogen electrode. Cr\n2 7\nYour diagram should be fully labelled to identify all apparatus, substances and conditions.\nsalt bridge\n[3]\no H+(aq)/Cr3+(aq) 2–(aq), of the Cr O electrode is +1.33 V. The E (iv)\n2 7\nLabel the negative electrode and the direction of electron flow in the external circuit when\nthe current flows in your diagram in (c)(iii). [1]\nTable 3.1 lists relevant electrode potentials for some electrode reactions for use in and (d) (d)(i)\n(d)(ii).\nTable 3.1\no electrode reaction E / V\n14H+ 6e– 2Cr3+ 2– +1.33 O + + + 7H O Cr\n2 7 2\n2H+ 2e– –0.61 CHO + + CH CH OH CH\n3 3 2\n2H+ 2e– –0.94 COOH + + CH CHO + H O CH\n3 3 2\n4H+ 4e– +1.23 + + 2H O O\n", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-mj-43-q03-6ad93f3270.pdf" }, { "id": "9701-2022-mj-43-q04", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-43-q04-p01-003ab88d1d.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-43-q04-p02-d119535bc7.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-mj-43-q04-p03-be9cf5f47c.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Fe2+ T he 3d orbitals in an isolated ion are degenerate. 4 (a)\nFe2+ C omplete the diagram to show the splitting of the 3d orbital energy levels in an isolated\nFe2+ forms an octahedral complex. ion and when\nenergy\nFe2+ Fe2+ isolated ion in an octahedral complex\n[2]\nBipyridine, bipy, is a bidentate ligand. (b) (i)\nbipy\nN N\nFig. 4.1\nExplain what is meant by bidentate ligand.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\n]2+ T he complex [Fe(bipy) exists as two stereoisomers. (ii)\n3\n]2+. Complete the three-dimensional diagrams to show the two stereoisomers of [Fe(bipy)\n3\nState the type of stereoisomerism shown.\nto represent bipy in your diagrams. Use\nN N\nFe Fe\ntype of stereoisomerism .....................................................................................................\n[3]\nStandard electrode potentials can be used to compare the stability of different complex ions for (c)\na given transition element.\nFe3+ Fe2+ / systems. T able 4.1 lists electrode potentials for some electrode reactions for\nTable 4.1\no electrode reaction E / V\n]3+ e– ]2+ +0.77 O) + [Fe(H O) [Fe(H\n2 6 2 6\n]3– e– ]4– +0.36 + [Fe(CN) [Fe(CN)\n6 6\n]3+ e– ]2+ +0.96 + [Fe(bipy) [Fe(bipy)\n3 3\niron(III) complex is hardest to reduce. U se relevant data from Table 4.1 to state which\nE xplain your choice.\niron(III) complex ...........................................\nexplanation ................................................................................................................................\n....................................................................................................................................................\n[1]\nThe ligand bipyridine consists of two pyridine rings. (d)\nH N, and benzene, C H , have similar planar, cyclic structures. P yridine, C\n5 5 6 6\npyridine\nN\nFig. 4.2\nB y reference to the hybridisation of the carbon atoms and the nitrogen atom, and orbital\nσ π overlap, suggest how the and bonds are formed in a pyridine molecule.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-mj-43-q04-39318f4ea1.pdf" }, { "id": "9701-2022-mj-43-q05", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-43-q05-p01-d31b585a47.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-43-q05-p02-1d5d0b7f60.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2022-mj-43-q05-p03-4653bb3712.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q05", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "C ompare the relative acidities of benzoic acid (C H COOH), phenylmethanol (C H CH OH), 5 (a)\n6 5 6 5 2\nH OH). and phenol (C\n6 5\nE xplain your reasoning.\n........................................... > ........................................... > ...........................................\nmost acidic least acidic\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\nA series of nine separate experiments is carried out as shown in Table 5.1. (b)\n(✓) C omplete the table by placing a tick in the relevant box if a reaction occurs. Place a\n(✗) cross in the box if no reaction occurs.\nTable 5.1\nbenzoic acid phenylmethanol phenol\nNa(s)\nNaOH(aq)\nNa CO (aq)\n2 3\n[3]\nCOCl, B enzoyl chloride, C H can be synthesised by the reaction of benzoic acid with (c) (i)\n6 5\nSOCl PCl or . either\n5 2\nComplete the equations for these reactions.\n→ PCl COCl H COOH + C H + ........................ + ........................ reaction 1 C\n6 5 5 6 5\n→ SOCl COCl H COOH + C H + ........................ + ........................ reaction 2 C\n6 5 2 6 5\n[1]\nCOCl H U se your answer to to suggest why it is easier to isolate, in a pure form, the C (ii) (c)(i)\n6 5\nfrom reaction 2 compared to reaction 1.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nBenzoyl chloride is hydrolysed by water at room temperature to form benzoic acid. (d)\nCOCl H and Complete the diagram to show the mechanism for the reaction between C (i)\n6 5\nO. H\n2\nInclude charges, dipoles, lone pairs of electrons and curly arrows as appropriate.\nO\nC products\nCl\nH O\n2\n[4]\nN ame the type of mechanism you showed in (d)(i). (ii)\n....................................................................................................................................... [1]\nAcyl chlorides react with sodium carboxylates to form acid anhydrides as shown in Fig. 5.1. (e)\nacyl chloride sodium carboxylate acid anhydride\nO O O O\nNaCl + +\nC C C C\nCl R R' ONa R O R'\nFig. 5.1\nT he condensation polymers, polyanhydride and polyester, are formed by similar methods.\nT he repeat unit for a polyanhydride is shown in Fig. 5.2.\npolyanhydri", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2022-mj-43-q05-89ed64f968.pdf" }, { "id": "9701-2022-mj-43-q06", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 16, 17, 18, 19 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-43-q06-p01-a81281f955.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-43-q06-p02-50a2f16757.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-43-q06-p03-10bbc687dd.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-mj-43-q06-p04-64bd07cbb2.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q06", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Describe what is meant by a racemic mixture. 6 (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nAsparagine is an amino acid that contains a chiral carbon atom and displays stereoisomerism. (b)\nCDCl and analysed using carbon-13 and S eparate samples of asparagine are dissolved in\n3\n(1H) NMR spectroscopy. proton\nasparagine\nO\nC H N CH\n2 2\nC C OH\nH NH\nO 2\nFig. 6.1\n(1H) NMR spectra of asparagine. P redict the number of peaks seen in the carbon-13 and proton\n(1H) carbon-13 NMR proton NMR\nnumber of peaks\n[1]\nThe isoelectric point of asparagine, asn, is at pH 5.4. (c)\nDescribe the meaning of the term isoelectric point. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nD raw the structure of asparagine at pH 1.0. (ii)\n[1]\nAsparagine can polymerise to form poly(asparagine). (d)\nD raw the structure of poly(asparagine), showing repeat units. The peptide linkage should two\nbe shown displayed.\n[2]\nThe isoelectric point of lysine, lys, is at pH 9.8. (e)\nlysine\nNH\n2\n(CH )\n2 4\nH N C COOH\n2\nH\nFig. 6.2\nA mixture of the dipeptide lys-asn and its two constituent amino acids, asparagine and lysine,\nis analysed by electrophoresis using a buffer at pH 5.0. The results obtained are shown in\nFig. 6.3.\nmixture applied here E F G\n– +\nFig. 6.3\nS uggest identities for the species responsible for spots E, and G. Explain your answers. F\nspot identity\nE\nF\nG\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n[3]\nThin-layer and gas-liquid chromatography can be used to analyse mixtures of substances. (f)\nE ach type of chromatography makes use of a stationary phase and a mobile phase.\nComplete Table 6.1 with an example of each of these. (i)\nTable 6.1\nstationary phase mobile phase\nthin-layer chromatography\ngas-liquid chromatography\n[1]\nA n unknown amino acid is analysed using thin-layer chromatography. Two chromatographs (ii)\nof the unknown amino acid and four reference amino acids, P, Q, and S, are obtained R\nusing two different solvents.\n5\n4\n3\n2\n1\ncm\n0\nP Q R S P Q R S\nunknown unknown\namino acid amino acid\nsolvent 1 solvent 2\nFig. 6.4\nIdentify the unknown amino acid. Justify your answer.\n.............................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-mj-43-q06-f1d0dc06a8.pdf" }, { "id": "9701-2022-mj-43-q07", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_43.pdf?download=true", "source_pages": [ 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2022-mj-43-q07-p01-d8f9455430.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-43-q07-p02-0d9ee6c76b.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-43-q07-p03-84ad6bf493.png", "9701-topic-36-organic-synthesis/assets/9701-2022-mj-43-q07-p04-62e1bb3019.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-43-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Procaine is used as an anaesthetic in medicine. It can be synthesised from methylbenzene in 7\nfive steps as shown in Fig. 7.1.\nmethylbenzene X\nCOCl CH COOH\n3\nsteps 1 and 2 step 3\nSOCl\n2\nNO NO\n2 2\nstep 4\nprocaine\nCH N(CH CH ) CH N(CH CH ) O O CH O O CH\n2 2 2 3 2 2 2 2 3 2\nC C\nstep 5\nNH NO\n2 2\nFig. 7.1\nN ame all the functional groups present in procaine. (a) (i)\n....................................................................................................................................... [1]\nA molecule of procaine has 13 carbon atoms. (ii)\nsp2 sp3 and hybridised in procaine. State the number of carbon atoms that are sp,\nsp2 sp3 carbons = ..................... carbons = ..................... [1] sp carbons = .....................\n(1H) The proton NMR spectrum of procaine dissolved in D O is recorded. (b)\n2\nP redict the number of peaks observed.\n.............................................................................................................................................. [1]\nState why procaine can act as a base. (c)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nCompound can be synthesised in two steps from methylbenzene. (d) X\nW\nmethylbenzene X\nCH COOH\n3\nstep 1 step 2\nNO\n2\nFig. 7.2\nDraw the structure of compound in the box provided. [1] (i) W\nS tate the reagents and conditions for step 1 and step 2. (ii)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nProcaine is synthesised in three steps from X. (e)\nS uggest the reagents and conditions for step 4 and for step 5 in Fig. 7.1.\nstep 4 .........................................................................................................................................\nstep 5 .........................................................................................................................................\n[3]\n. E xplain what is meant by partition coefficient, K (f) (i)\npc\n.............................................................................................................................................\n....................................................................................................................................... [2]\nT he partition coefficient of procaine between octan-1-ol and water is 1.77. (ii)\ncm3 Octan-1-ol and water are immiscible. A solution containing 0.500 g of procaine in 75.0\ncm3 of octan-1-ol. of water is shaken with 50.0\nCalculate the mass of procaine that is extracted into the octan-1-ol.\nmass of procaine extracted = .............................. g [2]\n[T", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2022-mj-43-q07-1f4ade1774.pdf" }, { "id": "9701-2022-mj-51-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-51-q01-p01-991898beb4.png", "9701-experimental-skills/assets/9701-2022-mj-51-q01-p02-2097087774.png", "9701-experimental-skills/assets/9701-2022-mj-51-q01-p03-fe684e4df7.png", "9701-experimental-skills/assets/9701-2022-mj-51-q01-p04-758d5de43d.png", "9701-experimental-skills/assets/9701-2022-mj-51-q01-p05-341f55b17a.png", "9701-experimental-skills/assets/9701-2022-mj-51-q01-p06-1c65a91b4b.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student plans an investigation to find the molar ratio of the reaction between sodium chloride, 1\nNaCl, and a lead compound.\ndm–3 NaCl aqueous lead compound. The student is provided with solid and 0.200 mol\nNaCl The reaction between (aq) and the aqueous lead compound produces an insoluble compound\nas a precipitate.\ndm–3 NaCl (aq). The student prepares 0.200 mol (a)\ncm3 dm–3 NaCl NaCl of 0.200 mol (aq). Calculate the mass of (s) needed to make 250.0\nNaCl mass of = .............................. g [1]\nNaCl The student weighs the mass of (s) calculated in in a weighing boat. The solid mass (b) (a)\nis then transferred into a small beaker.\nNaCl Describe how the student should accurately weigh by difference so the exact mass of\ntransferred into the small beaker is known.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nNaCl The student is given a small beaker containing the mass of calculated in (a). (c)\ncm3 dm–3 NaCl of 0.200 mol (aq). Describe how the student should prepare 250.0\nInclude the names and capacities of each piece of apparatus used in the preparation of the\nsolution.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\ndm–3 The student plans the following method using the 0.200 mol aqueous lead compound and (d)\ndm–3 NaCl (aq) prepared in (c). the 0.200 mol\nNaCl Mix the (aq) and the aqueous lead compound in eight separate beakers in the Step 1\nproportions by volume shown in Table 1.1.\nTable 1.1\ndm–3 dm–3 volume of 0.200 mol volume of 0.200 mol\nbeaker\ncm3 cm3 NaCl (aq) / aqueous lead compound /\n1 10.00 40.00\n2 15.00 35.00\n3 20.00 30.00\n4 25.00 25.00\n5 30.00 20.00\n6 35.00 15.00\n7 40.00 10.00\n8 45.00 5.00\nFilter the contents of each beaker to collect the precipitate. Step 2\nDry the precipitate for 3 minutes in an oven and allow t", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-51-q01-6b30e8a275.pdf" }, { "id": "9701-2022-mj-51-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_51.pdf?download=true", "source_pages": [ 8, 10, 11, 12, 15, 16 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-51-q02-p01-92892fa4e7.png", "9701-experimental-skills/assets/9701-2022-mj-51-q02-p02-17163d491b.png", "9701-experimental-skills/assets/9701-2022-mj-51-q02-p03-f695cb33ce.png", "9701-experimental-skills/assets/9701-2022-mj-51-q02-p04-c243a21d20.png", "9701-experimental-skills/assets/9701-2022-mj-51-q02-p05-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-mj-51-q02-p06-9ae988af7b.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student plans to study the rate of hydrolysis of 2-bromo-2-methylpropane. 2\nCH CH\n3 3\nH C C H\n3 3\nH+ – C + H O C + + Br\n2\nCH CH\n3 3\nHO Br\nAs the concentration of 2-bromo-2-methylpropane decreases during the reaction, the concentration\nof hydrogen ions increases.\nThe student plans the following method.\ncm3 of a mixture of propanone and water into a conical flask. Place 100 Step 1\n°C Heat the mixture to 35 and maintain this temperature. Step 2\ncm3 of 2-bromo-2-methylpropane to the mixture and start timing. Add 1.00 Step 3\ncm3 sample of the reaction mixture into a conical flask After 1 minute, transfer a 10.00 Step 4\ncontaining ice and 4 drops of methyl orange indicator.\ncm3 dm–3 of the reaction mixture with 0.0200 mol Immediately titrate the 10.00 Step 5\nsodium hydroxide.\nRepeat sampling and titrating at regular time intervals over a total time of 45 minutes. Step 6\n°C, Heat the reaction mixture to 50 remove the final sample, and titrate this. Step 7\nState the apparatus you would use to maintain the temperature of the reaction mixture. (a) (i)\n....................................................................................................................................... [1]\nSuggest why the experiment is carried out away from naked flames. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nState the pieces of equipment and their capacities that you would use to: (b)\ncm3 of 2-bromo-2-methylpropane in step 3 measure 1.00 (i)\n....................................................................................................................................... [1]\ncm3 sample of the mixture in step 4. transfer a 10.00 (ii)\n....................................................................................................................................... [1]\nExplain why the reaction mixture is transferred into a conical flask containing ice. (c)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nState the measured dependent variable for this experiment. (d)\n.............................................................................................................................................. [1]\ncm3 is the final titre volume, 47.25 in step 7. The student recorded the results. V (e) (i)\nfinal\n– V. Complete Table 2.1 by calculating the value of V\nfinal t\nRecord the values to places. 2 decimal\nTable 2.1\ncm3 cm3 time / s titre, V / V – V /\nt final t\n60 1.25\n300 7.75\n600 17.75\n900 20.00\n1200 24.25\n1500 28.40\n1800 31.15\n2700 38.00\nfinal 47.25\n[1]\nThe titre, V, is proporti", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-51-q02-b0fce60ee4.pdf" }, { "id": "9701-2022-mj-52-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-52-q01-p01-00f59f309d.png", "9701-experimental-skills/assets/9701-2022-mj-52-q01-p02-3bba6a8e7c.png", "9701-experimental-skills/assets/9701-2022-mj-52-q01-p03-44b9bf3e6a.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student plans an experiment to find a value for the molar volume, V , of hydrogen gas at room 1\nm\nconditions.\nHCl Hydrogen gas is formed when magnesium reacts with dilute hydrochloric acid, (aq).\n→ 2HCl MgCl Mg(s) + (aq) (aq) + H (g)\n2 2\nThe student is provided with the following materials:\n● a piece of magnesium ribbon\ndm–3 HCl ● 0.50 mol (aq)\n● a water trough\n● a side-arm conical flask\ncm3 cm3 ● a 250 measuring cylinder with 2 graduations for the collection of gas\ncm3 ● a 50 measuring cylinder\n● a balance that measures to 2 decimal places\n● access to any necessary laboratory equipment, except gas syringes.\nThe student plans the following procedure.\nPrepare the piece of magnesium ribbon for use in the experiment. Step 1\ncm3 HCl Measure 30 of (aq) and pour into a side-arm conical flask. Step 2\nAttach the conical flask to a collection system for the hydrogen gas. Step 3\nPlace the magnesium ribbon in the conical flask. Step 4\nStopper the flask. Step 5\nWait until the final volume of gas collected is constant. Step 6\nWait for an additional 2 minutes, then measure and record the final volume of gas Step 7\ncollected.\nComplete Fig. 1.1 to show how the apparatus should be assembled for the collection and (a)\nmeasurement of gas.\nLabel your diagram.\nFig. 1.1\n[2]\nThe surface of the magnesium ribbon has an oxide layer. (b)\nState how the student should prepare the piece of magnesium ribbon before it is used in (i)\nthis experiment.\n....................................................................................................................................... [1]\nState what additional information about the magnesium is required before the experiment (ii)\nis performed.\n....................................................................................................................................... [1]\ncm3 dm–3 HCl of 0.50 mol (aq) is enough to react Show by calculation that a volume of 30 (c) (i)\nwith 0.16 g of magnesium ribbon. Show your working.\n→ 2HCl MgCl (aq) + H (g) Mg(s) + (aq)\n2 2\n[2]\ncm3 dm–3 HCl of 0.50 mol (aq). State why it is necessary to use a burette to measure 30 (ii) not\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe student waits for 2 minutes before taking a reading of the volume. (d)\nSuggest why the student waits for 2 minutes before measuring the volume of gas in 7. step\n....................................................................................................................................................\n.............................................................................................................................................. [1]\ncm3 The student collects 146 of hydrogen gas during the experiment. (e)\nCalculate the percentage error in collecting the hydrogen gas.", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-52-q01-3b2fdc0809.pdf" }, { "id": "9701-2022-mj-52-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_52.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 11, 12 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-52-q02-p01-6d11804112.png", "9701-experimental-skills/assets/9701-2022-mj-52-q02-p02-5256b8101c.png", "9701-experimental-skills/assets/9701-2022-mj-52-q02-p03-6e3daa9214.png", "9701-experimental-skills/assets/9701-2022-mj-52-q02-p04-c443d53d37.png", "9701-experimental-skills/assets/9701-2022-mj-52-q02-p05-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-mj-52-q02-p06-9ae988af7b.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "In a neutral solution, aqueous potassium iodide acts as a catalyst for the decomposition of aqueous 2\nhydrogen peroxide.\n→ O (aq) 2H O(l) + O (g) 2H\n2 2 2 2\nA student plans to carry out an investigation to find how temperature affects the initial rate of the\nO (aq), in the presence of aqueous potassium decomposition of aqueous hydrogen peroxide, H\n2 2\nKI(aq). iodide,\nThe student knows that the initial rate of the reaction can be measured by timing the production of\nthe oxygen. The student carries out a series of experiments.\nKI(aq) O (aq) and under room conditions. In experiment 1 the student notes the temperature of the H\n2 2\nThe solutions are mixed in apparatus designed to collect the oxygen produced. A stop-watch is\nstarted at the beginning of the reaction. The volume of oxygen is noted at regular time intervals.\nIn experiments 2–8 the solutions are heated to different temperatures before mixing and\nmeasurement of the oxygen produced.\nThe data collected is used to determine a value for the activation energy of the decomposition of\nKI(aq). O (aq) in the presence of H\n2 2\nState the independent variable. (a)\n.............................................................................................................................................. [1]\nState variables that need to be controlled. (b) two\n1 .................................................................................................................................................\n2 .................................................................................................................................................\n[2]\ncm3 dm–3 of 0.100 mol H O (aq) from State how the student should prepare 250.0 (c) (i)\n2 2\ndm–3 H O (aq). 0.500 mol\n2 2\ndm–3 H O (aq) required for preparation of the Calculate the minimum volume of 0.500 mol\n2 2\ndm–3 H O solution. Give the name and capacity of any key apparatus which 0.100 mol\n2 2\nshould be used.\nWrite your answer as a series of numbered steps.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nHydrogen peroxide causes eye and skin irritation. (ii)\nState what precaution should be taken when preparing the solution in other than (c)(i)\nwearing goggles.\n..", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-52-q02-41bb2caa93.pdf" }, { "id": "9701-2022-mj-53-q01", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-53-q01-p01-991898beb4.png", "9701-experimental-skills/assets/9701-2022-mj-53-q01-p02-2097087774.png", "9701-experimental-skills/assets/9701-2022-mj-53-q01-p03-fe684e4df7.png", "9701-experimental-skills/assets/9701-2022-mj-53-q01-p04-758d5de43d.png", "9701-experimental-skills/assets/9701-2022-mj-53-q01-p05-341f55b17a.png", "9701-experimental-skills/assets/9701-2022-mj-53-q01-p06-1c65a91b4b.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student plans an investigation to find the molar ratio of the reaction between sodium chloride, 1\nNaCl, and a lead compound.\ndm–3 NaCl aqueous lead compound. The student is provided with solid and 0.200 mol\nNaCl The reaction between (aq) and the aqueous lead compound produces an insoluble compound\nas a precipitate.\ndm–3 NaCl (aq). The student prepares 0.200 mol (a)\ncm3 dm–3 NaCl NaCl of 0.200 mol (aq). Calculate the mass of (s) needed to make 250.0\nNaCl mass of = .............................. g [1]\nNaCl The student weighs the mass of (s) calculated in in a weighing boat. The solid mass (b) (a)\nis then transferred into a small beaker.\nNaCl Describe how the student should accurately weigh by difference so the exact mass of\ntransferred into the small beaker is known.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nNaCl The student is given a small beaker containing the mass of calculated in (a). (c)\ncm3 dm–3 NaCl of 0.200 mol (aq). Describe how the student should prepare 250.0\nInclude the names and capacities of each piece of apparatus used in the preparation of the\nsolution.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\ndm–3 The student plans the following method using the 0.200 mol aqueous lead compound and (d)\ndm–3 NaCl (aq) prepared in (c). the 0.200 mol\nNaCl Mix the (aq) and the aqueous lead compound in eight separate beakers in the Step 1\nproportions by volume shown in Table 1.1.\nTable 1.1\ndm–3 dm–3 volume of 0.200 mol volume of 0.200 mol\nbeaker\ncm3 cm3 NaCl (aq) / aqueous lead compound /\n1 10.00 40.00\n2 15.00 35.00\n3 20.00 30.00\n4 25.00 25.00\n5 30.00 20.00\n6 35.00 15.00\n7 40.00 10.00\n8 45.00 5.00\nFilter the contents of each beaker to collect the precipitate. Step 2\nDry the precipitate for 3 minutes in an oven and allow t", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-53-q01-78aeab1416.pdf" }, { "id": "9701-2022-mj-53-q02", "subject": "9701", "year": 2022, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-may-june/9701_s22_qp_53.pdf?download=true", "source_pages": [ 8, 10, 11, 12, 15, 16 ], "local_pdf": "_source-pdfs/2022-May-June/qp/9701_s22_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-mj-53-q02-p01-92892fa4e7.png", "9701-experimental-skills/assets/9701-2022-mj-53-q02-p02-17163d491b.png", "9701-experimental-skills/assets/9701-2022-mj-53-q02-p03-f695cb33ce.png", "9701-experimental-skills/assets/9701-2022-mj-53-q02-p04-c243a21d20.png", "9701-experimental-skills/assets/9701-2022-mj-53-q02-p05-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-mj-53-q02-p06-9ae988af7b.png" ], "answer": { "status": "pending", "id": "9701-2022-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student plans to study the rate of hydrolysis of 2-bromo-2-methylpropane. 2\nCH CH\n3 3\nH C C H\n3 3\nH+ – C + H O C + + Br\n2\nCH CH\n3 3\nHO Br\nAs the concentration of 2-bromo-2-methylpropane decreases during the reaction, the concentration\nof hydrogen ions increases.\nThe student plans the following method.\ncm3 of a mixture of propanone and water into a conical flask. Place 100 Step 1\n°C Heat the mixture to 35 and maintain this temperature. Step 2\ncm3 of 2-bromo-2-methylpropane to the mixture and start timing. Add 1.00 Step 3\ncm3 sample of the reaction mixture into a conical flask After 1 minute, transfer a 10.00 Step 4\ncontaining ice and 4 drops of methyl orange indicator.\ncm3 dm–3 of the reaction mixture with 0.0200 mol Immediately titrate the 10.00 Step 5\nsodium hydroxide.\nRepeat sampling and titrating at regular time intervals over a total time of 45 minutes. Step 6\n°C, Heat the reaction mixture to 50 remove the final sample, and titrate this. Step 7\nState the apparatus you would use to maintain the temperature of the reaction mixture. (a) (i)\n....................................................................................................................................... [1]\nSuggest why the experiment is carried out away from naked flames. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nState the pieces of equipment and their capacities that you would use to: (b)\ncm3 of 2-bromo-2-methylpropane in step 3 measure 1.00 (i)\n....................................................................................................................................... [1]\ncm3 sample of the mixture in step 4. transfer a 10.00 (ii)\n....................................................................................................................................... [1]\nExplain why the reaction mixture is transferred into a conical flask containing ice. (c)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nState the measured dependent variable for this experiment. (d)\n.............................................................................................................................................. [1]\ncm3 is the final titre volume, 47.25 in step 7. The student recorded the results. V (e) (i)\nfinal\n– V. Complete Table 2.1 by calculating the value of V\nfinal t\nRecord the values to places. 2 decimal\nTable 2.1\ncm3 cm3 time / s titre, V / V – V /\nt final t\n60 1.25\n300 7.75\n600 17.75\n900 20.00\n1200 24.25\n1500 28.40\n1800 31.15\n2700 38.00\nfinal 47.25\n[1]\nThe titre, V, is proporti", "pdf_path": "9701-experimental-skills/print/9701-2022-mj-53-q02-7baae013da.pdf" }, { "id": "9701-2022-on-41-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-on-41-q01-p01-61edcaeea7.png", "9701-topic-23-chemical-energetics/assets/9701-2022-on-41-q01-p02-df94500176.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "KCl, MgCl Potassium chloride, and magnesium chloride, , are both ionic solids. 1\n2\nTable 1.1\nmol–1 energy change value / kJ\nKCl standard enthalpy change of solution, , of +15\nKCl lattice energy, , of (s) –701\nK+ , of –322 standard enthalpy change of hydration,\n– –364 Cl standard enthalpy change of hydration, , of\nMgCl , of –155 standard enthalpy change of solution,\n2\nMgCl lattice energy, , of (s) –2493\n2\nComplete the energy cycle involving the enthalpy change of solution and the lattice energy of (a)\nKCl, potassium chloride, and the relevant enthalpy changes of hydration. Label your diagram.\nS tate symbols should be used.\nKCl (s)\n[2]\nUse the data in Table 1.1 to calculate the enthalpy change of hydration of magnesium ions, (b)\nMg2+. Show your working.\nMg2+ mol–1 of magnesium ions, = .............................. kJ [2]\nMgCl Explain the reasons why the lattice energy of is more exothermic than the lattice energy (c)\n2\nKCl. of\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nDefine the following terms. (d)\nenthalpy change of atomisation .......................................................................................... (i)\n....................................................................................................................................... [1]\nfirst electron affinity ............................................................................................................. (ii)\n....................................................................................................................................... [1]\nE xplain what is meant by entropy, S. (e) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n°C. P otassium chloride is very soluble in water at 20 (ii)\n∆S. Explain the solubility of potassium chloride by reference to change in entropy,\n.............................................................................................................................................\n....................................................................................................................................... [1]\nUse the Gibbs equation and your answer to to predict whether potassium chloride is (iii) (e)(ii)\n°C °C. more soluble in water at 20 or ", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-on-41-q01-05c17388f6.pdf" }, { "id": "9701-2022-on-41-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2022-on-41-q02-p01-987c029d32.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-on-41-q02-p02-51a0c9fcf5.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "E xplain what is meant by the following terms: 2 (a) (i)\nhomogeneous catalyst ........................................................................................................\n.............................................................................................................................................\nheterogeneous catalyst ......................................................................................................\n.............................................................................................................................................\n[1]\nI odide ions react with peroxydisulfate ions. (ii)\n→ 2I– 2– 2– I + S O + 2SO\n2 8 2 4\nFe2+ This reaction is slow, but it is catalysed by ions.\nFe2+ ions. Write two equations to explain how this reaction is catalysed by\n1 ..........................................................................................................................................\n2 ..........................................................................................................................................\n[2]\nFe2+ ions has a lower activation Suggest why the alternative route in the presence of (iii)\nenergy than the route in the absence of a catalyst.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nNitrogen monoxide reacts with oxygen. (b)\n→ (g) 2NO (g) 2NO(g) + O\n2 2\nThis reaction is second order with respect to nitrogen monoxide and first order with respect to\noxygen.\n× 106 mol–2 dm6 s–1. U nder certain conditions the value of the rate constant, k, is 8.60\nConstruct the rate equation for this reaction. (i)\nrate =\n[1]\nC alculate the initial rate of the reaction under these conditions when the initial concentration (ii)\n× 10–4 dm–3 mol and the initial concentration of oxygen is of nitrogen monoxide is 7.20\n× 10–3 dm–3. mol 1.90\ndm–3 s–1 rate of reaction = .............................. mol [1]\nCl The drug cisplatin, Pt(NH ) , hydrolyses in water. (c)\n3 2 2\n→ O)]+ – Cl Cl Cl ) + H O [Pt(NH ) (H + Pt(NH\n3 2 2 2 3 2 2\nT he rate equation is shown.\nCl ) ] rate = k [Pt(NH\n3 2 2\n× 10–5 s–1 under certain conditions. T he value of k is 2.50\nThis reaction has a constant half-life. (i)\nExplain why this is the case.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n× 104 s. U se the information in this question to show that the half-life of this reaction is 2.77 (ii)\n[1]\n× 10–6 cm3 Cl moles of Pt(NH ) are added to 100 of water. 8.00 (iii)\n3 2 2\n× 10–6 dm–3. Cl ) to fall to 2.50 mol Calculate the time taken for the concentration", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2022-on-41-q02-748fc1a1c4.pdf" }, { "id": "9701-2022-on-41-q03", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-on-41-q03-p01-6293f6958a.png", "9701-topic-24-electrochemistry/assets/9701-2022-on-41-q03-p02-b2b3efef04.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Data should be selected from Table 3.1 in order to answer some parts of this question. 3\nTable 3.1\no electrode reaction E / V\n2e– – 2Cl Cl +1.36 +\n2\n2H+ 2e– Cl 2HOCl +1.64 + + 2H O +\n2 2\nO– 2e– – 2OH– Cl Cl +0.89 + H O + +\n2\nSn4+ 2e– Sn2+ +0.15 +\nSn2+ 2e– –0.14 + Sn\nV2+ 2e– –1.20 + V\nV3+ e– V2+ –0.26 +\nVO2+ 2H+ e– V3+ +0.34 + + + H O\n2\n2H+ e– VO2+ + +1.00 + + + H O VO\n2 2\nStandard electrode potentials are measured under standard conditions. (a)\nSn4+ Sn2+ / half-cell. Describe the standard conditions used in the (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\no (Sn4+ Sn2+) / can be measured experimentally. C omplete the diagram below to show how E (ii)\nYour diagram should be fully labelled to identify all apparatus and substances.\n[3]\ndm–3 Sn2+(aq) dm–3 –(aq) Cl Equal volumes of 1.0 mol and 1.0 mol are mixed. (iii)\no values to explain whether a reaction occurs between these two ions. Use relevant E\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\ndm–3 Sn2+(aq) dm–3 VO2+(aq) of and acidified 1.0 mol are mixed. Equal volumes of 1.0 mol (iv)\nWrite an equation for the reaction that takes place in the resulting mixture.\n....................................................................................................................................... [2]\nSnCl (aq) is electrolysed for a measured time using a steady current. A solution of (b)\n2\nA mass of 2.95 g of tin metal is produced at the cathode.\nl O (l) is electrolysed for the same time by the same current. A\n2 3\nC alculate the mass of aluminium metal produced at the cathode. Give your answer to three\nsignificant figures. Show your working.\nmass of aluminium metal = .............................. g [2]\n[Total: 10]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-on-41-q03-368c34eb73.pdf" }, { "id": "9701-2022-on-41-q04", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2022-on-41-q04-p01-39b93ec0f4.png", "9701-topic-25-equilibria/assets/9701-2022-on-41-q04-p02-294ec89464.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q04", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "A sample of butanoic acid, CH (CH ) COOH, is shaken with a mixture of two immiscible 4 (a)\n3 2 2\nsolvents, ethoxyethane and water. The solvents form two layers. The butanoic acid is distributed\nbetween the two layers, its concentration in ethoxyethane being higher than its concentration\nin water.\nState what is meant by partition coefficient. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n, for butanoic acid between ethoxyethane and water is 3.50. The partition coefficient, K (ii)\npc\ncm3 ethoxyethane is added to water. This A solution of 2.00 g of butanoic acid in 100\nmixture is left until there is no further change in the concentration of butanoic acid in either\nsolvent. The mass of butanoic acid dissolved in the ethoxyethane layer is now 1.62 g.\nCalculate the volume of water used.\ncm3 [2] volume of water used = ..............................\nAn aqueous solution of butanoic acid can be used to make a buffer solution. (b)\nDefine buffer solution. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nS uggest one organic compound, and one inorganic compound, that can be added to two (ii)\ndifferent samples of aqueous butanoic acid to produce buffer solutions.\norganic compound ..............................................................................................................\ninorganic compound ...........................................................................................................\n[1]\n× 10–9 dm–3. Al The solubility of aluminium hydroxide, (OH) , in water is 2.47 mol (c)\n3\n, of aluminium hydroxide. Give the expression for the solubility product, K (i)\nsp\nK =\nsp\n[1]\nC alculate the numerical value of the K of aluminium hydroxide. Include the units of K in (ii)\nsp sp\nyour answer.\nK = ..............................\nsp\nunits = ..............................\n[3]\n[Total: 9]", "pdf_path": "9701-topic-25-equilibria/print/9701-2022-on-41-q04-b3bfc97d96.pdf" }, { "id": "9701-2022-on-41-q05", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-41-q05-p01-34477cec44.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-41-q05-p02-ca205f9d54.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-41-q05-p03-c45b7548b7.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "A transition element is a d-block element which forms one or more stable ions with incomplete 5\nd-orbitals.\norbital and the 3d orbital. Two of the 3d orbitals are the 3d (a)\n2 xy z\nS ketch the shapes of these two orbitals.\n3d 3d\n2 xy z\ny z\nz y\nx x\n[1]\nNi2+ ]2+ The ion forms many different complexes. A solution containing the [Ni(H O) complex ion (b)\n2 6\nNCH CH NH , is added, the colour of is green. When an excess of 1,2-diaminoethane, en, H\n2 2 2 2\n]2+ complex ion. the solution changes to blue. This is due to the formation of the [Ni(en)\n3\nExplain why the two solutions are coloured, and why the colours are different. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\n]2+ The [Ni(en) complex can exist as a mixture of two stereoisomers. (ii)\n3\nComplete the three-dimensional diagram to show one of the stereoisomers.\n. Each en ligand can be represented using\nN N\nNi\n[1]\nName the geometry of the complex ion drawn in and the type of stereoisomerism (iii) (b)(ii)\n]2+. shown by [Ni(en)\n3\ngeometry .............................................................................................................................\nstereoisomerism shown ......................................................................................................\n[1]\nIron(II) nickel(II) carbonate, FeCO , and carbonate, NiCO , both decompose when heated. (c)\n3 3\ndecomposes at a lower temperature than NiCO . F eCO\n3 3\nSuggest a possible reason for this difference. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n...........................................................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-41-q05-a5c1104389.pdf" }, { "id": "9701-2022-on-41-q06", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-41-q06-p01-7339c9dc23.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-41-q06-p02-9734050871.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "copper(II) ]2+ An aqueous solution of sulfate is a blue colour due to the presence of [Cu(H O) 6\n2 6\ncomplex ions.\n]2+ O) ions and NaOH(aq). W rite an equation for the reaction between [Cu(H (a) (i)\n2 6\n....................................................................................................................................... [1]\n]2+ HCl. O) ions and an excess of conc. W rite an equation for the reaction between [Cu(H (ii)\n2 6\n....................................................................................................................................... [1]\n]2+ If an excess of ammonia is added to a solution of [Cu(H O) a deep blue solution containing (b)\n2 6\n]2+ ) (H O) complex ions is formed. [Cu(NH\n3 4 2 2\n]2+. ) (H O) There are two possible stereoisomers with the formula [Cu(NH (i)\n3 4 2 2\nComplete the diagrams to show the two stereoisomers in the boxes below.\nisomer 1 isomer 2\nCu Cu\n[1]\nU se your answer in to deduce whether each of these isomers is polar or non-polar. (ii) (b)(i)\npolarity of isomer 1 .............................................................................................................\npolarity of isomer 2 .............................................................................................................\n[1]\n]2+ , of the [Cu(NH ) (H O) complex ion is The numerical value of the stability constant, K (c)\nstab 3 4 2 2\n× 1013. 1.40\nDefine stability constant. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+ ]2+ C ompare the stabilities of the [Cu(H O) and [Cu(NH ) (H O) complex ions. Explain (ii)\n2 6 3 4 2 2\nyour answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+ , of the [Cu(NH ) (H O) complex ion. Write an expression for the stability constant, K (iii)\nstab 3 4 2 2\nState the units of the stability constant.\nK =\nstab\nunits = ..............................\n[2]\n]2+ ) (H O) complex ion is In a particular solution the concentration of the [Cu(NH (iv)\n3 4 2 2\ndm–3 dm–3. and the concentration of NH is 0.57 mol 0.0074 mol\n3\n× 1013 value of 1.40 to calculate the concentration Use your expression in and the K (c)(iii)\nstab\n]2+ O) complex ion in this solution. of the [Cu(H\n2 6\n]2+ dm–3 O) = .............................. mol [1] concentration of [Cu(H\n2 6\n2–, Phenanthroline, C H N , and ethanedioate ions, C O are bidentate ligands. (d)\n12 8 2 2 4\nuthenium(III) Ru3+, ions, form an octahedral complex with phenanthroline and chloride ions. R\nThe complex ion contains two phenanthroline molecules.\nron(III) Fe3+, ions, form an octahedral", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-41-q06-c5918e6ff4.pdf" }, { "id": "9701-2022-on-41-q07", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 16, 17, 18, 19 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-41-q07-p01-2b53ab5f19.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-41-q07-p02-5435567451.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-41-q07-p03-a738f0eb90.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-41-q07-p04-88f8b490f9.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "The structure of compound is shown in Fig. 7.1. 7 (a) P\nP\nO H N\n2\nO\nFig. 7.1\nis optically active. (i) P\nUse an asterisk (*) to identify all chiral carbon atoms on the structure of in Fig. 7.1. [1] P\nP lane polarised light is passed through a pure sample of one enantiomer of P. This is then (ii)\nrepeated with a pure sample of the other enantiomer of P.\nDescribe the results of these two experiments, stating the similarities and differences of\nthe results.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\ncan be used to make compound in a single step reaction. (b) P Q\nQ\nO\nO\nHN\nO\nGive the structural formula of the compound that is added to to make and give the (i) P Q\nformula of the other product of this reaction.\ncompound added to ........................................................................................................ P\nother product ......................................................................................................................\n[1]\nLiAl W hen an ester is treated with H in dry ether the ester linkage is cleaved by the (ii)\n4\naddition of four hydrogen atoms and two alcohols are produced.\nLiAl Draw the structures of the compounds formed when is treated with an of H Q excess\n4\nin dry ether.\n[3]\nCompare the relative basicities of compound P, compound and phenylamine. (iii) Q\n........................................... < ........................................... < ...........................................\nleast basic most basic\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n[3]\ncan be used to make compound in a two-step reaction, shown in Fig. 7.2. (c) P R\nP R\nO O H N H N\n2 2\ntwo steps\nO H N OH\n2\nFig. 7.2\nIdentify the reagents and conditions used for the two steps of the reaction. (i)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nC omplete Table 7.1 by drawing the structures of the org", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-on-41-q07-027a49d851.pdf" }, { "id": "9701-2022-on-41-q08", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 20, 21 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2022-on-41-q08-p01-ff73611821.png", "9701-topic-30-hydrocarbons/assets/9701-2022-on-41-q08-p02-3cd6d6c35d.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q08", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "Benzene, C H , is an aromatic molecule. 8\n6 6\nState the C–C–C bond angle and the hybridisation shown by the carbon atoms in benzene. (a)\nbond angle .................................................................................................................................\nhybridisation ..............................................................................................................................\n[1]\nBenzene reacts with chloroethane in the presence of a catalyst. The reaction mechanism is (b)\ncalled electrophilic substitution.\n+CH CH electrophile. The first step in the reaction is the generation of the (i)\n2 3\nWrite an equation for the reaction that generates this electrophile.\n....................................................................................................................................... [1]\n+CH CH electrophile. D escribe the mechanism for the reaction between benzene and the (ii)\n2 3\nInclude all relevant curly arrows and charges.\nintermediate products\n→ → H H\n+C C H\nH H\n[3]\nChlorobenzene and chloroethane have different reactivities in nucleophilic substitution (c)\nreactions.\nIdentify a suitable reagent to illustrate this difference in reactivity. (i)\nThe reagent chosen should give different results with chlorobenzene and visibly\nchloroethane.\n....................................................................................................................................... [1]\nW rite equations to describe any reactions that occur. (ii)\n[1]\nExplain the difference in the reactivities of chlorobenzene and chloroethane in nucleophilic (iii)\nsubstitution reactions.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 8]", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2022-on-41-q08-862200393e.pdf" }, { "id": "9701-2022-on-41-q09", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_41.pdf?download=true", "source_pages": [ 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_41.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p01-7465fc0004.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p02-3e7b9051ab.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p03-3d0f31ebdf.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p04-9760f30e46.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p05-84ad6bf493.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-41-q09-p06-f7b546968f.png" ], "answer": { "status": "pending", "id": "9701-2022-on-41-q09", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Gas-liquid chromatography involves a stationary phase and a mobile phase. 9 (a)\nName, or describe in detail, a suitable substance that could be used for each phase. (i)\nstationary ............................................................................................................................\nmobile .................................................................................................................................\n[1]\nA mixture of three organic compounds is separated by gas-liquid chromatography. The\nchromatogram obtained is shown in Fig. 9.1. The amount of each substance is proportional to\nthe area under its peak.\nB\n100\n80\n60\nrecorder\nresponse\n40\nA\nC\n20\n0\n14 16 18 20 22 24 26 28 30\nretention time (min)\nFig. 9.1\nE xplain the meaning of retention time. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCalculate the percentage of in the mixture. Show your working. (iii) B\npercentage of = .............................. % [2] B\nComplete Table 9.1 to give the number of peaks in the carbon-13 NMR spectrum of each of the (b)\nH O that has an ester group. five isomers of C\n5 10 2\nTable 9.1\nstructural formula number of peaks\nCH CH CH CO CH\n3 2 2 2 3\nCH CH CO CH CH\n3 2 2 2 3\nCH CO CH CH CH\n3 2 2 2 3\n(CH ) CHCO CH\n3 2 2 3\nCH CO CH(CH )\n3 2 3 2\n[2]\n(1H) State the number of peaks that would be seen in the proton NMR spectrum of (c)\nCH CH CO CH . Name all the splitting patterns seen in this spectrum. methyl butanoate, CH\n3 2 2 2 3\nnumber of peaks ........................................................................................................................\nsplitting patterns ........................................................................................................................\n[2]\n(1H) and are both esters with the molecular formula C H O . Their proton NMR spectra are (d) D E\n5 10 2\nshown in Fig. 9.2 and Fig. 9.3.\nD\n3\n3\n2 2\n4 3 2 1 0\n(cid:31) chemical shift,\nFig. 9.2\nE\n3\n6\n1\n4 3 2 1 0\n(cid:31) chemical shift,\nFig. 9.3\nTable 9.2\nenvironment of proton example typical chemical shift\nδ range, / ppm\nalkane –CH , –CH –, >CH– 0.9–1.7\n3 2\nalkyl next to C=O CH –C=O, –CH –C=O, 2.2–3.0\n3 2\n>CH–C=O\n–Ar, –CH –Ar, 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n>CH–Ar\n3.2–4.0 –O, –CH –O, alkyl next to electronegative atom CH\n3 2\n–Cl –CH\n2\nattached to alkene =CHR 4.5–6.0\nDeduce the structures of the two esters and and draw their displayed formulae in the (i) D E\nboxes below.\nD E\nH O H O C C\n5 10 2 5 10 2\n[2]\nδ T he spectrum of includes a quartet at 4.1. (ii) D\nIdentify the protons responsible for this quartet on your structure in by labelling these (i)\nprotons with the letter F.\nExplain why this peak is split into a quartet.\n...........................................................................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2022-on-41-q09-99427d1854.pdf" }, { "id": "9701-2022-on-42-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-on-42-q01-p01-793ddbcc89.png", "9701-topic-23-chemical-energetics/assets/9701-2022-on-42-q01-p02-fe6a57b3d5.png", "9701-topic-23-chemical-energetics/assets/9701-2022-on-42-q01-p03-7cc7ae3e9c.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "CaCl Calcium chloride, , is an ionic solid. 1\n2\nThe values of some energy changes are shown in Table 1.1.\nTable 1.1\nmol–1 energy change value / kJ\nCaCl lattice energy, , (s) –2237\n2\nstandard enthalpy change of atomisation of calcium +193\nfirst ionisation energy of calcium +590\nsecond ionisation energy of calcium +1150\nstandard enthalpy change of atomisation of chlorine +121\nfirst electron affinity of chlorine –364\nDefine lattice energy. (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\n, of Use the data in Table 1.1 to calculate the standard enthalpy change of formation, (b)\ncalcium chloride. It may be helpful to draw an energy cycle. Show all your working.\nmol–1 (CaCl (s)) = .............................. kJ [2]\n2\nThree possible values for the first electron affinity of bromine are shown in Table 1.2. One of (c)\nthem is correct.\nP lace a tick by the correct value. Explain your choice.\nTable 1.2\n(✓) possible values place tick in this column one\nmol–1 –342 kJ\nmol–1 –364 kJ\nmol–1 –386 kJ\nexplanation ................................................................................................................................\n.............................................................................................................................................. [1]\nThe enthalpy change of hydration of the chloride ion can be calculated using the lattice energy (d)\nof calcium chloride and the data shown in Table 1.3.\nTable 1.3\nmol–1 energy change value / kJ\nCaCl standard enthalpy change of solution of (s) –83\n2\nCa2+(g) –1650 standard enthalpy change of hydration of\nDefine the following terms. (i)\nenthalpy change of solution ................................................................................................\n.............................................................................................................................................\nenthalpy change of hydration .............................................................................................\n.............................................................................................................................................\n[2]\n–(g). Cl It may be C alculate the standard enthalpy change of hydration of the chloride ion, (ii)\nhelpful to draw an energy cycle. Show all your working.\n–(g)) mol–1 (Cl = .............................. kJ [2]\nCalcium fluoride, CaF (s), can be synthesised directly from its elements. (e)\n2\nmol–1. (CaF (s)) is –1214 kJ T he value of\n2\n∆S o, for this synthesis. Explain your answer. Predict the sign of the entropy change, (i)\nThe sign of the entropy change is .............................. .\nexplanation ....................................................................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-on-42-q01-ac9e307363.pdf" }, { "id": "9701-2022-on-42-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 5, 6 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2022-on-42-q02-p01-83d7bd3670.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-on-42-q02-p02-c93389dd57.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "N itrogen monoxide, NO, reacts with ozone, O . 2 (a)\n3\n→ (g) NO (g) + O (g) NO(g) + O\n3 2 2\n. T his reaction is first order with respect to both NO and O\n3\nmol–1 dm3 s–1. A t 298 K, the rate constant k = 11 500\nComplete the rate equation for this reaction. (i)\nrate = ..................................................................................................................................\n[1]\nare both A reaction is carried out in which the initial concentrations of NO and O (ii)\n3\n× 10–6 dm–3. mol 1.20\nCalculate the initial rate of the reaction. State its units.\nrate of reaction = .............................. units = .............................. [2]\nThe reaction described in is monitored over a period of time. (iii) (a)(ii)\nPredict whether or not the graph of [NO] against time, under these conditions, shows that\nthe reaction has a constant half-life. Explain your answer.\nprediction ............................................................................................................................\nexplanation .........................................................................................................................\n....................................................................................................................................... [1]\nO, decomposes into its elements. Nitrous oxide, N (b)\n2\n→ O(g) 2N (g) + O (g) 2N\n2 2 2\nA t a high temperature, a small amount of platinum wire is added to a large amount of\nnitrous oxide. The reaction follows zero order kinetics. The platinum wire behaves as a catalyst.\nSketch a graph, on the axes below, of reaction rate against time for the catalysed (i)\nO under these conditions. decomposition of N\n2\nreaction rate\ntime\n[1]\nS ketch a graph, on the axes below, of [N O] against time for this reaction. (ii)\n2\n[N O]\n2\ntime\n[1]\nPlatinum behaves as a heterogeneous catalyst in this reaction. (iii)\nDescribe the mode of action of a heterogeneous catalyst.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [3]\nSuggest a reason why this reaction has zero order kinetics when the amount of nitrous oxide (iv)\nis large and the amount of platinum is small.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 10]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2022-on-42-q02-a7305d01e2.pdf" }, { "id": "9701-2022-on-42-q03", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-on-42-q03-p01-31c3fb9780.png", "9701-topic-24-electrochemistry/assets/9701-2022-on-42-q03-p02-44913f79f0.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Data should be selected from Table 3.1 in order to answer some parts of this question. 3\nTable 3.1\no electrode reaction E / V\nMg2+ 2e– –2.38 + Mg\nMn2+ 2e– –1.18 + Mn\nMn3+ e– Mn2+ +1.49 +\n4H+ 2e– Mn2+ +1.23 + + + 2H O MnO\n2 2\ne– – 2– +0.56 + MnO MnO\n4 4\n4H+ 3e– – +1.67 + + MnO + 2H O MnO\n4 2 2\n8H+ 5e– Mn2+ – +1.52 + + + 4H O MnO\n4 2\nMg2+ Mn2+ – / Mg half-cell and a MnO / An electrochemical cell can be constructed from a (a)\n4\nhalf-cell. The standard cell potential of this cell can be calculated using the standard electrode\npotentials of the two half-cells.\nDefine standard electrode potential. Include details of the standard conditions used. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\nMg2+ / Mg C omplete the diagram below to show an electrochemical cell constructed from a (ii)\nMn2+ – / half-cell. half-cell and a MnO\n4\nLabel your diagram.\n[3]\nUse a positive (+) sign and a negative (–) sign to identify the polarity of each of the two (iii)\nelectrodes in your diagram.\nUse an arrow and the symbol ‘e’ to show the direction of electron flow in the external\ncircuit. [1]\nCalculate the standard cell potential, , of this cell. (iv)\n= .............................. V [1]\nConstruct an equation for the cell reaction. (v)\n....................................................................................................................................... [1]\nMg2+ / Mg half-cell Predict how the cell reaction will change, if at all, when the solution in the (vi)\nis diluted by the addition of a large volume of water. Explain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nA molten magnesium salt is electrolysed for 15.0 minutes by a constant current. (b)\n× 1022 magnesium atoms are produced at the cathode. 4.75\nC alculate the value of the current used.\ncurrent = .............................. A [2]\n[Total: 11]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-on-42-q03-9bfa3585dc.pdf" }, { "id": "9701-2022-on-42-q04", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2022-on-42-q04-p01-3bbfbe96c2.png", "9701-topic-25-equilibria/assets/9701-2022-on-42-q04-p02-562954d2e7.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q04", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "iron(III) T he value of the solubility product, K , of hydroxide, Fe(OH) , is given by the following 4 (a)\nsp 3\nexpression.\n× [Fe3+][OH–]3 10–39 mol4 dm–12 = = 2.0 K\nsp\nCalculate the solubility of Fe(OH) in water. (i)\n3\ndm–3 [1] solubility = .............................. mol\ndm–3 in 0.010 mol barium hydroxide, Ba(OH) (aq). C alculate the solubility of Fe(OH) (ii)\n3 2\ndm–3 [2] solubility = .............................. mol\nis less soluble in Ba(OH) (aq) than it is in pure water. Fe(OH) (iii)\n3 2\nName this effect.\n....................................................................................................................................... [1]\n× 10–9. of HBrO is 2.00 The numerical value of the K (b)\na\n× 10–3 cm3 mol of HBrO in 100 of solution. In this is a solution of HBrO which contains 4.00 X\nsolution the following equilibrium is established in which there are two conjugate acid-base\npairs.\nBrO– O+ O + H HBrO + H\n2 3\nDefine conjugate acid-base pair. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nI dentify the two conjugate acid-base pairs shown in the equation above. (ii)\npair one .............................. ..............................\nacid base\npair two .............................. ..............................\nacid base\n[1]\nCalculate the pH of solution X. Show all your working. (iii)\npH = .............................. [2]\n× 10–3 mol of NaOH is added to solution X. A buffer solution is A solution containing 2.00 (iv)\nformed.\nCalculate the pH of this buffer solution.\npH = .............................. [1]\n[Total: 9]", "pdf_path": "9701-topic-25-equilibria/print/9701-2022-on-42-q04-9d98dbf895.pdf" }, { "id": "9701-2022-on-42-q05", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 12, 13, 14 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-42-q05-p01-c2d1c5d969.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-42-q05-p02-36b2293319.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-42-q05-p03-ed140fdd6b.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Copper is a transition element. It forms a wide variety of compounds. 5\nDefine transition element. (a)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\ncopper(II) ]2+ sulfate, CuSO , contains [Cu(H O) complex ions. If an An aqueous solution of (b)\n4 2 6\nexcess of concentrated hydrochloric acid is added to this solution a ligand exchange reaction\n]2– [CuCl complex ions are formed. occurs and\n4\nComplete Table 5.1 to state the geometry, the coordination number of copper, and one (i)\nbond angle in each of the two complex ions.\nTable 5.1\ncomplex ion geometry coordination number bond angle\n]2+ [Cu(H O)\n2 6\n]2– [CuCl\n4\n[3]\nCu2+ ion the d-orbitals are all degenerate. In a complex ion such as I n an isolated (ii)\n]2+ O) the d-orbitals are non-degenerate. [Cu(H\n2 6\nDefine degenerate and non-degenerate in this context.\ndegenerate .........................................................................................................................\nnon-degenerate ..................................................................................................................\n[1]\nExplain why the solutions of the two complex ions in Table 5.1 are colours. (iii) different\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCu2+ 2–, forms a complex ion containing water molecules and ethanedioate ions, C O as ligands. (c)\n2 4\n]2–. O ) (H O) The ethanedioate ion is a bidentate ligand. The formula of the complex is [Cu(C\n2 4 2 2 2\nExplain what is meant by bidentate. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2–. T here are three stereoisomers with the formula [Cu(C O ) (H O) (ii)\n2 4 2 2 2\nComplete the three-dimensional diagrams to show these three stereoisomers.\nstereoisomer 1 stereoisomer 2\nCu Cu\nstereoisomer 3\nCu\n[2]\nUse your answer to to answer this question. (iii) (c)(ii)\nStereoisomers 1, 2 and 3 show two different types of isomerism.\nName these two types of isomerism.\nFor each type of isomerism identify the pair of stereoisomers that demonstrate this\nisomerism.\ntype of isomerism pair of stereoisomers\nand\nand\n[2]\ncm3 A solution contains 3.70 g of Na [Cu(C O ) (H O) ] dissolved in 100 of solution. A (d)\n2 2 4 2 2 2\ncm3 dm–3 sample of this solution is warmed and then oxidised by 0.0100 mol acidified 25.0\nmanganate(VII). potassium\nT he equation for the ", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-42-q05-d4f07c4294.pdf" }, { "id": "9701-2022-on-42-q06", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 15 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-42-q06-p01-b204a8366b.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "cobalt(II) ]2+ An aqueous solution of chloride is a pink colour due to the presence of [Co(H O) 6\n2 6\ncomplex ions.\nC omplete Table 6.1 to describe what is observed when the named reagent is added to an (a) (i)\ncobalt(II) chloride. aqueous solution of\nTable 6.1\ncolour of state of\nreagent\ncobalt-containing product cobalt-containing product\nNaOH(aq)\nHCl an excess of conc.\n[2]\n]2+ O) ions and NaOH(aq). W rite an equation for the reaction between [Co(H (ii)\n2 6\n....................................................................................................................................... [1]\n]2+ HCl. O) ions and an excess of conc. Write an equation for the reaction between [Co(H (iii)\n2 6\n....................................................................................................................................... [1]\nD efine stability constant. (b) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+ , of the [Co(NH ) complex ion. W rite an expression for the stability constant, K (ii)\nstab 3 6\n= K\nstab\n[1]\n]2+ , of the [Co(NH ) complex ion. Give the units of the stability constant, K (iii)\nstab 3 6\nunits = .............................. [1]\n]2+ , of the [Co(NH ) complex ion is The numerical value of the stability constant, K (iv)\nstab 3 6\n× 104. 7.7\n]2+ dm–3 ) complex ion is 0.0740 mol In an aqueous solution the concentration of the [Co(NH\n3 6\ndm–3 is 0.480 mol at equilibrium. and the concentration of NH\n3\n]2+ O) in this solution. Calculate the concentration of [Co(H\n2 6\ndm–3 concentration = .............................. mol [1]\n[Total: 8]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-42-q06-c9daede94d.pdf" }, { "id": "9701-2022-on-42-q07", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2022-on-42-q07-p01-a3e6157f0c.png", "9701-topic-36-organic-synthesis/assets/9701-2022-on-42-q07-p02-0313db1c1b.png", "9701-topic-36-organic-synthesis/assets/9701-2022-on-42-q07-p03-1bf97c770b.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "T he structural and displayed formulae of three aromatic compounds, A, and C, are shown in 7 (a) B\nFig. 7.1.\nCHCl C H CH CH COOH CH C H OH C H CH CO H\n6 5 2 2 3 6 4 6 5 2 2\nHO O HO O\nOH\nCl\nA B C\nFig. 7.1\nC ompare the relative acidities of A, and C. B\n.................................. > .................................. > ..................................\nmost acidic least acidic\nE xplain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [3]\nH CH , can be made from benzene by an electrophilic substitution reaction. Methylbenzene, C (b)\n6 5 3\nIdentify a compound that reacts with benzene to form methylbenzene. (i)\nIdentify the catalyst used.\ncompound ...........................................................................................................................\ncatalyst ...............................................................................................................................\n[1]\n+ electrophile. T he first step in the reaction is the generation of the CH (ii)\n3\nWrite an equation for the reaction that generates this electrophile.\n....................................................................................................................................... [1]\n+ Describe the mechanism for the reaction between benzene and the CH electrophile. (iii)\n3\nInclude all relevant curly arrows and charges.\n(cid:31) (cid:31)\n+ CH\n3\n[3]\nH COOH. Identify a suitable reagent to oxidise methylbenzene to benzoic acid, C (iv)\n6 5\nWrite an equation for this reaction using [O] to represent one atom of oxygen from the\noxidising agent.\nreagent ...............................................................................................................................\nequation ..............................................................................................................................\n[2]\nMethylbenzene and benzoic acid are both nitrated with a mixture of concentrated nitric acid (v)\nand sulfuric acid to give mononitrated products. The structural formulae of these products\nC H NO and HOOCC H NO respectively. are CH\n3 6 4 2 6 4 2\nDraw the structures of these two products.\n[1]\nA reaction scheme is shown in Fig. 7.2. (c)\nreaction 1\nCH C H NO CH C H NH\n3 6 4 2 3 6 4 2\nreaction 2\nreaction 3\n+Cl – CH C H OH CH C H N\n3 6 4 3 6 4 2\nreaction 4\ndye molecule Y\nFig. 7.2\n– +Cl C H N from CH C H NH in Describe the reagents and conditions to produce CH (i)\n3 6 4 2 3 6 4 2\nreaction 2.\nreag", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2022-on-42-q07-175b477efb.pdf" }, { "id": "9701-2022-on-42-q08", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 19, 20 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2022-on-42-q08-p01-a1082f6367.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-42-q08-p02-76faedbc12.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "When answering this question it should be assumed that together all the hydrogen atoms in a 8\nδ (1H) NMR spectrum. benzene ring result in a single unsplit peak at = 7.2 in a proton\nThe structures of five isomeric ketones, P, Q, R, and are given. S T\nH COCH(CH ) C H CH CH COCH C S P\n6 5 3 2 6 5 2 2 3\nC H COCH CH CH C H CH(CH )COCH Q T\n6 5 2 2 3 6 5 3 3\nC H CH COCH CH R\n6 5 2 2 3\nIdentify all the chiral carbon atoms on the structures above. Label each chiral carbon atom with (a)\nan asterisk (*). [1]\n(1H) The proton NMR spectrum of one of the five isomers, P, Q, R, or T, is shown in Fig. 8.1. (b) S\n11 10 9 8 7 6 5 4 3 2 1 0\n(cid:31) / ppm\nFig. 8.1\nIdentify which of the compounds P, Q, R, or gives this spectrum. (i) S T\nDraw the displayed formula of the compound you have identified. Identify the protons\nδ δ δ responsible for the peaks at = 3.7, = 2.5 and = 1.0 on the structure you have drawn.\n[2]\nδ N ame the splitting pattern of the peak at = 3.7. Explain why it has this splitting pattern. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nChoose from the letters P, Q, R, and to identify: (c) S T\n(1H) NMR spectrum the compounds that each have a doublet peak in the proton (i) two\n....................................................................................................................................... [1]\n(1H) NMR spectrum. t he compound with only three peaks in its proton (ii)\n....................................................................................................................................... [1]\nSuggest a suitable solvent that should be used for obtaining the spectrum shown in Fig. 8.1. (d)\n.............................................................................................................................................. [1]\n(1H) The proton NMR spectrum of compound is compared in the presence of D O and in the (e) T\n2\nO. absence of D\n2\nD escribe any difference between the two spectra. Explain your answer.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nComplete Table 8.1 below to give the number of peaks in the carbon-13 NMR spectrum of each (f)\ncompound.\nTable 8.1\ncompound number of peaks compound number of peaks\n[2]\n[Total: 10]", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2022-on-42-q08-083d6d42f8.pdf" }, { "id": "9701-2022-on-42-q09", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_42.pdf?download=true", "source_pages": [ 21, 22, 23, 24 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-42-q09-p01-b68d64cb33.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-42-q09-p02-ab31fcaefb.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-42-q09-p03-84ad6bf493.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-42-q09-p04-62e1bb3019.png" ], "answer": { "status": "pending", "id": "9701-2022-on-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Tyrosine and lysine, shown in Fig. 9.1, are naturally occurring amino acids found in proteins. 9\nO O\nH N\n2\nOH OH\nNH NH\n2 2\nHO\ntyrosine lysine\nFig. 9.1\nThe isoelectric point of lysine is 9.47. (a)\nD raw the structure of lysine at the stated pH in the boxes below.\nlysine at pH 7.00 lysine at pH 9.47 lysine at pH 12.00\n[2]\nPCl When ethanoic acid is treated with product is formed. (b) D\n5\nW hen is added to tyrosine two different isomeric products, and F, are formed. D E\nhas an ester linkage, does not. E F\nD raw the structures of D, and in the boxes below. E F\nD E F\n[3]\nComplete Table 9.1 by drawing the structure of the organic product formed when tyrosine (c)\nreacts with each named reagent.\nCHNH COOH substituent. I gnore the directing effect of the –CH\n2 2\nTable 9.1\nreagent structure\nan excess of Br (aq)\n2\nan excess of NaOH(aq)\n(aq) an excess of HNO\n3\n[3]\nA mixture of tyrosine and lysine can be separated by thin-layer chromatography. Under certain (d)\nconditions the R value of lysine is 0.14 and the R value of tyrosine is 0.45.\nf f\nvalue. Explain what is meant by R (i)\nf\n.............................................................................................................................................\n....................................................................................................................................... [1]\nvalues. S uggest an explanation for the difference in R (ii)\nf\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 10]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n× 104 mol–1 Faraday constant F = 9.65 C\n× 1023 mol–1 Avogadro constant L = 6.022\n× 10–19 electronic charge e = –1.60 C\ndm3 mol–1 molar volume of gas V = 22.4 at s.t.p. (101 kPa and 273 K)\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n× °C)) 10–14 mol2 dm–6 ionic product of water K = 1.00 (at 298 K (25\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eH eN nR eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nmuicnerwal enissennet enimorb enirolhc enitatsa muitetul eniroulf 9.621 0.571 enidoi 0.91 5.53 9.97 uL 71 lC 301 sT rB 711 tA rL 71 53 35 58 17 F I – – – 9\nmuiromrevil muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib cinesra muiluht 8.121 0.902 9.861 mT dM cM bS 0.41 0.13 9.47 sA 51 101 511 iB N P 51 33 15 38 96 – – 7\nmuinamreg muivorelf muimref nobrac muibre 2.702 3.761 7.811 mF nocilis eG nS bP 0.21 1.82 6.27 41 001 rE 411 dael lF iS C 28 41 23 05 86 nit 6 – –\nmuinietsnie muinimula muinohin muimloh muillaht muillag 4.402 9.461 muidni 8.411 ", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-on-42-q09-10cf6ddd7e.pdf" }, { "id": "9701-2022-on-43-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2022-on-43-q01-p01-61edcaeea7.png", "9701-topic-23-chemical-energetics/assets/9701-2022-on-43-q01-p02-df94500176.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "KCl, MgCl Potassium chloride, and magnesium chloride, , are both ionic solids. 1\n2\nTable 1.1\nmol–1 energy change value / kJ\nKCl standard enthalpy change of solution, , of +15\nKCl lattice energy, , of (s) –701\nK+ , of –322 standard enthalpy change of hydration,\n– –364 Cl standard enthalpy change of hydration, , of\nMgCl , of –155 standard enthalpy change of solution,\n2\nMgCl lattice energy, , of (s) –2493\n2\nComplete the energy cycle involving the enthalpy change of solution and the lattice energy of (a)\nKCl, potassium chloride, and the relevant enthalpy changes of hydration. Label your diagram.\nS tate symbols should be used.\nKCl (s)\n[2]\nUse the data in Table 1.1 to calculate the enthalpy change of hydration of magnesium ions, (b)\nMg2+. Show your working.\nMg2+ mol–1 of magnesium ions, = .............................. kJ [2]\nMgCl Explain the reasons why the lattice energy of is more exothermic than the lattice energy (c)\n2\nKCl. of\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n.............................................................................................................................................. [2]\nDefine the following terms. (d)\nenthalpy change of atomisation .......................................................................................... (i)\n....................................................................................................................................... [1]\nfirst electron affinity ............................................................................................................. (ii)\n....................................................................................................................................... [1]\nE xplain what is meant by entropy, S. (e) (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n°C. P otassium chloride is very soluble in water at 20 (ii)\n∆S. Explain the solubility of potassium chloride by reference to change in entropy,\n.............................................................................................................................................\n....................................................................................................................................... [1]\nUse the Gibbs equation and your answer to to predict whether potassium chloride is (iii) (e)(ii)\n°C °C. more soluble in water at 20 or ", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2022-on-43-q01-5b594663bf.pdf" }, { "id": "9701-2022-on-43-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2022-on-43-q02-p01-987c029d32.png", "9701-topic-26-reaction-kinetics/assets/9701-2022-on-43-q02-p02-51a0c9fcf5.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "E xplain what is meant by the following terms: 2 (a) (i)\nhomogeneous catalyst ........................................................................................................\n.............................................................................................................................................\nheterogeneous catalyst ......................................................................................................\n.............................................................................................................................................\n[1]\nI odide ions react with peroxydisulfate ions. (ii)\n→ 2I– 2– 2– I + S O + 2SO\n2 8 2 4\nFe2+ This reaction is slow, but it is catalysed by ions.\nFe2+ ions. Write two equations to explain how this reaction is catalysed by\n1 ..........................................................................................................................................\n2 ..........................................................................................................................................\n[2]\nFe2+ ions has a lower activation Suggest why the alternative route in the presence of (iii)\nenergy than the route in the absence of a catalyst.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nNitrogen monoxide reacts with oxygen. (b)\n→ (g) 2NO (g) 2NO(g) + O\n2 2\nThis reaction is second order with respect to nitrogen monoxide and first order with respect to\noxygen.\n× 106 mol–2 dm6 s–1. U nder certain conditions the value of the rate constant, k, is 8.60\nConstruct the rate equation for this reaction. (i)\nrate =\n[1]\nC alculate the initial rate of the reaction under these conditions when the initial concentration (ii)\n× 10–4 dm–3 mol and the initial concentration of oxygen is of nitrogen monoxide is 7.20\n× 10–3 dm–3. mol 1.90\ndm–3 s–1 rate of reaction = .............................. mol [1]\nCl The drug cisplatin, Pt(NH ) , hydrolyses in water. (c)\n3 2 2\n→ O)]+ – Cl Cl Cl ) + H O [Pt(NH ) (H + Pt(NH\n3 2 2 2 3 2 2\nT he rate equation is shown.\nCl ) ] rate = k [Pt(NH\n3 2 2\n× 10–5 s–1 under certain conditions. T he value of k is 2.50\nThis reaction has a constant half-life. (i)\nExplain why this is the case.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n× 104 s. U se the information in this question to show that the half-life of this reaction is 2.77 (ii)\n[1]\n× 10–6 cm3 Cl moles of Pt(NH ) are added to 100 of water. 8.00 (iii)\n3 2 2\n× 10–6 dm–3. Cl ) to fall to 2.50 mol Calculate the time taken for the concentration", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2022-on-43-q02-5eeb2af675.pdf" }, { "id": "9701-2022-on-43-q03", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2022-on-43-q03-p01-6293f6958a.png", "9701-topic-24-electrochemistry/assets/9701-2022-on-43-q03-p02-b2b3efef04.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Data should be selected from Table 3.1 in order to answer some parts of this question. 3\nTable 3.1\no electrode reaction E / V\n2e– – 2Cl Cl +1.36 +\n2\n2H+ 2e– Cl 2HOCl +1.64 + + 2H O +\n2 2\nO– 2e– – 2OH– Cl Cl +0.89 + H O + +\n2\nSn4+ 2e– Sn2+ +0.15 +\nSn2+ 2e– –0.14 + Sn\nV2+ 2e– –1.20 + V\nV3+ e– V2+ –0.26 +\nVO2+ 2H+ e– V3+ +0.34 + + + H O\n2\n2H+ e– VO2+ + +1.00 + + + H O VO\n2 2\nStandard electrode potentials are measured under standard conditions. (a)\nSn4+ Sn2+ / half-cell. Describe the standard conditions used in the (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\no (Sn4+ Sn2+) / can be measured experimentally. C omplete the diagram below to show how E (ii)\nYour diagram should be fully labelled to identify all apparatus and substances.\n[3]\ndm–3 Sn2+(aq) dm–3 –(aq) Cl Equal volumes of 1.0 mol and 1.0 mol are mixed. (iii)\no values to explain whether a reaction occurs between these two ions. Use relevant E\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\ndm–3 Sn2+(aq) dm–3 VO2+(aq) of and acidified 1.0 mol are mixed. Equal volumes of 1.0 mol (iv)\nWrite an equation for the reaction that takes place in the resulting mixture.\n....................................................................................................................................... [2]\nSnCl (aq) is electrolysed for a measured time using a steady current. A solution of (b)\n2\nA mass of 2.95 g of tin metal is produced at the cathode.\nl O (l) is electrolysed for the same time by the same current. A\n2 3\nC alculate the mass of aluminium metal produced at the cathode. Give your answer to three\nsignificant figures. Show your working.\nmass of aluminium metal = .............................. g [2]\n[Total: 10]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2022-on-43-q03-fce926f2a9.pdf" }, { "id": "9701-2022-on-43-q04", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2022-on-43-q04-p01-39b93ec0f4.png", "9701-topic-25-equilibria/assets/9701-2022-on-43-q04-p02-294ec89464.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q04", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "A sample of butanoic acid, CH (CH ) COOH, is shaken with a mixture of two immiscible 4 (a)\n3 2 2\nsolvents, ethoxyethane and water. The solvents form two layers. The butanoic acid is distributed\nbetween the two layers, its concentration in ethoxyethane being higher than its concentration\nin water.\nState what is meant by partition coefficient. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n, for butanoic acid between ethoxyethane and water is 3.50. The partition coefficient, K (ii)\npc\ncm3 ethoxyethane is added to water. This A solution of 2.00 g of butanoic acid in 100\nmixture is left until there is no further change in the concentration of butanoic acid in either\nsolvent. The mass of butanoic acid dissolved in the ethoxyethane layer is now 1.62 g.\nCalculate the volume of water used.\ncm3 [2] volume of water used = ..............................\nAn aqueous solution of butanoic acid can be used to make a buffer solution. (b)\nDefine buffer solution. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nS uggest one organic compound, and one inorganic compound, that can be added to two (ii)\ndifferent samples of aqueous butanoic acid to produce buffer solutions.\norganic compound ..............................................................................................................\ninorganic compound ...........................................................................................................\n[1]\n× 10–9 dm–3. Al The solubility of aluminium hydroxide, (OH) , in water is 2.47 mol (c)\n3\n, of aluminium hydroxide. Give the expression for the solubility product, K (i)\nsp\nK =\nsp\n[1]\nC alculate the numerical value of the K of aluminium hydroxide. Include the units of K in (ii)\nsp sp\nyour answer.\nK = ..............................\nsp\nunits = ..............................\n[3]\n[Total: 9]", "pdf_path": "9701-topic-25-equilibria/print/9701-2022-on-43-q04-9f0a200f04.pdf" }, { "id": "9701-2022-on-43-q05", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-43-q05-p01-34477cec44.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-43-q05-p02-ca205f9d54.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-43-q05-p03-c45b7548b7.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "A transition element is a d-block element which forms one or more stable ions with incomplete 5\nd-orbitals.\norbital and the 3d orbital. Two of the 3d orbitals are the 3d (a)\n2 xy z\nS ketch the shapes of these two orbitals.\n3d 3d\n2 xy z\ny z\nz y\nx x\n[1]\nNi2+ ]2+ The ion forms many different complexes. A solution containing the [Ni(H O) complex ion (b)\n2 6\nNCH CH NH , is added, the colour of is green. When an excess of 1,2-diaminoethane, en, H\n2 2 2 2\n]2+ complex ion. the solution changes to blue. This is due to the formation of the [Ni(en)\n3\nExplain why the two solutions are coloured, and why the colours are different. (i)\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [4]\n]2+ The [Ni(en) complex can exist as a mixture of two stereoisomers. (ii)\n3\nComplete the three-dimensional diagram to show one of the stereoisomers.\n. Each en ligand can be represented using\nN N\nNi\n[1]\nName the geometry of the complex ion drawn in and the type of stereoisomerism (iii) (b)(ii)\n]2+. shown by [Ni(en)\n3\ngeometry .............................................................................................................................\nstereoisomerism shown ......................................................................................................\n[1]\nIron(II) nickel(II) carbonate, FeCO , and carbonate, NiCO , both decompose when heated. (c)\n3 3\ndecomposes at a lower temperature than NiCO . F eCO\n3 3\nSuggest a possible reason for this difference. Explain your answer.\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n....................................................................................................................................................\n...........................................................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-43-q05-0ae21f1366.pdf" }, { "id": "9701-2022-on-43-q06", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-43-q06-p01-7339c9dc23.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2022-on-43-q06-p02-9734050871.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "copper(II) ]2+ An aqueous solution of sulfate is a blue colour due to the presence of [Cu(H O) 6\n2 6\ncomplex ions.\n]2+ O) ions and NaOH(aq). W rite an equation for the reaction between [Cu(H (a) (i)\n2 6\n....................................................................................................................................... [1]\n]2+ HCl. O) ions and an excess of conc. W rite an equation for the reaction between [Cu(H (ii)\n2 6\n....................................................................................................................................... [1]\n]2+ If an excess of ammonia is added to a solution of [Cu(H O) a deep blue solution containing (b)\n2 6\n]2+ ) (H O) complex ions is formed. [Cu(NH\n3 4 2 2\n]2+. ) (H O) There are two possible stereoisomers with the formula [Cu(NH (i)\n3 4 2 2\nComplete the diagrams to show the two stereoisomers in the boxes below.\nisomer 1 isomer 2\nCu Cu\n[1]\nU se your answer in to deduce whether each of these isomers is polar or non-polar. (ii) (b)(i)\npolarity of isomer 1 .............................................................................................................\npolarity of isomer 2 .............................................................................................................\n[1]\n]2+ , of the [Cu(NH ) (H O) complex ion is The numerical value of the stability constant, K (c)\nstab 3 4 2 2\n× 1013. 1.40\nDefine stability constant. (i)\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+ ]2+ C ompare the stabilities of the [Cu(H O) and [Cu(NH ) (H O) complex ions. Explain (ii)\n2 6 3 4 2 2\nyour answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n]2+ , of the [Cu(NH ) (H O) complex ion. Write an expression for the stability constant, K (iii)\nstab 3 4 2 2\nState the units of the stability constant.\nK =\nstab\nunits = ..............................\n[2]\n]2+ ) (H O) complex ion is In a particular solution the concentration of the [Cu(NH (iv)\n3 4 2 2\ndm–3 dm–3. and the concentration of NH is 0.57 mol 0.0074 mol\n3\n× 1013 value of 1.40 to calculate the concentration Use your expression in and the K (c)(iii)\nstab\n]2+ O) complex ion in this solution. of the [Cu(H\n2 6\n]2+ dm–3 O) = .............................. mol [1] concentration of [Cu(H\n2 6\n2–, Phenanthroline, C H N , and ethanedioate ions, C O are bidentate ligands. (d)\n12 8 2 2 4\nuthenium(III) Ru3+, ions, form an octahedral complex with phenanthroline and chloride ions. R\nThe complex ion contains two phenanthroline molecules.\nron(III) Fe3+, ions, form an octahedral", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2022-on-43-q06-fb797accee.pdf" }, { "id": "9701-2022-on-43-q07", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 16, 17, 18, 19 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-43-q07-p01-2b53ab5f19.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-43-q07-p02-5435567451.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-43-q07-p03-a738f0eb90.png", "9701-topic-34-nitrogen-compounds/assets/9701-2022-on-43-q07-p04-88f8b490f9.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "The structure of compound is shown in Fig. 7.1. 7 (a) P\nP\nO H N\n2\nO\nFig. 7.1\nis optically active. (i) P\nUse an asterisk (*) to identify all chiral carbon atoms on the structure of in Fig. 7.1. [1] P\nP lane polarised light is passed through a pure sample of one enantiomer of P. This is then (ii)\nrepeated with a pure sample of the other enantiomer of P.\nDescribe the results of these two experiments, stating the similarities and differences of\nthe results.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [2]\ncan be used to make compound in a single step reaction. (b) P Q\nQ\nO\nO\nHN\nO\nGive the structural formula of the compound that is added to to make and give the (i) P Q\nformula of the other product of this reaction.\ncompound added to ........................................................................................................ P\nother product ......................................................................................................................\n[1]\nLiAl W hen an ester is treated with H in dry ether the ester linkage is cleaved by the (ii)\n4\naddition of four hydrogen atoms and two alcohols are produced.\nLiAl Draw the structures of the compounds formed when is treated with an of H Q excess\n4\nin dry ether.\n[3]\nCompare the relative basicities of compound P, compound and phenylamine. (iii) Q\n........................................... < ........................................... < ...........................................\nleast basic most basic\nExplain your answer.\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n.............................................................................................................................................\n[3]\ncan be used to make compound in a two-step reaction, shown in Fig. 7.2. (c) P R\nP R\nO O H N H N\n2 2\ntwo steps\nO H N OH\n2\nFig. 7.2\nIdentify the reagents and conditions used for the two steps of the reaction. (i)\nstep 1 ..................................................................................................................................\nstep 2 ..................................................................................................................................\n[2]\nC omplete Table 7.1 by drawing the structures of the org", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2022-on-43-q07-c4d02a2897.pdf" }, { "id": "9701-2022-on-43-q08", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 20, 21 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2022-on-43-q08-p01-ff73611821.png", "9701-topic-30-hydrocarbons/assets/9701-2022-on-43-q08-p02-3cd6d6c35d.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q08", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "Benzene, C H , is an aromatic molecule. 8\n6 6\nState the C–C–C bond angle and the hybridisation shown by the carbon atoms in benzene. (a)\nbond angle .................................................................................................................................\nhybridisation ..............................................................................................................................\n[1]\nBenzene reacts with chloroethane in the presence of a catalyst. The reaction mechanism is (b)\ncalled electrophilic substitution.\n+CH CH electrophile. The first step in the reaction is the generation of the (i)\n2 3\nWrite an equation for the reaction that generates this electrophile.\n....................................................................................................................................... [1]\n+CH CH electrophile. D escribe the mechanism for the reaction between benzene and the (ii)\n2 3\nInclude all relevant curly arrows and charges.\nintermediate products\n→ → H H\n+C C H\nH H\n[3]\nChlorobenzene and chloroethane have different reactivities in nucleophilic substitution (c)\nreactions.\nIdentify a suitable reagent to illustrate this difference in reactivity. (i)\nThe reagent chosen should give different results with chlorobenzene and visibly\nchloroethane.\n....................................................................................................................................... [1]\nW rite equations to describe any reactions that occur. (ii)\n[1]\nExplain the difference in the reactivities of chlorobenzene and chloroethane in nucleophilic (iii)\nsubstitution reactions.\n.............................................................................................................................................\n....................................................................................................................................... [1]\n[Total: 8]", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2022-on-43-q08-abe711bb7b.pdf" }, { "id": "9701-2022-on-43-q09", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_43.pdf?download=true", "source_pages": [ 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_43.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p01-7465fc0004.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p02-3e7b9051ab.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p03-3d0f31ebdf.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p04-9760f30e46.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p05-84ad6bf493.png", "9701-topic-37-analytical-techniques/assets/9701-2022-on-43-q09-p06-f7b546968f.png" ], "answer": { "status": "pending", "id": "9701-2022-on-43-q09", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Gas-liquid chromatography involves a stationary phase and a mobile phase. 9 (a)\nName, or describe in detail, a suitable substance that could be used for each phase. (i)\nstationary ............................................................................................................................\nmobile .................................................................................................................................\n[1]\nA mixture of three organic compounds is separated by gas-liquid chromatography. The\nchromatogram obtained is shown in Fig. 9.1. The amount of each substance is proportional to\nthe area under its peak.\nB\n100\n80\n60\nrecorder\nresponse\n40\nA\nC\n20\n0\n14 16 18 20 22 24 26 28 30\nretention time (min)\nFig. 9.1\nE xplain the meaning of retention time. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nCalculate the percentage of in the mixture. Show your working. (iii) B\npercentage of = .............................. % [2] B\nComplete Table 9.1 to give the number of peaks in the carbon-13 NMR spectrum of each of the (b)\nH O that has an ester group. five isomers of C\n5 10 2\nTable 9.1\nstructural formula number of peaks\nCH CH CH CO CH\n3 2 2 2 3\nCH CH CO CH CH\n3 2 2 2 3\nCH CO CH CH CH\n3 2 2 2 3\n(CH ) CHCO CH\n3 2 2 3\nCH CO CH(CH )\n3 2 3 2\n[2]\n(1H) State the number of peaks that would be seen in the proton NMR spectrum of (c)\nCH CH CO CH . Name all the splitting patterns seen in this spectrum. methyl butanoate, CH\n3 2 2 2 3\nnumber of peaks ........................................................................................................................\nsplitting patterns ........................................................................................................................\n[2]\n(1H) and are both esters with the molecular formula C H O . Their proton NMR spectra are (d) D E\n5 10 2\nshown in Fig. 9.2 and Fig. 9.3.\nD\n3\n3\n2 2\n4 3 2 1 0\n(cid:31) chemical shift,\nFig. 9.2\nE\n3\n6\n1\n4 3 2 1 0\n(cid:31) chemical shift,\nFig. 9.3\nTable 9.2\nenvironment of proton example typical chemical shift\nδ range, / ppm\nalkane –CH , –CH –, >CH– 0.9–1.7\n3 2\nalkyl next to C=O CH –C=O, –CH –C=O, 2.2–3.0\n3 2\n>CH–C=O\n–Ar, –CH –Ar, 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n>CH–Ar\n3.2–4.0 –O, –CH –O, alkyl next to electronegative atom CH\n3 2\n–Cl –CH\n2\nattached to alkene =CHR 4.5–6.0\nDeduce the structures of the two esters and and draw their displayed formulae in the (i) D E\nboxes below.\nD E\nH O H O C C\n5 10 2 5 10 2\n[2]\nδ T he spectrum of includes a quartet at 4.1. (ii) D\nIdentify the protons responsible for this quartet on your structure in by labelling these (i)\nprotons with the letter F.\nExplain why this peak is split into a quartet.\n...........................................................................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2022-on-43-q09-37a4c523bd.pdf" }, { "id": "9701-2022-on-51-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_51.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-51-q01-p01-76583e6d8a.png", "9701-experimental-skills/assets/9701-2022-on-51-q01-p02-c74ef25b56.png" ], "answer": { "status": "pending", "id": "9701-2022-on-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student attempts to determine the percentage by mass of magnesium chloride in the solid mixture 1\nMgCl , and anhydrous magnesium nitrate, Mg(NO ) , using the containing magnesium chloride,\n2 3 2\nfollowing method.\nAccurately weigh about 1.5 g of the solid mixture and record the mass. step 1\nDissolve the solid mixture in distilled water. step 2\nAdd an excess of silver nitrate solution. step 3\nFilter the solid mixture and wash the precipitate collected with distilled water. step 4\nDry the precipitate in an oven. step 5\nWeigh the precipitate and record the mass. step 6\nIn this process only the chloride ions from the magnesium chloride form a precipitate with the\nsilver nitrate solution.\n→ 2AgCl MgCl (aq) + 2AgNO (aq) Mg(NO ) (aq) + (s)\n2 3 3 2\nOne student in the class obtains the following results.\nmass of solid mixture = 1.52 g\nAgCl mass of solid after drying = 3.63 g\nC alculate the amount, in mol, of magnesium chloride present in the sample. (a) (i)\namount of magnesium chloride = .............................. mol [1]\nU se your answer to to calculate the percentage by mass of magnesium chloride in the (ii) (i)\nsample. (If you were unable to answer use 0.0102 mol. This is not the correct answer.) (i)\npercentage by mass = .............................. [2]\nS uggest what the student could do in to ensure the solid dissolves as quickly as (b) (i) step 2\npossible.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nE xplain why the precipitate was washed with distilled water before it was dried. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nSuggest why the precipitate is dried in an oven and not by direct heating with a Bunsen (iii)\nburner.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nIn 1, a small beaker was weighed, using a balance accurate to two decimal places, (c) (i) step\nand its mass recorded. The sample was placed in the beaker and", "pdf_path": "9701-experimental-skills/print/9701-2022-on-51-q01-23e728aca7.pdf" }, { "id": "9701-2022-on-51-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_51.pdf?download=true", "source_pages": [ 4, 6, 7, 8 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-51-q02-p01-96408ed1d3.png", "9701-experimental-skills/assets/9701-2022-on-51-q02-p02-db9786dd9c.png", "9701-experimental-skills/assets/9701-2022-on-51-q02-p03-3301aaf71a.png", "9701-experimental-skills/assets/9701-2022-on-51-q02-p04-0b82d6a550.png" ], "answer": { "status": "pending", "id": "9701-2022-on-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Charles’ law states that for a fixed mass of gas at constant pressure, its volume is proportional to 2\nits absolute temperature. Most gases are non-ideal and do not obey this law, but at lower pressures\nand high temperatures some gases are close to ideal behaviour. One gas that behaves like this is\noxygen.\nmanganese(IV) Oxygen can be prepared by decomposing hydrogen peroxide with the catalyst\n. oxide, MnO\n2\nThe equation for the decomposition of hydrogen peroxide is shown.\n→ O (aq) 2H O(l) + O (g) 2H\n2 2 2 2\nSafety hazard: hydrogen peroxide is corrosive to skin and can cause serious eye damage.\ngas syringe\nthermometer\nbeaker\nwater\noxygen\nheat\nFig. 2.1\ncm3. There are Once the apparatus is assembled the volume of oxygen in the gas syringe is 2\ncm3 cm3. of oxygen remaining in the flask. The total volume of oxygen is 82 80\nCharles’ law is investigated by the following method.\nOnce assembled allow the apparatus to reach room temperature. step 1\nRecord this temperature and the total volume of oxygen reading on the syringe. step 2\n°C Gently heat the apparatus until the temperature reaches 30 and record the total volume step 3\nof oxygen.\n°C °C. Repeat at intervals of 5 until the temperature reaches 70 step 4\nThe student carried out the experiment and obtained the following results:\nTable 2.1\ntemperature absolute total volume of\n°C cm3 / temperature / K oxygen gas /\n24 297 82\n30 303 84\n35 308 88\n40 313 88\n45 318 89\n50 323 91\n55 328 93\n60 333 95\n65 338 97\n70 343 98\nOther than the wearing of safety goggles, give a safety precaution that the student must take (a)\nduring the preparation of oxygen.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nC omplete the following diagram to show how the student can obtain oxygen by gas (b) (i)\ncollection over water for use in the experiment shown in Fig. 2.1.\nH O (aq)\n2 2\nMnO catalyst\n2 [2]\nSuggest how the student could ensure they collect pure oxygen gas in the conical flask. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nP lot a graph on the grid to show the relationship between volume of oxygen and absolute (c) (i)\n(×) temperature. Use a cross to plot each data point. Draw a line of best fit.\n100\n98\n96\n94\n92\ntotal volume of\ncm3 oxygen gas /\n90\n88\n86\n84\n82\n80\n290 300 310 320 330 340 350\nabsolute temperature / K\n[2]\nDetermine the gradient of your line of best fit. State the coordinates of both points you used (ii)\nin your calculation. These must be selected from your line of best fit. Give the gradient to\nthree significant figures.\ncoordinate", "pdf_path": "9701-experimental-skills/print/9701-2022-on-51-q02-df0f8f4184.pdf" }, { "id": "9701-2022-on-51-q03", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 3, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_51.pdf?download=true", "source_pages": [ 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-51-q03-p01-f0f32156a3.png", "9701-experimental-skills/assets/9701-2022-on-51-q03-p02-8a1f6a73b7.png", "9701-experimental-skills/assets/9701-2022-on-51-q03-p03-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-on-51-q03-p04-273b059c02.png" ], "answer": { "status": "pending", "id": "9701-2022-on-51-q03", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "bromate(V) Potassium reacts with potassium bromide and sulfuric acid to form potassium sulfate, 3\nbromine and water according to the following equation.\n→ (aq) + 5KBr(aq) + 3H SO (aq) 3K SO (aq) + 3Br (aq) + 3H O(l) KBrO\n3 2 4 2 4 2 2\nA student is investigating how the rate of this reaction is affected by changing the concentration\nof the reactants in turn. This is done by keeping the total volume of mixture constant and adding\ndifferent, small volumes of each reagent.\nThe reaction produces bromine which is orange in colour. The student times the reaction and then\n1\n. determines the rate as\ntime\nThe rate equation for the reaction is of the form:\n]x[KBr]y[H ]z SO rate = k [KBrO\n3 2 4\nk is the rate constant for the reaction and x, y and z are the respective orders of the reaction for\neach reagent.\nThe student carried out the experiment and obtained the following data.\nTable 3.1\n[KBrO ] [KBr] [H SO ] rate of reaction\n3 2 4 mixture\ndm–3 dm–3 dm–3 s–1 / mol / mol / mol /\nA 0.025 0.125 0.075 0.059\nB 0.050 0.125 0.075 0.117\nC 0.025 0.250 0.075 0.118\nD 0.025 0.125 0.150 0.235\nE 0.050 0.250 0.150 0.941\nS uggest how the student might time the reaction and judge the end point of the reaction (a) (i)\nfor each mixture.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nB y comparing the data for the mixtures deduce the values of x, y and z. (ii)\n[2]\ncm3) The student carried out each reaction using a boiling tube (capacity 50 and varied the (b)\ncm3 concentration by adding different volumes of each reagent. For example, in mixture A, 5.0\n(aq) is required. of KBrO\n3\nN ame a suitable piece of apparatus which could be used to measure this volume.\n.............................................................................................................................................. [1]\nSuggest why the reagents are heated to the same temperature before mixing. (c)\n.............................................................................................................................................. [1]\ndm–3. This The solution of sulfuric acid used in each mixture was of concentration 0.150 mol (d)\ndm–3. acid was prepared from a solution of concentration 1 mol\nBriefly describe how to make the more dilute solution, stating the capacity of any apparatus\nused.\n....................................................................................................................................................\n....................................................................................................................................................\n........................................", "pdf_path": "9701-experimental-skills/print/9701-2022-on-51-q03-1436d82785.pdf" }, { "id": "9701-2022-on-52-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-52-q01-p01-4aaabe1f1e.png", "9701-experimental-skills/assets/9701-2022-on-52-q01-p02-6340bf4756.png", "9701-experimental-skills/assets/9701-2022-on-52-q01-p03-534f133d80.png" ], "answer": { "status": "pending", "id": "9701-2022-on-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Eggshells contain a high percentage by mass of calcium carbonate, CaCO . A student wants to find 1\n3\nout what percentage of an eggshell is calcium carbonate and uses the following method.\nThis method uses a known excess of acid to dissolve the eggshell. The amount of unreacted acid\nin the is then determined by titration with an alkali. Assume the acid only reacts with the CaCO\n3\neggshell.\nW ash an empty eggshell with distilled water. step 1\nW arm the eggshell in an oven for a few minutes until dry. step 2\nG rind the eggshell into a powder. step 3\nW eigh approximately 2 g of the eggshell powder into a conical flask using a balance which step 4\nmeasures to three decimal places.\ncm3 dm–3 of 2.00 mol hydrochloric acid to the conical flask. Add 100 step 5\nL oosely cover the conical flask and leave for two days. step 6\ncm3 volumetric flask F ilter the contents of the conical flask, with any rinsings, into a 250.0 step 7\nand top‑up to the mark using distilled water.\ncm3 of the solution prepared in into a conical flask, add a few drops T ransfer 25.00 step 7 step 8\ndm–3 cm3 sodium hydroxide using a 50 of thymol blue indicator and titrate against 1.00 mol\nburette.\nThe calcium carbonate in the eggshell reacts with the excess hydrochloric acid as follows.\n→ 2HCl CaCl (s) + (aq) (aq) + CO (g) + H O(l) CaCO\n3 2 2 2\nThe excess acid reacts with the sodium hydroxide solution as follows.\n→ HCl NaCl O(l) NaOH(aq) + (aq) (aq) + H\n2\nS uggest how the student could confirm the eggshell is completely dry in 2. (a) (i) step\n.............................................................................................................................................\n....................................................................................................................................... [1]\nS tate why the eggshell is made into a powder in before making up the solution. (ii) step 3\nExplain your answer.\n.............................................................................................................................................\n....................................................................................................................................... [1]\nSuggest why the solution is left for two days in before being used. (iii) step 6\n.............................................................................................................................................\n....................................................................................................................................... [1]\nThe student uses exactly 2.136 g of powdered eggshell and obtains the results shown in (b)\nTable 1.1.\nTable 1.1\ntitration number rough 1 2 3\ncm3 16.55 32.85 16.10 32.30 final burette reading /\ncm3 0.00 16.55 0.10 16.10 initial burette reading /\ncm3 titre /\nComplete Table 1.1. Calculate the mean titre. (i)\ncm3 mean titre = ..............................\n[2]\nHCl C alculate the amount, in mol, of unreacted (aq) in the solution prepar", "pdf_path": "9701-experimental-skills/print/9701-2022-on-52-q01-9aae18919f.pdf" }, { "id": "9701-2022-on-52-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 11, 12 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-52-q02-p01-f25da52e4e.png", "9701-experimental-skills/assets/9701-2022-on-52-q02-p02-d77317d125.png", "9701-experimental-skills/assets/9701-2022-on-52-q02-p03-63a3b8337b.png", "9701-experimental-skills/assets/9701-2022-on-52-q02-p04-879054709d.png", "9701-experimental-skills/assets/9701-2022-on-52-q02-p05-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-on-52-q02-p06-1014e899da.png" ], "answer": { "status": "pending", "id": "9701-2022-on-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "manganate(VII), It is possible to measure the rate at which potassium KMnO (aq), M = 158, 2\n4 r\ndiffuses through a permeable gel using the following method.\npetri dish containing\npermeable gel hole containing sample of aqueous\npotassium manganate(VII)\nFig. 2.1\nA petri dish is prepared with a permeable gel. step 1\nA hole of diameter 0.5 cm is cut in the centre of the permeable gel. step 2\n(aq) is placed into the hole and at the same time a stopwatch is A sample of KMnO step 3\n4\nstarted.\nA fter 3 minutes the diameter of the coloured spot is measured and recorded. step 4\nT he diameter is measured every 3 minutes until there are three successive equal step 5\nmeasurements.\nA student obtained the results shown in Table 2.1.\nTable 2.1\ntime diameter of the diameter increase\n/ minute coloured spot / cm of the coloured spot / cm\n0 0.5 0.0\n3 1.1 0.6\n6 1.7 1.2\n9 2.3 1.8\n12 2.7 2.2\n15 3.1 2.6\n18 3.2 2.7\n21 3.7 3.2\n24 3.9 3.4\n27 4.0 3.5\n30 4.1 3.6\n33 4.1 3.6\n36 4.1 3.6\nPlot a graph on the grid to show the relationship between diameter increase of the coloured (a)\n(×) spot and time. Use a cross to plot each data point. Draw a line of best fit.\n4.0\n3.0\ndiameter\nincrease of\nthe coloured\n/ cm spot\n2.0\n1.0\n0\n25 30 35 40 0 5 10 15 20\ntime / minute\n[2]\nOn the graph, circle the point which you believe to be the most anomalous. [1] (b) (i)\nS uggest a possible explanation for this anomaly. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nDraw a suitable tangent to the line at time = 15 minutes. Calculate the gradient of your tangent. (c)\nState both sets of coordinates used in your calculation. The stated coordinates must be from\nyour tangent. Give the gradient to three significant figures.\ncoordinates 1 ................................................... coordinates 2 .................................................\nminute–1 gradient = .............................. cm\n[3]\nSelect appropriate data from Table 2.1 and calculate the average rate of diffusion of KMnO (aq) (d)\n4\nminute–1. in cm\nminute–1 = .............................. cm [1] average rate of diffusion of KMnO\n4\nIdentify the independent variable in this experiment. (e)\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nSuggest how the experiment could be made to be more reliable. (f)\n..................................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2022-on-52-q02-94eecd69c2.pdf" }, { "id": "9701-2022-on-53-q01", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_53.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-53-q01-p01-76583e6d8a.png", "9701-experimental-skills/assets/9701-2022-on-53-q01-p02-c74ef25b56.png" ], "answer": { "status": "pending", "id": "9701-2022-on-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student attempts to determine the percentage by mass of magnesium chloride in the solid mixture 1\nMgCl , and anhydrous magnesium nitrate, Mg(NO ) , using the containing magnesium chloride,\n2 3 2\nfollowing method.\nAccurately weigh about 1.5 g of the solid mixture and record the mass. step 1\nDissolve the solid mixture in distilled water. step 2\nAdd an excess of silver nitrate solution. step 3\nFilter the solid mixture and wash the precipitate collected with distilled water. step 4\nDry the precipitate in an oven. step 5\nWeigh the precipitate and record the mass. step 6\nIn this process only the chloride ions from the magnesium chloride form a precipitate with the\nsilver nitrate solution.\n→ 2AgCl MgCl (aq) + 2AgNO (aq) Mg(NO ) (aq) + (s)\n2 3 3 2\nOne student in the class obtains the following results.\nmass of solid mixture = 1.52 g\nAgCl mass of solid after drying = 3.63 g\nC alculate the amount, in mol, of magnesium chloride present in the sample. (a) (i)\namount of magnesium chloride = .............................. mol [1]\nU se your answer to to calculate the percentage by mass of magnesium chloride in the (ii) (i)\nsample. (If you were unable to answer use 0.0102 mol. This is not the correct answer.) (i)\npercentage by mass = .............................. [2]\nS uggest what the student could do in to ensure the solid dissolves as quickly as (b) (i) step 2\npossible.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nE xplain why the precipitate was washed with distilled water before it was dried. (ii)\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nSuggest why the precipitate is dried in an oven and not by direct heating with a Bunsen (iii)\nburner.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nIn 1, a small beaker was weighed, using a balance accurate to two decimal places, (c) (i) step\nand its mass recorded. The sample was placed in the beaker and", "pdf_path": "9701-experimental-skills/print/9701-2022-on-53-q01-89c93e7299.pdf" }, { "id": "9701-2022-on-53-q02", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_53.pdf?download=true", "source_pages": [ 4, 6, 7, 8 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-53-q02-p01-96408ed1d3.png", "9701-experimental-skills/assets/9701-2022-on-53-q02-p02-db9786dd9c.png", "9701-experimental-skills/assets/9701-2022-on-53-q02-p03-3301aaf71a.png", "9701-experimental-skills/assets/9701-2022-on-53-q02-p04-0b82d6a550.png" ], "answer": { "status": "pending", "id": "9701-2022-on-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Charles’ law states that for a fixed mass of gas at constant pressure, its volume is proportional to 2\nits absolute temperature. Most gases are non-ideal and do not obey this law, but at lower pressures\nand high temperatures some gases are close to ideal behaviour. One gas that behaves like this is\noxygen.\nmanganese(IV) Oxygen can be prepared by decomposing hydrogen peroxide with the catalyst\n. oxide, MnO\n2\nThe equation for the decomposition of hydrogen peroxide is shown.\n→ O (aq) 2H O(l) + O (g) 2H\n2 2 2 2\nSafety hazard: hydrogen peroxide is corrosive to skin and can cause serious eye damage.\ngas syringe\nthermometer\nbeaker\nwater\noxygen\nheat\nFig. 2.1\ncm3. There are Once the apparatus is assembled the volume of oxygen in the gas syringe is 2\ncm3 cm3. of oxygen remaining in the flask. The total volume of oxygen is 82 80\nCharles’ law is investigated by the following method.\nOnce assembled allow the apparatus to reach room temperature. step 1\nRecord this temperature and the total volume of oxygen reading on the syringe. step 2\n°C Gently heat the apparatus until the temperature reaches 30 and record the total volume step 3\nof oxygen.\n°C °C. Repeat at intervals of 5 until the temperature reaches 70 step 4\nThe student carried out the experiment and obtained the following results:\nTable 2.1\ntemperature absolute total volume of\n°C cm3 / temperature / K oxygen gas /\n24 297 82\n30 303 84\n35 308 88\n40 313 88\n45 318 89\n50 323 91\n55 328 93\n60 333 95\n65 338 97\n70 343 98\nOther than the wearing of safety goggles, give a safety precaution that the student must take (a)\nduring the preparation of oxygen.\n....................................................................................................................................................\n.............................................................................................................................................. [1]\nC omplete the following diagram to show how the student can obtain oxygen by gas (b) (i)\ncollection over water for use in the experiment shown in Fig. 2.1.\nH O (aq)\n2 2\nMnO catalyst\n2 [2]\nSuggest how the student could ensure they collect pure oxygen gas in the conical flask. (ii)\n.............................................................................................................................................\n....................................................................................................................................... [1]\nP lot a graph on the grid to show the relationship between volume of oxygen and absolute (c) (i)\n(×) temperature. Use a cross to plot each data point. Draw a line of best fit.\n100\n98\n96\n94\n92\ntotal volume of\ncm3 oxygen gas /\n90\n88\n86\n84\n82\n80\n290 300 310 320 330 340 350\nabsolute temperature / K\n[2]\nDetermine the gradient of your line of best fit. State the coordinates of both points you used (ii)\nin your calculation. These must be selected from your line of best fit. Give the gradient to\nthree significant figures.\ncoordinate", "pdf_path": "9701-experimental-skills/print/9701-2022-on-53-q02-6a9e43ff15.pdf" }, { "id": "9701-2022-on-53-q03", "subject": "9701", "year": 2022, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 3, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2022-oct-nov/9701_w22_qp_53.pdf?download=true", "source_pages": [ 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2022-Oct-Nov/qp/9701_w22_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2022-on-53-q03-p01-f0f32156a3.png", "9701-experimental-skills/assets/9701-2022-on-53-q03-p02-8a1f6a73b7.png", "9701-experimental-skills/assets/9701-2022-on-53-q03-p03-b520fd1310.png", "9701-experimental-skills/assets/9701-2022-on-53-q03-p04-273b059c02.png" ], "answer": { "status": "pending", "id": "9701-2022-on-53-q03", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "bromate(V) Potassium reacts with potassium bromide and sulfuric acid to form potassium sulfate, 3\nbromine and water according to the following equation.\n→ (aq) + 5KBr(aq) + 3H SO (aq) 3K SO (aq) + 3Br (aq) + 3H O(l) KBrO\n3 2 4 2 4 2 2\nA student is investigating how the rate of this reaction is affected by changing the concentration\nof the reactants in turn. This is done by keeping the total volume of mixture constant and adding\ndifferent, small volumes of each reagent.\nThe reaction produces bromine which is orange in colour. The student times the reaction and then\n1\n. determines the rate as\ntime\nThe rate equation for the reaction is of the form:\n]x[KBr]y[H ]z SO rate = k [KBrO\n3 2 4\nk is the rate constant for the reaction and x, y and z are the respective orders of the reaction for\neach reagent.\nThe student carried out the experiment and obtained the following data.\nTable 3.1\n[KBrO ] [KBr] [H SO ] rate of reaction\n3 2 4 mixture\ndm–3 dm–3 dm–3 s–1 / mol / mol / mol /\nA 0.025 0.125 0.075 0.059\nB 0.050 0.125 0.075 0.117\nC 0.025 0.250 0.075 0.118\nD 0.025 0.125 0.150 0.235\nE 0.050 0.250 0.150 0.941\nS uggest how the student might time the reaction and judge the end point of the reaction (a) (i)\nfor each mixture.\n.............................................................................................................................................\n.............................................................................................................................................\n....................................................................................................................................... [1]\nB y comparing the data for the mixtures deduce the values of x, y and z. (ii)\n[2]\ncm3) The student carried out each reaction using a boiling tube (capacity 50 and varied the (b)\ncm3 concentration by adding different volumes of each reagent. For example, in mixture A, 5.0\n(aq) is required. of KBrO\n3\nN ame a suitable piece of apparatus which could be used to measure this volume.\n.............................................................................................................................................. [1]\nSuggest why the reagents are heated to the same temperature before mixing. (c)\n.............................................................................................................................................. [1]\ndm–3. This The solution of sulfuric acid used in each mixture was of concentration 0.150 mol (d)\ndm–3. acid was prepared from a solution of concentration 1 mol\nBriefly describe how to make the more dilute solution, stating the capacity of any apparatus\nused.\n....................................................................................................................................................\n....................................................................................................................................................\n........................................", "pdf_path": "9701-experimental-skills/print/9701-2022-on-53-q03-144eb427f6.pdf" }, { "id": "9701-2023-m-42-q01", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-m-42-q01-p01-2ebd949992.png", "9701-topic-23-chemical-energetics/assets/9701-2023-m-42-q01-p02-110b7e9476.png", "9701-topic-23-chemical-energetics/assets/9701-2023-m-42-q01-p03-089165bca5.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "zinc(II) The most common zinc mineral contains sulfide, ZnS. 1 (a)\nComplete the electrons in boxes diagram in Fig. 1.1 to show the electronic configuration (i)\nzinc(II) ion. of a\n3d 4s 4p\n[Ar]\nFig. 1.1\n[1]\nComplete Fig. 1.2 to show the Born–Haber diagram for the ionic solid ZnS. (ii)\nInclude state symbols of relevant species.\nZn2+(g) S2–(g) +\nZn2+(g) 2e– + S(g) +\nEA2 EA1\nIE2\nZn2+(g) S–(g) e– + +\nIE1\nΔH\nlatt\nΔH (S)\nat\nΔH (Zn)\nat\nΔH\nf\nZnS(s)\nFig. 1.2\n[3]\nDescribe the trend in the first electron affinity of the Group 16 elements S to Te. (iii)\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n∆H , of ZnO is more exothermic than that of ZnS. Explain why the lattice energy, (iv)\nlatt\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nZinc metal can be obtained in a two-step process as shown. (b)\n(g) 2ZnO(s) + 2SO (g) step 1 2ZnS(s) + 3O\n2 2\nZn(l) + CO(g) step 2 ZnO(s) + C(s)\nThe reactions are carried out at 800 °C.\no ∆S , of the reaction in 1. Predict the sign of the entropy change, step (i)\nExplain your answer.\n...........................................................................................................................................\n..................................................................................................................................... [1]\no ∆S of the reaction shown in 2. Use the data in Table 1.1 to calculate step (ii)\nTable 1.1\nchemical ZnO(s) C(s) Zn(l) CO(g)\no K–1 mol–1 43.7 5.7 50.8 197.7 S / J\no K–1 mol–1 ∆S = ....................................... J [1]\nAn equation for the direct reduction of ZnS by carbon is shown. (iii)\no mol–1 ∆H 2Zn(l) + CS (g) = +733 kJ 2ZnS(s) + C(s)\n2\no K–1 mol–1 ∆S = +218 J\nThis reaction is feasible at 800 °C. not\no ∆G for this reaction at 800 °C. Calculate\no mol–1 ∆G = ........................................... kJ [2]\n) undergoes thermal decomposition when heated. The reaction is similar to the Zn(NO (c)\n3 2\nthermal decomposition of Group 2 nitrates.\n) . C", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-m-42-q01-e1c31ee671.pdf" }, { "id": "9701-2023-m-42-q02", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 5, 6, 7, 8 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2023-m-42-q02-p01-6acfa3a785.png", "9701-topic-24-electrochemistry/assets/9701-2023-m-42-q02-p02-68d14440e1.png", "9701-topic-24-electrochemistry/assets/9701-2023-m-42-q02-p03-afe2db9bcd.png", "9701-topic-24-electrochemistry/assets/9701-2023-m-42-q02-p04-1334ae0d26.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q02", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Hypophosphorous acid is an inorganic acid. 2\n–. PO The conjugate base of hypophosphorous acid is H\n2 2\nGive the formula of hypophosphorous acid. (a)\n............................................................................................................................................. [1]\n– PO is a strong reducing agent. It can be used to reduce metal cations without the need H (b)\n2 2\nfor electrolysis.\no 2e– 3OH– 2– – + 2H O + H PO + E = –1.57 V equation 1 HPO\n3 2 2 2\n2–/H – PO half-cell is constructed with In an experiment, an alkaline HPO (i)\n3 2 2\nmoldm–3. –] PO = 0.050 [H\n2 2\nAll other ions are at their standard concentration.\no\nvalue. Predict how the value of E of this half-cell differs from its E\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n3+/Cr half-cell has a standard electrode potential of –0.74 V. The Cr (ii)\nCr3+/Cr 2–/H – PO half-cell and a An electrochemical cell consists of an alkaline HPO\n3 2 2\nhalf-cell.\no . Calculate the standard cell potential, E\ncell\no E = ...................................................... V [1]\ncell\nComplete the diagram in Fig. 2.1 to show how the standard electrode potential of the (iii)\nCr3+/Cr half-cell can be measured relative to that of the standard hydrogen electrode.\nIdentify the chemicals, conditions and relevant pieces of apparatus.\nFig. 2.1\n[3]\nLabel Fig. 2.1 to show: (iv)\n• which is the positive electrode\n• the direction of electron flow in the external circuit.\n[1]\nNi2+ – PO reduces to Ni in alkaline conditions. H (v)\n2 2\nUse equation 1 to construct the ionic equation for this reaction.\n2e– 3OH– 2– – + 2H O + H PO + equation 1 HPO\n3 2 2 2\n..................................................................................................................................... [1]\nOH–(aq). –(aq) H PO reacts with (c)\n2 2\nOH–(aq) –(aq) 2–(g) PO + HPO + H (g) H\n2 2 3 2\nTable 2.1 shows the results of a series of experiments used to investigate the rate of this\nreaction.\nTable 2.1\nvolume of H\n[OH–(aq)] –(aq)] PO [H 2\n2 2 experiment produced in 60 s\ndm–3 dm–3 / mol / mol\ncm3 /\n1 0.40 2.00 6.4\n2 0.80 2.00 12.8\n3 1.20 1.00 4.8\nwas measured under room conditions. The volume of H (i)\n2\n, and the data from experiment 1 to calculate the rate of Use the molar volume of gas, V\nm\ndm–3 s–1. reaction in mol\ndm–3 s–1 rate of reaction = ..................................... mol [1]\nThe rate equation was found to be: (ii)\n[OH–(aq)]2 –(aq)] PO rate = k [H\n2 2\nShow that the data in Table 2.1 ", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2023-m-42-q02-928db45527.pdf" }, { "id": "9701-2023-m-42-q03", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 9, 10, 11 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-m-42-q03-p01-82a5eb4011.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-m-42-q03-p02-a153fd1604.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-m-42-q03-p03-2a8830a2f6.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Vanadium is a transition element in Period 4 of the Periodic Table. 3\nDefine transition element. (a)\n...................................................................................................................................................\n............................................................................................................................................. [1]\nVanadium shows typical chemical properties of transition elements, including variable (b)\noxidation states.\nState other typical chemical properties of transition elements. (i) two\n1 ........................................................................................................................................\n2 ........................................................................................................................................\n[1]\nExplain why transition elements have variable oxidation states. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nV2+ + 2– VO can be reduced to by C O in acidic conditions. (c)\n2 2 4\n8H+ 2V2+ + 2– + 3C O + + 6CO + 4H O equation 2 2VO\n2 2 4 2 2\ncm3 dm–3 10cm3 +(aq) of 0.0300 mol VO is added to of dilute sulfuric In a titration, 25.00 (i)\n2\nacid.\ndm–3 2–(aq) C O is then added from a burette until the end-point A solution of 0.0400 mol\n2 4\nis reached.\nThe titration is repeated and concordant results obtained, as shown in Table 3.1.\nTable 3.1\n1 2\ncm3 2–(aq) O added / 28.15 28.10 volume of C\n2 4\nShow that these results are consistent with the stoichiometry of equation 2.\n[2]\n2– + O reacts with VO to form a mixture of two octahedral complex ions. An excess of C (ii)\n2 4 2\nThe complex ions are stereoisomers of each other.\nV2+ 2– cation and three C O ions. Each complex ion contains a\n2 4\nComplete the diagram to show the three-dimensional structure of of the complex one\nions.\nInclude the charge of the complex ion.\n2– to represent a C O ion. Use O O\n2 4\nV\n[2]\nV2+(aq) can be oxidised by H O (aq). (d)\n2 2\nTable 3.2 gives some relevant data.\nTable 3.2\no half-equation / V E\n2H+(aq) 2e– +1.77 1 O (aq) + + 2H O(l) H\n2 2 2\n2H+(aq) e– VO2+(aq) +(aq) +1.00 2 + + + H O(l) VO\n2 2\nVO2+(aq) 2H+(aq) e– V3+(aq) +0.34 3 + + + H O(l)\n2\nV3+(aq) e– V2+(aq) –0.26 4 +\nV2+(aq) O (aq) reacts with Identify the vanadium species that forms when an excess of H (i)\n2 2\nunder standard conditions.\nExplain your answer with reference to the data in Table 3.2.\n...........................................................................................................................................\n...........................................................................................................................................\n......................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-m-42-q03-956183df95.pdf" }, { "id": "9701-2023-m-42-q04", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 27, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 12, 13, 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p01-9d116bf3b5.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p02-ab9f6b8088.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p03-b80a787dc3.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p04-3c9ce7421e.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p05-b0d52c5dc3.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-m-42-q04-p06-996c7af7b0.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q04", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Ethylamine and phenylamine are primary amines. 4\nethylamine phenylamine\nNH\n2\nCH CH NH\n3 2 2\nFig. 4.1\nThese two compounds are synthesised by different methods.\nSeveral methods can be used to form ethylamine. (a)\nLiAl CONH , is reduced by H . Ethylamine forms when ethanamide, CH (i)\n3 2 4\nWrite an equation for this reaction. Use [H] to represent one atom of hydrogen from the\nreducing agent.\n..................................................................................................................................... [1]\nEthylamine is a product of the reaction of bromoethane with ammonia. (ii)\nName the mechanism of this reaction and state the conditions used.\nmechanism ........................................................................................................................\nconditions ..........................................................................................................................\n[2]\nThe reaction in also forms secondary and tertiary amines. (iii) (a)(ii)\nSuggest the identity of a secondary or tertiary amine formed by the reaction in (a)(ii).\n..................................................................................................................................... [1]\nEthylamine is a weak base. (b)\nState the relative basicities of ammonia, ethylamine and phenylamine.\nExplain your answer.\n.............................................. < .............................................. < ..............................................\nleast basic most basic\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [4]\nH NH , can be prepared from benzene in two steps. Pure phenylamine, C (c)\n6 5 2\nDraw the structure of the intermediate compound.\nSuggest reagents and conditions for each step.\n...................................................................................................................................................\n.................................................................................................................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-m-42-q04-22f51389e9.pdf" }, { "id": "9701-2023-m-42-q05", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 22, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 18, 19, 20, 21, 22, 23 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p01-474576b403.png", "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p02-25d3212933.png", "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p03-a5887a5720.png", "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p04-5807a16f72.png", "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p05-78c375b1be.png", "9701-topic-30-hydrocarbons/assets/9701-2023-m-42-q05-p06-f7b34ecc2b.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q05", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "Tulobuterol is used in some medicines. 5\ntulobuterol\nCl OH\nH\nN\nFig. 5.1\nTulobuterol contains a benzene ring in its structure. (a)\nDescribe and explain the shape of benzene.\nIn your answer, include:\n• the bond angle between carbon atoms\n• the hybridisation of the carbon atoms\n• v r how orbital overlap forms and bonds between the carbon atoms.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nIn a synthesis of tulobuterol, the first step involves the formation of chlorobenzene. Benzene (b)\nAl Cl Cl in the presence of an catalyst. reacts with\n2 3\nCl\nstep 1\nCl AlCl and\n2 3\nFig. 5.2\nAl Cl Cl reacts with to generate an electrophile. Write an equation to show how (i)\n2 3\n..................................................................................................................................... [1]\nComplete the mechanism in Fig. 5.3 for the reaction of benzene with the electrophile (ii)\ngenerated in (b)(i).\nInclude all relevant curly arrows and charges.\nDraw the structure of the intermediate.\nintermediate\nCl\nFig. 5.3\n[3]\nCl Cl, The second step of the synthesis involves the reaction of chlorobenzene with COCH (c)\n2\nAl Cl catalyst, forming compound Q. also in the presence of an\n3\nQ\nCl Cl O\nstep 2\nCl\nO\nCl\nCl\nAlCl and\n3\nFig. 5.4\nName the mechanism of the reaction in step 2. (i)\n..................................................................................................................................... [1]\nDraw the structure of an isomer of that forms as an organic by-product of the reaction (ii) Q\nin step 2.\n[1]\nThe reactants used in step 2 contain acyl chloride, alkyl chloride and aryl chloride (iii)\nfunctional groups.\nState and explain the relative ease of hydrolysis of acyl chlorides, alkyl chlorides and aryl\nchlorides.\n............................................ , ............................................. , .............................................\neasiest to hydrolyse hardest to hydrolyse\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...................................................................................................", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2023-m-42-q05-1fbe9fbc15.pdf" }, { "id": "9701-2023-m-42-q06", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_42.pdf?download=true", "source_pages": [ 24, 25, 26, 27, 28 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2023-m-42-q06-p01-61ec53d548.png", "9701-topic-25-equilibria/assets/9701-2023-m-42-q06-p02-95418f8382.png", "9701-topic-25-equilibria/assets/9701-2023-m-42-q06-p03-2e439fc82c.png", "9701-topic-25-equilibria/assets/9701-2023-m-42-q06-p04-a42b33e199.png", "9701-topic-25-equilibria/assets/9701-2023-m-42-q06-p05-30e3b9706d.png" ], "answer": { "status": "pending", "id": "9701-2023-m-42-q06", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "A student uses thin-layer chromatography (TLC) to analyse a mixture containing different metal 6\ncations. The student repeats the experiment using different solvents.\nFig. 6.1 shows the chromatogram obtained by the student using water as a solvent.\nsolvent front\n5\n4\n3\nM\n2\n1\nbaseline\n0\ncm\nFig. 6.1\nSuggest a compound that could be used as the stationary phase in this experiment. (a) (i)\n..................................................................................................................................... [1]\nvalues for different metal cations when separated by TLC using Table 6.1 shows the R (ii)\nf\nwater as a solvent.\nTable 6.1\ncation R value (water)\nf\nCd2+(aq) 0.40\nCo2+(aq) 0.77\nCu2+(aq) 0.32\nFe3+(aq) 0.12\nHg2+(aq) 0.23\nNi2+(aq) 0.75\nSuggest the identity of the cation that causes the spot at in Fig. 6.1. M\nExplain your answer.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nThe student repeats the experiment using butan-1-ol as a solvent. (b)\nThe metal cations do travel as far up the TLC plate in this experiment. not\nSuggest why the metal cations do not move as far up the TLC plate with butan-1-ol as a\nsolvent.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nThe student sprays the TLC plate in Fig. 6.1 with KSCN(aq). (c)\nThe colour of some of the spots changes, as some of the metal cations undergo a ligand\nexchange reaction.\nIdentify the ligands involved in the ligand exchange reaction.\n............................................................ exchanges with ............................................................\n[1]\nIn a third experiment, the pH of the mixture of metal ions is kept constant using a buffer (d)\nsolution.\ncm3 dm–3 of 0.150 mol KOH(aq) and The student prepares the buffer solution by mixing 20.0\ncm3 dm–3 of 0.100 mol C H O K(aq). 50.0\n8 5 4\nH O K is a weak carboxylic acid that has pK = 5.40. C\n8 5 4 a\nC H O K\n8 5 4\nO\nOH\nO–K+\nO\nFig. 6.2\nH O K(aq) with KOH(aq). Complete the equation for the reaction of C (i)\n8 5 4\n������������������������������������������������������������������������������������������������������������������������������� H O K + [1] C\n8 5 4\nCalculate the pH of the buffer solution. Show all your working. (ii)\npH = ......................................................... [4]\n[Total: 9]\nImportant values, constants and standards\n–1 –1 molar gas constant R = 8.31 J K mol\n4 –1 Faraday constant F = 9.65 10 C mol ×\n23 –1 Avogadro constant L = 6.022 10 mol ×\n–19 electronic charge e = –1.60 10 C ×\n3 –1 molar volume of gas V = 22.4 dm mol ", "pdf_path": "9701-topic-25-equilibria/print/9701-2023-m-42-q06-9e0c7fcefd.pdf" }, { "id": "9701-2023-m-52-q01", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-m-52-q01-p01-8f188ef29a.png", "9701-experimental-skills/assets/9701-2023-m-52-q01-p02-36f13707fd.png", "9701-experimental-skills/assets/9701-2023-m-52-q01-p03-aa497b0175.png" ], "answer": { "status": "pending", "id": "9701-2023-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Fe2+(aq), iron(II) Aqueous ions, are usually kept in acidic conditions to prevent them readily 1\nFe3+(aq). iron(III) ions, oxidising to aqueous\nFe2+(aq) Ag+(aq) ions react with ions in a redox reaction. The following equilibrium is established.\nFe2+(aq) Ag+(aq) Fe3+(aq) + + Ag(s)\nFe2+(aq) at equilibrium can be found by titration with a standard solution The concentration of\nmanganate(VII), KMnO (aq). KMnO (aq) is deep purple in colour. The of aqueous potassium\n4 4\nequilibrium constant for the reaction can be found using the following equation.\n[Fe3+(aq)]\neqm\nK =\n[Fe2+(aq)] [Ag+(aq)] c ×\neqm eqm\nA student carries out the experiment using the following instructions.\ncm3 dm–3 cm3 dm–3 of 0.200 mol AgNO (aq) to 100.0 of 0.200 mol Fe(NO ) (aq) Add 100.0 step 1\n3 3 2\ncm3 conical flask and stopper the flask. Label the conical flask A. in a 500\nLeave conical flask for four hours, shaking intermittently. Then leave conical flask step 2 A A\nuntouched for one hour.\n3 of the solution from conical flask into a clean Use a pipette to transfer 25.00 cm A step 3\ncm3 conical flask. Label this conical flask B. 250\ncm3 dm–3 NaCl of 1.00 mol (aq) to the solution in conical flask B. A white precipitate Add 5 step 4\nof silver chloride forms.\ncm3 dm–3 of 1.00 mol sulfuric acid to conical flask B. Use a measuring cylinder to add 20 step 5\n(aq). Rinse a burette and fill it with a standard solution of KMnO step 6\n4\n(aq) to the mixture in conical flask until an end-point is reached. Add KMnO B step 7\n4\nEmpty conical flask and rinse it with distilled water ready for the next titration. step 8 B\nThe student repeats the titration until concordant readings are achieved.\nThe student records their results in Table 1.1. (a)\nTable 1.1\nrough titration 1 titration 2 titration 3\ncm3 final burette reading / 10.60 20.35 30.25 9.85\ncm3 initial burette reading / 0.10 10.70 20.35 0.10\ncm3 titre /\nComplete Table 1.1. [1] (i)\nCalculate a suitable mean titre to be used in the student’s calculations. (ii)\nShow clearly how you obtain the mean titre.\ncm3 [1] mean titre = ..............................\nState what is meant by a standard solution in 6. (b) step\n............................................................................................................................................. [1]\nSuggest why conical flask is left for four hours in 2. (c) (i) A step\n..................................................................................................................................... [1]\nSuggest why conical flask is shaken during the final hour in 2. (ii) A not step\n..................................................................................................................................... [1]\nSuggest why a measuring cylinder is the most appropriate apparatus to use for measuring (d)\nsulfuric acid in 5. step\n............................................................................................................................................. [1]\nState what the bu", "pdf_path": "9701-experimental-skills/print/9701-2023-m-52-q01-469c83138e.pdf" }, { "id": "9701-2023-m-52-q02", "subject": "9701", "year": 2023, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-march/9701_m23_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2023-March/qp/9701_m23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-m-52-q02-p01-8d719bd49d.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p02-4aef172961.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p03-57b9405a9e.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p04-1b348397f6.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p05-bc7df6b6e9.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p06-06b5a7caf4.png", "9701-experimental-skills/assets/9701-2023-m-52-q02-p07-e54f721be2.png" ], "answer": { "status": "pending", "id": "9701-2023-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "I–(aq), The reaction between iodide ions, and aqueous hydrogen peroxide, H O (aq), takes place 2\n2 2\nin acidic conditions.\n2I–(aq) 2H+(aq) I + H O (aq) + (aq) + 2H O(l) reaction 1\n2 2 2 2\nA student carries out a series of experiments to investigate the order of reaction with respect to\nI–(aq) ions. The student does this by measuring the time taken for a fixed the concentration of\namount of iodine to form.\n2–(aq), I O in the reaction mixture react with (aq) A known amount of aqueous thiosulfate ions, S\n2 3 2\nformed in reaction 1.\n2I–(aq) 2–(aq) 2–(aq) I (aq) + 2S O + S O reaction 2\n2 2 3 4 6\n2–(aq) I O ions have reacted in reaction 2, any further (aq) formed is detected After all of the S\n2 3 2\nusing starch indicator.\nThe following materials are used:\ncm3 ● 50 beaker containing the correct mass of solid potassium iodide crystals needed to make\ncm3 dm–3 KI(aq) of 0.100 mol 250.0\ndm–3 ● 0.100 mol Na S O (aq)\n2 2 3\ndm–3 ● 0.100 mol H O (aq)\n2 2\ndm–3 ● 0.200 mol H SO (aq)\n2 4\n● starch indicator\n● distilled water.\nA second student looked at the equation for reaction 1 and stated the order with respect (a)\nI–(aq) ions must be second order because the balanced equation to the concentration of\n2I–(aq). contains\nSuggest why a balanced equation alone cannot be used to determine the order of a reaction.\n............................................................................................................................................. [1]\n3 dm–3 KI(aq) of 0.100 mol starting from the sample Describe how the student makes 250.0 cm (b)\ncm3 beaker. of solid potassium iodide in the 50\nGive the name and size of any key apparatus used. Describe how the student ensures the\ncm3. volume is exactly 250.0\nYou may wish to write your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nThe student carries out Experiment 1 using the following steps. (c)\ncm3 dm–3 of 0.200 mol H SO (aq) to a conical flask. Add 25 step 1\n2 4\ncm3 of distilled water to the conical flask from a burette. Add 20.00 step 2\ncm3 dm–3 KI(aq) of 0.100 mol to the conical flask from a burette. Add 5.00 step 3\ncm3 dm–3 of 0.100 mol Na S O (", "pdf_path": "9701-experimental-skills/print/9701-2023-m-52-q02-84dc295262.pdf" }, { "id": "9701-2023-mj-41-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-41-q01-p01-204a998202.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-41-q01-p02-8158e6175b.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-41-q01-p03-08a9032d3a.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-41-q01-p04-fc522cec71.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Group 2 nitrates decompose when heated. 1 (a)\nDescribe how the thermal stability of Group 2 nitrates changes with increasing proton number.\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nCopper(II) nitrate decomposes in a similar manner to Group 2 nitrates. (b)\n) . Write an equation for the decomposition of Cu(NO\n3 2\n............................................................................................................................................. [1]\n) is added to water to form solution A. Cu(NO (c)\n3 2\nFig. 1.1 shows some reactions of solution A.\nH O\n2\nCu(NO ) (s) solution solution A C\n3 2 excess\n(aq) NH\n3 (aq) NH\n3\nprecipitate B excess\nHCl concentrated\nsolution D\nFig. 1.1\nComplete Table 1.1 to show the formula and colour of each of the copper‑containing species\npresent in A, B, and D. C\nTable 1.1\nformula of copper‑containing colour of copper‑containing\nspecies formed species formed\nA\nB\nC\nD\n[4]\nEDTA4– is a polydentate ligand. (d)\nExplain what is meant by a polydentate ligand. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nGroup 2 metal ions can form complexes similar to those of transition elements. (ii)\n4– ]2+ is added to water containing [Ca(H O) to form a new complex, A solution of EDTA\n2 6\n[CaEDTA]2–, as shown.\n]2+ EDTA4– [CaEDTA]2– O) + + 6H O equilibrium 1 [Ca(H\n2 6 2\nEDTA4– in Fig. 1.2 the atoms that form bonds with the metal Circle on the structure of six\nion.\nEDTA4–\nO O\nO– –O CCH CH C\n2 2\nNCH CH N\n2 2\n–O O– CH CCH C\n2 2\nO O\nFig. 1.2\n[1]\n]2+ [CaEDTA]2– O) and have a coordination number of 6. The calcium ions in [Ca(H (iii)\n2 6\nExplain what is meant by coordination number.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[CaEDTA]2– The co", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-mj-41-q01-3f8441ffee.pdf" }, { "id": "9701-2023-mj-41-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q02-p01-b9891fca56.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q02-p02-f1867310c6.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q02-p03-dcaa83236e.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q02", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Some transition element complexes can show stereoisomerism. 2 (a)\nState types of stereoisomerism shown by transition element complexes. two\n1 ................................................................................................................................................\n2 ................................................................................................................................................\n[1]\n]2+ Cl ) ] and [Pt(en) have the same geometry (shape) around the The complexes [Pt(NH (b)\n3 2 2 2\nmetal ion.\n]2+ Cl ) ] exists as two stereoisomers whereas [Pt(en) only has one possible structure. [Pt(NH\n3 2 2 2\nState the geometry around the metal ion.\n............................................................................................................................................. [1]\n]2+ exists as two stereoisomers whereas the complex The complex [Cr(en) (c)\n3\n]− CH NH ) exists as four stereoisomers. [Cr(OCH\n2 2 2 3\nComplete the three‑dimensional diagrams in Fig. 2.1 to show the four stereoisomers of\n]−. CH NH ) [Cr(OCH\n2 2 2 3\n–OCH CH NH by using . Represent the ligand\n2 2 2\nO N\nCr Cr\nCr Cr\nFig. 2.1\n[3]\n]− 2+(aq) The complex [Cr(OCH CH NH ) is formed by reacting Cr with the conjugate base of (d)\n2 2 2 3\n2‑aminoethanol.\nA synthesis of 2‑aminoethanol is shown in Fig. 2.2.\noxirane 2-aminoethanol\nO\nOH\nH C C H + NH\nN H 3\n2\nH H\nFig. 2.2\nSuggest the mechanism for step 1 of the reaction of oxirane with ammonia in Fig. 2.3. (i)\nInclude all relevant curly arrows, lone pairs of electrons, charges and partial charges.\nDraw the structure of the organic intermediate.\noxirane 2-aminoethanol intermediate\nO\nstep 2 step 1 OH\nC H H C\nN H\n2\nH H\nN H\n3\nFig. 2.3\n[3]\nA small amount of by‑product E, shown in Fig. 2.4, is produced during the reaction shown (ii)\nin Fig. 2.2.\nE\nHO OH\nN\nH\nFig. 2.4\nSuggest how the formation of by‑product can be minimised. E\n...........................................................................................................................................\n..................................................................................................................................... [1]\nCompound F, C H NO, can be formed from the reaction of by‑product E, C H NO , (iii)\n4 9 4 11 2\nSO . with concentrated H\n2 4\nCompound is a and basic organic compound. F saturated\nSuggest a structure for compound F. State the type of reaction undergone by to form F. E\nF\ntype of reaction ..................................................................................................................\n[2]\n[Total: 11]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-mj-41-q02-781048a86c.pdf" }, { "id": "9701-2023-mj-41-q03", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-41-q03-p01-e9a7c2e381.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-41-q03-p02-5837f3ec11.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "–, iodate(V) IO Aqueous acidified ions, react with iodide ions, as shown. 3 (a)\n3\n6H+ 5I– – 3I IO + + + 3H O\n3 2 2\nThe initial rate of this reaction is investigated. Table 3.1 shows the results obtained.\nTable 3.1\n[H+] dm–3 dm–3min–1 dm–3 [I–] dm–3 –] [IO experiment / mol initial rate / mol / mol / mol\n3\n10–2 × 1 0.0400 0.0150 0.0250 4.20\n10–2 × 2 0.120 to be calculated 0.0125 7.09\n–][H+]2[I–]2. [IO The rate equation for this reaction is rate = k\n3\nExplain what is meant by order of reaction. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nComplete Table 3.2. (ii)\nTable 3.2\n–] [IO the order of reaction with respect to\n3\n[H+] the order of reaction with respect to\n[I–] the order of reaction with respect to\nthe overall order of reaction\n[1]\nUse your answer to to sketch lines in Fig. 3.1 to show the relationship between the (iii) (a)(ii)\n[I–]. –] [IO and initial rates and the concentrations of\n3\ninitial rate initial rate\n0 0\n0 0 [I–] –] [IO\n3\nFig. 3.1\n[1]\nUse data from Table 3.1 to calculate the rate constant, k, for this reaction. (iv)\nInclude the units of k.\nk = .............................. units .............................. [2]\n+], in Use data from Table 3.1 to calculate the concentration of hydrogen ions, [H (v)\nexperiment 2.\n[H+] dm–3 = .............................. mol [1]\nThis reaction is repeated in two separate experiments. (vi)\nThe experiments are carried out at the same temperature and with the same\nI– –. IO and concentrations of\n3\nOne experiment takes place at pH 1.0 and the other experiment takes place at pH 2.0.\nrate at pH 1.0\n. Calculate the value of\nrate at pH 2.0\nrate at pH 1.0\nvalue of = .............................. [1]\nrate at pH 2.0\niron(III) ions react with iodide ions, as shown. In aqueous solution, (b)\n2Fe3+ 2I– 2Fe2+ I + +\n2\nFe3+ The initial rate of reaction is first order with respect to and second order with respect\nI–. to\nThe mechanism for this reaction has three steps.\nEach step involves only ions reacting together. two\nSuggest equations for the steps of this mechanism. Identify the rate‑determining step. three\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\nstep 3 ........................................................................................................................................\nrate‑determining step = .............................\n[3]\n[Total: 10]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-mj-41-q03-6eea087aae.pdf" }, { "id": "9701-2023-mj-41-q04", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2023-mj-41-q04-p01-e8e4803996.png", "9701-topic-36-organic-synthesis/assets/9701-2023-mj-41-q04-p02-d898185990.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q04", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "State the hybridisation of the carbon atoms and the C–C–H bond angle in benzene, C H . 4 (a)\n6 6\nσ π Explain how orbital overlap leads to the formation of and bonds in benzene.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nCompound can be synthesised from benzene in three steps by the route shown in Fig. 4.1. (b) Z\nbenzene Z\nNH\n2\nstep 1 step 3\nX Y\nstep 2\nFig. 4.1\nDraw structures for and in Fig. 4.1. [2] (i) X Y\nGive the reagents and conditions for steps 1, 2 and 3. (ii)\nstep 1 ................................................................................................................................\nstep 2 ................................................................................................................................\nstep 3 ................................................................................................................................\n[3]\nCompound is an isomer of Z. (c) W\nW\nNH\n2\nFig. 4.2\nGive the systematic name of W.\n............................................................................................................................................. [1]\nComplete Table 4.1 to show the number of peaks observed in the carbon‑13 NMR spectrum (d)\nfor and Z. W\nTable 4.1\ncompound number of peaks observed\nW\nZ\n[1]\n[Total: 10]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2023-mj-41-q04-bd9c1f993a.pdf" }, { "id": "9701-2023-mj-41-q05", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 14, 15, 16 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q05-p01-636b67e606.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q05-p02-7457ad99fe.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q05-p03-8b9de9b4f7.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q05", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "The exhaust systems of most modern gasoline‑fuelled cars contain a catalytic converter with 5 (a)\nthree metal catalysts.\nThese metals act as heterogeneous catalysts.\nName metal catalysts used in catalytic converters. (i) three\n1 ................................. 2 ................................. 3 ................................. [1]\nExplain what is meant by a heterogeneous catalyst. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nThe exhaust systems of many diesel‑fuelled cars contain an additional system to reduce (b)\nvehicle emissions. This uses a liquid that is added to the exhaust system.\n) CO, which decomposes on heating to isocyanic acid, HNCO, This liquid contains urea, (NH\n2 2\nand ammonia.\n) CO HNCO + NH reaction 1 (NH\n2 2 3\nIsocyanic acid reacts with water vapour to form ammonia and carbon dioxide.\nO(g) NH (g) + CO (g) reaction 2 HNCO(g) + H\n2 3 2\no, o, ΔH and standard entropies, S Some values for standard enthalpy changes of formation,\nf\nare given in Table 5.1.\nTable 5.1\nmol–1 o K–1 mol–1 o ΔH compound / kJ S / J\nf\nHNCO(g) –101.7 +238.2\nO(g) –241.8 +188.8 H\n2\n(g) –45.9 +192.8 NH\n3\n(g) –393.5 +213.8 CO\n2\nExplain what is meant by the term entropy of a system. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\no ΔG °C. Use the data in Table 5.1 to calculate for at 25 (ii) reaction 2\nShow your working.\no mol–1 ΔG = .............................. kJ [4]\nThe ammonia formed in reactions 1 and 2 can be used to remove nitrogen dioxide from (c)\nexhaust emissions, as shown.\n+ 6NO 7N + 12H O reaction 3 8NH\n3 2 2 2\nUse the equations for reactions 1, 2 and 3 to construct an overall equation for the reduction of\nNO by (NH ) CO.\n2 2 2\n............................................................................................................................................. [1]\nH N O , under certain conditions. Isocyanic acid, HNCO, can form cyanuric acid, C (d)\n3 3 3 3\nH N O has a cyclic structure containing alternating carbon and nitrogen atoms in the ring C\n3 3 3 3\nsystem.\nSuggest a structure for cyanuric acid.\n[1]\nIsocyanic acid, HNCO, is a weak acid. (e)\nO+ NCO– °C O H + pK = 3.70 at 25 HNCO + H\n2 3 a\nand pH. Write the mathematical expressions for pK (i)\na\npK = .................................................................................................................................\na\npH = ...................................................................................................................................\n[1]\ndm–3 HNCO(aq). Calculate the pH of 0.120 mol (ii)\nGive you", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-mj-41-q05-6191852900.pdf" }, { "id": "9701-2023-mj-41-q06", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2023-mj-41-q06-p01-4751f20bc6.png", "9701-topic-35-polymerisation/assets/9701-2023-mj-41-q06-p02-38c92bdca0.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q06", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "Compound has the structural formula CH =CHCH(NH )COOH. 6 (a) H\n2 2\nName all the functional groups in H. (i)\n...........................................................................................................................................\n..................................................................................................................................... [2]\nCompound exhibits stereoisomerism. (ii) H\nDraw three‑dimensional structures for the two stereoisomers of H.\nName this type of stereoisomerism.\ntype of stereoisomerism ....................................................................................................\n[2]\nCompound can be prepared from the reaction of with an excess of hot aqueous acid. (b) H J\nJ\nO\nO\nN\nH\nO\nFig. 6.1\nComplete Fig. 6.2 to show the equation for this reaction. (i)\nO\nO\n=CHCH(NH )COOH + + CH\n2 2\nN\nH\nO\nFig. 6.2\n[1]\nName the type of reaction in (b)(i). (ii)\n..................................................................................................................................... [1]\nPolymers consist of monomers joined together by undergoing either addition or condensation (c)\npolymerisation.\nCompound can react to form an addition polymer, K, or a condensation polymer, L, H\ndepending on the conditions.\nDraw repeat unit of addition polymer K. (i) one\n[1]\nDraw repeat units of condensation polymer L. (ii) two\nThe new functional group formed should be displayed.\n[2]\nExplain why condensation polymers can normally biodegrade more readily than addition (iii)\npolymers.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[Total: 10]", "pdf_path": "9701-topic-35-polymerisation/print/9701-2023-mj-41-q06-6cbbe70413.pdf" }, { "id": "9701-2023-mj-41-q07", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 20, 21, 22, 23 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q07-p01-68dd49312a.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q07-p02-5798be5086.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q07-p03-aa6121d6c7.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-41-q07-p04-bf40ba6acb.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "State the relative basicities of ethanamide, diethylamine and ethylamine in aqueous solution. 7 (a)\nExplain your answer.\n............................................. > ............................................. > .............................................\nmost basic least basic\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[4]\nNCH(CH )COOH, can act as a buffer. The amino acid alanine, H (b)\n2 3\nDefine a buffer solution. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nWrite equations to show how an aqueous solution of alanine can act as a buffer (ii) two\nsolution.\n...........................................................................................................................................\n..................................................................................................................................... [2]\nGlutamic acid is another amino acid that acts as a buffer. (c)\nglutamic acid\nCH COOH CH\n2 2\nH C N COOH\n2\nH\nFig. 7.1\nDraw the formula for glutamic acid. (i) skeletal\n[1]\nDraw the structure for the dipeptide, ala‑glu, formed from one molecule of alanine and (ii)\none molecule of glutamic acid.\nThe peptide bond formed should be displayed.\n[2]\nThe isoelectric point of alanine is 6.0 and of glutamic acid is 3.2. (d)\nA mixture of the dipeptide, ala‑glu, and its two constituent amino acids, alanine and glutamic\nacid, is analysed by electrophoresis using a buffer at pH 6.0.\n– +\nmixture applied here\nFig. 7.2\nDraw and label spots on Fig. 7.2 to indicate the predicted position of each of these three\nthree species after electrophoresis.\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n..........................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-mj-41-q07-33b10d171f.pdf" }, { "id": "9701-2023-mj-41-q08", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_41.pdf?download=true", "source_pages": [ 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q08-p01-c317aade3c.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q08-p02-6d56daef3b.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q08-p03-263930e0a9.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-41-q08-p04-3cab8ed218.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-41-q08", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "✓ Complete Table 8.1 by placing tick ( ) in each row to indicate the sign of each type of 8 (a) one\nenergy change under standard conditions.\nTable 8.1\ncan be either\nenergy change always positive always negative\nnegative or positive\nlattice energy\nenthalpy change of hydration\nenthalpy change of solution\n[1]\nDefine enthalpy change of hydration. (b)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTable 8.2 shows various energy changes which can be used in the following questions. (c)\nTable 8.2\nmol–1 energy change value / kJ\nstandard enthalpy change of atomisation of calcium +178.2\nfirst ionisation energy of calcium +590\nsecond ionisation energy of calcium +1145\nstandard enthalpy change of atomisation of bromine +111.9\nBr–Br bond energy +192.9\n(s) –103.1 standard enthalpy change of solution of calcium bromide, CaBr\n2\n(s) –682.8 standard enthalpy change of formation of calcium bromide, CaBr\n2\nCa2+ –1579 standard enthalpy change of hydration of\nfirst electron affinity of bromine –324.6\nfirst ionisation energy of bromine +1140\no\nΔH Select and use relevant data from Table 8.2 to calculate the lattice energy, , of (i)\nlatt\n(s). CaBr\n2\nIt may be helpful to draw a labelled energy cycle.\nShow your working.\no\nmol–1 ΔH of CaBr (s) = .............................. kJ [3]\nlatt 2\nSelect and use relevant data from Table 8.2 and your answer to to calculate the (ii) (c)(i)\no\n–. ΔH , of Br standard enthalpy change of hydration,\nhyd\nIt may be helpful to draw a labelled energy cycle.\no –1 ΔH as your value for of If you were not able to answer (c)(i), use –2500 kJ mol\nlatt\n(s). This is the correct value. CaBr not\n2\nShow your working.\no\n– mol–1 ΔH of Br = .............................. kJ [2]\nhyd\n– ion is more negative than the enthalpy The enthalpy change of hydration of the Br (iii)\nI– ion. Explain why. change of hydration of the\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n[Total: 9]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n104 mol–1 × Faraday constant F = 9.65 C\n1023 mol–1 × Avogadro constant L = 6.022\n10–19 × electronic charge e = –1.60 C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n10–14 mol2 dm–6 × °C)) = 1", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-mj-41-q08-3c0aa2f21b.pdf" }, { "id": "9701-2023-mj-42-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2023-mj-42-q01-p01-3ca70e4308.png", "9701-topic-27-group-2/assets/9701-2023-mj-42-q01-p02-8ed22267ab.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Group 2 carbonates decompose when heated to form the metal oxide and carbon dioxide. 1 (a)\nSuggest a mechanism for the decomposition of the carbonate ion by adding curly (i) two\narrows in Fig. 1.1.\nO\nO2– + C CO\n2\n–O O–\nFig. 1.1\n[1]\nDescribe the variation in the thermal stability of Group 2 carbonates. Explain your (ii)\nanswer.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [3]\nDefine lattice energy. (b) (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\no\nΔH (MCO ), becomes less exothermic The lattice energy of the Group 2 carbonates, (ii)\nlatt 3\ndown the group.\no\nΔH The lattice energy of the Group 2 oxides, (MO), also becomes less exothermic\nlatt\ndown the group.\no o\nΔH ΔH (MCO ) and (MO) change by amounts going down the group. different\nlatt latt 3\nSuggest how the standard enthalpy change of the decomposition reaction for Group 2\ncarbonates changes down the group.\nExplain your reasoning in terms of the relative sizes of the anions and the relative\nchanges in lattice energy down the group.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nPotassium sulfite, K SO , is used as a food additive. (c)\n2 3\n2–, can be determined by titration using aqueous The concentration of sulfite ions, SO\n3\n–. manganate(VII) ions, MnO acidified\n4\ncm3 • A 250 solution contains 3.40 g of impure K SO .\n2 3\ncm3 cm3 dm–3 – • 25.0 of this ", "pdf_path": "9701-topic-27-group-2/print/9701-2023-mj-42-q01-2394b1169b.pdf" }, { "id": "9701-2023-mj-42-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-42-q02-p01-9cb04242a0.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-42-q02-p02-2034c8b606.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "State typical chemical properties of a transition element. 2 (a) two\n1 ................................................................................................................................................\n2 ................................................................................................................................................\n[1]\n]2+. cobalt(II) salts contain the complex ion [Co(H O) Aqueous solutions of (b)\n2 6\nDefine complex ion. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n]2+ O) are reacted separately with an excess of aqueous ammonia, Samples of [Co(H (ii)\n2 6\nHCl with an excess of concentrated and with an excess of aqueous sodium hydroxide,\nas shown in Fig. 2.1.\nexcess excess\nNH (aq) NaOH(aq)\n3\n]2+(aq) O) [Co(H A C\n2 6\nexcess\nHCl concentrated\nB\nFig. 2.1\n]2+. O) Complete Table 2.1 about the reactions shown by [Co(H\n2 6\nTable 2.1\nformula of cobalt colour and state of reagent added to\ntype of reaction\n]2+(aq) O) species formed cobalt species formed [Co(H\n2 6\nan excess of NH (aq) = A\n3\nan excess of\n= B\nHCl concentrated\nan excess of NaOH(aq) = C\n[4]\n2–, The ethanedioate ion, C O can act as a bidentate ligand. (c)\n2 4\nExplain what is meant by a bidentate ligand. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n]− )BrCl O) (C O exists as stereoisomers. The complex [Co(H (ii)\n2 2 2 4\nComplete the three-dimensional diagrams in Fig. 2.2 to show stereoisomers of four\n]−. )BrCl O) (C O [Co(H\n2 2 2 4\n2– O ligand is represented using . The C O O\n2 4\nO O\nCo Co\nO O\nO O\nCo Co\nO O\nFig. 2.2\n[3]\nState the oxidation state of cobalt in this complex and a type of stereoisomerism shown. (iii)\noxidation state of cobalt ...............................................................\ntype of stereoisomerism ...............................................................\n[1]\n[Total: 12]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-mj-42-q02-7ccb95a283.pdf" }, { "id": "9701-2023-mj-42-q03", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 6, 7, 8 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-mj-42-q03-p01-298037364b.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-42-q03-p02-3f7ad52b24.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-42-q03-p03-14ef0c3153.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "3 Complete Table 3.1 by placing tick ( ) in each row to indicate the sign of each type of 3 (a) one\nenergy change under standard conditions.\nTable 3.1\ncan be either\nenergy change always positive always negative\nnegative or positive\nbond energy\nenthalpy change of atomisation\nenthalpy change of formation\n[1]\nDefine standard enthalpy change of atomisation. (b)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\nTable 3.2 shows some energy changes. (c)\nTable 3.2\nmol–1 energy change value / kJ\nstandard enthalpy change of atomisation of silver +285\nfirst ionisation energy of silver +731\nsecond ionisation energy of silver +2074\nbond energy of O=O +496\nbond energy of O–O +150\nfirst electron affinity of oxygen –141\nsecond electron affinity of oxygen +798\nfirst ionisation energy of oxygen +1314\nO(s) –31 standard enthalpy change of formation of silver oxide, Ag\n2\no\nΔH Calculate the lattice energy, , of Ag O(s) using relevant data from Table 3.2.\nlatt 2\nIt may be helpful to draw a labelled energy cycle.\nShow your working.\no\nmol–1 ΔH of Ag O(s) = ........................................... kJ [3]\nlatt 2\nS, Suggest the trend in the magnitude of the lattice energies of the silver compounds Ag (d)\n2\nAg O and Ag Se.\n2 2\nExplain your answer.\n......................................... ......................................... .........................................\nleast exothermic most exothermic\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[2]\nSilver sulfite, Ag SO (s), is sparingly soluble in water. (e)\n2 3\n, of Ag SO . Give an expression for the solubility product, K (i)\nsp 2 3\n= K\nsp\n[1]\nAg+ in a saturated solution of Ag SO at 298 K. Calculate the equilibrium concentration of (ii)\n2 3\n10–14 mol3 dm–9 × : Ag SO , 1.50 at 298 K] [K\nsp 2 3\n[Ag+] dm–3 = .............................. mol [1]\no\nmol–1. ΔH The standard enthalpy change of solution, , of AgNO (s) in water is +22.6 kJ (f)\nsol 3\n(s) in water changes with temperature. Suggest how the feasibility of dissolving AgNO\n3\nExplain your answer.\n...................................................................................................................................................\n.................................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-mj-42-q03-cbe51ef8da.pdf" }, { "id": "9701-2023-mj-42-q04", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 9, 10 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-42-q04-p01-616611b14a.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-42-q04-p02-652d7fbe19.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q04", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "iron(III) In aqueous solution, ions react with iodide ions, as shown. 4 (a)\n2Fe3+ 2I– 2Fe2+ I + +\n2\nFe3+ I–, A series of experiments is carried out using different concentrations of and as shown\nin Table 4.1.\nTable 4.1\n[Fe3+] dm–3 dm–3 s–1 [I–] dm–3 experiment / mol initial rate / mol / mol\n10–4 × 1 0.0400 0.0200 2.64\n10–4 × 2 0.1200 0.0200 7.92\n10–3 × 3 0.0800 0.0400 2.11\nExplain what is meant by overall order of reaction. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n3+ and with Use the data in Table 4.1 to deduce the order of reaction with respect to Fe (ii)\nI–. respect to\nExplain your reasoning.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nUse your answer to to construct the rate equation for this reaction. (iii) (a)(ii)\nrate = [1]\nUse your answer to and the data from experiment 1 to calculate the rate constant, (iv) (a)(iii)\nk, for this reaction. Include the units of k.\nk = ................................ units ................................ [2]\nDescribe qualitatively the effect of an increase in temperature on the rate constant and (v)\non the rate of this reaction.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nIn aqueous solution, iodide ions react with acidified hydrogen peroxide, as shown. (b)\n2I– 2H+ I + H O + + 2H O\n2 2 2 2\nI–, The initial rate of reaction is found to be first order with respect to first order with respect to\nH+. O and zero order with respect to H\n2 2\nFig. 4.1 shows a possible four-step mechanism for this reaction.\nI– IO– step 1 H O + + H O\n2 2 2\nH+ IO– HIO + step 2\nI– OH– I HIO + step 3 +\n2\nOH– H+ step 4 + H O\n2\nFig. 4.1\nSuggest which of the steps, 1, 2, 3 or 4, in this mechanism is the rate-determining step. (i)\nExplain your answer.\n...........................................................................................................................................\n..............................................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-mj-42-q04-6b5beb8216.pdf" }, { "id": "9701-2023-mj-42-q05", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 11, 12, 13 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2023-mj-42-q05-p01-223aa6a8a3.png", "9701-topic-30-hydrocarbons/assets/9701-2023-mj-42-q05-p02-7f046cb1ed.png", "9701-topic-30-hydrocarbons/assets/9701-2023-mj-42-q05-p03-edf5b326a8.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q05", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "Methylbenzene can undergo different reactions, as shown in Fig. 5.1. 5 (a)\n/ Pt Br / UV light H\n2 2\nreaction 1 reaction 2\n/ FeBr reaction 3 Br\n2 3\n+\nFig. 5.1\nDraw structures in Fig. 5.1 for the possible organic products of the three reactions shown. (i)\n[3]\nComplete Table 5.1. (ii)\nTable 5.1\ntype of reaction mechanism\nreaction 1\nreaction 2\n[2]\nWhen methylbenzene reacts with an electrophile, a substitution reaction occurs. No addition (b)\nreaction takes place under these conditions.\nExplain why no addition reaction takes place.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nThe reaction of methylbenzene with thionyl bromide, SOBr , in the presence of an (c)\n2\niron(III) bromide catalyst, FeBr , is shown in Fig. 5.2.\n3\nO\nS\nFeBr\n3 Br\n+ SOBr + HBr\n2\nFig. 5.2\nThe mechanism of this reaction is similar to that of the bromination of benzene.\n+ electrophile, as shown. The first step of the mechanism generates the SOBr\nSOBr+ – + FeBr + FeBr SOBr\n2 3 4\nSOBr+ The reaction of methylbenzene with ions is shown in Fig. 5.3. Complete the (i)\nmechanism in Fig. 5.3.\nInclude all relevant curly arrows and charges.\nDraw the structure of the organic intermediate.\nintermediate\nO\nS+\nBr\nO\nS\nBr + ......................\nFig. 5.3\n[3]\nThe reaction shown in Fig. 5.2 produces a small amount of a by-product, P, with the (ii)\nH OS. molecular formula C\n14 14\nSuggest a structure for by-product P.\n[1]\n. Acyl bromides, RCOBr, can be synthesised by the reaction of a carboxylic acid and SOBr (d)\n2\nSOCl . This is a similar reaction to the synthesis of acyl chlorides using\n2\n. Give an equation for the reaction between ethanoic acid and SOBr (i)\n2\n..................................................................................................................................... [1]\nRCOCl, Suggest the relative ease of hydrolysis of acyl bromides, RCOBr, acyl chlorides, (ii)\nRCl. and alkyl chlorides,\nExplain your answer.\n> > ......................................... ......................................... .........................................\neasiest to hydrolyse hardest to hydrolyse\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...............................................................................................................", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2023-mj-42-q05-4dec7d04c9.pdf" }, { "id": "9701-2023-mj-42-q06", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-mj-42-q06-p01-de9ab4a68f.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-mj-42-q06-p02-7485de3b0b.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q06", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "Perindopril is a drug used to treat heart disease. 6 (a)\nperindopril\nO\nOH O O H\nN\nN\nO\nFig. 6.1\nState the number of chiral carbon atoms present in one molecule of perindopril. (i)\n..................................................................................................................................... [1]\nSuggest benefit and disadvantage of producing a drug such as perindopril as a (ii) one one\nsingle pure optical isomer.\nbenefit ...............................................................................................................................\n...........................................................................................................................................\ndisadvantage .....................................................................................................................\n...........................................................................................................................................\n[2]\nName all the functional groups in perindopril. (b) (i)\n...........................................................................................................................................\n..................................................................................................................................... [2]\nA sample of perindopril is hydrolysed with hot aqueous acid. (ii)\nDraw the structures of the organic products of the acid hydrolysis of three complete\nperindopril.\n[3]\n[Total: 8]", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2023-mj-42-q06-9744e15a01.pdf" }, { "id": "9701-2023-mj-42-q07", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2023-mj-42-q07-p01-9f718b1467.png", "9701-topic-32-hydroxy-compounds/assets/9701-2023-mj-42-q07-p02-56991fb55a.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q07", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Explain why phenol is brominated much more easily than benzene is brominated. 7 (a)\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nI–Br, Al catalyst. Iodine monobromide, reacts with benzene in the presence of an Br (b)\n3\nPredict whether the organic product will be bromobenzene or iodobenzene.\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [1]\nFig. 7.1 shows some reactions of phenol. (c)\nexcess Br Na(s) (aq)\n2\nOH Q R\nreaction 1 reaction 2\nO N N N OH OH\n2\nFig. 7.1\nGive an equation for the reaction of phenol with Na(s). (i)\n..................................................................................................................................... [1]\nDraw the structure of the organic product, R, formed when phenol reacts with an excess (ii)\n(aq). of Br\n2\n[1]\nState the reagents and conditions for reaction 1 and reaction 2 in Fig. 7.1. (iii)\nreaction 1 ..........................................................................................................................\nreaction 2 ..........................................................................................................................\n[2]\n[Total: 8]", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2023-mj-42-q07-9abca70b3b.pdf" }, { "id": "9701-2023-mj-42-q08", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 31, "topic": "Halogen compounds", "topic_slug": "9701-topic-31-halogen-compounds", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 18, 19, 20, 21 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-31-halogen-compounds/assets/9701-2023-mj-42-q08-p01-d8b6cbcc46.png", "9701-topic-31-halogen-compounds/assets/9701-2023-mj-42-q08-p02-aa6a94233c.png", "9701-topic-31-halogen-compounds/assets/9701-2023-mj-42-q08-p03-fccea00600.png", "9701-topic-31-halogen-compounds/assets/9701-2023-mj-42-q08-p04-c653ac9c1c.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q08", "html": "9701-topic-31-halogen-compounds/answers.html" }, "text_excerpt": "OH–(aq). Describe the difference in reactivity between chloroethane and chlorobenzene with 8 (a)\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\nCl, H O is a useful synthetic intermediate. Compound T, C (b)\n5 9 2\nFig. 8.1 shows some reactions of T.\nT\nW X\nO excess\nNaOH(aq)\n+\nO Cl heat\nstep 1\nY\nO\nexcess\nHCl (aq)\nOH\n+\nO NC\nheat\nstep 2\nH NO Z, C\n6 13 2\nFig. 8.1\nGive the systematic name for T. (i)\n..................................................................................................................................... [1]\nDraw the structures of W, X, and in Fig. 8.1. [4] (ii) Y Z\nState the reagents and conditions for steps 1 and 2 in Fig. 8.1. (iii)\nstep 1 ................................................................................................................................\nstep 2 ................................................................................................................................\n[2]\n(1H) Cl, CDCl The proton NMR spectrum of compound T, C H O in is shown in Fig. 8.2. (c)\n5 9 2 3\nT\nO\nO Cl\nδ 1.2\nδ 3.7 δ 2.8\nδ 3.9\n5 4 3 2 1 0\nδ chemical shift / ppm\nFig. 8.2\nTable 8.1\nchemical shift range\nenvironment of proton example\nδ / ppm\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–Cl –O, –CH –O, –CH 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nalkyl amine R–NH– 1.0–5.0\n3.0–6.0 aryl amine Ar–NH\n2\namide RCONHR 5.0–12.0\n(1H) CDCl CHCl Suggest why is used as a solvent instead of for the proton NMR (i)\n3 3\nspectrum.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n1H) NMR spectrum of T. Complete Table 8.2 for the proton ( (ii)\nTable 8.2\n1H chemical number of atoms\nenvironment of proton splitting pattern\nδ shift / ppm responsible for the peak\n1.2\n2.8\n3.7\n3.9\n[4]\nδ Explain the splitting pattern of the peak at 3.9 ppm. (iii)\n...........................................................................................................................................\n.......", "pdf_path": "9701-topic-31-halogen-compounds/print/9701-2023-mj-42-q08-df65eb4720.pdf" }, { "id": "9701-2023-mj-42-q09", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_42.pdf?download=true", "source_pages": [ 22, 23, 24 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2023-mj-42-q09-p01-5d5ce81d15.png", "9701-topic-24-electrochemistry/assets/9701-2023-mj-42-q09-p02-59740d1447.png", "9701-topic-24-electrochemistry/assets/9701-2023-mj-42-q09-p03-3cab8ed218.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-42-q09", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "o\nDefine standard cell potential, E . 9 (a)\ncell\n...................................................................................................................................................\n............................................................................................................................................. [1]\no\nFe3+ Fe2+ of a cell consisting of an / half-cell An electrochemical cell is set up to measure E (b)\ncell\n– Cl Cl / half-cell. and a\n2\nDraw a labelled diagram of this electrochemical cell.\nInclude all necessary substances. It is necessary to state conditions used. not\n[3]\nThe cell reaction for the electrochemical cell in is shown. (c) (b)\no\n2Fe2+ 2Fe3+ – 2Cl Cl + + E = +0.59 V\ncell 2\no mol–1, ΔG , in kJ for this cell reaction. Calculate\no mol–1 ΔG = .............................. kJ [2]\nAnother experiment is set up using the same electrochemical cell. (d)\nFe2+ dm–3. concentration is 0.15 mol All other concentrations remain at In this experiment the\ntheir standard values.\nThe Nernst equation is shown.\n[oxidised species]\no\n+ (0.059 / z) log E = E\n[reduced species]\nFe3+ Fe2+ / half-cell Use the Nernst equation to calculate the electrode potential, E, for the (i)\nin this experiment.\no Fe3+ Fe2+ : / = +0.77 V] [E\nE = .............................. V [1]\nUse your answer to to calculate E for this electrochemical cell. (ii) (d)(i)\ncell\nE = .............................. V [1]\ncell\n[Total: 8]\nImportant values, constants and standards\n–1 –1 molar gas constant R = 8.31 J K mol\n4 –1 Faraday constant F = 9.65 10 C mol ×\n23 –1 Avogadro constant L = 6.022 10 mol ×\n–19 electronic charge e = –1.60 10 C ×\n3 –1 molar volume of gas V = 22.4 dm mol at s.t.p. (101 kPa and 273 K)\nm\n3 –1 V = 24.0 dm mol at room conditions\nm\n10–14 mol2 dm–6 × ionic product of water K = 1.00 °C)) (at 298 K (25\nw\n–1 –1 –1 –1 specific heat capacity of water c = 4.18 kJ kg K (4.18 J g K )\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eH eN nR eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nmuicnerwal enissennet enimorb enirolhc enitatsa muitetul eniroulf 9.621 0.571 enidoi 0.91 5.53 9.97 uL 71 lC 301 sT rB 711 tA rL 71 53 35 58 17 F I – – – 9\nmuiromrevil muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib muiluht cinesra 8.121 0.902 9.861 mT dM cM bS 0.41 0.13 9.47 sA 51 101 511 iB N P 51 33 15 38 96 – – 7\nmuinamreg muivorelf muimref nobrac muibre 2.702 3.761 7.811 mF nocilis eG nS bP 0.21 1.82 6.27 41 001 rE 411 dael lF iS C 28 41 23 05 86 nit 6 – –\nmuinietsnie muinimula muinohin muimloh muillaht muillag 4.402 9.461 muidni 8.411 aG norob hN oH 8.01 0.72 7.96 sE 31 nI 311 lA lT 18 31 13 94 B 76 99 5 – –\nmuicinrepoc muisorpsyd muinrofilac muimdac yrucrem 6.002 5.261 4.211 dC gH nC yD 4.56 nZ 21 fC 211 cniz 08 84 03 89 66 – –\nmuinegtneor stnemelE muilekreb muibret reppoc 9.701 0.791 9.851", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2023-mj-42-q09-7c7f6f6507.pdf" }, { "id": "9701-2023-mj-43-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-43-q01-p01-204a998202.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-43-q01-p02-8158e6175b.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-43-q01-p03-08a9032d3a.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-mj-43-q01-p04-fc522cec71.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Group 2 nitrates decompose when heated. 1 (a)\nDescribe how the thermal stability of Group 2 nitrates changes with increasing proton number.\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nCopper(II) nitrate decomposes in a similar manner to Group 2 nitrates. (b)\n) . Write an equation for the decomposition of Cu(NO\n3 2\n............................................................................................................................................. [1]\n) is added to water to form solution A. Cu(NO (c)\n3 2\nFig. 1.1 shows some reactions of solution A.\nH O\n2\nCu(NO ) (s) solution solution A C\n3 2 excess\n(aq) NH\n3 (aq) NH\n3\nprecipitate B excess\nHCl concentrated\nsolution D\nFig. 1.1\nComplete Table 1.1 to show the formula and colour of each of the copper‑containing species\npresent in A, B, and D. C\nTable 1.1\nformula of copper‑containing colour of copper‑containing\nspecies formed species formed\nA\nB\nC\nD\n[4]\nEDTA4– is a polydentate ligand. (d)\nExplain what is meant by a polydentate ligand. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nGroup 2 metal ions can form complexes similar to those of transition elements. (ii)\n4– ]2+ is added to water containing [Ca(H O) to form a new complex, A solution of EDTA\n2 6\n[CaEDTA]2–, as shown.\n]2+ EDTA4– [CaEDTA]2– O) + + 6H O equilibrium 1 [Ca(H\n2 6 2\nEDTA4– in Fig. 1.2 the atoms that form bonds with the metal Circle on the structure of six\nion.\nEDTA4–\nO O\nO– –O CCH CH C\n2 2\nNCH CH N\n2 2\n–O O– CH CCH C\n2 2\nO O\nFig. 1.2\n[1]\n]2+ [CaEDTA]2– O) and have a coordination number of 6. The calcium ions in [Ca(H (iii)\n2 6\nExplain what is meant by coordination number.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[CaEDTA]2– The co", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-mj-43-q01-b240ccfaad.pdf" }, { "id": "9701-2023-mj-43-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q02-p01-b9891fca56.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q02-p02-f1867310c6.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q02-p03-dcaa83236e.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q02", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Some transition element complexes can show stereoisomerism. 2 (a)\nState types of stereoisomerism shown by transition element complexes. two\n1 ................................................................................................................................................\n2 ................................................................................................................................................\n[1]\n]2+ Cl ) ] and [Pt(en) have the same geometry (shape) around the The complexes [Pt(NH (b)\n3 2 2 2\nmetal ion.\n]2+ Cl ) ] exists as two stereoisomers whereas [Pt(en) only has one possible structure. [Pt(NH\n3 2 2 2\nState the geometry around the metal ion.\n............................................................................................................................................. [1]\n]2+ exists as two stereoisomers whereas the complex The complex [Cr(en) (c)\n3\n]− CH NH ) exists as four stereoisomers. [Cr(OCH\n2 2 2 3\nComplete the three‑dimensional diagrams in Fig. 2.1 to show the four stereoisomers of\n]−. CH NH ) [Cr(OCH\n2 2 2 3\n–OCH CH NH by using . Represent the ligand\n2 2 2\nO N\nCr Cr\nCr Cr\nFig. 2.1\n[3]\n]− 2+(aq) The complex [Cr(OCH CH NH ) is formed by reacting Cr with the conjugate base of (d)\n2 2 2 3\n2‑aminoethanol.\nA synthesis of 2‑aminoethanol is shown in Fig. 2.2.\noxirane 2-aminoethanol\nO\nOH\nH C C H + NH\nN H 3\n2\nH H\nFig. 2.2\nSuggest the mechanism for step 1 of the reaction of oxirane with ammonia in Fig. 2.3. (i)\nInclude all relevant curly arrows, lone pairs of electrons, charges and partial charges.\nDraw the structure of the organic intermediate.\noxirane 2-aminoethanol intermediate\nO\nstep 2 step 1 OH\nC H H C\nN H\n2\nH H\nN H\n3\nFig. 2.3\n[3]\nA small amount of by‑product E, shown in Fig. 2.4, is produced during the reaction shown (ii)\nin Fig. 2.2.\nE\nHO OH\nN\nH\nFig. 2.4\nSuggest how the formation of by‑product can be minimised. E\n...........................................................................................................................................\n..................................................................................................................................... [1]\nCompound F, C H NO, can be formed from the reaction of by‑product E, C H NO , (iii)\n4 9 4 11 2\nSO . with concentrated H\n2 4\nCompound is a and basic organic compound. F saturated\nSuggest a structure for compound F. State the type of reaction undergone by to form F. E\nF\ntype of reaction ..................................................................................................................\n[2]\n[Total: 11]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-mj-43-q02-d5ce03ba59.pdf" }, { "id": "9701-2023-mj-43-q03", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-43-q03-p01-e9a7c2e381.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-mj-43-q03-p02-5837f3ec11.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "–, iodate(V) IO Aqueous acidified ions, react with iodide ions, as shown. 3 (a)\n3\n6H+ 5I– – 3I IO + + + 3H O\n3 2 2\nThe initial rate of this reaction is investigated. Table 3.1 shows the results obtained.\nTable 3.1\n[H+] dm–3 dm–3min–1 dm–3 [I–] dm–3 –] [IO experiment / mol initial rate / mol / mol / mol\n3\n10–2 × 1 0.0400 0.0150 0.0250 4.20\n10–2 × 2 0.120 to be calculated 0.0125 7.09\n–][H+]2[I–]2. [IO The rate equation for this reaction is rate = k\n3\nExplain what is meant by order of reaction. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nComplete Table 3.2. (ii)\nTable 3.2\n–] [IO the order of reaction with respect to\n3\n[H+] the order of reaction with respect to\n[I–] the order of reaction with respect to\nthe overall order of reaction\n[1]\nUse your answer to to sketch lines in Fig. 3.1 to show the relationship between the (iii) (a)(ii)\n[I–]. –] [IO and initial rates and the concentrations of\n3\ninitial rate initial rate\n0 0\n0 0 [I–] –] [IO\n3\nFig. 3.1\n[1]\nUse data from Table 3.1 to calculate the rate constant, k, for this reaction. (iv)\nInclude the units of k.\nk = .............................. units .............................. [2]\n+], in Use data from Table 3.1 to calculate the concentration of hydrogen ions, [H (v)\nexperiment 2.\n[H+] dm–3 = .............................. mol [1]\nThis reaction is repeated in two separate experiments. (vi)\nThe experiments are carried out at the same temperature and with the same\nI– –. IO and concentrations of\n3\nOne experiment takes place at pH 1.0 and the other experiment takes place at pH 2.0.\nrate at pH 1.0\n. Calculate the value of\nrate at pH 2.0\nrate at pH 1.0\nvalue of = .............................. [1]\nrate at pH 2.0\niron(III) ions react with iodide ions, as shown. In aqueous solution, (b)\n2Fe3+ 2I– 2Fe2+ I + +\n2\nFe3+ The initial rate of reaction is first order with respect to and second order with respect\nI–. to\nThe mechanism for this reaction has three steps.\nEach step involves only ions reacting together. two\nSuggest equations for the steps of this mechanism. Identify the rate‑determining step. three\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\nstep 3 ........................................................................................................................................\nrate‑determining step = .............................\n[3]\n[Total: 10]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-mj-43-q03-b5c159388e.pdf" }, { "id": "9701-2023-mj-43-q04", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2023-mj-43-q04-p01-e8e4803996.png", "9701-topic-36-organic-synthesis/assets/9701-2023-mj-43-q04-p02-d898185990.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q04", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "State the hybridisation of the carbon atoms and the C–C–H bond angle in benzene, C H . 4 (a)\n6 6\nσ π Explain how orbital overlap leads to the formation of and bonds in benzene.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nCompound can be synthesised from benzene in three steps by the route shown in Fig. 4.1. (b) Z\nbenzene Z\nNH\n2\nstep 1 step 3\nX Y\nstep 2\nFig. 4.1\nDraw structures for and in Fig. 4.1. [2] (i) X Y\nGive the reagents and conditions for steps 1, 2 and 3. (ii)\nstep 1 ................................................................................................................................\nstep 2 ................................................................................................................................\nstep 3 ................................................................................................................................\n[3]\nCompound is an isomer of Z. (c) W\nW\nNH\n2\nFig. 4.2\nGive the systematic name of W.\n............................................................................................................................................. [1]\nComplete Table 4.1 to show the number of peaks observed in the carbon‑13 NMR spectrum (d)\nfor and Z. W\nTable 4.1\ncompound number of peaks observed\nW\nZ\n[1]\n[Total: 10]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2023-mj-43-q04-50d51e0c15.pdf" }, { "id": "9701-2023-mj-43-q05", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 14, 15, 16 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q05-p01-636b67e606.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q05-p02-7457ad99fe.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q05-p03-8b9de9b4f7.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q05", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "The exhaust systems of most modern gasoline‑fuelled cars contain a catalytic converter with 5 (a)\nthree metal catalysts.\nThese metals act as heterogeneous catalysts.\nName metal catalysts used in catalytic converters. (i) three\n1 ................................. 2 ................................. 3 ................................. [1]\nExplain what is meant by a heterogeneous catalyst. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nThe exhaust systems of many diesel‑fuelled cars contain an additional system to reduce (b)\nvehicle emissions. This uses a liquid that is added to the exhaust system.\n) CO, which decomposes on heating to isocyanic acid, HNCO, This liquid contains urea, (NH\n2 2\nand ammonia.\n) CO HNCO + NH reaction 1 (NH\n2 2 3\nIsocyanic acid reacts with water vapour to form ammonia and carbon dioxide.\nO(g) NH (g) + CO (g) reaction 2 HNCO(g) + H\n2 3 2\no, o, ΔH and standard entropies, S Some values for standard enthalpy changes of formation,\nf\nare given in Table 5.1.\nTable 5.1\nmol–1 o K–1 mol–1 o ΔH compound / kJ S / J\nf\nHNCO(g) –101.7 +238.2\nO(g) –241.8 +188.8 H\n2\n(g) –45.9 +192.8 NH\n3\n(g) –393.5 +213.8 CO\n2\nExplain what is meant by the term entropy of a system. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\no ΔG °C. Use the data in Table 5.1 to calculate for at 25 (ii) reaction 2\nShow your working.\no mol–1 ΔG = .............................. kJ [4]\nThe ammonia formed in reactions 1 and 2 can be used to remove nitrogen dioxide from (c)\nexhaust emissions, as shown.\n+ 6NO 7N + 12H O reaction 3 8NH\n3 2 2 2\nUse the equations for reactions 1, 2 and 3 to construct an overall equation for the reduction of\nNO by (NH ) CO.\n2 2 2\n............................................................................................................................................. [1]\nH N O , under certain conditions. Isocyanic acid, HNCO, can form cyanuric acid, C (d)\n3 3 3 3\nH N O has a cyclic structure containing alternating carbon and nitrogen atoms in the ring C\n3 3 3 3\nsystem.\nSuggest a structure for cyanuric acid.\n[1]\nIsocyanic acid, HNCO, is a weak acid. (e)\nO+ NCO– °C O H + pK = 3.70 at 25 HNCO + H\n2 3 a\nand pH. Write the mathematical expressions for pK (i)\na\npK = .................................................................................................................................\na\npH = ...................................................................................................................................\n[1]\ndm–3 HNCO(aq). Calculate the pH of 0.120 mol (ii)\nGive you", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-mj-43-q05-89b31dfc26.pdf" }, { "id": "9701-2023-mj-43-q06", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2023-mj-43-q06-p01-4751f20bc6.png", "9701-topic-35-polymerisation/assets/9701-2023-mj-43-q06-p02-38c92bdca0.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q06", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "Compound has the structural formula CH =CHCH(NH )COOH. 6 (a) H\n2 2\nName all the functional groups in H. (i)\n...........................................................................................................................................\n..................................................................................................................................... [2]\nCompound exhibits stereoisomerism. (ii) H\nDraw three‑dimensional structures for the two stereoisomers of H.\nName this type of stereoisomerism.\ntype of stereoisomerism ....................................................................................................\n[2]\nCompound can be prepared from the reaction of with an excess of hot aqueous acid. (b) H J\nJ\nO\nO\nN\nH\nO\nFig. 6.1\nComplete Fig. 6.2 to show the equation for this reaction. (i)\nO\nO\n=CHCH(NH )COOH + + CH\n2 2\nN\nH\nO\nFig. 6.2\n[1]\nName the type of reaction in (b)(i). (ii)\n..................................................................................................................................... [1]\nPolymers consist of monomers joined together by undergoing either addition or condensation (c)\npolymerisation.\nCompound can react to form an addition polymer, K, or a condensation polymer, L, H\ndepending on the conditions.\nDraw repeat unit of addition polymer K. (i) one\n[1]\nDraw repeat units of condensation polymer L. (ii) two\nThe new functional group formed should be displayed.\n[2]\nExplain why condensation polymers can normally biodegrade more readily than addition (iii)\npolymers.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[Total: 10]", "pdf_path": "9701-topic-35-polymerisation/print/9701-2023-mj-43-q06-92db08ff47.pdf" }, { "id": "9701-2023-mj-43-q07", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 20, 21, 22, 23 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q07-p01-68dd49312a.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q07-p02-5798be5086.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q07-p03-aa6121d6c7.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-mj-43-q07-p04-bf40ba6acb.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "State the relative basicities of ethanamide, diethylamine and ethylamine in aqueous solution. 7 (a)\nExplain your answer.\n............................................. > ............................................. > .............................................\nmost basic least basic\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[4]\nNCH(CH )COOH, can act as a buffer. The amino acid alanine, H (b)\n2 3\nDefine a buffer solution. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nWrite equations to show how an aqueous solution of alanine can act as a buffer (ii) two\nsolution.\n...........................................................................................................................................\n..................................................................................................................................... [2]\nGlutamic acid is another amino acid that acts as a buffer. (c)\nglutamic acid\nCH COOH CH\n2 2\nH C N COOH\n2\nH\nFig. 7.1\nDraw the formula for glutamic acid. (i) skeletal\n[1]\nDraw the structure for the dipeptide, ala‑glu, formed from one molecule of alanine and (ii)\none molecule of glutamic acid.\nThe peptide bond formed should be displayed.\n[2]\nThe isoelectric point of alanine is 6.0 and of glutamic acid is 3.2. (d)\nA mixture of the dipeptide, ala‑glu, and its two constituent amino acids, alanine and glutamic\nacid, is analysed by electrophoresis using a buffer at pH 6.0.\n– +\nmixture applied here\nFig. 7.2\nDraw and label spots on Fig. 7.2 to indicate the predicted position of each of these three\nthree species after electrophoresis.\nExplain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n..........................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-mj-43-q07-a3f1c3ec89.pdf" }, { "id": "9701-2023-mj-43-q08", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_43.pdf?download=true", "source_pages": [ 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q08-p01-c317aade3c.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q08-p02-6d56daef3b.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q08-p03-263930e0a9.png", "9701-topic-23-chemical-energetics/assets/9701-2023-mj-43-q08-p04-3cab8ed218.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-43-q08", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "✓ Complete Table 8.1 by placing tick ( ) in each row to indicate the sign of each type of 8 (a) one\nenergy change under standard conditions.\nTable 8.1\ncan be either\nenergy change always positive always negative\nnegative or positive\nlattice energy\nenthalpy change of hydration\nenthalpy change of solution\n[1]\nDefine enthalpy change of hydration. (b)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTable 8.2 shows various energy changes which can be used in the following questions. (c)\nTable 8.2\nmol–1 energy change value / kJ\nstandard enthalpy change of atomisation of calcium +178.2\nfirst ionisation energy of calcium +590\nsecond ionisation energy of calcium +1145\nstandard enthalpy change of atomisation of bromine +111.9\nBr–Br bond energy +192.9\n(s) –103.1 standard enthalpy change of solution of calcium bromide, CaBr\n2\n(s) –682.8 standard enthalpy change of formation of calcium bromide, CaBr\n2\nCa2+ –1579 standard enthalpy change of hydration of\nfirst electron affinity of bromine –324.6\nfirst ionisation energy of bromine +1140\no\nΔH Select and use relevant data from Table 8.2 to calculate the lattice energy, , of (i)\nlatt\n(s). CaBr\n2\nIt may be helpful to draw a labelled energy cycle.\nShow your working.\no\nmol–1 ΔH of CaBr (s) = .............................. kJ [3]\nlatt 2\nSelect and use relevant data from Table 8.2 and your answer to to calculate the (ii) (c)(i)\no\n–. ΔH , of Br standard enthalpy change of hydration,\nhyd\nIt may be helpful to draw a labelled energy cycle.\no –1 ΔH as your value for of If you were not able to answer (c)(i), use –2500 kJ mol\nlatt\n(s). This is the correct value. CaBr not\n2\nShow your working.\no\n– mol–1 ΔH of Br = .............................. kJ [2]\nhyd\n– ion is more negative than the enthalpy The enthalpy change of hydration of the Br (iii)\nI– ion. Explain why. change of hydration of the\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n[Total: 9]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n104 mol–1 × Faraday constant F = 9.65 C\n1023 mol–1 × Avogadro constant L = 6.022\n10–19 × electronic charge e = –1.60 C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n10–14 mol2 dm–6 × °C)) = 1", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-mj-43-q08-1621fb0a4f.pdf" }, { "id": "9701-2023-mj-51-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-51-q01-p01-33388f3b52.png", "9701-experimental-skills/assets/9701-2023-mj-51-q01-p02-0f5de31be4.png", "9701-experimental-skills/assets/9701-2023-mj-51-q01-p03-ae514e2c47.png", "9701-experimental-skills/assets/9701-2023-mj-51-q01-p04-7c39622d76.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "The partition coefficient, K , shows the distribution of a solute between two immiscible solvents. 1\npc\nis determined by measuring the concentration of the solute in each solvent. K\npc\nCH OCH CH , and water are immiscible. A student is The organic solvent ethoxyethane, CH\n3 2 2 3\nof butanedioic acid, HOOCCH CH COOH, between ethoxyethane and water. asked to find K\npc 2 2\nwhen butanedioic acid is in equilibrium between ethoxyethane and water is The expression for K\npc\nshown.\n[HOOCCH CH COOH(ethoxyethane)]\n2 2 = K\npc CH COOH(aq)] [HOOCCH\n2 2\ncm–3; cm–3] water, 1.00 g [density: ethoxyethane, 0.71 g\nThe student uses the following method to find the partition coefficient. A diagram of the apparatus\nis shown in Fig. 1.1.\n3 of distilled water to a separating funnel. Add 30.0 cm step 1\nWeigh by difference 2.81 g of butanedioic acid into the separating funnel. step 2\nStopper the separating funnel and shake it until the butanedioic acid has dissolved. step 3\n3 of ethoxyethane to the separating funnel. Remove the stopper and add 30.0 cm step 4\nReplace the stopper and shake the separating funnel gently. step 5\nPlace the separating funnel into a clamp. Allow the liquids to settle so that the two layers step 6\ncan be seen.\nRemove the stopper and open the separating funnel tap to allow the lower layer to run step 7\ninto a beaker labelled A. Run the upper layer into a beaker labelled B.\n3 dm–3 of the aqueous layer into a conical flask. Titrate with 0.500 mol Transfer 10.0 cm step 8\nNaOH(aq). Use thymolphthalein as the indicator.\ncm3 cm3 of the ethoxyethane layer and add 10.0 of water to it. Titrate this Take 10.0 step 9\ndm–3 NaOH(aq). Use thymolphthalein as the indicator. mixture with 0.100 mol\nstopper\nseparating funnel\ntap\nFig. 1.1\nState whether beaker in step 7 contains the aqueous layer or the ethoxyethane layer. (a) (i) A\nExplain your answer.\nBeaker contains the ................................................. layer. A\nexplanation ........................................................................................................................\n...........................................................................................................................................\n[1]\n3 of the Identify the piece of apparatus that should be used in step 8 to transfer 10.0 cm (ii)\naqueous layer.\n..................................................................................................................................... [1]\nSuggest why water is added to the ethoxyethane layer in step 9 before the titration can (iii)\ntake place.\n...........................................................................................................................................\n..................................................................................................................................... [1]\ncm3 For a 2.81 g sample of butanedioic acid, the titre for the aqueous layer is 27.25 and the (b)\ncm3. titre for the ethoxyethane layer is 22.50\nThe ", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-51-q01-2d35456b39.pdf" }, { "id": "9701-2023-mj-51-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_51.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-51-q02-p01-ca2cf9c372.png", "9701-experimental-skills/assets/9701-2023-mj-51-q02-p02-909319d081.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Paper chromatography can be used to separate the individual amino acids formed when tripeptides 2\nare hydrolysed.\nOne molecule of a tripeptide produces three amino acid molecules when hydrolysed.\nA student is asked to identify the amino acids formed from the hydrolysis of three different\ntripeptides, A, and C, using paper chromatography. B\nFig. 2.1 shows the results of the student’s chromatography experiment.\n10\n9\n8\nsolvent\n7 front\n6\n5\n4\n3\n2\n1 hydrolysed\nsamples of\ntripeptides 0\ncm\nA B C\nFig. 2.1\nvalues. The individual amino acids can be identified from their R\nf\ndistance travelled by the amino acid spot\n= R\nf distance travelled by the solvent front\nSuggest why each sample is applied to the chromatography paper using a thin capillary tube (a)\nrather than a dropping pipette.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nSuggest why it is necessary to spray a developing agent over the chromatography paper (b)\nbefore the chromatogram can be analysed.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTable 2.1 shows R values for some amino acids in the solvent used in Fig. 2.1. (c)\nf\nTable 2.1\namino acid R value\nf\nlysine 0.14\nglycine 0.26\nserine 0.27\nglutamic acid 0.30\nalanine 0.38\nproline 0.43\ntryptophan 0.50\nvaline 0.60\nleucine 0.73\nUse the data in Table 2.1 to identify the amino acids in tripeptide A.\n...................................................................................................................................................\n............................................................................................................................................. [2]\nSuggest why the hydrolysed sample of produces only two spots. (d) B\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTwo of the spots from the hydrolysed sample of overlap. (e) C\nState the reason for the overlap. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nSuggest an improvement to the method that would allow the overlapping spots to be (ii)\ndistinguished clearly.\n..........................................", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-51-q02-269567904b.pdf" }, { "id": "9701-2023-mj-51-q03", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 3, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_51.pdf?download=true", "source_pages": [ 9, 10, 11, 12, 15, 16 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-51-q03-p01-8837fc8da5.png", "9701-experimental-skills/assets/9701-2023-mj-51-q03-p02-8a138e641d.png", "9701-experimental-skills/assets/9701-2023-mj-51-q03-p03-fd9126ae2a.png", "9701-experimental-skills/assets/9701-2023-mj-51-q03-p04-74e3361720.png", "9701-experimental-skills/assets/9701-2023-mj-51-q03-p05-06b5a7caf4.png", "9701-experimental-skills/assets/9701-2023-mj-51-q03-p06-b306cf46a6.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-51-q03", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A scientist is asked to find the rate of decomposition of an aromatic diazonium compound and 3\ndetermine the order of the reaction with respect to the aromatic diazonium compound.\ncm3 beaker. The scientist is given 1.02 g of an aromatic diazonium compound in a 50 (a)\ncm3 standard solution containing Describe the steps the scientist should take to make a 100.0\n1.02 g of this compound.\nGive the name and capacity of the apparatus the scientist should use.\nWrite your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nBenzenediazonium chloride, an aromatic diazonium compound, decomposes in solution (b)\n3 of the solution to 50 °C. to produce phenol and nitrogen gas. The scientist warms 50 cm\nThe scientist records the volume of nitrogen gas produced at different times during the\ndecomposition.\nIdentify the piece of apparatus that should be used to maintain the temperature of the (i)\nsolution.\n..................................................................................................................................... [1]\nIdentify the dependent variable. (ii)\n..................................................................................................................................... [1]\nSuggest why the scientist does monitor the reaction by measuring the loss in mass. (iii) not\n...........................................................................................................................................\n..................................................................................................................................... [1]\nTable 3.1 shows the results of the experiment. (c)\nTable 3.1\ncm3 cm3 time, t / min volume, V / V – V /\nt final t\n0 0.0\n5 17.3\n9 27.0\n16 39.5\n21 42.6\n28 49.0\n36 52.8\nfinal 57.2 0.0\nis the final volume of nitrogen gas measured once the decomposition is complete. V\nfinal\nis the volume collected at time = t. V\nt\n– V is proportional to the concentration of the benzenediazonium chloride. V\nfinal", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-51-q03-044bdde955.pdf" }, { "id": "9701-2023-mj-52-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-52-q01-p01-a43def3eb3.png", "9701-experimental-skills/assets/9701-2023-mj-52-q01-p02-c2521dab36.png", "9701-experimental-skills/assets/9701-2023-mj-52-q01-p03-d7709e95ee.png", "9701-experimental-skills/assets/9701-2023-mj-52-q01-p04-8825c69a50.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Three students are asked to prepare samples of benzoic acid, C H COOH, from the alkaline 1\n6 5\nH COOCH . Sodium benzoate, C H COONa, is the salt formed, hydrolysis of methyl benzoate, C\n6 5 3 6 5\nH COOH. which is then acidified with hydrochloric acid to form C\n6 5\nH COOCH (l) + NaOH(aq) C H COONa(aq) + CH OH(l) C\n6 5 3 6 5 3\nHCl NaCl H COONa(aq) + (aq) C H COOH(s) + (aq) C\n6 5 6 5\nThe students use the following method.\n3 round-bottomed flask. Put 1.242 g of liquid methyl benzoate into a 50 cm step 1\ncm3 dm–3 of 1.00 mol aqueous sodium hydroxide, NaOH(aq). Prepare 100.0 step 2\ncm3, an excess, of the prepared NaOH(aq) to the round-bottomed flask. Add 10 step 3\nAdd some anti-bumping granules to the round-bottomed flask. step 4\nFit a condenser to make reflux apparatus. Reflux the reaction mixture for 20 minutes. step 5\nAllow the reaction mixture to cool and carefully pour the liquid into a beaker. step 6\nAcidify the liquid with dilute hydrochloric acid. step 7\nFilter the mixture formed in step 7. step 8\nPurify the benzoic acid by recrystallisation from hot water. Filter, dry and record the mass step 9\nof pure benzoic acid obtained.\nCalculate the volume of methyl benzoate used in step 1. (a) (i)\n3. Give your answer to the nearest 0.05 cm\ncm–3] [density: methyl benzoate, 1.08 g\ncm3 volume of methyl benzoate = .............................. [1]\nIdentify a suitable piece of apparatus to measure the volume of methyl benzoate required (ii)\nin step 1.\n..................................................................................................................................... [1]\nCalculate the mass of NaOH(s) that is needed to prepare the solution in step 2. (iii)\nmass of NaOH(s) = .............................. g [1]\nStudent 1 added the mass of NaOH(s) calculated in into a beaker. (b) (a)(iii)\ncm3 dm–3 of 1.00 mol NaOH(aq). Describe the steps the student should take to make 100.0\nGive the name and capacity of any apparatus that should be used.\nWrite your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\n–3 dm–3 NaOH(aq) instead of 1.00 mol NaOH(aq) in step 2. Student 2 prepared 0.100 mol d", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-52-q01-9827a2bc7b.pdf" }, { "id": "9701-2023-mj-52-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-52-q02-p01-b81bb6ad8d.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p02-73d2a564e8.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p03-c6f463aa12.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p04-793a2388ef.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p05-531c259479.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p06-a499fc00ea.png", "9701-experimental-skills/assets/9701-2023-mj-52-q02-p07-e500a3ce6e.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Pure water dissociates according to the equation shown. 2\nH+(aq) OH–(aq) O(l) + H\n2\n, the ionic product of water. The equilibrium constant for this reaction is known as K\nw\n[H+(aq)] [OH–(aq)] = K\nw\n10–14 mol2 dm–6. × has a value of 1.00 The pH of pure water at 25 °C is 7.00. At 25 °C, K\nw\nA student finds the pH of pure water at 35 °C is 6.84. The student investigates how temperature\naffects the pH of pure water and determines a value for the enthalpy change for the dissociation of\nΔH. water,\nThe student records the pH of pure water at different temperatures. A line of best fit from the\nresults of the student’s investigation is shown in Fig. 2.1.\n7.20\n7.10\n7.00\n6.90\n6.80\npH\n6.70\n6.60\n6.50\n6.40\n6.30\n20 25 30 35 40 45 50 55\ntemperature\n/ °C\nFig. 2.1\nUse Fig. 2.1 to calculate the hydrogen ion concentration of pure water at 45 °C. (a) (i)\n[H+(aq)] pH = –log\ndm–3 [1] hydrogen ion concentration = .............................. mol\nfor pure water at 45 °C. Calculate the value of K (ii)\nw\nmol2 dm–6 = .............................. [1] K\nw\nand temperature. State the relationship between K (iii)\nw\n...........................................................................................................................................\n..................................................................................................................................... [1]\nThe student determines K at a range of temperatures. (b)\nw\nThe results are shown in Table 2.1.\nTable 2.1\nK temperature, T 1 w\nlog K K–1 / w / K mol2 dm–6 T /\n10–15 × 283 2.93\n10–15 × 293 6.81\n10–14 × 303 1.47\n10–14 × 313 2.92\n10–14 × 323 5.48\n10–13 × 333 1.09\n10–13 × 343 1.45\nComplete Table 2.1. (i)\n1\nRecord to decimal to significant figures using standard form. Record log K two three\nw T\nplaces.\n[2]\n1\n(×) and . Use a cross Plot a graph on the grid to show the relationship between log K (ii)\nw T\nto plot each data point.\n[2] Draw a line of best fit.\nCircle the point on the graph that you consider to be most anomalous. [1] (iii) one\nSuggest reason to explain the anomalous point you have circled. Assume there was (iv) one\n. no error in determining K\nw\n...........................................................................................................................................\n..................................................................................................................................... [1]\nUse your graph to determine the gradient of the line of best fit. (v)\nState the coordinates of both points you used in your calculation. These must be selected\nfrom your line of best fit.\ncoordinates 1 ....................................... coordinates 2 .......................................\ngradient = ...............................................................\n[2]\n–12.2\n–12.4\n–12.6\n–12.8\n–13.0\n–13.2\nlog K\nw\n–13.4\n–13.6\n–13.8\n–14.0\n–14.2\n–14.4\n–14.6\n2.9 3.0 3.1 3.2 3.3 3.4 3.5 3.6 2.8\n1\n10–3 K–1 × /\nT\n1\nThe relationship between log K and is given by the equation shown", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-52-q02-fbd5b75004.pdf" }, { "id": "9701-2023-mj-53-q01", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-53-q01-p01-33388f3b52.png", "9701-experimental-skills/assets/9701-2023-mj-53-q01-p02-0f5de31be4.png", "9701-experimental-skills/assets/9701-2023-mj-53-q01-p03-ae514e2c47.png", "9701-experimental-skills/assets/9701-2023-mj-53-q01-p04-7c39622d76.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "The partition coefficient, K , shows the distribution of a solute between two immiscible solvents. 1\npc\nis determined by measuring the concentration of the solute in each solvent. K\npc\nCH OCH CH , and water are immiscible. A student is The organic solvent ethoxyethane, CH\n3 2 2 3\nof butanedioic acid, HOOCCH CH COOH, between ethoxyethane and water. asked to find K\npc 2 2\nwhen butanedioic acid is in equilibrium between ethoxyethane and water is The expression for K\npc\nshown.\n[HOOCCH CH COOH(ethoxyethane)]\n2 2 = K\npc CH COOH(aq)] [HOOCCH\n2 2\ncm–3; cm–3] water, 1.00 g [density: ethoxyethane, 0.71 g\nThe student uses the following method to find the partition coefficient. A diagram of the apparatus\nis shown in Fig. 1.1.\n3 of distilled water to a separating funnel. Add 30.0 cm step 1\nWeigh by difference 2.81 g of butanedioic acid into the separating funnel. step 2\nStopper the separating funnel and shake it until the butanedioic acid has dissolved. step 3\n3 of ethoxyethane to the separating funnel. Remove the stopper and add 30.0 cm step 4\nReplace the stopper and shake the separating funnel gently. step 5\nPlace the separating funnel into a clamp. Allow the liquids to settle so that the two layers step 6\ncan be seen.\nRemove the stopper and open the separating funnel tap to allow the lower layer to run step 7\ninto a beaker labelled A. Run the upper layer into a beaker labelled B.\n3 dm–3 of the aqueous layer into a conical flask. Titrate with 0.500 mol Transfer 10.0 cm step 8\nNaOH(aq). Use thymolphthalein as the indicator.\ncm3 cm3 of the ethoxyethane layer and add 10.0 of water to it. Titrate this Take 10.0 step 9\ndm–3 NaOH(aq). Use thymolphthalein as the indicator. mixture with 0.100 mol\nstopper\nseparating funnel\ntap\nFig. 1.1\nState whether beaker in step 7 contains the aqueous layer or the ethoxyethane layer. (a) (i) A\nExplain your answer.\nBeaker contains the ................................................. layer. A\nexplanation ........................................................................................................................\n...........................................................................................................................................\n[1]\n3 of the Identify the piece of apparatus that should be used in step 8 to transfer 10.0 cm (ii)\naqueous layer.\n..................................................................................................................................... [1]\nSuggest why water is added to the ethoxyethane layer in step 9 before the titration can (iii)\ntake place.\n...........................................................................................................................................\n..................................................................................................................................... [1]\ncm3 For a 2.81 g sample of butanedioic acid, the titre for the aqueous layer is 27.25 and the (b)\ncm3. titre for the ethoxyethane layer is 22.50\nThe ", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-53-q01-7e62520c09.pdf" }, { "id": "9701-2023-mj-53-q02", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_53.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-53-q02-p01-ca2cf9c372.png", "9701-experimental-skills/assets/9701-2023-mj-53-q02-p02-909319d081.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Paper chromatography can be used to separate the individual amino acids formed when tripeptides 2\nare hydrolysed.\nOne molecule of a tripeptide produces three amino acid molecules when hydrolysed.\nA student is asked to identify the amino acids formed from the hydrolysis of three different\ntripeptides, A, and C, using paper chromatography. B\nFig. 2.1 shows the results of the student’s chromatography experiment.\n10\n9\n8\nsolvent\n7 front\n6\n5\n4\n3\n2\n1 hydrolysed\nsamples of\ntripeptides 0\ncm\nA B C\nFig. 2.1\nvalues. The individual amino acids can be identified from their R\nf\ndistance travelled by the amino acid spot\n= R\nf distance travelled by the solvent front\nSuggest why each sample is applied to the chromatography paper using a thin capillary tube (a)\nrather than a dropping pipette.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nSuggest why it is necessary to spray a developing agent over the chromatography paper (b)\nbefore the chromatogram can be analysed.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTable 2.1 shows R values for some amino acids in the solvent used in Fig. 2.1. (c)\nf\nTable 2.1\namino acid R value\nf\nlysine 0.14\nglycine 0.26\nserine 0.27\nglutamic acid 0.30\nalanine 0.38\nproline 0.43\ntryptophan 0.50\nvaline 0.60\nleucine 0.73\nUse the data in Table 2.1 to identify the amino acids in tripeptide A.\n...................................................................................................................................................\n............................................................................................................................................. [2]\nSuggest why the hydrolysed sample of produces only two spots. (d) B\n...................................................................................................................................................\n............................................................................................................................................. [1]\nTwo of the spots from the hydrolysed sample of overlap. (e) C\nState the reason for the overlap. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nSuggest an improvement to the method that would allow the overlapping spots to be (ii)\ndistinguished clearly.\n..........................................", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-53-q02-a6014cafc6.pdf" }, { "id": "9701-2023-mj-53-q03", "subject": "9701", "year": 2023, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 3, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-may-june/9701_s23_qp_53.pdf?download=true", "source_pages": [ 9, 10, 11, 12, 15, 16 ], "local_pdf": "_source-pdfs/2023-May-June/qp/9701_s23_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-mj-53-q03-p01-8837fc8da5.png", "9701-experimental-skills/assets/9701-2023-mj-53-q03-p02-8a138e641d.png", "9701-experimental-skills/assets/9701-2023-mj-53-q03-p03-fd9126ae2a.png", "9701-experimental-skills/assets/9701-2023-mj-53-q03-p04-74e3361720.png", "9701-experimental-skills/assets/9701-2023-mj-53-q03-p05-06b5a7caf4.png", "9701-experimental-skills/assets/9701-2023-mj-53-q03-p06-b306cf46a6.png" ], "answer": { "status": "pending", "id": "9701-2023-mj-53-q03", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A scientist is asked to find the rate of decomposition of an aromatic diazonium compound and 3\ndetermine the order of the reaction with respect to the aromatic diazonium compound.\ncm3 beaker. The scientist is given 1.02 g of an aromatic diazonium compound in a 50 (a)\ncm3 standard solution containing Describe the steps the scientist should take to make a 100.0\n1.02 g of this compound.\nGive the name and capacity of the apparatus the scientist should use.\nWrite your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nBenzenediazonium chloride, an aromatic diazonium compound, decomposes in solution (b)\n3 of the solution to 50 °C. to produce phenol and nitrogen gas. The scientist warms 50 cm\nThe scientist records the volume of nitrogen gas produced at different times during the\ndecomposition.\nIdentify the piece of apparatus that should be used to maintain the temperature of the (i)\nsolution.\n..................................................................................................................................... [1]\nIdentify the dependent variable. (ii)\n..................................................................................................................................... [1]\nSuggest why the scientist does monitor the reaction by measuring the loss in mass. (iii) not\n...........................................................................................................................................\n..................................................................................................................................... [1]\nTable 3.1 shows the results of the experiment. (c)\nTable 3.1\ncm3 cm3 time, t / min volume, V / V – V /\nt final t\n0 0.0\n5 17.3\n9 27.0\n16 39.5\n21 42.6\n28 49.0\n36 52.8\nfinal 57.2 0.0\nis the final volume of nitrogen gas measured once the decomposition is complete. V\nfinal\nis the volume collected at time = t. V\nt\n– V is proportional to the concentration of the benzenediazonium chloride. V\nfinal", "pdf_path": "9701-experimental-skills/print/9701-2023-mj-53-q03-af08584d54.pdf" }, { "id": "9701-2023-on-41-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-on-41-q01-p01-6cdca47064.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-on-41-q01-p02-f19b028931.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q01", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Cl Fluorine reacts with chlorine dioxide, O , as shown. 1\n2\n2Cl 2FCl (g) + O (g) O (g) F\n2 2 2\nand first order with The rate of the reaction is first order with respect to the concentration of F\n2\nCl . No catalyst is involved. respect to the concentration of O\n2\nSuggest a two-step mechanism for this reaction. (a) (i)\nstep 1\nstep 2\n[2]\nIdentify the rate-determining step in this mechanism. Explain your answer. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n−3 s−1 the numerical value of the rate When the rate of the reaction is measured in mol dm (b)\nconstant, k, is 1.22 under certain conditions.\nComplete the rate equation for this reaction, stating the overall order of the reaction. (i)\nrate =\no verall order of reaction =\n[1]\nUse your rate equation in to calculate the rate of the reaction when the concentrations (ii) (i)\n10−3 dm−3. × Cl and O are both 2.00 mol of F\n2 2\ndm−3 s−1 rate = .............................. mol [1]\nClO Under different conditions, and in the presence of a large excess of , the rate equation is (c)\n2\nas shown.\n[F ] rate = k\n1 2\n, of the concentration of F is 4.00 s under these conditions. The half-life, t 1\n2 2\n, giving its units. Calculate the numerical value of k (i)\n1\nGive your answer to significant figures. three\n= .............................. units .............................. k\n1\n[2]\nAn experiment is performed under these conditions in which the starting concentration of (ii)\ndm–3. is 0.00200 mol F\n2\nchanges over Draw a graph on the grid in Fig. 1.1 to show how the concentration of F\n2\nthe first 12 s of the reaction.\n0.0020\n0.0018\n0.0016\n0.0014\n0.0012\ndm–3 [F ] / mol 0.0010\n2\n0.0008\n0.0006\n0.0004\n0.0002\n0\n0 1 2 3 4 5 6 7 8 9 10 11 12\ntime / s\nFig. 1.1\n[1]\nis Use your graph in Fig. 1.1 to find the rate of the reaction when the concentration of F (iii)\n2\ndm–3. Show your working on the graph. 0.00100 mol\ndm–3 s−1 [1] rate = .............................. mol\n[Total: 9]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-on-41-q01-aa06e38181.pdf" }, { "id": "9701-2023-on-41-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2023-on-41-q02-p01-cf3434a221.png", "9701-topic-25-equilibria/assets/9701-2023-on-41-q02-p02-c2d29a8b18.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Define K mathematically by completing the expression. 2 (a)\nw\nK = ..........................................................................................................................................\nw\n[1]\nTwo solutions, and W, are described. (b) V\n• HCl is (aq). V\n• is NaOH(aq). W\n• HCl The concentration of in is the same as the concentration of NaOH in W. V\n• The pH values of and differ by exactly 11.00 at 298 K. V W\nHCl Calculate the concentration of in V. (i)\ndm−3 HCl [2] concentration of in = .............................. mol V\nEqual volumes of the two solutions and are mixed, giving solution X. (ii) V W\nName solution and state its pH. X\nsolution .............................. pH .............................. X\n[1]\n3 dm−3 cm3 sample of 1.0 mol HNO is added to 100 of solution X, forming mixture Y. A 1 cm (iii)\n3\ncm3 dm−3 cm3 sample of 1.0 mol KOH is added to 100 of solution X, forming mixture Z. A 1\nEstimate the pH of mixtures and Z. No calculations are required. Y\nmixture .............................. mixture .............................. Y Z\n[1]\nCCl CH COOH, CH COOH and H SO are all acidic. CH (c) (i)\n3 2 3 2 2 4\nSuggest the trend in the relative acid strength of these three compounds.\nExplain your answer.\n....................................... ....................................... .......................................\nstrongest acid weakest acid\nexplanation ........................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[3]\nWhen concentrated H SO is added to water a series of acid-base reactions occurs. (ii)\n2 4\nThere are three conjugate acid-base pairs that can be identified during this series of reactions.\nWrite the formulae of these three conjugate acid-base pairs.\nconjugate acid 1 ......................................... conjugate base 1 .........................................\nconjugate acid 2 ......................................... conjugate base 2 .........................................\nconjugate acid 3 ......................................... conjugate base 3 .........................................\n[2]\n, of a substance, Q, between hexane and water is 7.84 at 298 K. The partition coefficient, K (d)\npc\nis more soluble in hexane than it is in water. Q\n. Define partition coefficient, K (i)\npc\n.....................................................................................................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2023-on-41-q02-e03cb88f21.pdf" }, { "id": "9701-2023-on-41-q03", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 6, 7, 8, 9 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-on-41-q03-p01-350793c0f6.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-41-q03-p02-aec3c97781.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-41-q03-p03-ffe53d6687.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-41-q03-p04-9d5d749431.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Hydrogen peroxide is a liquid at 298 K. It is moderately stable under room conditions but will 3\ndecompose quickly if a catalyst is added.\nO (l) 2H O (l) + O (g) reaction 1 2H\n2 2 2 2\nDefine entropy. (a) (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nPredict the sign of the standard entropy change of reaction 1. (ii)\nExplain your answer.\nsign ..............................\nexplanation ........................................................................................................................\n...........................................................................................................................................\n[1]\nSome bond energy data are shown in Table 3.1. (b)\nTable 3.1\nmol–1 type of bond bond energy / kJ\nO–O 150\nO–H 460\nO=O 496\nUse the data in Table 3.1 to show that the enthalpy change of the following reaction is\n–1. –196 kJ mol\nO (g) 2H O(g) + O (g) 2H\n2 2 2 2\n[1]\no\nSome standard entropies, S , are shown in Table 3.2. (c)\nTable 3.2\no K–1 mol–1 substance S / J\nH O (l) +102\n2 2\nO(l) +70 H\n2\nThe enthalpy change and Gibbs free energy change for the following reaction are shown.\no mol–1 ΔH O (l) 2H O(l) + O (g) = –196 kJ 2H\n2 2 2 2\no mol–1 ΔG = –238 kJ\no\nUse the data given to calculate the standard entropy of oxygen, S , O (g).\n2\no K–1 mol–1 S , O (g) = .............................. J [3]\n2\niron(III) O (aq) is catalysed by aqueous chloride and by silver metal. The decomposition of H (d)\n2 2\nIdentify which of these two catalysts is acting as a homogeneous catalyst.\nExplain your answer.\nhomogeneous catalyst ..............................................................................................................\nexplanation ...............................................................................................................................\n[1]\no\nThe E values for two electrode reactions are given. (e)\no 2H+ 2e− O + + 2H O E = +1.77 V H\n2 2 2\no Cr3+ e− Cr2+ + E = −0.41 V\nAn electrochemical cell is constructed with the following half-cells (electrodes): (i)\n• an acidified solution of H O , a platinum wire\n2 2\nCr2+ Cr3+, • mixed with a platinum wire.\no\n. Identify the positive half-cell and calculate the standard cell potential, E\ncell\no\npositive half-cell .............................. E = .............................. V\ncell\n[1]\no ΔG for the cell reaction that occurs, per mole of H O . Calculate the value of (ii)\n2 2\no mol–1 ΔG = .............................. kJ [2]\no\nvalues for two electrode reactions are given. The E (f)\no 2H+ 2e– O + + 2H O E = +1.77 V H\n2 2 2\no Co3+ e– Co2+ + E = +1.82 V\nAn electrochemical cell is constructed with the following half-cells.\nO under standard conditions, a platinum wire half-cell 1 an acidified solution of H\n2 2\ndm–3 Co3+ dm–3 Co2+, and 2", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-on-41-q03-0121c99f02.pdf" }, { "id": "9701-2023-on-41-q04", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 10 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2023-on-41-q04-p01-fe0d9d0701.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q04", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Cobalt(II) nitrate, Co(NO ) , is a reddish-brown crystalline solid. It dissolves in water to form 4 (a)\n3 2\n]2+ O) complex ions. a solution containing [Co(H\n2 6\nComplete Table 4.1 giving the formula of the cobalt-containing species that is formed in (i)\neach of the three reactions described.\nTable 4.1\n]2+(aq) reaction reagent added to [Co(H O) cobalt-containing species formed\n2 6\n1 NaOH(aq)\n(aq) 2 an excess of NH\n3\nHCl 3 an excess of conc. (aq)\n[2]\nDescribe the colour change seen in reaction 3. (ii)\n]2+(aq) O) .................................................................................... original colour of [Co(H\n2 6\nHCl final colour after addition of an excess of conc. (aq) ..................................................\n[1]\n) , is a white crystalline solid. When heated, it starts to decompose at Calcium nitrate, Ca(NO (b)\n3 2\napproximately 500°C.\n) . Write an equation for the decomposition of Ca(NO (i)\n3 2\n..................................................................................................................................... [1]\n) and Ba(NO ) start to decompose. Suggest temperatures at which Mg(NO (ii)\n3 2 3 2\nExplain your answer.\n) starts to decompose ................................................. °C temperature at which Mg(NO\n3 2\n) starts to decompose ...................................................°C temperature at which Ba(NO\n3 2\nexplanation ........................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[3]\n[Total: 7]", "pdf_path": "9701-topic-27-group-2/print/9701-2023-on-41-q04-8a2c05baca.pdf" }, { "id": "9701-2023-on-41-q05", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-41-q05-p01-98335528f5.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-41-q05-p02-9c78a19db9.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Transition elements behave as catalysts and can form complex ions. 5\nExplain why transition elements behave as catalysts. (a)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\n]–. Silver forms the linear complex ion [Ag(CN) (b)\n2\n]3−. Copper forms the tetrahedral complex ion [Cu(CN)\n4\n[TiCl (diars) ], where diars is a neutral bidentate ligand. Titanium forms the complex\n4 2\n[TiCl (diars) ]. State the oxidation state and the coordination number of titanium in (i)\n4 2\noxidation state ..............................\ncoordination number ..............................\n[1]\n]– ]3−, and [Cu(CN) in Draw three-dimensional diagrams to show the shapes of [Ag(CN) (ii)\n2 4\nthe boxes.\nLabel one bond angle on each diagram.\nAg Cu\n[2]\n]3– copper(I) , of the complex [Cu(CN) is The numerical value of the stability constant, K (c)\nstab 4\n1027. × 2.0\n]3−. of [Cu(CN) Write an expression for the K (i)\nstab 4\nK =\nstab\n[1]\nCN− ]3− dm−3. In a solution the concentrations of and [Cu(CN) are both 0.0010 mol (ii)\n4\nto calculate the concentration of Use your expression from and the value of K (c)(i)\nstab\nCu+(aq) in this solution.\nCu+(aq) dm–3 concentration of = .............................. mol [1]\nA piece of a copper-containing alloy has a mass of 0.567 g. It is dissolved in an acid giving (d)\ncm3 Cu2+ of a blue solution in which all the copper is present as ions. 100.0\ncm3 KI(aq) sample of this solution. An excess of is added to a 25.0\nCuI(s). All of the copper is precipitated as white\n2+ KI(aq). ions are the only component in the solution that react with This is reaction 1. Cu\n2Cu2+ 4I− 2CuI I + + reaction 1\n2\ndm–3 2−. I The liberated is then titrated with 0.0200 mol S O This is reaction 2.\n2 2 3\n2I− 2– 2– I + 2S O + S O reaction 2\n2 2 3 4 6\ncm3 dm–3 2– The titration requires 20.10 of 0.0200 mol S O to reach the end-point.\n2 3\nI that are reduced in this titration. Calculate the number of moles of (i)\n2\nI number of moles of = .............................. mol [1]\n2\nCalculate the number of moles of copper in the original piece of alloy. (ii)\nnumber of moles of copper = .............................. mol [1]\nCalculate the percentage of copper in the alloy. (iii)\npercentage of copper = .............................. % [1]\nCu2+ CuI is coloured but solid is white. Suggest why a solution of (iv)\n...........................................................................................................................................\n...........................................................................................................................................\n..........................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-41-q05-9cf3f09833.pdf" }, { "id": "9701-2023-on-41-q06", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 14 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-41-q06-p01-acd354696b.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Five ligands are listed in Table 6.1. 6 (a)\nTable 6.1\nligand type of ligand\nNH\n3\nEDTA4−\nCN−\nH NCH CH NHCH CH NH tridentate\n2 2 2 2 2 2\n2− O C\n2 4\nComplete Table 6.1 using the words monodentate, bidentate and polydentate only. (i)\nEach of these three words may be used once, more than once, or not at all. [2]\nNCH CH NHCH CH NH is a tridentate ligand. The molecule H (ii)\n2 2 2 2 2 2\nSuggest the meaning of tridentate ligand.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNCH CH NHCH CH NH acts as a tridentate ligand. Suggest how H (iii)\n2 2 2 2 2 2\n...........................................................................................................................................\n..................................................................................................................................... [1]\n]2+. (H O) This complex can exist in three Nickel forms the octahedral complex [Ni(en) (b)\n2 2 2\nisomeric forms, listed in Table 6.2.\nOne of these forms is a trans isomer, the other forms are two different cis isomers.\nTable 6.2\nisomer polarity\ntrans isomer\ncis isomer 1\ncis isomer 2\nComplete Table 6.2 using the terms polar or non-polar. (i)\nEach term may be used once, more than once, or not at all. [1]\nDescribe the difference between cis isomer 1 and cis isomer 2. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[Total: 6]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-41-q06-13a1faca8c.pdf" }, { "id": "9701-2023-on-41-q07", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 15 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-41-q07-p01-2d04f662aa.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Sunset Yellow is an additive used for colouring foods. 7\nA synthetic route for making Sunset Yellow is shown.\n– group. These groups are unchanged in the formation Molecules and each contain one –SO E G\n3\nof Sunset Yellow.\n– O SC H NH E\n3 6 4 2\nstep 1\n– HOC H SO F G\n10 6 3\nstep 2\nSunset Yellow anion\nHO\nN\nN\n–O – S SO\n3 3\nFig. 7.1\nState the molecular formula of the Sunset Yellow anion. (a)\n............................................................................................................................................. [1]\nDeduce the structures of E, and and draw them in the boxes in Fig. 7.1. [3] (b) F G\nSuggest suitable reagents and conditions for step 1 and 2. (c)\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\n[3]\nPredict the number of peaks in the carbon-13 NMR spectrum of the Sunset Yellow anion. (d)\n.............................................................................................................................................. [1]\n[Total: 8]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-on-41-q07-31079999c6.pdf" }, { "id": "9701-2023-on-41-q08", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2023-on-41-q08-p01-96db34ba66.png", "9701-topic-36-organic-synthesis/assets/9701-2023-on-41-q08-p02-a478ae6f3c.png", "9701-topic-36-organic-synthesis/assets/9701-2023-on-41-q08-p03-b0311e599c.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q08", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Capsaicin is found in chilli peppers. 8\ncapsaicin\nO\nCH O\n3\nN\nH\nHO\nYou should assume the CH O group is unreactive in the reactions involved in this question.\n3\nO group. Name all the functional groups in capsaicin in addition to the CH (a)\n3\n............................................................................................................................................. [1]\n(aq) in the dark. Complete the equation for the reaction of capsaicin with an excess of Br (b)\n2\nDraw the structure of the organic product in the labelled box.\ncapsaicin\nO\nCH O\n+ ………Br 3\nN 2\nH\nHO\norganic product\n+ …………………\n[3]\nCapsaicin is heated with an excess of hydrogen gas in the presence of platinum metal. (c)\nThe six-membered ring reacts in the same way as benzene under these conditions.\nDraw the structure of the organic product formed.\n[2]\nWhen capsaicin is treated with reagent under suitable conditions one of the products is (d) J\nCH(CH )COOH. methylpropanoic acid, CH\n3 3\nIdentify reagent and any necessary conditions. (i) J\n..................................................................................................................................... [1]\n1H) NMR spectrum of CH CH(CH )COOH There are three different peaks in the proton ( (ii)\n3 3\nCDCl . in\n3\nTable 8.1\nenvironment of proton example chemical shift\nrange\nδ / ppm\n>CH– , –CH –, 0.9–1.7 alkane –CH\n3 2\n>CH–C=O –C=O, –CH –C=O, 2.2–3.0 alkyl next to C=O CH\n3 2\n>CH–Ar –Ar, –CH –Ar, 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–Cl –O, –CH –O, –CH 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nUse Table 8.1 to complete Table 8.2 and state:\n1H) (δ) chemical shift values for the protons ● the typical proton (\n● the splitting pattern (singlet, doublet, triplet, quartet or multiplet) shown by each peak\nprotons and the CH proton. ● the explanation for the splitting patterns of the CH\n3\nTable 8.2\nδ / environment ppm splitting pattern explanation for splitting pattern\nCH\n3\nCH\nCOOH\n[3]\nCapsaicin is heated with an excess of hot aqueous NaOH. (e) (i)\ncapsaicin\nO\nCH O\n3\nN\nH\nHO\nDraw the structures of the two organic products and K. H\nC H NO Na C H O Na H K\n8 10 2 10 17 2\n[2]\nName the types of reaction occurring in (e)(i). (ii) two\n..................................................................................................................................... [1]\nLiAl in Draw the structure of the organic product formed when capsaicin is treated with H (f) L\n4\ndry ether.\nL\n[1]\n[Total: 14]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2023-on-41-q08-2617d3fa50.pdf" }, { "id": "9701-2023-on-41-q09", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_41.pdf?download=true", "source_pages": [ 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-41-q09-p01-7dcd382590.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-41-q09-p02-c136d4ea38.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-41-q09-p03-115b24a830.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-41-q09-p04-9ee8030c62.png" ], "answer": { "status": "pending", "id": "9701-2023-on-41-q09", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "COCl, Benzoyl chloride, C H can be made from ethyl benzene in a two-step process. 9 (a)\n6 5\nA reaction scheme is shown.\ncompound M\nethyl benzene benzoyl chloride\nCH CH\n2 3 Cl\nstep 1 step 2\nO\nDraw the intermediate organic compound in the box. [1] (i) M\nSuggest suitable reagents and conditions for step 1 and step 2. (ii)\nstep 1 .................................................................................................................................\nstep 2 .................................................................................................................................\n[2]\nIdentify the type of reaction in step 1 and step 2. (iii)\nstep 1 .................................................................................................................................\nstep 2 .................................................................................................................................\n[2]\nCOCl C H reacts with phenol, C H OH, to give the ester phenyl benzoate, C H COOC H . (b)\n6 5 6 5 6 5 6 5\nAn incomplete description of the mechanism of this reaction is shown in Fig. 9.1.\nbox one box two box three\nCl\nCl\nO\nC O\nC O\nC O\nO O\nH H\nand .....................\nreactants intermediate products\nFig. 9.1\nComplete the mechanism in Fig. 9.1 and include: (i)\n(δ+ δ–) ● all relevant dipoles and and full electric charges (+ and –) on the species in\nbox one and in box two\n● all relevant lone pairs on the species in box one and in box two\n● all relevant curly arrows to show the movement of electron pairs in box one and in\nbox two\n● the formula of the second product in box three.\n[4]\nName this mechanism. (ii)\n..................................................................................................................................... [1]\nBenzoyl chloride, chlorobenzene and chloroethane differ in their rates of hydrolysis when (c)\neach compound is added separately to water at 25 °C.\nSuggest the relative ease of hydrolysis of these three compounds.\nExplain your answer.\n......................................... ......................................... .........................................\nhardest to hydrolyse easiest to hydrolyse\nexplanation ...............................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[3]\n[Total: 13]\nImportant values, constants and standards\nK–1 mol–1 molar gas con", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2023-on-41-q09-0b636ba543.pdf" }, { "id": "9701-2023-on-42-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-on-42-q01-p01-2e1c9cbad7.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-on-42-q01-p02-64958da515.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-on-42-q01-p03-2efff701db.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q01", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "I Propanone, CH COCH , reacts with iodine, , in the presence of an acid catalyst. 1\n3 3 2\nH+ I– I I COCH + CH COCH + + CH\n3 3 2 3 2\nThe rate equation for this reaction is shown.\n][H+] COCH rate = k[CH\n3 3\nComplete Table 1.1 to describe the order of the reaction. (a)\nTable 1.1\norder of the reaction with respect to [CH COCH ]\n3 3\n[I order of the reaction with respect to ]\n2\n[H+] order of the reaction with respect to\noverall order of the reaction\n[2]\nH+(aq). COCH and a large excess of An experiment is performed using a large excess of CH (b)\n3 3\n10–5 dm–3. × I I is 1.00 mol The initial rate of decrease in the The initial concentration of\n2 2\n10–7 dm–3 s–1. × mol concentration is 2.27\n[I ] against time for the first 10 seconds of the reaction. Use the axes to draw a graph of (i)\n2\n10–5 × 1.00\n10–5 × 0.90\n10–5 × 0.80\n10–5 × 0.70\n10–5 × 0.60\ndm–3 10–5 [I ] / mol × 0.50\n2\n10–5 × 0.40\n10–5 × 0.30\n10–5 × 0.20\n10–5 × 0.10\n0\n0 1 2 3 4 5 6 7 8 9 10\ntime / s\n[1]\nState whether it is possible to calculate the numerical value of the rate constant, k, for (ii)\nthis reaction from your graph. Explain your answer.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n+ I ions, The experiment is repeated at a different temperature. The initial concentrations of H (c)\n2\ndm–3. COCH are all 0.200 mol and CH\n3 3\n10–5 mol–1 dm3 s–1. × The value of k at this temperature is 2.31\nCalculate the initial rate of this reaction.\ndm–3 s–1 [1] rate = ..................................... mol\nH+(aq). The new rate equation is shown. The experiment is repeated using an excess of (d)\n[CH COCH ] rate = k\n1 3 3\n10–3 s–1. × is 1.1 Calculate the value of the half-life, t . The value of k (i) 1 1\n2\n= ...................................................... s [1] t\n1\n2\nCOCH ] against time for this reaction. The Use your answer to to draw a graph of [CH (ii) (i)\n3 3\ndm–3. COCH ] on your graph should be 0.200 mol The final value of initial value of [CH\n3 3\ndm–3. COCH ] on your graph should be 0.0250 mol [CH\n3 3\n0.200X\n0.175\n0.150\n0.125\nCOCH ] [CH\n3 3\n0.100\ndm–3 mol /\n0.075\n0.050\n0.025\ntime / s\n[1]\nA four-step mechanism is suggested for the overall reaction. (e)\nH+ I– ][H+ I I COCH + CH COCH + + rate = k [CH COCH ] CH\n3 3 2 3 2 3 3\nPart of this mechanism is shown.\nH+ C+(OH)CH COCH + CH step 1: CH\n3 3 3 3\nC+(OH)CH H+ step 2: CH CH C(OH)=CH +\n3 3 3 2\nstep 3:\nC+(OH)CH H+ I I CH COCH + step 4: CH\n3 2 3 2\nWrite an equation for step 3. (i)\n..................................................................................................................................... [1]\nSuggest the slowest step of the mechanism. Explain your answer. (ii)\n...........................................................................................................................................\n..", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-on-42-q01-0727004838.pdf" }, { "id": "9701-2023-on-42-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2023-on-42-q02-p01-14f887502c.png", "9701-topic-25-equilibria/assets/9701-2023-on-42-q02-p02-570880f1f6.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "10–5 dm–3 × Benzoic acid, C H COOH, is a weak acid. The K of benzoic acid is 6.31 mol at 298 K. 2\n6 5 a\ndm3 buffer solution is made at 298 K containing 1.00 g of C H COOH and a slightly greater A 1.00\n6 5\nCOO–Na+. H mass of sodium benzoate, C\n6 5\nThis buffer solution has a pH of 4.15.\nDefine buffer solution. (a)\n...................................................................................................................................................\n............................................................................................................................................. [1]\nWrite equations to show how this solution acts as a buffer solution when the named (b)\nsubstances are added to it:\ndilute aqueous sodium hydroxide (i)\n..................................................................................................................................... [1]\ndilute aqueous nitric acid. (ii)\n..................................................................................................................................... [1]\n+ concentration and the C H COOH concentration in the buffer solution Calculate the H (c)\n6 5\nof C H COOH to calculate the concentration of described. Use the expression for the K\na 6 5\nCOO–Na+ H in the buffer solution. C\n6 5\nShow your working and give each answer to a minimum of significant figures. three\n[H+] dm–3 = .............................. mol\ndm–3 [C H COOH] = .............................. mol\n6 5\nCOO–Na+] dm–3 [C H = .............................. mol\n6 5\n[3]\ncm3 cm3 dm–3 A 10.0 sample of the buffer solution is mixed with 10.0 of 1.00 mol KOH. Both (d)\nsolutions are at 298 K. A reaction is allowed to occur without stirring.\nTwo observations are recorded:\n● the temperature, after the reaction is complete, is fractionally above 298 K\n● the pH, after the reaction, is greater than 13.\nExplain these two observations.\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\ndm–3 H COO) , has a solubility in water of less than 1.00 g Magnesium benzoate, Mg(C (e)\n6 5 2\nat 298 K.\n[Mg2+][C COO–]2 10–7 × = H = 1.76 at 298 K K\nsp 6 5\ndm–3. H COO) in water at 298 K. Give your answer in g Calculate the solubility of Mg(C (i)\n6 5 2\nShow your working.\n: Mg(C H COO) , 266.3] [M\nr 6 5 2\ndm–3 solubility = .............................. g [2]\ndm–3 H COO) is added to a sample of 0.50 mol MgSO at 298 K. An excess of Mg(C (ii)\n6 5 2 4\nH COO) is higher than, the same State whether the equilibrium concentration of Mg(C\n6 5 2\nas, or lower than your answer to (i). Explain your answer.\nThe concentration is ...............................", "pdf_path": "9701-topic-25-equilibria/print/9701-2023-on-42-q02-b540fc4c6e.pdf" }, { "id": "9701-2023-on-42-q03", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 8, 9, 10, 11 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2023-on-42-q03-p01-875ab369d5.png", "9701-topic-24-electrochemistry/assets/9701-2023-on-42-q03-p02-d7c3ab417b.png", "9701-topic-24-electrochemistry/assets/9701-2023-on-42-q03-p03-5d10144231.png", "9701-topic-24-electrochemistry/assets/9701-2023-on-42-q03-p04-0a46ea4675.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q03", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Some electrode potentials are shown in Table 3.1. 3\nTable 3.1\no– electrode reaction E / V\nV2+ 2e– –1.20 + V\nV3+ e– V2+ –0.26 +\nVO2+ 2H+ e– V3+ +0.34 + + + H O\n2\n2H+ e– VO2+ + +1.00 + + + H O VO\n2 2\nFe2+ 2e– –0.44 + Fe\nFe3+ 3e– –0.04 + Fe\nFe3+ e– Fe2+ +0.77 +\n2H+ 2e– 0.00 + H\n2\nO– 2e– – 2OH– +0.89 Cl Cl + H O + +\n2\nComplete the diagram to show a standard hydrogen electrode. (a) (i)\nLabel your diagram. Identify all substances. You do need to state standard conditions. not\n[1]\nFe3+ Fe2+ / electrode and a standard hydrogen An electrochemical cell is set up using an (ii)\nelectrode.\nIdentify the positive electrode in the electrochemical cell and the direction of electron\nflow in the external circuit.\npositive electrode ..............................................................................................................\nElectrons flow from the .............................. electrode to the .............................. electrode.\n[1]\nV2+, The vanadium-containing species in the electrode reactions given in Table 3.1 are V, (b)\nV3+, VO2+ +. and VO\n2\nFe2+ ions under Identify vanadium-containing species that does react with (i) one not\nstandard conditions.\nUse data from Table 3.1 to explain your answer.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n2+ ions under standard Identify the vanadium-containing species that will react with Fe (ii) all\nconditions.\n..................................................................................................................................... [1]\nWrite an equation for of the possible reactions identified in (ii). (iii) one\n..................................................................................................................................... [1]\n3+ Fe2+ O– – Cl Cl / electrode and an alkaline / Another electrochemical cell is set up using an Fe (c)\nelectrode.\nFe3+ Fe2+ is 1000 times greater than the concentration of in the The concentration of\nFe3+ Fe2+ / electrode. All other conditions are standard.\nFe3+ Fe2+ / electrode. Use the Nernst equation to calculate the E value of the (i)\nShow your working.\nE = .............................. V [2]\nWrite an equation for the reaction that occurs in the cell, under these conditions. (ii)\n..................................................................................................................................... [1]\n2+ O– – Cl Cl / Fe electrode and an alkaline / Another electrochemical cell is set up using an Fe (d)\nelectrode under standard conditions.\no– ΔG for the cell. Calculate the value of\nΔGo – mol–1 = .............................. kJ [3]\niron(II) A solution of sulfate, FeSO (aq) is electrolysed with iron electrodes. Under the (e)\n4\nconditions used, no gas is evolved at the cathode.\nA current of 0.640 A is pa", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2023-on-42-q03-0895b48068.pdf" }, { "id": "9701-2023-on-42-q04", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-42-q04-p01-3d95a472e7.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-42-q04-p02-8dc79f6afd.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "EDTA4–, The structure of the polydentate ligand, is shown in Fig. 4.1. 4\nO O\nCCH O CH C O\n2 2\nNCH CH N\n2 2\nO CCH CH C O\n2 2\nO O\nFig. 4.1\nThe stability constants, at 298 K, of five octahedral complexes are given in Table 4.1.\nTable 4.1\ncomplex K\nstab\n[Cu(EDTA)]2– 1019 × 6.31\n[Cr(EDTA)]2– 1013 × 1.00\n[Cr(EDTA)]– 1024 × 1.00\n[Fe(EDTA)]2– 1014 × 2.00\n[Fe(EDTA)]– 1025 × 1.26\nDefine stability constant. (a)\n...................................................................................................................................................\n............................................................................................................................................. [1]\n2– [Cr(EDTA)]–. and Cr in Calculate the oxidation states of Cu in [Cu(EDTA)] (b)\nCu ..............................\nCr ..............................\n[1]\n4– [Fe(EDTA)]2– ligand in a single Deduce the number of lone pairs donated by each EDTA (c)\ncomplex ion.\n............................................................................................................................................. [1]\nIdentify the most stable complex in Table 4.1. Explain your choice. (d)\n...................................................................................................................................................\n............................................................................................................................................. [1]\n]2+] 10–10 dm–3 × In a solution at equilibrium at 298 K, [[Cu(H O) = 3.00 mol and (e)\n2 6\n[EDTA4–] 10–12 dm–3. × = 5.00 mol\n[Cu(EDTA)]2– to calculate the concentration of in this solution. Use the expression for K\nstab\nShow your working.\n[[Cu(EDTA)]2–] dm–3 = .............................. mol [2]\n[Cu(EDTA)]2– ]2+ ions is pale blue while a solution of [Cu(NH ) (H O) ions is A solution of (f)\n3 4 2 2\ndeep blue.\nExplain this difference in colour.\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\n[Total: 8]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-42-q04-42236db44e.pdf" }, { "id": "9701-2023-on-42-q05", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 14 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2023-on-42-q05-p01-8131e1f36a.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q05", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Some of the ionic compounds of Group 2 elements undergo thermal decomposition. 5\nO , occurs above Thermal decomposition of solid anhydrous magnesium ethanedioate, MgC\n2 4\n650 °C. The products are magnesium oxide and a mixture of two different gases, one of which\ngives a white precipitate with saturated calcium hydroxide solution.\nO . Complete the equation for the thermal decomposition of MgC (a)\n2 4\nO [1] MgC\n2 4\nSuggest which of MgC O or CaC O undergoes thermal decomposition at a (b) lower\n2 4 2 4\ntemperature. Explain your answer.\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\n. The ethanedioate ion is oxidised by acidified KMnO (c)\n4\n16H+ 2Mn2+ 2– – O + 2MnO + 10CO + + 8H O 5C\n2 4 4 2 2\nO in water. An experiment is performed to find the solubility of MgC\n2 4\ncm3 cm3 dm–3 sample of saturated aqueous MgC O requires 27.05 of 0.00200 mol A 40.0\n2 4\n2– to oxidise all the C O ions. acidified KMnO\n4 2 4\ndm–3, of MgC O in water. Show your working. Calculate the solubility, in mol\n2 4\ndm–3 [3] solubility = .............................. mol\n[Total: 6]", "pdf_path": "9701-topic-27-group-2/print/9701-2023-on-42-q05-1b2f1b90d9.pdf" }, { "id": "9701-2023-on-42-q06", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 15, 16, 17 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-42-q06-p01-9efe0d204d.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-42-q06-p02-b6ecbf5349.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-42-q06-p03-d2963be664.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Phosphine, :PH , and carbon monoxide, :CO, are monodentate ligands found in some 6 (a)\n3\ntransition element complexes.\nDefine monodentate ligand. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nDefine transition element complex. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nExplain why transition elements form complexes. (iii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nThe formulae of six complexes are given in Table 6.1. (b)\nThe abbreviation en is used for 1,2-diaminoethane.\nNCH CH NHCH CH NH . The abbreviation dien is used for the tridentate ligand H\n2 2 2 2 2 2\n]2+ Cl Au(dien)Cl O) and . The dien ligand forms three bonds to the gold ion in [Au(dien)(H\n2 2 3\nThese three bonds all lie in the same plane.\n]+. Cl The CO ligand coordinates through the carbon atom in [Rh(CO)\n2 2\nTable 6.1\nformula isomerism shown geometry\n]+ Cl [Rh(en) yes\n2 2\n]+ Cl [Rh(CO) yes\n2 2\n]2+ Cl [Au(dien)(H O)\n2 2\nAu(dien)Cl no octahedral\n3\nCl Ni(PH ) no\n3 2 2\n]2+ [Ni(H O) (NH ) yes\n2 2 3 4\nComplete Table 6.1 to state the geometry of the first three complexes. Each complex is (i)\neither square planar, tetrahedral or octahedral. [1]\n]2+ Cl Au(dien)Cl O) and to write an equation showing Use complexes [Au(dien)(H (ii)\n2 2 3\nligand exchange.\n..................................................................................................................................... [1]\nAu(dien)Cl Draw the three-dimensional structure of in the box. The dien ligand can be (iii)\n3\nN drawn as .\nN N\nAu\n[1]\nCl ) in the box. Draw the three-dimensional structure of Ni(PH (iv)\n3 2 2\nNi\n[1]\n]+ ]+, Cl Cl or [Rh(CO) can exist in three isomeric forms. One of the complexes, [Rh(en) (v)\n2 2 2 2\nIdentify this complex and the types of isomerism shown.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n]2+ Draw the three-dimensional structures of the two isomers of [Ni(H O) (NH ) in the (vi)\n2 2 3 4\nboxes and identify the type of isomerism shown.\nNi Ni\ntype of isomerism shown ..............................\n[2]\n[Total: 10]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-42-q06-094bf73617.pdf" }, { "id": "9701-2023-on-42-q07", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2023-on-42-q07-p01-dca8c479f3.png", "9701-topic-30-hydrocarbons/assets/9701-2023-on-42-q07-p02-75a98ba6f9.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q07", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "Benzene can be used to make benzoic acid in the two-step process shown in Fig. 7.1. 7\nbenzene methylbenzene benzoic acid\nstep 1 step 2\nCH COOH\n3\nFig. 7.1\nGive the reagents and conditions for step 1 and step 2. (a)\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\n[2]\n(13C) Methylbenzene and benzoic acid each have five different peaks in the carbon NMR (b)\nspectrum.\nTable 7.1\nhybridisation environment of carbon example chemical\nof the carbon atom shift range\natom / ppm\n3 alkyl CH –, –CH –, –CH<, >C< 0–50 sp\n3 2\nsp3 next to alkene/arene –C–C=C, –C–Ar 25–50\nsp3 next to carbonyl/carboxyl C–COR, C–O R 30–65\n2\nsp3 next to halogen C–X 30–60\nsp3 next to oxygen C–O 50–70\nc c\nsp2 alkene or arene c c >C=C<, 110–160\nc c\nsp2 carboxyl R–COOH, R–COOR 160–185\nsp2 carbonyl R–CHO, R–CO–R 190–220\nsp nitrile R–C≡N 100–125\nUse Table 7.1 to complete the two sentences to suggest descriptions of these two spectra.\n13C) NMR spectrum of methylbenzene: The carbon (\n● has ................. peak(s) in the chemical shift range of ..................... and\n● has ................. peak(s) in the chemical shift range of ..................... .\n(13C) The carbon NMR spectrum of benzoic acid:\n● has ................. peak(s) in the chemical shift range of ..................... and\n● has ................. peak(s) in the chemical shift range of ..................... .\n[2]\nCl When treated with under suitable conditions, methylbenzene forms compound J. (c) (i)\n2\nCl When treated with under conditions with reagents, methylbenzene different different\n2\nforms compound K.\nSuggest and draw structures of compounds and in the boxes. The molecular formula J K\nof each compound is given.\nmethylbenzene\nCl Cl C H C H J K\n7 7 7 7\nCH\n3\nState the reagents and conditions required to form each product.\nto form compound .......................................................................................................... J\nto form compound .......................................................................................................... K\n[4]\nWhen treated with a chlorine-containing reagent under suitable conditions, benzoic acid (ii)\nforms compound L.\nWhen treated with a chlorine-containing reagent under conditions, different different\nbenzoic acid forms compound M.\nSuggest and draw structures of compounds and in the boxes. The molecular formula L M\nof each product is given.\nbenzoic acid\nClO ClO C H C H L M\n7 5 2 7 5\nCOOH\nState the reagents and conditions to form compound from benzoic acid. M\n..................................................................................................................................... [3]\n[Total: 11]", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2023-on-42-q07-b6103a53f4.pdf" }, { "id": "9701-2023-on-42-q08", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 20, 21, 22 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2023-on-42-q08-p01-9cc368a6cd.png", "9701-topic-37-analytical-techniques/assets/9701-2023-on-42-q08-p02-052abcb2f4.png", "9701-topic-37-analytical-techniques/assets/9701-2023-on-42-q08-p03-ebb8ff833e.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "Lactic acid, CH CH(OH)COOH, is the only monomer needed to form the polymer polylactic acid, 8\n3\nPLA.\nDraw a short length of the PLA polymer chain, including a minimum of two monomer (a) (i)\nbut all other bonds should be residues. The methyl groups may be written as –CH\n3\nshown fully displayed.\nLabel one repeat unit of polylactic acid on your diagram.\n[2]\nGive the name of the type of polymerisation involved in the formation of PLA and the (ii)\nname of the functional group that forms between the monomers.\ntype of polymerisation .......................................................................................................\nfunctional group .................................................................................................................\n[1]\nPredict whether PLA is readily biodegradable. Explain your answer. (iii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n1H) CDCl NMR spectrum of CH CH(OH)COOH in is shown in Fig. 8.1. The The proton ( (b)\n3 3\nproton NMR chemical shift ranges are shown in Table 8.1.\nLactic acid\n12 11 10 9 8 7 6 5 4 3 2 1 0\nδ / ppm\nFig. 8.1\nTable 8.1\nenvironment of proton example chemical\nshift range\nδ / ppm\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–Cl –O, –CH –O, –CH 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nUse Fig. 8.1 and Table 8.1 to complete Table 8.2. (i)\nTable 8.2\n(δ) proton environment chemical shift name of splitting pattern\n–COOH\nCH\n–OH\n–CH\n3\n[3]\nδ Name the substance responsible for the peak at = 0.0. (ii)\n..................................................................................................................................... [1]\nCHCl CDCl is a better solvent than for use in proton NMR. Explain why (iii)\n3 3\n...........................................................................................................................................\n..................................................................................................................................... [1]\nAn impure sample of CH CH(OH)COOH contains pentan-3-one as the only contaminant. The (c)\n3\nmixture is analysed using gas/liquid chromatography. The pentan-3-one is found to have a\nlonger retention time than the lactic acid.\nExplain what is meant by retention time. (i)\n...........................................................................................................................................\n............................................................................................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2023-on-42-q08-9dfbf899fa.pdf" }, { "id": "9701-2023-on-42-q09", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_42.pdf?download=true", "source_pages": [ 23, 24, 27, 28 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-42-q09-p01-2709ce339b.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-42-q09-p02-fc72d4fcef.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-42-q09-p03-09b9d71615.png", "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-42-q09-p04-c22244e9e2.png" ], "answer": { "status": "pending", "id": "9701-2023-on-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "State the reactants and conditions for two different types of reactions that both produce 9 (a)\nCH NHCH CH . diethylamine, CH\n3 2 2 3\nreaction one ..............................................................................................................................\n...................................................................................................................................................\nreaction two ...............................................................................................................................\n...................................................................................................................................................\n[4]\nDescribe the relative basicities of diethylamine, phenylamine and ammonia in aqueous (b)\nsolution.\nExplain your answer in terms of structure.\n............................................... ............................................... ...............................................\nleast basic most basic\nexplanation ...............................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[3]\n(aq) at 4° C to form compound P. Compound reacts with Phenylamine reacts with HNO P (c)\n2\nphenol under alkaline conditions at 4° C. The product of this reaction is acidified, forming azo\ncompound Q.\nDraw the structure of compound Q.\nCircle the azo group on your structure.\nState one use of an azo compound such as Q.\ncompound Q:\nAn azo compound can be used .............................................................................................. .\n[2]\nCOCl, CH CH NHCH CH reacts with ethanoyl chloride, CH to give the amide (d)\n3 2 2 3 3\nCON(C H ) . N,N-diethylethanamide, CH\n3 2 5 2\nAn incomplete description of the mechanism of this reaction is shown in Fig. 9.1.\nbox one box three box two\nO\nCl\nCl\nC H C H C N\nC H C O 2 5 3\n3 C H C O\n3\nC H\n2 5\nN C H\n2 5\nH N C H\n2 5\nH C H\n2 5\nC H\n2 5\nand .........................\nreactants products intermediate\nFig. 9.1\nComplete the mechanism in Fig. 9.1. You should include: (i)\n(δ+ δ–) ● all relevant dipoles and and full electric charges (+ and –) on the species in\nbox one and in box two\n● all relevant lone pairs on the species in box one and in box two\n● all relevant curly arrows to show the movement of electron pairs in box one and in\nbox two\n● the formula of the second product in box th", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-on-42-q09-e7353b2d5b.pdf" }, { "id": "9701-2023-on-43-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2023-on-43-q01-p01-6cdca47064.png", "9701-topic-26-reaction-kinetics/assets/9701-2023-on-43-q01-p02-f19b028931.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q01", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Cl Fluorine reacts with chlorine dioxide, O , as shown. 1\n2\n2Cl 2FCl (g) + O (g) O (g) F\n2 2 2\nand first order with The rate of the reaction is first order with respect to the concentration of F\n2\nCl . No catalyst is involved. respect to the concentration of O\n2\nSuggest a two-step mechanism for this reaction. (a) (i)\nstep 1\nstep 2\n[2]\nIdentify the rate-determining step in this mechanism. Explain your answer. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n−3 s−1 the numerical value of the rate When the rate of the reaction is measured in mol dm (b)\nconstant, k, is 1.22 under certain conditions.\nComplete the rate equation for this reaction, stating the overall order of the reaction. (i)\nrate =\no verall order of reaction =\n[1]\nUse your rate equation in to calculate the rate of the reaction when the concentrations (ii) (i)\n10−3 dm−3. × Cl and O are both 2.00 mol of F\n2 2\ndm−3 s−1 rate = .............................. mol [1]\nClO Under different conditions, and in the presence of a large excess of , the rate equation is (c)\n2\nas shown.\n[F ] rate = k\n1 2\n, of the concentration of F is 4.00 s under these conditions. The half-life, t 1\n2 2\n, giving its units. Calculate the numerical value of k (i)\n1\nGive your answer to significant figures. three\n= .............................. units .............................. k\n1\n[2]\nAn experiment is performed under these conditions in which the starting concentration of (ii)\ndm–3. is 0.00200 mol F\n2\nchanges over Draw a graph on the grid in Fig. 1.1 to show how the concentration of F\n2\nthe first 12 s of the reaction.\n0.0020\n0.0018\n0.0016\n0.0014\n0.0012\ndm–3 [F ] / mol 0.0010\n2\n0.0008\n0.0006\n0.0004\n0.0002\n0\n0 1 2 3 4 5 6 7 8 9 10 11 12\ntime / s\nFig. 1.1\n[1]\nis Use your graph in Fig. 1.1 to find the rate of the reaction when the concentration of F (iii)\n2\ndm–3. Show your working on the graph. 0.00100 mol\ndm–3 s−1 [1] rate = .............................. mol\n[Total: 9]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2023-on-43-q01-b6ddb19af2.pdf" }, { "id": "9701-2023-on-43-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2023-on-43-q02-p01-cf3434a221.png", "9701-topic-25-equilibria/assets/9701-2023-on-43-q02-p02-c2d29a8b18.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Define K mathematically by completing the expression. 2 (a)\nw\nK = ..........................................................................................................................................\nw\n[1]\nTwo solutions, and W, are described. (b) V\n• HCl is (aq). V\n• is NaOH(aq). W\n• HCl The concentration of in is the same as the concentration of NaOH in W. V\n• The pH values of and differ by exactly 11.00 at 298 K. V W\nHCl Calculate the concentration of in V. (i)\ndm−3 HCl [2] concentration of in = .............................. mol V\nEqual volumes of the two solutions and are mixed, giving solution X. (ii) V W\nName solution and state its pH. X\nsolution .............................. pH .............................. X\n[1]\n3 dm−3 cm3 sample of 1.0 mol HNO is added to 100 of solution X, forming mixture Y. A 1 cm (iii)\n3\ncm3 dm−3 cm3 sample of 1.0 mol KOH is added to 100 of solution X, forming mixture Z. A 1\nEstimate the pH of mixtures and Z. No calculations are required. Y\nmixture .............................. mixture .............................. Y Z\n[1]\nCCl CH COOH, CH COOH and H SO are all acidic. CH (c) (i)\n3 2 3 2 2 4\nSuggest the trend in the relative acid strength of these three compounds.\nExplain your answer.\n....................................... ....................................... .......................................\nstrongest acid weakest acid\nexplanation ........................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[3]\nWhen concentrated H SO is added to water a series of acid-base reactions occurs. (ii)\n2 4\nThere are three conjugate acid-base pairs that can be identified during this series of reactions.\nWrite the formulae of these three conjugate acid-base pairs.\nconjugate acid 1 ......................................... conjugate base 1 .........................................\nconjugate acid 2 ......................................... conjugate base 2 .........................................\nconjugate acid 3 ......................................... conjugate base 3 .........................................\n[2]\n, of a substance, Q, between hexane and water is 7.84 at 298 K. The partition coefficient, K (d)\npc\nis more soluble in hexane than it is in water. Q\n. Define partition coefficient, K (i)\npc\n.....................................................................................................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2023-on-43-q02-bdde32c53b.pdf" }, { "id": "9701-2023-on-43-q03", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 6, 7, 8, 9 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2023-on-43-q03-p01-350793c0f6.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-43-q03-p02-aec3c97781.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-43-q03-p03-ffe53d6687.png", "9701-topic-23-chemical-energetics/assets/9701-2023-on-43-q03-p04-9d5d749431.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Hydrogen peroxide is a liquid at 298 K. It is moderately stable under room conditions but will 3\ndecompose quickly if a catalyst is added.\nO (l) 2H O (l) + O (g) reaction 1 2H\n2 2 2 2\nDefine entropy. (a) (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nPredict the sign of the standard entropy change of reaction 1. (ii)\nExplain your answer.\nsign ..............................\nexplanation ........................................................................................................................\n...........................................................................................................................................\n[1]\nSome bond energy data are shown in Table 3.1. (b)\nTable 3.1\nmol–1 type of bond bond energy / kJ\nO–O 150\nO–H 460\nO=O 496\nUse the data in Table 3.1 to show that the enthalpy change of the following reaction is\n–1. –196 kJ mol\nO (g) 2H O(g) + O (g) 2H\n2 2 2 2\n[1]\no\nSome standard entropies, S , are shown in Table 3.2. (c)\nTable 3.2\no K–1 mol–1 substance S / J\nH O (l) +102\n2 2\nO(l) +70 H\n2\nThe enthalpy change and Gibbs free energy change for the following reaction are shown.\no mol–1 ΔH O (l) 2H O(l) + O (g) = –196 kJ 2H\n2 2 2 2\no mol–1 ΔG = –238 kJ\no\nUse the data given to calculate the standard entropy of oxygen, S , O (g).\n2\no K–1 mol–1 S , O (g) = .............................. J [3]\n2\niron(III) O (aq) is catalysed by aqueous chloride and by silver metal. The decomposition of H (d)\n2 2\nIdentify which of these two catalysts is acting as a homogeneous catalyst.\nExplain your answer.\nhomogeneous catalyst ..............................................................................................................\nexplanation ...............................................................................................................................\n[1]\no\nThe E values for two electrode reactions are given. (e)\no 2H+ 2e− O + + 2H O E = +1.77 V H\n2 2 2\no Cr3+ e− Cr2+ + E = −0.41 V\nAn electrochemical cell is constructed with the following half-cells (electrodes): (i)\n• an acidified solution of H O , a platinum wire\n2 2\nCr2+ Cr3+, • mixed with a platinum wire.\no\n. Identify the positive half-cell and calculate the standard cell potential, E\ncell\no\npositive half-cell .............................. E = .............................. V\ncell\n[1]\no ΔG for the cell reaction that occurs, per mole of H O . Calculate the value of (ii)\n2 2\no mol–1 ΔG = .............................. kJ [2]\no\nvalues for two electrode reactions are given. The E (f)\no 2H+ 2e– O + + 2H O E = +1.77 V H\n2 2 2\no Co3+ e– Co2+ + E = +1.82 V\nAn electrochemical cell is constructed with the following half-cells.\nO under standard conditions, a platinum wire half-cell 1 an acidified solution of H\n2 2\ndm–3 Co3+ dm–3 Co2+, and 2", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2023-on-43-q03-0976953078.pdf" }, { "id": "9701-2023-on-43-q04", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 10 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2023-on-43-q04-p01-fe0d9d0701.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q04", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Cobalt(II) nitrate, Co(NO ) , is a reddish-brown crystalline solid. It dissolves in water to form 4 (a)\n3 2\n]2+ O) complex ions. a solution containing [Co(H\n2 6\nComplete Table 4.1 giving the formula of the cobalt-containing species that is formed in (i)\neach of the three reactions described.\nTable 4.1\n]2+(aq) reaction reagent added to [Co(H O) cobalt-containing species formed\n2 6\n1 NaOH(aq)\n(aq) 2 an excess of NH\n3\nHCl 3 an excess of conc. (aq)\n[2]\nDescribe the colour change seen in reaction 3. (ii)\n]2+(aq) O) .................................................................................... original colour of [Co(H\n2 6\nHCl final colour after addition of an excess of conc. (aq) ..................................................\n[1]\n) , is a white crystalline solid. When heated, it starts to decompose at Calcium nitrate, Ca(NO (b)\n3 2\napproximately 500°C.\n) . Write an equation for the decomposition of Ca(NO (i)\n3 2\n..................................................................................................................................... [1]\n) and Ba(NO ) start to decompose. Suggest temperatures at which Mg(NO (ii)\n3 2 3 2\nExplain your answer.\n) starts to decompose ................................................. °C temperature at which Mg(NO\n3 2\n) starts to decompose ...................................................°C temperature at which Ba(NO\n3 2\nexplanation ........................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[3]\n[Total: 7]", "pdf_path": "9701-topic-27-group-2/print/9701-2023-on-43-q04-5718590887.pdf" }, { "id": "9701-2023-on-43-q05", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-43-q05-p01-98335528f5.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-43-q05-p02-9c78a19db9.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Transition elements behave as catalysts and can form complex ions. 5\nExplain why transition elements behave as catalysts. (a)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\n]–. Silver forms the linear complex ion [Ag(CN) (b)\n2\n]3−. Copper forms the tetrahedral complex ion [Cu(CN)\n4\n[TiCl (diars) ], where diars is a neutral bidentate ligand. Titanium forms the complex\n4 2\n[TiCl (diars) ]. State the oxidation state and the coordination number of titanium in (i)\n4 2\noxidation state ..............................\ncoordination number ..............................\n[1]\n]– ]3−, and [Cu(CN) in Draw three-dimensional diagrams to show the shapes of [Ag(CN) (ii)\n2 4\nthe boxes.\nLabel one bond angle on each diagram.\nAg Cu\n[2]\n]3– copper(I) , of the complex [Cu(CN) is The numerical value of the stability constant, K (c)\nstab 4\n1027. × 2.0\n]3−. of [Cu(CN) Write an expression for the K (i)\nstab 4\nK =\nstab\n[1]\nCN− ]3− dm−3. In a solution the concentrations of and [Cu(CN) are both 0.0010 mol (ii)\n4\nto calculate the concentration of Use your expression from and the value of K (c)(i)\nstab\nCu+(aq) in this solution.\nCu+(aq) dm–3 concentration of = .............................. mol [1]\nA piece of a copper-containing alloy has a mass of 0.567 g. It is dissolved in an acid giving (d)\ncm3 Cu2+ of a blue solution in which all the copper is present as ions. 100.0\ncm3 KI(aq) sample of this solution. An excess of is added to a 25.0\nCuI(s). All of the copper is precipitated as white\n2+ KI(aq). ions are the only component in the solution that react with This is reaction 1. Cu\n2Cu2+ 4I− 2CuI I + + reaction 1\n2\ndm–3 2−. I The liberated is then titrated with 0.0200 mol S O This is reaction 2.\n2 2 3\n2I− 2– 2– I + 2S O + S O reaction 2\n2 2 3 4 6\ncm3 dm–3 2– The titration requires 20.10 of 0.0200 mol S O to reach the end-point.\n2 3\nI that are reduced in this titration. Calculate the number of moles of (i)\n2\nI number of moles of = .............................. mol [1]\n2\nCalculate the number of moles of copper in the original piece of alloy. (ii)\nnumber of moles of copper = .............................. mol [1]\nCalculate the percentage of copper in the alloy. (iii)\npercentage of copper = .............................. % [1]\nCu2+ CuI is coloured but solid is white. Suggest why a solution of (iv)\n...........................................................................................................................................\n...........................................................................................................................................\n..........................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-43-q05-2d1a2eebaf.pdf" }, { "id": "9701-2023-on-43-q06", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 14 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2023-on-43-q06-p01-acd354696b.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Five ligands are listed in Table 6.1. 6 (a)\nTable 6.1\nligand type of ligand\nNH\n3\nEDTA4−\nCN−\nH NCH CH NHCH CH NH tridentate\n2 2 2 2 2 2\n2− O C\n2 4\nComplete Table 6.1 using the words monodentate, bidentate and polydentate only. (i)\nEach of these three words may be used once, more than once, or not at all. [2]\nNCH CH NHCH CH NH is a tridentate ligand. The molecule H (ii)\n2 2 2 2 2 2\nSuggest the meaning of tridentate ligand.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNCH CH NHCH CH NH acts as a tridentate ligand. Suggest how H (iii)\n2 2 2 2 2 2\n...........................................................................................................................................\n..................................................................................................................................... [1]\n]2+. (H O) This complex can exist in three Nickel forms the octahedral complex [Ni(en) (b)\n2 2 2\nisomeric forms, listed in Table 6.2.\nOne of these forms is a trans isomer, the other forms are two different cis isomers.\nTable 6.2\nisomer polarity\ntrans isomer\ncis isomer 1\ncis isomer 2\nComplete Table 6.2 using the terms polar or non-polar. (i)\nEach term may be used once, more than once, or not at all. [1]\nDescribe the difference between cis isomer 1 and cis isomer 2. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[Total: 6]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2023-on-43-q06-cd29eb5430.pdf" }, { "id": "9701-2023-on-43-q07", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 15 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2023-on-43-q07-p01-2d04f662aa.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Sunset Yellow is an additive used for colouring foods. 7\nA synthetic route for making Sunset Yellow is shown.\n– group. These groups are unchanged in the formation Molecules and each contain one –SO E G\n3\nof Sunset Yellow.\n– O SC H NH E\n3 6 4 2\nstep 1\n– HOC H SO F G\n10 6 3\nstep 2\nSunset Yellow anion\nHO\nN\nN\n–O – S SO\n3 3\nFig. 7.1\nState the molecular formula of the Sunset Yellow anion. (a)\n............................................................................................................................................. [1]\nDeduce the structures of E, and and draw them in the boxes in Fig. 7.1. [3] (b) F G\nSuggest suitable reagents and conditions for step 1 and 2. (c)\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\n[3]\nPredict the number of peaks in the carbon-13 NMR spectrum of the Sunset Yellow anion. (d)\n.............................................................................................................................................. [1]\n[Total: 8]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2023-on-43-q07-7ec3197b2b.pdf" }, { "id": "9701-2023-on-43-q08", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2023-on-43-q08-p01-96db34ba66.png", "9701-topic-36-organic-synthesis/assets/9701-2023-on-43-q08-p02-a478ae6f3c.png", "9701-topic-36-organic-synthesis/assets/9701-2023-on-43-q08-p03-b0311e599c.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q08", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Capsaicin is found in chilli peppers. 8\ncapsaicin\nO\nCH O\n3\nN\nH\nHO\nYou should assume the CH O group is unreactive in the reactions involved in this question.\n3\nO group. Name all the functional groups in capsaicin in addition to the CH (a)\n3\n............................................................................................................................................. [1]\n(aq) in the dark. Complete the equation for the reaction of capsaicin with an excess of Br (b)\n2\nDraw the structure of the organic product in the labelled box.\ncapsaicin\nO\nCH O\n+ ………Br 3\nN 2\nH\nHO\norganic product\n+ …………………\n[3]\nCapsaicin is heated with an excess of hydrogen gas in the presence of platinum metal. (c)\nThe six-membered ring reacts in the same way as benzene under these conditions.\nDraw the structure of the organic product formed.\n[2]\nWhen capsaicin is treated with reagent under suitable conditions one of the products is (d) J\nCH(CH )COOH. methylpropanoic acid, CH\n3 3\nIdentify reagent and any necessary conditions. (i) J\n..................................................................................................................................... [1]\n1H) NMR spectrum of CH CH(CH )COOH There are three different peaks in the proton ( (ii)\n3 3\nCDCl . in\n3\nTable 8.1\nenvironment of proton example chemical shift\nrange\nδ / ppm\n>CH– , –CH –, 0.9–1.7 alkane –CH\n3 2\n>CH–C=O –C=O, –CH –C=O, 2.2–3.0 alkyl next to C=O CH\n3 2\n>CH–Ar –Ar, –CH –Ar, 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–Cl –O, –CH –O, –CH 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nUse Table 8.1 to complete Table 8.2 and state:\n1H) (δ) chemical shift values for the protons ● the typical proton (\n● the splitting pattern (singlet, doublet, triplet, quartet or multiplet) shown by each peak\nprotons and the CH proton. ● the explanation for the splitting patterns of the CH\n3\nTable 8.2\nδ / environment ppm splitting pattern explanation for splitting pattern\nCH\n3\nCH\nCOOH\n[3]\nCapsaicin is heated with an excess of hot aqueous NaOH. (e) (i)\ncapsaicin\nO\nCH O\n3\nN\nH\nHO\nDraw the structures of the two organic products and K. H\nC H NO Na C H O Na H K\n8 10 2 10 17 2\n[2]\nName the types of reaction occurring in (e)(i). (ii) two\n..................................................................................................................................... [1]\nLiAl in Draw the structure of the organic product formed when capsaicin is treated with H (f) L\n4\ndry ether.\nL\n[1]\n[Total: 14]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2023-on-43-q08-b0b5d07ccf.pdf" }, { "id": "9701-2023-on-43-q09", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_43.pdf?download=true", "source_pages": [ 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-43-q09-p01-7dcd382590.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-43-q09-p02-c136d4ea38.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-43-q09-p03-115b24a830.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2023-on-43-q09-p04-9ee8030c62.png" ], "answer": { "status": "pending", "id": "9701-2023-on-43-q09", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "COCl, Benzoyl chloride, C H can be made from ethyl benzene in a two-step process. 9 (a)\n6 5\nA reaction scheme is shown.\ncompound M\nethyl benzene benzoyl chloride\nCH CH\n2 3 Cl\nstep 1 step 2\nO\nDraw the intermediate organic compound in the box. [1] (i) M\nSuggest suitable reagents and conditions for step 1 and step 2. (ii)\nstep 1 .................................................................................................................................\nstep 2 .................................................................................................................................\n[2]\nIdentify the type of reaction in step 1 and step 2. (iii)\nstep 1 .................................................................................................................................\nstep 2 .................................................................................................................................\n[2]\nCOCl C H reacts with phenol, C H OH, to give the ester phenyl benzoate, C H COOC H . (b)\n6 5 6 5 6 5 6 5\nAn incomplete description of the mechanism of this reaction is shown in Fig. 9.1.\nbox one box two box three\nCl\nCl\nO\nC O\nC O\nC O\nO O\nH H\nand .....................\nreactants intermediate products\nFig. 9.1\nComplete the mechanism in Fig. 9.1 and include: (i)\n(δ+ δ–) ● all relevant dipoles and and full electric charges (+ and –) on the species in\nbox one and in box two\n● all relevant lone pairs on the species in box one and in box two\n● all relevant curly arrows to show the movement of electron pairs in box one and in\nbox two\n● the formula of the second product in box three.\n[4]\nName this mechanism. (ii)\n..................................................................................................................................... [1]\nBenzoyl chloride, chlorobenzene and chloroethane differ in their rates of hydrolysis when (c)\neach compound is added separately to water at 25 °C.\nSuggest the relative ease of hydrolysis of these three compounds.\nExplain your answer.\n......................................... ......................................... .........................................\nhardest to hydrolyse easiest to hydrolyse\nexplanation ...............................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[3]\n[Total: 13]\nImportant values, constants and standards\nK–1 mol–1 molar gas con", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2023-on-43-q09-cca8ca802c.pdf" }, { "id": "9701-2023-on-51-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-51-q01-p01-ed34412a16.png", "9701-experimental-skills/assets/9701-2023-on-51-q01-p02-4d137ee48e.png", "9701-experimental-skills/assets/9701-2023-on-51-q01-p03-1edf69de93.png", "9701-experimental-skills/assets/9701-2023-on-51-q01-p04-1bfe4ec7c3.png" ], "answer": { "status": "pending", "id": "9701-2023-on-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "The concentration of dissolved oxygen in a sample of water can be measured using the following 1\nmethod.\nManganese(II) hydroxide, Mn(OH) , is oxidised by the oxygen dissolved in a sample of water to\n2\nmanganese(III) hydroxide, Mn(OH) . form\n3\n(aq) + 4Mn(OH) (s) + 2H O(l) 4Mn(OH) (s) O\n2 2 2 3\nmanganese(III) hydroxide then reacts with iodide ions to produce aqueous iodine. The\n2KI(aq) I 6HCl 2MnCl 2KCl (s) + (aq) + (aq) + (aq) + (aq) + 6H O(l) 2Mn(OH)\n3 2 2 2\nThe amount of iodine produced is proportional to the amount of dissolved oxygen.\n3 of the solution containing aqueous iodine is transferred into a conical flask and titrated 25.0 cm\n10–3 dm–3 × mol sodium thiosulfate, Na S O . against 1.00\n2 2 3\n2NaI(aq) I (aq) + 2Na S O (aq) Na S O (aq) +\n2 2 2 3 2 4 6\nComplete Table 1.1 and determine the mean titre to be used in calculating the (a) (i)\nconcentration of dissolved oxygen.\nTable 1.1\ntrial run run 1 run 2 run 3\nfinal burette\n27.30 28.10 28.25 26.95\ncm3 reading /\ninitial burette\n0.00 1.10 1.55 0.15\n3 reading / cm\ncm3 titre /\ncm3 mean titre = .............................. [2]\ncm3 of solution. Calculate the concentration of dissolved oxygen in the 25.0 (ii)\nShow your working.\ncm3 dm–3 of solution = .............................. mol [3] concentration of dissolved oxygen in 25.0\ncm3 Suggest a suitable piece of apparatus for the transfer of 25.0 of the solution containing (b)\naqueous iodine.\n............................................................................................................................................. [1]\nWater samples are collected in full sealed flasks. (c)\nExplain why the sealed flask must be completely full.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nThe concentration of oxygen in water at different temperatures is shown in Table 1.2. The (d)\nconcentration value is missing for 25 °C.\nTable 1.2\nconcentration of\ntemperature / °C\n10–4 dm–3 × / mol oxygen\n0 4.58\n5 3.97\n10 3.20\n15 3.13\n20 2.82\n25\n30 2.33\n35 2.15\n40 2.05\nPlot a graph of concentration of oxygen (y-axis) against temperature (x-axis) on the grid. (i)\nUse a cross (×) to plot each data point. Draw a smooth curve of best fit.\n5.00\n4.50\n3–md\nlom\n4.00 /\n4–01\n×\nnegyxo\n3.50\nfo\nnoitartnecnoc\n3.00\n2.50\n2.00\n0 5 10 15 20 25 30 35 40\ntemperature / °C\n[2]\nUse the graph to deduce the concentration of oxygen at 25 °C. (ii)\ndm–3 concentration of oxygen at 25 °C = .............................. mol [1]\nCircle the most anomalous point on the graph. (iii)\nSuggest an explanation for this anomaly. Assume that there was no error in measuring\noxygen concentration.\n...........................................................................................................................................\n...............................", "pdf_path": "9701-experimental-skills/print/9701-2023-on-51-q01-4972a09b08.pdf" }, { "id": "9701-2023-on-51-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_51.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-51-q02-p01-542b7a676e.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p02-34628a7540.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p03-094b07c0ea.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p04-8bfc9af888.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p05-07044c5f90.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p06-06b5a7caf4.png", "9701-experimental-skills/assets/9701-2023-on-51-q02-p07-50596d75c6.png" ], "answer": { "status": "pending", "id": "9701-2023-on-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Cl, Benzenediazonium chloride, C H N decomposes in water as shown in the following equation. 2\n6 5 2\nCl(aq) HCl (aq) H N + H O(l) C H OH(aq) + N (g) + C\n6 5 2 2 6 5 2\ndm–3 Cl of C H N (aq) decomposes at a constant temperature of 50 °C. A solution of 0.0750 mol\n6 5 2\n(g), collected is recorded every 5 minutes for 45 minutes. The volume of nitrogen gas, N\n2\nDraw a labelled diagram to show how the apparatus could be set up to carry out this (a)\nexperiment.\n[3]\nUsing this method, a student obtains the graph shown in Fig. 2.1. (b)\n60\n50\n40\n30\nvolume N\n2\ncm3 /\n20\n10\n0\n5 10 15 20 25 0 30 35 40 45\ntime / min\nFig. 2.1\nOn Fig. 2.1, draw a tangent to the curve at t = 0 mins. Calculate the initial rate of reaction (i)\ncm3 min–1. in\ncm3 min–1 [2] initial rate of reaction = ..............................\nExplain why the initial rate of reaction is calculated at t = 0 mins rather than dividing the (ii)\ntotal volume of gas produced by the time taken to produce it.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nDescribe how the curve in Fig. 2.1 would be different, if at all, if the atmospheric pressure (iii)\nincreases. All other conditions stay the same.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nOn Fig. 2.1, draw a second curve to show the graph produced if the same volume of (iv)\n–3 Cl C H N (aq) decomposes at a constant temperature of 50 °C. All 0.0375 mol dm\n6 5 2\nother conditions stay the same. [1]\nCl H N (aq) Another student investigates the effect of changing the concentration of C (c)\n6 5 2\ndm3 of N (g) and calculates the rate of at 50 °C. He measures the time taken to collect 0.0150\n2\ndm3 production by dividing 0.0150 by the time taken. The results are shown in Table 2.1. N\n2\nTable 2.1\nrate of N concentration of time taken to\n2\ndm3 Cl H N (aq) C collect 0.0150 production\n6 5 2\ndm–3 dm3 s–1 / s / mol of N /\n2\n0.500 21\n0.400 33\n0.300 48\n0.200 64\n0.100 122\nproduction. Complete the table to calculate the values for the rate of N (i)\n2\nGive your answers to significant figures. [1] three\nThe reaction is first order and obeys the following rate equation. (ii)\nCl] H N rate = k [C\n6 5 2\nExplain how the data in Table 2.1 supports this statement.\n.......................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2023-on-51-q02-ebf20ed26a.pdf" }, { "id": "9701-2023-on-52-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_52.pdf?download=true", "source_pages": [ 2, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-52-q01-p01-5446ca9112.png", "9701-experimental-skills/assets/9701-2023-on-52-q01-p02-29a519e134.png", "9701-experimental-skills/assets/9701-2023-on-52-q01-p03-69823a3d37.png", "9701-experimental-skills/assets/9701-2023-on-52-q01-p04-ed3432b843.png", "9701-experimental-skills/assets/9701-2023-on-52-q01-p05-d3961b4ec3.png" ], "answer": { "status": "pending", "id": "9701-2023-on-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Thermometric titrations can be used to determine the standard enthalpy change of neutralisation. 1\nThe maximum temperature reached in a thermometric titration occurs at the point of neutralisation\nbetween an acid and an alkali.\nA diagram of the apparatus used is shown in Fig. 1.1.\nburette containing sodium hydroxide\nthermometer\nstirrer\npolystyrene cup\ncm3 25.00\nhydrochloric acid\nFig. 1.1\nA student uses the following method.\n3 dm–3 HCl of 1.00 mol dilute hydrochloric acid, (aq), to a polystyrene cup. Transfer 25.00 cm Step 1\nHCl Place a thermometer with 0.2 °C divisions into the (aq) in the polystyrene cup and Step 2\nleave it for 3 minutes. Record the temperature.\n3 aqueous sodium hydroxide, NaOH(aq), from a burette. Stir and record the Add 5.00 cm Step 3\ntemperature of the solution in the polystyrene cup.\ncm3 of NaOH(aq). Stir and record the temperature of the Immediately add another 5.00 Step 4\nsolution in the polystyrene cup.\nRepeat Step 4 until there is no further increase in temperature. Once the temperature Step 5\nstarts to decrease, repeat Step 4 three more times.\nThe student obtains the results shown in Table 1.1.\nTable 1.1\nvolume of\ntemperature\nNaOH(aq)\n/ °C\ncm3 added /\n0.00 18.8\n5.00 21.3\n10.00 23.8\n15.00 26.4\n20.00 27.4\n25.00 26.2\n30.00 25.1\n35.00 24.0\n40.00 23.2\nPlot a graph of temperature (y-axis) against volume of NaOH(aq) added (x-axis) on the (a) (i)\n(×) grid. Use a cross to plot each data point.\nDraw two straight lines of best fit. One for the rise in temperature and one for the fall in\ntemperature. Extrapolate the two lines so they intersect. [2]\nUse your graph to determine the maximum temperature change of the mixture. Assume (ii)\nthe initial temperature of NaOH(aq) is 18.8 °C.\nmaximum temperature change of the mixture = .............................. °C [1]\n3 of Use your graph to determine the volume of NaOH(aq) needed to neutralise 25.00 cm (iii)\ndm–3 HCl (aq). 1.00 mol\ncm3 [1] volume of NaOH(aq) = ..............................\ndm–3. Use your answer to to calculate the concentration of NaOH(aq) in mol (iv) (iii)\ndm–3 [2] concentration of NaOH(aq) = .............................. mol\n30\n29\n28\n27\n26\n25\ntemperature\n°C /\n24\n23\n22\n21\n20\n19\n18\n0 5 10 15 20 25 30 35 40\ncm3 volume of NaOH(aq) added /\nSuggest why a titration using an indicator is more accurate than a thermometric titration. (v)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n3 dm–3 HCl of 1.00 mol (aq) Suggest a suitable piece of apparatus for the transfer of 25.00 cm (b)\nin 1. Step\n............................................................................................................................................. [1]\n3 Determine the percentage error of the measured temperature increase when the first 5.00 cm (c)\nof NaOH(aq) is added.", "pdf_path": "9701-experimental-skills/print/9701-2023-on-52-q01-cc589edaa8.pdf" }, { "id": "9701-2023-on-52-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_52.pdf?download=true", "source_pages": [ 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-52-q02-p01-50163ea19b.png", "9701-experimental-skills/assets/9701-2023-on-52-q02-p02-3497666e28.png", "9701-experimental-skills/assets/9701-2023-on-52-q02-p03-22637d4b80.png", "9701-experimental-skills/assets/9701-2023-on-52-q02-p04-efb676fc76.png", "9701-experimental-skills/assets/9701-2023-on-52-q02-p05-bf69210e8e.png" ], "answer": { "status": "pending", "id": "9701-2023-on-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "HCl A student investigates the rate of reaction when zinc reacts with dilute hydrochloric acid, (aq). 2\nZnCl 2HCl (aq) + H (g) Zn(s) + (aq)\n2 2\nThe student uses the following method.\nAccurately weigh 1.00 g of zinc foil. Step 1\n3 dm–3 HCl of 2.00 mol (aq) to a conical flask. Add 50 cm Step 2\ncm3 HCl of (aq) in the flask and immediately start a timer. Add the zinc foil to the 50 Step 3\ncm3 of H (g) has been collected. Stop the timer when 20.0 Step 4\n2\nHCl Repeat to using lower concentrations of (aq). Step 5 Steps 1 4\nComplete Fig. 2.1 to show the apparatus that the student can use to collect and measure the (a)\nvolume of hydrogen produced. Label your diagram.\nFig. 2.1\n[3]\ndm–3 HCl The student wants to perform a similar experiment using 0.100 mol (aq). (b)\ncm3 dm–3 of 0.100 mol Describe how the student should make a standard solution of 250.0\ndm–3 HCl HCl (aq). (aq) starting from a solution of 2.00 mol\nGive the name and size of any key apparatus which should be used and describe how the\ncm3. student should ensure the volume is exactly 250.0\nWrite your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nHCl The student carries out further experiments using higher concentrations of (aq). (c)\n–3 HCl (aq). The student wears chemically resistant gloves when using 6.00 mol dm (i)\nSuggest why.\n..................................................................................................................................... [1]\nThe student obtains the results shown in Table 2.1. (ii)\nTable 2.1\ntime (t) taken to collect\nHCl 1/t concentration of\ncm3 of H 20\ndm–3 s–1 2 / / mol\n/ s\n2.00 15.62\n3.00 10.41\n4.00 7.81\n5.00 6.25\n6.00 5.24\nIn these experiments 1/t can be considered to be proportional to the initial rate of reaction.\nComplete the table by calculating 1/t for each concentration.\nGive your answers to significant figures. [1] three\nUse your data from Table 2.1 to produce a sketch graph of 1/t against concentration in (iii)\nFig. 2.2.\nIt is necessary to include a scale on the axes. not\nLabel the sketched line ‘A’.\n1 / t\nconcentration\n[1] Fig. 2.2\nOn Fig. 2.2 sketch a second line to show the graph of concentration against 1/t if (iv)\npowdered zinc is used in the experiment instead of zinc foil.\nLabel this line ‘B’. [1]\nUsing your data in Tabl", "pdf_path": "9701-experimental-skills/print/9701-2023-on-52-q02-b7fef00b24.pdf" }, { "id": "9701-2023-on-53-q01", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-53-q01-p01-ed34412a16.png", "9701-experimental-skills/assets/9701-2023-on-53-q01-p02-4d137ee48e.png", "9701-experimental-skills/assets/9701-2023-on-53-q01-p03-1edf69de93.png", "9701-experimental-skills/assets/9701-2023-on-53-q01-p04-1bfe4ec7c3.png" ], "answer": { "status": "pending", "id": "9701-2023-on-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "The concentration of dissolved oxygen in a sample of water can be measured using the following 1\nmethod.\nManganese(II) hydroxide, Mn(OH) , is oxidised by the oxygen dissolved in a sample of water to\n2\nmanganese(III) hydroxide, Mn(OH) . form\n3\n(aq) + 4Mn(OH) (s) + 2H O(l) 4Mn(OH) (s) O\n2 2 2 3\nmanganese(III) hydroxide then reacts with iodide ions to produce aqueous iodine. The\n2KI(aq) I 6HCl 2MnCl 2KCl (s) + (aq) + (aq) + (aq) + (aq) + 6H O(l) 2Mn(OH)\n3 2 2 2\nThe amount of iodine produced is proportional to the amount of dissolved oxygen.\n3 of the solution containing aqueous iodine is transferred into a conical flask and titrated 25.0 cm\n10–3 dm–3 × mol sodium thiosulfate, Na S O . against 1.00\n2 2 3\n2NaI(aq) I (aq) + 2Na S O (aq) Na S O (aq) +\n2 2 2 3 2 4 6\nComplete Table 1.1 and determine the mean titre to be used in calculating the (a) (i)\nconcentration of dissolved oxygen.\nTable 1.1\ntrial run run 1 run 2 run 3\nfinal burette\n27.30 28.10 28.25 26.95\ncm3 reading /\ninitial burette\n0.00 1.10 1.55 0.15\n3 reading / cm\ncm3 titre /\ncm3 mean titre = .............................. [2]\ncm3 of solution. Calculate the concentration of dissolved oxygen in the 25.0 (ii)\nShow your working.\ncm3 dm–3 of solution = .............................. mol [3] concentration of dissolved oxygen in 25.0\ncm3 Suggest a suitable piece of apparatus for the transfer of 25.0 of the solution containing (b)\naqueous iodine.\n............................................................................................................................................. [1]\nWater samples are collected in full sealed flasks. (c)\nExplain why the sealed flask must be completely full.\n...................................................................................................................................................\n............................................................................................................................................. [1]\nThe concentration of oxygen in water at different temperatures is shown in Table 1.2. The (d)\nconcentration value is missing for 25 °C.\nTable 1.2\nconcentration of\ntemperature / °C\n10–4 dm–3 × / mol oxygen\n0 4.58\n5 3.97\n10 3.20\n15 3.13\n20 2.82\n25\n30 2.33\n35 2.15\n40 2.05\nPlot a graph of concentration of oxygen (y-axis) against temperature (x-axis) on the grid. (i)\nUse a cross (×) to plot each data point. Draw a smooth curve of best fit.\n5.00\n4.50\n3–md\nlom\n4.00 /\n4–01\n×\nnegyxo\n3.50\nfo\nnoitartnecnoc\n3.00\n2.50\n2.00\n0 5 10 15 20 25 30 35 40\ntemperature / °C\n[2]\nUse the graph to deduce the concentration of oxygen at 25 °C. (ii)\ndm–3 concentration of oxygen at 25 °C = .............................. mol [1]\nCircle the most anomalous point on the graph. (iii)\nSuggest an explanation for this anomaly. Assume that there was no error in measuring\noxygen concentration.\n...........................................................................................................................................\n...............................", "pdf_path": "9701-experimental-skills/print/9701-2023-on-53-q01-44410d4a43.pdf" }, { "id": "9701-2023-on-53-q02", "subject": "9701", "year": 2023, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2023-oct-nov/9701_w23_qp_53.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2023-Oct-Nov/qp/9701_w23_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2023-on-53-q02-p01-542b7a676e.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p02-34628a7540.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p03-094b07c0ea.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p04-8bfc9af888.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p05-07044c5f90.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p06-06b5a7caf4.png", "9701-experimental-skills/assets/9701-2023-on-53-q02-p07-50596d75c6.png" ], "answer": { "status": "pending", "id": "9701-2023-on-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Cl, Benzenediazonium chloride, C H N decomposes in water as shown in the following equation. 2\n6 5 2\nCl(aq) HCl (aq) H N + H O(l) C H OH(aq) + N (g) + C\n6 5 2 2 6 5 2\ndm–3 Cl of C H N (aq) decomposes at a constant temperature of 50 °C. A solution of 0.0750 mol\n6 5 2\n(g), collected is recorded every 5 minutes for 45 minutes. The volume of nitrogen gas, N\n2\nDraw a labelled diagram to show how the apparatus could be set up to carry out this (a)\nexperiment.\n[3]\nUsing this method, a student obtains the graph shown in Fig. 2.1. (b)\n60\n50\n40\n30\nvolume N\n2\ncm3 /\n20\n10\n0\n5 10 15 20 25 0 30 35 40 45\ntime / min\nFig. 2.1\nOn Fig. 2.1, draw a tangent to the curve at t = 0 mins. Calculate the initial rate of reaction (i)\ncm3 min–1. in\ncm3 min–1 [2] initial rate of reaction = ..............................\nExplain why the initial rate of reaction is calculated at t = 0 mins rather than dividing the (ii)\ntotal volume of gas produced by the time taken to produce it.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nDescribe how the curve in Fig. 2.1 would be different, if at all, if the atmospheric pressure (iii)\nincreases. All other conditions stay the same.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nOn Fig. 2.1, draw a second curve to show the graph produced if the same volume of (iv)\n–3 Cl C H N (aq) decomposes at a constant temperature of 50 °C. All 0.0375 mol dm\n6 5 2\nother conditions stay the same. [1]\nCl H N (aq) Another student investigates the effect of changing the concentration of C (c)\n6 5 2\ndm3 of N (g) and calculates the rate of at 50 °C. He measures the time taken to collect 0.0150\n2\ndm3 production by dividing 0.0150 by the time taken. The results are shown in Table 2.1. N\n2\nTable 2.1\nrate of N concentration of time taken to\n2\ndm3 Cl H N (aq) C collect 0.0150 production\n6 5 2\ndm–3 dm3 s–1 / s / mol of N /\n2\n0.500 21\n0.400 33\n0.300 48\n0.200 64\n0.100 122\nproduction. Complete the table to calculate the values for the rate of N (i)\n2\nGive your answers to significant figures. [1] three\nThe reaction is first order and obeys the following rate equation. (ii)\nCl] H N rate = k [C\n6 5 2\nExplain how the data in Table 2.1 supports this statement.\n.......................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2023-on-53-q02-41674053b5.pdf" }, { "id": "9701-2024-m-42-q01", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 26, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p01-95703b9953.png", "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p02-f6c2909a07.png", "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p03-1a379545d3.png", "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p04-a2ad4c25b7.png", "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p05-3831b9932d.png", "9701-topic-23-chemical-energetics/assets/9701-2024-m-42-q01-p06-bbdf61ead6.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "KI, Potassium iodide, is used as a reagent in both inorganic and organic chemistry. 1\nKI forms an ionic lattice that is soluble in water. (a)\nΔH . Define enthalpy change of solution, (i)\nsol\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nKI(s) has a high solubility in water although its enthalpy change of solution is endothermic. (ii)\nExplain how this high solubility is possible.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n–, – I–, Cl Br and and their potassium salts. Table 1.1 gives some data about the halide ions, (b)\nTable 1.1\nenthalpy change of hydration, lattice energy of potassium halide,\nhalide ion\nmol–1 mol–1 ΔH ΔH / kJ / kJ\nhyd latt\n– Cl –364 –701\n– –335 –670 Br\nI– –293 –629\nExplain the trend in the enthalpy change of hydration of the halide ions. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nΔH values of these potassium halides are almost constant. The (ii)\nsol\nΔH ΔH and data in Table 1.1 to suggest why. Use the\nhyd latt\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nmol–1. KI(s) The enthalpy change of solution of is +21.0 kJ (iii)\nUse this information and the data in Table 1.1 to calculate the enthalpy change of\nK+(g). hydration of the potassium ion,\nK+(g) mol–1 ΔH of = ............................................kJ [1]\nhyd\nPb2+(aq) KI(aq) PbI forms when is mixed with ions. Solid (iv)\n2\n10–9 mol3 dm–9 × PbI , of is 7.1 at 25 °C. The so", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-m-42-q01-07647baa00.pdf" }, { "id": "9701-2024-m-42-q02", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 8, 9, 10, 11 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2024-m-42-q02-p01-77d365d2e5.png", "9701-topic-25-equilibria/assets/9701-2024-m-42-q02-p02-ed2400a059.png", "9701-topic-25-equilibria/assets/9701-2024-m-42-q02-p03-4a19af7fe6.png", "9701-topic-25-equilibria/assets/9701-2024-m-42-q02-p04-0b7b1251fe.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Water is an amphoteric compound that also acts as a good solvent of polar and ionic compounds. 2\nEquation 1 shows water acting as a Brønsted–Lowry acid. (a)\nOH– – O + NO HNO + equation 1 H\n2 2 2\nIdentify the conjugate acid–base pairs in equation 1. (i) two\nacid I conjugate base of acid I O H\n2\nacid II conjugate base of acid II\n[1]\nNH . Water also behaves as a Brønsted–Lowry acid when it dissolves CH (ii)\n3 2\nNH to act as a base. Explain the ability of CH\n3 2\n..................................................................................................................................... [1]\nCOOH. Write an equation to show water acting as a base with CH (iii)\n3\n..................................................................................................................................... [1]\n, measures the extent to which water dissociates. The ionic product of water, K (b)\nw\nH+(aq) OH–(aq) O(l) + H\n2\nvaries with temperature. Fig. 2.1 shows how K\nw\n6.00\n5.00\n4.00\nK 3.00\nw\n10–14 mol2 dm–6 /\n2.00\n1.00\n0.00\n0 10 20 30 40 50\n/ °C temperature\nFig. 2.1\n. Write an expression for K (i)\nw\n..................................................................................................................................... [1]\nUse information from Fig. 2.1 to deduce whether the dissociation of water is an (ii)\nexothermic or an endothermic process.\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nAn aqueous solution has pH = 7.00 at 30 °C. (iii)\nUse information from Fig. 2.1 to explain why this solution can be considered to be\nalkaline at 30 °C.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\no\nThe three physical states of H O have different standard entropies, S , associated with them. (c)\n2\no\nvalues. Table 2.1 shows these S\nTable 2.1\nstandard entropy,\nstate of H O\no K–1 mol–1 2 / J S\nsolid +48.0\nliquid +70.1\ngas +188.7\no\nvalues of H O(s) and H O(l). Explain the difference in the S (i)\n2 2\n...........................................................................................................................................\n..........................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2024-m-42-q02-f89a9932a5.pdf" }, { "id": "9701-2024-m-42-q03", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 12, 13, 14 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q03-p01-dc34923ed6.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q03-p02-87c852bf99.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q03-p03-50a420a76a.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Iron is a transition metal in Group 8 of the Periodic Table. 3\nExplain why iron has variable oxidation states. (a) (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n3+. Complete the shorthand electronic configurations of Fe and Fe (ii)\nFe [Ar] .......................................................................................................................\n3+ [Ar] ....................................................................................................................... Fe\n[1]\n]3+. ) contains the complex [Fe(H O) An aqueous solution of Fe(NO (b)\n3 3 2 6\n]3+(aq) O) are mixed, a colour change is observed. When solutions of KSCN(aq) and [Fe(H\n2 6\nSCN]2+ O) forms. The red complex [Fe(H\n2 5\nDefine complex. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n]3+. O) State the coordination number of Fe in [Fe(H (ii)\n2 6\n..................................................................................................................................... [1]\nThe H—O—H bond angle in water is 104.5°. (iii)\n]3+. O) Suggest the H—O—H bond angle in [Fe(H\n2 6\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nExplain why iron complexes are coloured. (iv)\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [3", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-m-42-q03-b96a92b1f6.pdf" }, { "id": "9701-2024-m-42-q04", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 15, 16, 17 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q04-p01-94c0e1cdd2.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q04-p02-89b4495e87.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-m-42-q04-p03-42ac7ca8e6.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Ruthenium and osmium are transition metals below iron in Group 8 of the Periodic Table. 4\nRuCl reacts with water Two different complex ions, and Y, can form when anhydrous (a) X\n3\nunder certain conditions.\nand have octahedral geometry. X Y\n(aq). Different Aqueous samples of and react separately with an excess of AgNO X Y\n3\nAgCl amounts of are precipitated:\n• AgCl 1 mole of complex ion produces 2 moles of X\n• AgCl. 1 mole of complex ion produces 1 mole of Y\nComplete Table 4.1 to suggest formulae for and Y. (i) X\nTable 4.1\nX Y\nformula of complex\n[2]\nBoth complexes react with an excess of bipyridine, bipy, to form a mixture of two (ii)\n]3+. stereoisomers of [Ru(bipy)\n3\nbipy\nN N\nBipyridine is a bidentate ligand.\n]3+. Draw three-dimensional diagrams of the two stereoisomers of [Ru(bipy)\n3\nto represent the bipy ligand in your structures. Use N N\nRu Ru\n[2]\nFig. 4.1 shows another ruthenium complex. (b)\n5+\nN) Ru N N Ru(NH ) (H\n3 5 3 5\nFig. 4.1\nThis complex contains the neutral ligand pyrazine.\npyrazine\nN N\nSuggest how pyrazine is able to bond to two separate ruthenium ions. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nPyrazine is an aromatic compound. The bonding and structure of pyrazine is similar to (ii)\nthat of benzene.\nDescribe and explain the shape of pyrazine.\nIn your answer, include:\n• the hybridisation of the nitrogen and carbon atoms\n• π how orbital overlap forms bonds between the atoms in the ring.\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nPredict the number of peaks seen in the carbon–13 NMR spectrum of pyrazine. (iii)\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nThe overall charge of the ruthenium complex in Fig. 4.1 is 5+. (iv)\nDeduce the possible oxidation states of the two ruth", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-m-42-q04-ae1ee61303.pdf" }, { "id": "9701-2024-m-42-q05", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 18, 19, 20, 21 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-m-42-q05-p01-eaf3025966.png", "9701-topic-36-organic-synthesis/assets/9701-2024-m-42-q05-p02-75a2bcbbaf.png", "9701-topic-36-organic-synthesis/assets/9701-2024-m-42-q05-p03-3e27dbd31d.png", "9701-topic-36-organic-synthesis/assets/9701-2024-m-42-q05-p04-78c75976af.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q05", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Compound can be synthesised from chlorobenzene in seven steps, using the route shown in 5 Q\nFig. 5.1.\nchlorobenzene J K\nCl Cl Cl\nCH CHO AlCl and\n3 3\n[O] Cl CH\n3\nstep 1 step 2\nstep 3\nL\nCl CN\nOH\nstep 4\nP N M\nCl Cl Cl COOCH COOCH COOH\n3 3 acidified CH OH\n3 SOCl\n2\nCl OH OH\nstep 5\nstep 6\nstep 7\nHN\nCO (aq) and K\n2 3\nS\nQ\nCl COOCH\n3\nN\nS\nFig. 5.1\nWrite an equation for the formation of the electrophile for step 1. (a) (i)\n..................................................................................................................................... [1]\nComplete the mechanism in Fig. 5.2 for step 1, the alkylation of chlorobenzene. (ii)\nInclude all relevant curly arrows and charges.\nDraw the structure of the intermediate.\nintermediate\nCl Cl\nCH\n3\n+................\nFig. 5.2\n[3]\nStep 2 is an oxidation reaction. (iii)\nConstruct an equation for the reaction in step 2.\nUse [O] to represent an atom of oxygen from an oxidising agent.\n..................................................................................................................................... [1]\nSuggest reagents for the conversion of to in steps 3 and 4. (iv) K M\nstep 3 ................................................................................................................................\nstep 4 ................................................................................................................................\n[2]\nIdentify the type of reaction that occurs in step 5. (v)\n..................................................................................................................................... [1]\nStep 7 takes place when is heated with a weak base such as K CO (aq). (vi) P\n2 3\nHN\nQ P S\nCl Cl COOCH COOCH\n3 3 and K CO (aq)\n2 3\nCl N\nstep 7\nS\nSuggest why a strong base such as NaOH(aq) is used for this reaction. not\n...........................................................................................................................................\n..................................................................................................................................... [1]\nis optically active. (vii) Q\nExplain the meaning of optically active.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nGive reasons why it might be desirable to synthesise a single optical isomer of for (viii) two Q\nuse as a drug.\n1 ........................................................................................................................................\n...........................................................................................................................................\n2 ...........", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-m-42-q05-6ca8664fed.pdf" }, { "id": "9701-2024-m-42-q06", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_42.pdf?download=true", "source_pages": [ 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p01-e9e60e7f97.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p02-9350d26fb9.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p03-945003780b.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p04-32ab740e77.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p05-1a6c4520f2.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-m-42-q06-p06-ca4f39c5d8.png" ], "answer": { "status": "pending", "id": "9701-2024-m-42-q06", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Amino acids are molecules that contain —NH and —COOH functional groups. 6\n2\nNCH COOH, is the simplest stable amino acid. Glycine, H\n2 2\nThe isoelectric point of glycine is 6.2. (a)\nDefine isoelectric point. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nDraw the structure of glycine at pH 4. (ii)\n[1]\nFig. 6.1 shows two syntheses starting with glycine. (b)\nglycine\nC H Br\n2 5\nN COOH\nreaction 1 H N COOH\n2\nreaction 2\nhippuric acid\nO\nN COOH\nH\nLiAl an excess of H\n4\nreaction 3\nU\nFig. 6.1\nState the essential conditions for reaction 1. (i)\n..................................................................................................................................... [1]\nIdentify the reagent used in reaction 2. (ii)\n..................................................................................................................................... [1]\nDraw the structure of the organic product that forms when hippuric acid reacts with an (iii) U\nLiAl in reaction 3. excess of H\n4\n[2]\nA molecule of phenylalanine, R, can react with a molecule of glycine to form two (iv)\ndipeptides, and T. S\nand are structural isomers. S T\nR glycine\nH N COOH\n2\nand S T\n+ H N COOH\n2\nDraw the structures of these dipeptides. The peptide bond formed should be shown fully\ndisplayed.\nT S\n[2]\nA student proposes a synthesis of hippuric acid by the reaction of benzamide, C H CONH , (c)\n6 5 2\nCl COOH. and chloroethanoic acid, CH\n2\nThe reaction does work well because benzamide is a very weak base. not\nExplain why amides are weaker bases than amines. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nof chloroethanoic acid is 2.86 whereas the pK of ethanoic acid is 4.76. The pK (ii)\na a\nvalues. Explain the difference between these two pK\na\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n........................................................................................................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2024-m-42-q06-8f663b90c1.pdf" }, { "id": "9701-2024-m-52-q01", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-m-52-q01-p01-dd4dbf4691.png", "9701-experimental-skills/assets/9701-2024-m-52-q01-p02-90a4266789.png", "9701-experimental-skills/assets/9701-2024-m-52-q01-p03-319c86f9f9.png" ], "answer": { "status": "pending", "id": "9701-2024-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "dm–3 –(aq). Cl Sea water contains about 20 g of chloride ions, 1\n–(aq) Cl in sea water can be determined by titration with aqueous The exact concentration of\nAg+(aq), chromate(VI), using aqueous potassium K CrO (aq), as an indicator. silver ions,\n2 4\n(aq), is added to a sample of sea water, silver ions react with When aqueous silver nitrate, AgNO\n3\nchloride ions to form a precipitate of silver chloride.\nAg+(aq) –(aq) Cl AgCl + (s)\n–(aq) Ag+(aq), Ag+(aq) Cl has reacted with the presence of unreacted is detected When all of the\n2–(aq). chromate(VI) ions, CrO A red precipitate of Ag CrO (s) is seen. by\n4 2 4\n2Ag+(aq) 2–(aq) + CrO Ag CrO (s)\n4 2 4\nAg+(aq) –(aq) Cl reacting with in the sample of sea water can be calculated in order The amount of\n–(aq) Cl in the sample of sea water. to determine the concentration of\nA student uses the following method.\n(s) into a Use a weighing boat to weigh by difference approximately 10.6 g of AgNO step 1\n3\ncm3 glass beaker. 100\ncm3 (s) in the glass beaker to prepare 250.0 of AgNO (aq). Use the sample of AgNO step 2\n3 3\nTransfer this solution into a dark brown glass bottle. Label this solution X. step 3\nCollect a sample of sea water and remove any solid material present. step 4\n3 of the sea water into a conical flask. Transfer 10.00 cm step 5\ncm3 of K CrO (aq) to the conical flask. Add 1 step 6\n2 4\nRinse a burette in preparation for the titration. step 7\nFill the burette with solution X. step 8\nSlowly add solution to the conical flask until the white precipitate turns red. This is the step 9 X\nend-point.\nDescribe how the student should carry out step 1. Include a table in your answer to show how (a)\nthis process is recorded.\n...................................................................................................................................................\n...................................................................................................................................................\n[2]\n3 of AgNO (aq) in step 2, starting with the Describe how the student should prepare 250.0 cm (b)\n3\ncm3 (s) in the 100 beaker in step 1. AgNO\n3\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nSuggest why solution is kept in a dark brown glass bottle in step 3 rather than a colourless (c) X\nglass bottle.\n.......................", "pdf_path": "9701-experimental-skills/print/9701-2024-m-52-q01-12b64ebe79.pdf" }, { "id": "9701-2024-m-52-q02", "subject": "9701", "year": 2024, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-march/9701_m24_qp_52.pdf?download=true", "source_pages": [ 5, 6, 7, 11, 12 ], "local_pdf": "_source-pdfs/2024-March/qp/9701_m24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-m-52-q02-p01-e1bda06df9.png", "9701-experimental-skills/assets/9701-2024-m-52-q02-p02-e7f2b18097.png", "9701-experimental-skills/assets/9701-2024-m-52-q02-p03-a7200772bd.png", "9701-experimental-skills/assets/9701-2024-m-52-q02-p04-8dcf6aa47b.png", "9701-experimental-skills/assets/9701-2024-m-52-q02-p05-c55b0563cb.png" ], "answer": { "status": "pending", "id": "9701-2024-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "A student wants to investigate the rate of the hydrolysis of methyl methanoate, HCOOCH . 2\n3\n+ H O HCOOH + CH OH HCOOCH\n3 2 3\nHCl The reaction is catalysed by dilute hydrochloric acid, (aq).\nThe amount of methanoic acid, HCOOH, produced as the reaction progresses can be monitored by\ntitration with aqueous sodium hydroxide, NaOH(aq), of known concentration using thymolphthalein\nas the indicator.\n+(aq) from the catalyst To determine this, the volume of NaOH(aq) needed to neutralise the H\nneeds to be found beforehand.\nThe student uses the following procedure.\n3 cm3 of iced water to a 250 conical flask, A. Add approximately 150 cm step 1\ncm3 dm–3 cm3 HCl of 0.250 mol (aq) to a 500 conical flask, B. Add 200 step 2\nConical flask is the flask in which the reaction takes place. B\n3 dm–3 HCl of 0.250 mol (aq) from conical flask to conical flask A. Transfer 2.00 cm B step 3\nCarry out a single titration of the contents of conical flask with NaOH(aq) of known A\nconcentration.\n3 of methyl methanoate to conical flask B, swirl the reaction mixture and Add 10.0 cm step 4\nimmediately start a stopwatch.\ncm3 of the reaction mixture from conical flask into conical After 1 minute transfer 2.00 B step 5\nflask A. Carry out a further single titration of the contents of conical flask against A\nNaOH(aq). Do empty the contents of conical flask between titrations. not A\n3 of the reaction mixture from conical flask into conical After 10 minutes transfer 2.00 cm B step 6\nflask A. Titrate the contents of conical flask against NaOH(aq). A\nRepeat step 6 at intervals of 10 minutes for 1 hour. step 7\nH+(aq) ions from the catalyst in the State which step is used to determine the concentration of (a)\nmixture.\n............................................................................................................................................. [1]\nThe iced water in conical flask is used to significantly reduce the rate of reaction. (b) A\nSuggest reasons why the rate of reaction is significantly reduced when the reaction two\nmixture is transferred to conical flask A.\nreason 1 ....................................................................................................................................\n...................................................................................................................................................\nreason 2 ....................................................................................................................................\n...................................................................................................................................................\n[2]\nTable 2.1 shows the readings taken by the student. (c)\nH+(aq) The titrations in steps 4–7 show the volume of NaOH(aq) needed to neutralise both the\nHCl ions from the catalyst, (aq), and from the HCOOH produced in the reaction.\ncm3, H+(aq) cm3 to neutralise from catalyst = 11.40 volume of NaOH(aq) needed, in\ncm3, H+(aq) volume of NaOH(aq), in u", "pdf_path": "9701-experimental-skills/print/9701-2024-m-52-q02-584390d806.pdf" }, { "id": "9701-2024-mj-41-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2024-mj-41-q01-p01-d413943350.png", "9701-topic-27-group-2/assets/9701-2024-mj-41-q01-p02-6a68ba2ed0.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Describe the trend in the solubility of the hydroxides of magnesium, calcium and 1 (a) (i)\nstrontium.\nExplain your answer.\n.......................................... > .......................................... > ..........................................\nmost soluble least soluble\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[4]\nSuggest the variation in pH of saturated solutions of the hydroxides of magnesium, (ii)\ncalcium and strontium.\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n, is a strong base. Barium hydroxide, Ba(OH) (b)\n2\ncm3 solution of Ba(OH) with a pH of 12.2 is made by dissolving Ba(OH) in distilled A 250.0\n2 2\nwater.\nrequired to make this solution. Calculate the mass of Ba(OH)\n2\nShow your working.\n: Ba(OH) , 171.3] [M\nr 2\nmass of Ba(OH) = .............................. g [4]\n2\n10–6 dm–3 iron(II) × The solubility of hydroxide, Fe(OH) , is 5.85 mol at 298 K. (c)\n2\n, of Fe(OH) . Write the expression for the solubility product, K (i)\nsp 2\nK =\nsp\n[1]\nCalculate the value of K of Fe(OH) . Include its units. (ii)\nsp 2\nK = ..............................\nsp\nunits = ..............................\n[2]\n[Total: 12]", "pdf_path": "9701-topic-27-group-2/print/9701-2024-mj-41-q01-871cf9f1ed.pdf" }, { "id": "9701-2024-mj-41-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 4, 5, 6 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-41-q02-p01-c3450b9b5f.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-41-q02-p02-e5fd214ce8.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-41-q02-p03-221bed7004.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Define transition element. 2 (a) (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nExplain why transition elements can form complex ions. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n+ ion are degenerate. The 3d orbitals in an isolated Ag (b)\nDefine degenerate d orbitals. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\norbital in Fig. 2.1. Sketch the shape of a 3d (ii)\nxy\ny\nz\nx\nFig. 2.1\n[1]\nTollens’ reagent can be used to distinguish between aldehydes and ketones. Tollens’ reagent (c)\n) ]OH, which can be prepared in a two-step process. contains [Ag(NH\n3 2\nto form Ag O as a brown Aqueous NaOH is added dropwise to aqueous AgNO step 1\n3 2\nprecipitate.\nis added dropwise to Ag O to form a colourless solution containing Aqueous NH step 2\n3 2\n) ]OH. [Ag(NH\n3 2\n) ]OH. Construct equations for each of the steps in the preparation of [Ag(NH\n3 2\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\n[2]\n]+. Name the shape of the complex ion [Ag(NH ) (d)\n3 2\nState the bond angle for H-N-Ag and for N-Ag-N.\nshape ........................................................................................................................................\nbond angle for H-N-Ag = .............. °\nbond angle for N-Ag-N = .............. °\n[2]\nAn electrochemical cell uses Ag O as the positive electrode and Zn as the negative electrode (e)\n2\nimmersed in an alkaline electrolyte.\nThe overall cell reaction is shown.\nAg O + Zn + H O 2Ag + Zn(OH)\n2 2 2\nComplete the half-equation for the reaction at each electrode.\nat the positive electrode Ag O + .....................................................................................\n2\nat the negative electrode Zn + ........................................................................................\n[2]\nCoordination polymers are made when a bidentate ligand acts as a bridge between different (f)\nmetal ions.\nRu3+(aq) Under certain conditions and the bidentate ligand dps ca", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-mj-41-q02-ab32ca8889.pdf" }, { "id": "9701-2024-mj-41-q03", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 7, 8 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-41-q03-p01-e236e7d1b7.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-41-q03-p02-6ff08c236b.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "When a sample of hydrated lithium ethanedioate, Li C O •H O, is gently heated, two gaseous 3 (a)\n2 2 4 2\nproducts are formed and a white solid residue remains.\n(aq). A gas is produced that turns limewater milky. The residue is added to HNO\n3\nC O •H O. Complete the equation for the decomposition of Li\n2 2 4 2\nC O •H O .................................... + .................................... + .................................... Li\n2 2 4 2\n[1]\nThe trend in the decomposition temperatures of the Group 2 ethanedioates is similar to that (b)\nof the Group 2 nitrates.\nO and BaC O will decompose at the temperature. Explain Suggest which of CaC lower\n2 4 2 4\nyour answer.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\niron(III) ethanedioate, K [Fe(C O ) ], dissolves in water to form a green solution. Potassium (c)\n3 2 4 3\nExplain why transition elements can form coloured complexes.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\niron(III) compound K [Fe(C O ) ] decomposes on heating to form a mixture The anhydrous (d)\n3 2 4 3\n[Fe(C O ) ], K C O and CO . of K\n2 2 4 2 2 2 4 2\n[Fe(C O ) ]. Complete the equation for the decomposition of K\n3 2 4 3\n[Fe(C O ) ] ............ K [Fe(C O ) ] + ............ K C O + ............ CO .............. K\n3 2 4 3 2 2 4 2 2 2 4 2\n[1]\n]3– The [Fe(C O ) complex ion shows stereoisomerism. (e)\n2 4 3\nComplete the three-dimensional diagrams in Fig. 3.1 to show the stereoisomers of two\n]3–. O ) [Fe(C\n2 4 3\n2– O ligand can be represented using O. The C O\n2 4\nisomer 2 isomer 1\nFe Fe\nFig. 3.1\n[2]\nBuffer solutions are used to regulate pH. (f)\n– O ions acts as a buffer Write equatio", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-mj-41-q03-a97acf40ea.pdf" }, { "id": "9701-2024-mj-41-q04", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 9, 10, 11 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-mj-41-q04-p01-a11b820ae5.png", "9701-topic-23-chemical-energetics/assets/9701-2024-mj-41-q04-p02-20f94d2409.png", "9701-topic-23-chemical-energetics/assets/9701-2024-mj-41-q04-p03-9eae76802d.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Eo, Define standard electrode potential, including a description of standard conditions. 4 (a)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\no Ag+(aq)/Ag(s) of the electrode. An electrochemical cell is set up to measure E (b) (i)\nDraw a labelled diagram of this electrochemical cell.\nInclude all necessary substances. It is necessary to state conditions used. not\n[3]\n+(aq) than A separate electrochemical cell is set up using a concentration of Ag (ii) lower\nthat used in (b)(i).\nAg+(aq)/Ag(s) electrode would change Suggest how the electrode potential, E, for the\nEo value. Explain your answer. from its\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\no\nΔH . Define enthalpy change of solution, (c)\nsol\n...................................................................................................................................................\n............................................................................................................................................. [1]\nSome relevant energy changes for AgNO are shown in Table 4.1. (d)\n3\nTable 4.1\nmol–1 energy change value / kJ\nenthalpy change of solution of AgNO (s) +22.6\n3\nenthalpy change of hydration of silver ions –475\nenthalpy change of hydration of nitrate ions –314\nComplete the energy cycle in Fig. 4.1 to show the relationship between the lattice energy, (i)\no\nΔH , of AgNO (s) and the energy changes shown in Table 4.1.\n3 latt\nInclude state symbols for all the species.\nAgNO (s)\n3\nFig. 4.1\n[2]\no\nΔH , of AgNO (s). Calculate the lattice energy, (ii)\n3 latt\no\nmol–1 ΔH = .............................. kJ [1]\nlatt\nSuggest the trend in the magnitude of the lattice energies of the metal nitrates, NaNO (s), (e)\n3\n) (s) and RbNO (s). Mg(NO\n3 2 3\nExplain your answer.\n.......................................... .......................................... ..........................................\nmost exothermic least exothermic\n...................................................................................................................................................\n...................................................................................................................................................\n.....................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-mj-41-q04-8bb73076e4.pdf" }, { "id": "9701-2024-mj-41-q05", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-41-q05-p01-487fa19f7a.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-41-q05-p02-572d9bac95.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "2–, In aqueous solution, persulfate ions, S O react with iodide ions, as shown in reaction 1. 5 (a)\n2 8\n2I– 2– 2– I O + 2SO + reaction 1 S\n2 8 4 2\nThe rate of reaction 1 is investigated.\n2– O is mixed with a large excess of iodide ions of known concentration. The A sample of S\n2 8\ngraph in Fig. 5.1 shows the results obtained.\n0.900\n0.800\n0.700\n0.600\n0.500\ndm–3 2–] [S O / mol 0.400\n2 8\n0.300\n0.200\n0.100\n0.000\n0 25 50 75 100 125 150 175 200\n/ min time\nFig. 5.1\nUse Fig. 5.1 to determine the initial rate of reaction 1. Show your working. (i)\n–3 min–1 [1] rate = .............................. mol dm\n[I–]. 2–] O The rate equation for reaction 1 is rate = k [S (ii)\n2 8\nSuggest why a large excess of iodide ions allows the rate constant to be determined\nfrom the half-life in this investigation.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nFe2+ 2–, The reaction of persulfate ions, S O with iodide ions is catalysed by ions. (b)\n2 8\nFe2+ catalyses reaction 1. Write equations to show how two\nequation 1 .................................................................................................................................\nequation 2 .................................................................................................................................\n[2]\nDescribe the effect of an increase in temperature on the rate constant and the rate of (c)\nreaction 1.\n...................................................................................................................................................\n............................................................................................................................................. [1]\n2–, O react with hydrogen ions, as shown in reaction 2. In aqueous solution, thiosulfate ions, S (d)\n2 3\n2H+ 2– O + SO + S + H O reaction 2 S\n2 3 2 2\n[H+] 2–] O and zero order with respect to The rate of reaction is first order with respect to [S\n2 3\nunder certain conditions.\n10–2 s–1. × The rate constant, k, for this reaction is 1.58\n, for reaction 2. Calculate the half-life, t\n1\n2\n= .............................. s [1] t\n1\n2\nThe compound nitrosyl bromide, NOBr, can be formed as shown in reaction 3. (e)\nreaction 3 2NO(g) + Br (g) 2NOBr(g)\n2\n]. The rate is first order with respect to [NO] and first order with respect to [Br\n2\nThe reaction mechanism has two steps.\nSuggest equations for the steps of this mechanism. State which is the rate-determining two\nstep.\nstep 1 ........................................................................................................................................\nstep 2 ..............................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-mj-41-q05-8276a47868.pdf" }, { "id": "9701-2024-mj-41-q06", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2024-mj-41-q06-p01-18ef9a94a1.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-41-q06-p02-7fa24cd084.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-41-q06-p03-dfb53ff02f.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-41-q06-p04-45424c40de.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q06", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "State what is meant by partition coefficient, K . 6 (a) (i)\npc\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n, for a compound, X, between carbon disulfide, CS , and The partition coefficient, K (ii)\npc 2\nwater is 10.5.\ncm3 in a volumetric flask. 1.85 g of is dissolved in water and made up to 100.0 X\ncm3 cm3 of this aqueous solution is shaken with 25.0 of CS . 40.0\n2\nThe mixture is left to reach equilibrium.\nlayer. Calculate the mass of X, in g, extracted into the CS\n2\nmass of = .............................. g [2] X\nH has many structural isomers. Four suggested structures of C H are The compound C (b)\n6 6 6 6\nshown in Fig. 6.1.\nKekulé benzene Dewar benzene Ladenburg benzene delocalised benzene\nFig. 6.1\nsp2 Using Fig. 6.1, complete Table 6.1 to predict the number of carbon atoms that have sp,\nsp3 hybridisation in Kekulé benzene, Dewar benzene and Ladenburg benzene. and\nTable 6.1\nsp2 sp3 C H structure sp hybridised hybridised hybridised\n6 6\nKekulé benzene\nDewar benzene\nLadenburg benzene\n[2]\nDescribe the shape of delocalised benzene. (c)\nInclude the geometry of each carbon, the C-C-H bond angle and the type of bond(s) between\nthe carbon atoms and between the carbon and hydrogen atoms.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\nH . Suggest why Dewar benzene and Ladenburg benzene are unstable isomers of C (d)\n6 6\n...................................................................................................................................................\n............................................................................................................................................. [1]\n1H) NMR spectrum for Complete Table 6.2 to predict the number of peaks in the proton ( (e)\nDewar benzene, Ladenburg benzene and delocalised benzene.\nTable 6.2\nnumber of peaks\nDewar benzene\nLadenburg benzene\ndelocalised benzene\n[1]\nThe reaction of phenylethanone with 1,4-dibromobutane, BrCH CH CH CH Br, in th", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2024-mj-41-q06-9afc7eafb2.pdf" }, { "id": "9701-2024-mj-41-q07", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 18, 19, 20 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-mj-41-q07-p01-c953c75bdc.png", "9701-topic-36-organic-synthesis/assets/9701-2024-mj-41-q07-p02-7d35ffd23b.png", "9701-topic-36-organic-synthesis/assets/9701-2024-mj-41-q07-p03-706c12a1cc.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Four esters, A, B, and D, with the molecular formula C H O are shown in Fig. 7.1. 7 C\n6 12 2\nA B\nO O\nO O\nC D\nO\nO\nO\nO\nFig. 7.1\nGive the systematic name of ester A. (a)\n............................................................................................................................................. [1]\nA mixture of these esters, A, B, and D, is analysed by gas–liquid chromatography. (b) C\nThe chromatogram produced is shown in Fig. 7.2. The number above each peak represents\nthe area under the peak.\nThe area under each peak is proportional to the mass of the respective ester in the mixture.\nester B\ndetector\nresponse\n52 ester A\nester D 38\n25\n14\nester C\n/ min time\nFig. 7.2\nState what is meant by retention time. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nCalculate the percentage by mass of ester in the original mixture. (ii) D\npercentage by mass of ester = .............................. % [1] D\n(1H) Separate samples of the esters, A, B, and D, are analysed using proton NMR and (c) C\ncarbon-13 NMR spectroscopy.\nComplete Table 7.1 to show the number of peaks in each NMR spectrum for esters (i) B\nand C.\nTable 7.1\nnumber of peaks in number of peaks in\nester\n(1H) NMR spectrum carbon-13 NMR spectrum proton\nB\nC\n[2]\nIdentify of the esters from A, B, and that have at least one triplet peak in their (ii) all C D\n1H) NMR spectrum. proton (\n..................................................................................................................................... [1]\nQuestion 7 continues on page 20.\nCompound F, C H O , shows stereoisomerism and effervesces with Na CO (aq). (d)\n6 8 3 2 3\nI (aq) to form yellow precipitate and compound H. Compound reacts with alkaline G F\n2\nLiAl to form compound J, C H O . Compound reacts with H F\n4 6 12 2\nCl SOCl to form compound K, C H O . Compound reacts with F\n2 6 7 2\nCompound reacts with propan-2-ol to form compound L. K\nDraw the structures of compounds F, G, H, J, and in the boxes in Fig. 7.3. K L\nF, C H O G H\n6 8 3\nalkaline\nI (aq)\n2 +\nSOCl\n2\nLiAl H\n4\nCl K, C H O\n6 7 2\nJ, C H O\n6 12 2\npropan-2-ol\nL\nFig. 7.3\n[6]\n[Total: 12]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-mj-41-q07-97105d2c00.pdf" }, { "id": "9701-2024-mj-41-q08", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 21, 22 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-41-q08-p01-0d5335a2f0.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-41-q08-p02-1efee5409c.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Neotame is an artificial sweetener added to some foods. 8\nneotame\nH O\nO N\nN\nO O H\nOH\nFig. 8.1\nState the number of chiral carbon atoms in a molecule of neotame. (a) (i)\n..................................................................................................................................... [1]\nNeotame contains the arene functional group. (ii)\nIdentify all the functional groups present in neotame. other\n...........................................................................................................................................\n..................................................................................................................................... [2]\nNeotame reacts with an excess of hot NaOH(aq) to form three organic products. (b)\nState the types of reaction that occur when neotame reacts with hot NaOH(aq). (i) two\n1 .........................................................................................................................................\n2 .........................................................................................................................................\n[2]\nneotame\nH O\nO N\nN\nO O H\nOH\nFig. 8.1\nDraw the structures of the organic products formed from the reaction of neotame (ii) three\nwith an excess of hot NaOH(aq).\n[3]\n[Total: 8]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2024-mj-41-q08-59d3a0a69e.pdf" }, { "id": "9701-2024-mj-41-q09", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_41.pdf?download=true", "source_pages": [ 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_41.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-41-q09-p01-7e323f6ade.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-41-q09-p02-41b8ad7799.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-41-q09-p03-9d77054569.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-41-q09-p04-263930e0a9.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-41-q09-p05-ac45e38efc.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-41-q09", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Samples of phenol, C H OH, are reacted separately with sodium and with dilute nitric acid. 9 (a)\n6 5\nphenol\nOH\nFig. 9.1\nH OH with Na. Write the equation for the reaction of C (i)\n6 5\n..................................................................................................................................... [1]\nDraw the structures of the major isomeric organic products formed in the reaction of (ii) two\n. phenol with dilute HNO\n3\n[1]\nSalicylic acid can be synthesised from phenol. (b)\nsalicylic acid\nCOOH\nOH\nFig. 9.2\nOne of the steps in this synthesis is the electrophilic substitution reaction of carbon dioxide\nO–. H with the phenoxide ion, C\n6 5\nO– H with CO . Complete the mechanism in Fig. 9.3 for the reaction of C\n6 5 2\nInclude all relevant curly arrows, dipoles and charges. Draw the structure of the organic\nintermediate.\norganic intermediate\nO\nC\nO\nO–\nCOO–\nO– + ............\nFig. 9.3\n[3]\nSome syntheses use Diels–Alder reactions, which normally involve a diene and an alkene (c)\nreacting together to form a cyclohexene.\nDraw curly arrows in Fig. 9.4 to complete the mechanism for the Diels–Alder (i) three\nreaction between buta-1,3-diene and ethene.\nethene buta-1,3-diene cyclohexene\n+\nFig. 9.4\n[1]\nAnother Diels–Alder reaction of buta-1,3-diene is shown in Fig. 9.5. (ii)\nPredict the product formed in this reaction.\n+\nFig. 9.5\n[1]\n[Total: 7]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n104 mol–1 × Faraday constant F = 9.65 C\n1023 mol–1 × Avogadro constant L = 6.022\n10–19 × electronic charge e = –1.60 C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n10–14 mol2 dm–6 × °C)) = 1.00 (at 298 K (25 ionic product of water K\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eH eN nR eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 9.621 0.571 enidoi 0.91 5.53 9.97 uL 71 lC 301 sT rB 711 tA rL 71 53 35 58 17 F I – – – 9\nmuiromrevil muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib muiluht cinesra 8.121 0.902 9.861 mT dM cM bS 0.41 0.13 9.47 sA 51 101 511 iB N P 51 33 15 38 96 – – 7\nmuinamreg muivorelf muimref nobrac muibre 2.702 3.761 7.811 mF nocilis eG nS bP 0.21 1.82 6.27 41 001 rE 411 dael lF iS C 28 41 23 05 86 nit 6 – –\nmuinietsnie muinimula muinohin muimloh muillaht muillag 4.402 9.461 muidni 8.411 aG norob hN oH 8.01 0.72 7.96 sE 31 nI 311 lA lT 18 31 13 94 B 76 99 5 – –\nmuicinrepoc muisorpsyd muinrofilac muimdac yrucrem 6.002 5.261 4.211 dC gH nC yD 4.56 nZ 21 fC 211 cniz 08 84 03 89 66 – –\nmuinegtneor stnemelE muilekreb muibret reppoc 9.701 0.791 9.851 uC gR gA uA 5.36 bT kB revlis 11 dlog 111 74 97 79 92 56 – –\nmuitdatsmrad muinilodag muidallap m", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2024-mj-41-q09-5e02f1eeea.pdf" }, { "id": "9701-2024-mj-42-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-mj-42-q01-p01-1d4de5073b.png", "9701-topic-23-chemical-energetics/assets/9701-2024-mj-42-q01-p02-162dba1d78.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:1)(cid:3)(cid:44)\n1 (a) Describe the trend in the solubility of the sulfates of magnesium, calcium and strontium.\nSIHT\nNI Explain your answer .\nETIRW\n............................... ............ > ........................................... > ...........................................\nTON most soluble least soluble\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\n[4]\nTON\n. (b) Define lattice energy, ΔH OD\nlatt\n...................................................................................................................................................\n............................................................................................................................................. [2]\nNIGRAM\n(c) State and explain the main factors that affect the magnitude of lattice energies.\nSIHT\n...................................................................................................................................................\nNI\nETIRW ...................................................................................................................................................\n................................................................................................................................................... TON\nOD\n...................................................................................................................................................\n............................................................................................................................................. [2]\n(d) Table 1.1 shows some energy changes. NIGRAM\nTable 1.1\nSIHT\nmo–l1 energy change value / kJ\nNI\nETIRW\nstandard enthalpy change of atomisation of potassium +89\nfirst ionisation energy of potassium +419\nTON\nsecond ionisation energy of potassium +3070 OD\nstandard enthalpy change of atomisation of sulfur +279\nS–S bond energy +265\nNIGRAM\nfirst ionisation energy of sulfur +1000\nsecond ionisation energy of sulfur +2260\nSIHT\nfirst electron affinity of sulfur –200\nNI\nsecond electr", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-mj-42-q01-f8785d8216.pdf" }, { "id": "9701-2024-mj-42-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2024-mj-42-q02-p01-5e1ba964e5.png", "9701-topic-24-electrochemistry/assets/9701-2024-mj-42-q02-p02-e3347ca39d.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q02", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:1)(cid:5)(cid:44)\n2 (a) (i) Lithium nitrate, LiNO , decomposes on heating in a similar way to Group 2 nitrates to\nSIHT 3\ngive the metal oxide, a brown gas and oxygen.\nNI\nETIRW\n. Write an equation for the decomposition of LiNO\n3\nTON ..................................................................................................................................... [1]\nOD\n, decompose on heating to form the metal nitrite, (ii) The other Group 1 nitrates, MNO\n3\n, and oxygen. MNO\n2\nThe thermal stability of these nitrates increases down the group.\nNIGRAM\nincreases down the group. Suggest why the thermal stability of MNO\n3\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\n–, manganate(VII) can be used to analyse solutions containing nitrite (b) Acidified ions, MnO\n4\n–, by titration. ions, NO\n2\nNIGRAM . X is a solution of NaNO\n2\n3 cm3 dm–3 –(aq). –(aq) of X is added to 50.0 of 0.125 mol acidified MnO The MnO 250.0 cm\n4 4 SIHT\n– ions are oxidised in the reaction. ions are in excess; all the NO\n2\nNI\ncm3 dm–3 2+(aq) –(aq) ETIRW required 22.50 of 0.0400 mol Fe to reach the The unreacted MnO\n4\nend‑point.\nTON\nThe relevant half‑equations are shown.\nOD\n2H+ 2e– – – NO + + + H O NO\n3 2 2\n8H+ 5e– 2+ – Mn + 4H O MnO + +\n4 2\nNIGRAM\n2+ 3+ e– Fe + Fe\ndm–3, Calculate the concentration, in mol of NaNO in X. SIHT\n2\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\ndm–3 in X = .............................. mol [3] concentration of NaNO\nTON 2\nNIGRAM\n(c) Table 2.1 shows electrode potentials for some electrode reactions involving m anganese\nSIHT\ncompounds.\nNI\nETIRW\nTable 2.1\nTON o\nelectrode reaction E / V\nOD\n2+ 2e– –1.18 Mn + Mn\n4H+ 2e– Mn2+ +1.23 + + + 2H O MnO\n2 2\ne– – 2– +0.56 MnO + MnO NIGRAM\n4 4\n4H+ 3e– – +1.67 MnO MnO + 2H O + +\n4 2 2\nSIHT\n8H+ 5e– Mn2+ – +1.52 + + + 4H O MnO\n4 2\nNI\n4OH– 3e– – +0.59 MnO + + 2H O + MnO ETIRW\n4 2 2\n2e– 4OH– MnO2– +0.60 + 2H O + MnO +\n4 2 2 TON\n4H+ 2e– 2– +1.70 MnO MnO + 2H O + +\nOD 4 2 2\n2–, manganate(VI) are unstable in acidic conditions and undergo a (i) Aqueous ions, MnO\n4\ndisproportionation reaction.\nNIGRAM\no\nfor this reaction is +1.14 V. The E\ncell\nSIHT\nConstruct an overall ionic equation for this disproportionation reaction.\nNI\nETIRW\nTON\nOD\n..................................................................................................................................... [2]\nvalue of the disproportionation reaction changes with (ii) Suggest and explain how the E\ncell\nan increase in pH. NIGRAM\n..........................................................................", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2024-mj-42-q02-ef398c5f21.pdf" }, { "id": "9701-2024-mj-42-q03", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 5, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 6 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-mj-42-q03-p01-9a32beda6a.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:1)(cid:7)(cid:44)\n3 (a) Carbon disulfide, CS , is flammable and reacts readily with oxygen, as shown in reaction 1.\nSIHT 2\nNI (g) + 3O (g) CO (g) + 2SO (g) reaction 1 CS\n2 2 2 2 ETIRW\no o\n, and the standard entropy, S , for T able 3.1 shows the standard enthalpy of formation, ΔH\nf\nTON some substances.\nOD\nTable 3.1\nCS (g) O (g) CO (g) SO (g)\n2 2 2 2\nNIGRAM o\nmo–l1 116.7 0.0 –393.5 –296.8 ΔH / kJ\nf\no\nK–1 mol–1 237.8 205.2 213.8 248.2 / J S\nSIHT\nNI o\nmol–1, Calculate the standard Gibbs free energy change, ΔG , in kJ for reaction 1 at 25 °C. ETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON o\nmo–l1 = .............................. kJ [3] ΔG\nOD\n(b) Carbon disulfide reacts with chlorine to form tetrachloromethane, as shown in reaction 2.\no\nmo–l1 CCl + S Cl ΔH = –261.6 kJ + 3Cl reaction 2 CS\n2 2 4 2 2\nNIGRAM\no\nK–1 mol–1 ΔS = –365.5 J\nSIHT\nCalculate the maximum temperature, in K, for reaction 2 to be feasible.\nNI\nETIRW\nTON\nOD\ntemperature = .............................. K [2]\nNIGRAM\n[Total: 5]\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-mj-42-q03-fddeaee3f6.pdf" }, { "id": "9701-2024-mj-42-q04", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-42-q04-p01-eba25975ed.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-42-q04-p02-dfd81d219b.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-42-q04-p03-2eeb5cf876.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:1)(cid:8)(cid:44)\n4 (a) (i) Explain why transition elements have variable oxidation states.\nSIHT\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [1]\nTON\norbital in Fig. 4.1. (ii) Sketch the shape of a 3d\nOD z2\nz\nNIGRAM\ny\nSIHT\nx\nNI\nETIRW\nTON Fig. 4.1\n[1]\nOD\n]2+(aq) O) are reacted separately with an excess of solution A and with an (b) Samples of [Cu(H\n2 6\nexcess of solution B.\nNIGRAM\n]2+(aq) O) with solution A is a precipitation reaction. The reaction of [Cu(H\n2 6\n]2+(aq) SIHT O) with solution B is a ligand substitution reaction. The reaction of [Cu(H\n2 6\nNI\nSuggest a possible identity for solution A and for solution B. Give relevant observations and\nETIRW\nthe formula of the copper‑containing product for each reaction.\nTON\nsolution A ..................................................................................................................................\nOD\nobservations .............................................................................................................................\nformula of the copper‑containing product .................................................................................\nNIGRAM\nsolution B ..................................................................................................................................\nSIHT\nobservations .............................................................................................................................\nNI\nETIRW formula of the copper‑containing product .................................................................................\n[3]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n]+ (c) Solutions containing the [Ag(NH ) complex are colourless.\nSIHT 3 2\nNI Explain why this complex is colourless.\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n............................................................................................................................................. [2]\nNIGRAM\n(d) Two bidentate ligands are shown in Fig. 4.2.\nSIHT\ndpys\nen NI\nETIRW S\nTON\nH N NH N N\nOD 2 2\nFig. 4.2\nNIGRAM\nExplain what is meant by a bidentate ligand.\nSIHT ...................................................................................................................................................\nNI\n....................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-mj-42-q04-18e0aced6a.pdf" }, { "id": "9701-2024-mj-42-q05", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-42-q05-p01-0bfdeaa7ed.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-42-q05-p02-5f3b62fb98.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:2)(cid:1)(cid:44)\n5 (a) Nitrosyl chloride, NOCl, can be formed by the reaction between nitrogen m onoxide and\nSIHT\nchlorine, as shown.\nNI\nETIRW\n2NOCl 2NO + Cl\n2\nTON The initial rate of this reaction is investigated, starting with dif ferent concentrations of NO and\n. The results obtained are shown in Table 5.1. Cl\nOD 2\nTable 5.1\ndm–3 m–3 dm–3 min–1 experiment [NO] / mol [Cl ] / mold initial rate / mol\nNIGRAM 2\n10–2 1 0.0250 0.0150 3.68 ×\nSIHT 10–1 2 0.0750 0.0150 3.32 ×\nNI 10–1 3 0.0500 0.0600 5.89 ×\nETIRW\n(i) Use the data in Table 5.1 to deduce the rate equation for this reaction. TON\nOD\nExplain your reasoning.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [3] OD\n(ii) Use your rate equation from (a)(i) and the data from experiment 1 to calculate the rate\nconstant, k, for this reaction. Include the units of k.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nk = .............................. units ..............................\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) NO Cl is another compound containing nitrogen, oxygen and chlorine.\nSIHT 2\nNI Cl can undergo homolytic fission to release chlorine radicals which can In sunlight, NO\n2\nETIRW\n, into oxygen. catalyse the conversion of ozone, O\n3\nTON Complete the mechanism for this process.\nOD\nCl .................... + .................... initiation (homolytic fission) NO\n2\n.................... + .................... propagation step 1 .................... + O\n3\nNIGRAM\n.................... + .................... propagation step 2 .................... + ....................\n[2]\nSIHT\n(c) Ozone reacts with nitrogen dioxide, as shown.\nNI\nETIRW\nN O + O + 2NO O\n2 5 2 3 2\nTON\nThe rate of reaction is first order with respect to O and first order with respect to NO .\n3 2\nOD\nSuggest equations for a two‑step mechanism for this reaction.\nstep 1 ........................................................................................................................................\nNIGRAM\nstep 2 ........................................................................................................................................\n[2]\nSIHT\n[T", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-mj-42-q05-ae1f8ffb5f.pdf" }, { "id": "9701-2024-mj-42-q06", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2024-mj-42-q06-p01-80b27508df.png", "9701-topic-25-equilibria/assets/9701-2024-mj-42-q06-p02-afaece540b.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q06", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:5)(cid:10)(cid:2)(cid:3)(cid:44)\n6 (a) Aqueous solutions of methanoic acid, HCOOH, and propanoic acid, CH CH COOH, are\nSIHT 3 2\nmixed together.\nNI\nETIRW\nAn equilibrium is set up between two conjugate acid–base pairs.\nTON (i) Define conjugate acid–base pair.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nof HCOOH is 3.75 and of CH CH COOH is 4.87. (ii) The pK\na 3 2\nSIHT Complete the equation for the Brønsted–Lowry equilibrium between the stronger of\nthese two acids and water.\nNI\nETIRW\nO ..................................... + ..................................... ..................................... + H\n2\n[1]\nTON\nOD , for butanoic acid, (b) (i) Write an expression for the acid dissociation constant, K\na\nCH CH COOH. CH\n3 2 2\nNIGRAM K =\na\nSIHT\n[1]\nNI\nETIRW\n(ii) The pK of CH CH CH COOH is 4.82.\na 3 2 2\nTON CH CH COOH(aq) has a pH of 3.25. A solution of CH\n3 2 2\nOD\ndm–3, of CH CH CH COOH in this solution. Calculate the concentration, in mol\n3 2 2\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\ndm–3 concentration of CH CH CH COOH = .............................. mol [2]\n3 2 2\nNIGRAM\n(c) (i) Define buffer solution.\n...........................................................................................................................................\nSIHT\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [2]\nTON\nNIGRAM\n(ii) A buffer solution containing a mixture of CH COOH and CH COONa is prepared as\nSIHT 3 3\nfollows.\nNI\nETIRW cm3 cm3 dm–3 of CH COOH is mixed with 400 of 0.125 mol CH COONa. A solution of 600\n3 3\nTON 10–5 dm–3. of CH COOH is 1.78 × mol The buffer solution has pH 5.70. The K\na 3\nOD\ndm–3, of CH COOH used. Calculate the initial concentration, in mol\n3\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\ndm–3 concentration of CH COOH = .............................. mol [3]\n3\nNIGRAM (d) A fuel cell is an electrochemical cell that can be used to generate electrical energy by using\noxygen to oxidise a fuel.\nSIHT\nMethanoic acid, HCOOH, is being investigated as a fuel in fuel cells.\nNI\nETIRW When the cell operates, HCOOH is oxidised to carbon diox ide.\n4H+ 4e– 2H O. + + The half‑equation for the reaction at the cathode is: O TON\n2 2\nOD\nIn this fuel cell, the overall cell reaction is the same as that for the complete combustion of\nHCOOH.\n(i) Deduce the half‑equation for the reaction at the anode.\nNIGRAM\nSIHT\nNI ...................................................................................................................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2024-mj-42-q06-03e852348b.pdf" }, { "id": "9701-2024-mj-42-q07", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-mj-42-q07-p01-bb3219a998.png", "9701-topic-36-organic-synthesis/assets/9701-2024-mj-42-q07-p02-6db873444a.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:6)(cid:1)(cid:2)(cid:5)(cid:44)\n7 Methyl red can be synthesised as shown in Fig. 7.1.\nSIHT\nP NI\nCOOH\nETIRW\nTON\nOD NO\n2\nNIGRAM\nstep 1\nSIHT\nQ\nNI\nETIRW\nTON\nOD\nNIGRAM\nstep 2\nSIHT\nNI R S\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nstep 3\nTON\nmethyl red\nOD\nCOOH\nNIGRAM\nN N N\nSIHT\nNI\nFig. 7.1\nETIRW\nTON\nNIGRAM\n(a) (i) Give the systematic name of P.\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\n(ii) P can be synthesised as shown in Fig. 7.2.\nTON\nP\nOD CH COOH\n3\nNIGRAM\nNO NO\n2 2\nSIHT\nFig. 7.2 NI\nETIRW\nSuggest reagents and conditions for this reaction.\nTON\n..................................................................................................................................... [1]\nOD\n(iii) A student attempts to synthesise P by an alternative route, as shown in Fig. 7.3.\nCompound T is the major product in this reaction rather than P.\nNIGRAM\nT\nCOOH COOH\nSIHT\nNI\nconc. HNO\nETIRW 3\nTON\nconc. H SO\n2 4\nOD\nNO\n2\nNIGRAM Fig. 7.3\nExplain why T is the major product in this reaction.\nSIHT\n........................................................................................................................................... NI\nETIRW\n..................................................................................................................................... [1]\nTON\n(b) S reacts in a similar way to phenol in step 3.\nOD\n(i) Draw the structures of Q, R and S in the boxes in Fig. 7.1. [3]\n(ii) Suggest reagents and conditions for steps 1 and 2 in Fig. 7.1.\nNIGRAM\nstep 1 ................................................................................................................................\nSIHT\nstep 2 ................................................................................................................................\nNI\n[3]\nETIRW\n[Total: 9]\nTON", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-mj-42-q07-4a057df80e.pdf" }, { "id": "9701-2024-mj-42-q08", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-42-q08-p01-422bbef03e.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-42-q08-p02-37581edc67.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-42-q08-p03-e33c9b3ee7.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:6)(cid:1)(cid:2)(cid:7)(cid:44)\n8 (a) State the relative basicities of phenylamine, C H NH , benzylamine, C H CH NH , and\nSIHT 6 5 2 6 5 2 2\n, in aqueous solution. Explain your answer. ammonia, NH\n3\nNI\nETIRW\n............................... ............ > ........................................... > ...........................................\nmost basic least basic\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\n[3]\nETIRW\n(aq) is added to separate samples of C H NH and benzene, C H . (b) An excess of Br\nTON 2 6 5 2 6 6\nOD H NH reacts readily with Br (aq) to form organic product M. (i) C\n6 5 2 2\nState the expected observations for this reaction. Draw the structure of M.\nNIGRAM observations ......................................................................................................................\nstructure of M\nSIHT\nNI\nETIRW\nTON\nOD\n[2]\nH does not react with Br (aq). (ii) C\n6 6 2 NIGRAM\n(aq) reacts with C H NH but not with C H . Suggest why Br\n2 6 5 2 6 6\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nH CONH , is a much weaker base than ammonia, NH . (c) Explain why benzamide, C\n6 5 2 3\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) C H CONH is formed by reacting benzoyl chloride, C H COCl, with NH .\nSIHT 6 5 2 6 5 3\nNI H COCl with NH . Complete the mechanism in Fig. 8.1 for the reaction of C\n6 5 3\nETIRW\nInclude all relevant lone pairs of electrons, curly arrows, charges and dipoles. Draw the\nTON structure of the organic intermediate.\nOD\norganic intermediate\nNIGRAM O\nC\nSIHT\nCl NI\nETIRW\nTON\nNH\n3", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2024-mj-42-q08-f69ab3c1dc.pdf" }, { "id": "9701-2024-mj-42-q09", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_42.pdf?download=true", "source_pages": [ 19, 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2024-mj-42-q09-p01-1c83252c17.png", "9701-topic-37-analytical-techniques/assets/9701-2024-mj-42-q09-p02-b361c330fa.png", "9701-topic-37-analytical-techniques/assets/9701-2024-mj-42-q09-p03-eef82424df.png", "9701-topic-37-analytical-techniques/assets/9701-2024-mj-42-q09-p04-04e261c3e2.png", "9701-topic-37-analytical-techniques/assets/9701-2024-mj-42-q09-p05-93b1715a9e.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-42-q09", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:6)(cid:4)(cid:2)(cid:6)(cid:1)(cid:2)(cid:10)(cid:44)\n9 (a) Explain why trichloroethanoic acid, CCl COOH, is more acidic than ethanoic acid, CHCOOH.\nSIHT 3 3\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\n. (b) Acyl chlorides are formed by reacting carboxylic acids with thionyl chloride, SOCl\n2\n), can be prepared by reacting ethanedioic acid, (COOH) , (i) Ethanedioyl chloride, (COCl\n2 2\nNIGRAM . with an excess of SOCl\n2\nWrite an equation for this reaction.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nare reacted separately with an excess of warm acidified KMnO (aq) (ii) Samples of (COCl )\n2 4\nNCH CH NH . and with H\nTON 2 2 2 2\nOD HNCH CH NH has the molecular The carbon‑containing product from the reaction with\n2 2 2 2\nH N O . formula C\n4 6 2 2\nComplete the boxes in Fig. 9.1 to suggest the structure of the carbon‑containing product\nNIGRAM in each reaction.\nwith warm with\nSIHT\nacidified H KMnO NCH CH NH (aq)\n2 2 2 2 4\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nFig. 9.1\n[2] NI\nETIRW\nwith ethane‑1,2‑diol, (iii) A polyester can be synthesised from the reaction of (COCl )\n2\nCH OH. HOCH TON\n2 2\nOD\nDraw two repeat units of the polymer formed.A ny functional groups should be displayed.\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\nNIGRAM\n(c) Compound H, C H O , reacts with alkaline I (aq) to form yellow precipitate J but does not\nSIHT 6 10 3 2\nCO (aq). react with Na\n2 3\nNI\nETIRW\n1H) NMR spectrum of H in CDCl is shown in Fig. 9.2. The proton (\n3\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n1.0 4.0 3.0 2.0\nTON\n/ ppm chemical shift δ\nOD\nFig. 9.2\nTable 9.1\nNIGRAM\nchemical shift range\nenvironment of proton example\nSIHT δ / ppm\nNI , –CH –, >CH– 0.9–1.7 alkane –CH\n3 2 ETIRW\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\nTON\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\nOD\n–O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0 NIGRAM\naldehyde HCOR 9.3–10.5\nSIHT\nalcohol ROH 0.5–6.0\nNI\nphenol Ar–OH 4.5–7.0\nETIRW\ncarboxylic acid RCOOH 9.0–13.0\nTON\nalkyl amine R–NH– 1.0–5.0\nOD\n3.0–6.0 aryl amine Ar–NH\n2\namide RCONHR 5.0–12.0\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(i) Identify yellow precipitate J.\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\n(1H) NMR spectrum of H, C H O . (ii) Complete Table 9.2 for the proton\n6 10 3\nTON\nTable 9.2\nO", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2024-mj-42-q09-8f2a77f180.pdf" }, { "id": "9701-2024-mj-43-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2024-mj-43-q01-p01-d413943350.png", "9701-topic-27-group-2/assets/9701-2024-mj-43-q01-p02-6a68ba2ed0.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "Describe the trend in the solubility of the hydroxides of magnesium, calcium and 1 (a) (i)\nstrontium.\nExplain your answer.\n.......................................... > .......................................... > ..........................................\nmost soluble least soluble\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[4]\nSuggest the variation in pH of saturated solutions of the hydroxides of magnesium, (ii)\ncalcium and strontium.\nExplain your answer.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n, is a strong base. Barium hydroxide, Ba(OH) (b)\n2\ncm3 solution of Ba(OH) with a pH of 12.2 is made by dissolving Ba(OH) in distilled A 250.0\n2 2\nwater.\nrequired to make this solution. Calculate the mass of Ba(OH)\n2\nShow your working.\n: Ba(OH) , 171.3] [M\nr 2\nmass of Ba(OH) = .............................. g [4]\n2\n10–6 dm–3 iron(II) × The solubility of hydroxide, Fe(OH) , is 5.85 mol at 298 K. (c)\n2\n, of Fe(OH) . Write the expression for the solubility product, K (i)\nsp 2\nK =\nsp\n[1]\nCalculate the value of K of Fe(OH) . Include its units. (ii)\nsp 2\nK = ..............................\nsp\nunits = ..............................\n[2]\n[Total: 12]", "pdf_path": "9701-topic-27-group-2/print/9701-2024-mj-43-q01-31eafc5f70.pdf" }, { "id": "9701-2024-mj-43-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 4, 5, 6 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-43-q02-p01-c3450b9b5f.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-43-q02-p02-e5fd214ce8.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-43-q02-p03-221bed7004.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Define transition element. 2 (a) (i)\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nExplain why transition elements can form complex ions. (ii)\n...........................................................................................................................................\n..................................................................................................................................... [1]\n+ ion are degenerate. The 3d orbitals in an isolated Ag (b)\nDefine degenerate d orbitals. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\norbital in Fig. 2.1. Sketch the shape of a 3d (ii)\nxy\ny\nz\nx\nFig. 2.1\n[1]\nTollens’ reagent can be used to distinguish between aldehydes and ketones. Tollens’ reagent (c)\n) ]OH, which can be prepared in a two-step process. contains [Ag(NH\n3 2\nto form Ag O as a brown Aqueous NaOH is added dropwise to aqueous AgNO step 1\n3 2\nprecipitate.\nis added dropwise to Ag O to form a colourless solution containing Aqueous NH step 2\n3 2\n) ]OH. [Ag(NH\n3 2\n) ]OH. Construct equations for each of the steps in the preparation of [Ag(NH\n3 2\nstep 1 ........................................................................................................................................\nstep 2 ........................................................................................................................................\n[2]\n]+. Name the shape of the complex ion [Ag(NH ) (d)\n3 2\nState the bond angle for H-N-Ag and for N-Ag-N.\nshape ........................................................................................................................................\nbond angle for H-N-Ag = .............. °\nbond angle for N-Ag-N = .............. °\n[2]\nAn electrochemical cell uses Ag O as the positive electrode and Zn as the negative electrode (e)\n2\nimmersed in an alkaline electrolyte.\nThe overall cell reaction is shown.\nAg O + Zn + H O 2Ag + Zn(OH)\n2 2 2\nComplete the half-equation for the reaction at each electrode.\nat the positive electrode Ag O + .....................................................................................\n2\nat the negative electrode Zn + ........................................................................................\n[2]\nCoordination polymers are made when a bidentate ligand acts as a bridge between different (f)\nmetal ions.\nRu3+(aq) Under certain conditions and the bidentate ligand dps ca", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-mj-43-q02-9857c0024b.pdf" }, { "id": "9701-2024-mj-43-q03", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 7, 8 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-43-q03-p01-e236e7d1b7.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-mj-43-q03-p02-6ff08c236b.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "When a sample of hydrated lithium ethanedioate, Li C O •H O, is gently heated, two gaseous 3 (a)\n2 2 4 2\nproducts are formed and a white solid residue remains.\n(aq). A gas is produced that turns limewater milky. The residue is added to HNO\n3\nC O •H O. Complete the equation for the decomposition of Li\n2 2 4 2\nC O •H O .................................... + .................................... + .................................... Li\n2 2 4 2\n[1]\nThe trend in the decomposition temperatures of the Group 2 ethanedioates is similar to that (b)\nof the Group 2 nitrates.\nO and BaC O will decompose at the temperature. Explain Suggest which of CaC lower\n2 4 2 4\nyour answer.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\niron(III) ethanedioate, K [Fe(C O ) ], dissolves in water to form a green solution. Potassium (c)\n3 2 4 3\nExplain why transition elements can form coloured complexes.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\niron(III) compound K [Fe(C O ) ] decomposes on heating to form a mixture The anhydrous (d)\n3 2 4 3\n[Fe(C O ) ], K C O and CO . of K\n2 2 4 2 2 2 4 2\n[Fe(C O ) ]. Complete the equation for the decomposition of K\n3 2 4 3\n[Fe(C O ) ] ............ K [Fe(C O ) ] + ............ K C O + ............ CO .............. K\n3 2 4 3 2 2 4 2 2 2 4 2\n[1]\n]3– The [Fe(C O ) complex ion shows stereoisomerism. (e)\n2 4 3\nComplete the three-dimensional diagrams in Fig. 3.1 to show the stereoisomers of two\n]3–. O ) [Fe(C\n2 4 3\n2– O ligand can be represented using O. The C O\n2 4\nisomer 2 isomer 1\nFe Fe\nFig. 3.1\n[2]\nBuffer solutions are used to regulate pH. (f)\n– O ions acts as a buffer Write equatio", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-mj-43-q03-aeefc78f38.pdf" }, { "id": "9701-2024-mj-43-q04", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 9, 10, 11 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-mj-43-q04-p01-a11b820ae5.png", "9701-topic-23-chemical-energetics/assets/9701-2024-mj-43-q04-p02-20f94d2409.png", "9701-topic-23-chemical-energetics/assets/9701-2024-mj-43-q04-p03-9eae76802d.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "Eo, Define standard electrode potential, including a description of standard conditions. 4 (a)\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\no Ag+(aq)/Ag(s) of the electrode. An electrochemical cell is set up to measure E (b) (i)\nDraw a labelled diagram of this electrochemical cell.\nInclude all necessary substances. It is necessary to state conditions used. not\n[3]\n+(aq) than A separate electrochemical cell is set up using a concentration of Ag (ii) lower\nthat used in (b)(i).\nAg+(aq)/Ag(s) electrode would change Suggest how the electrode potential, E, for the\nEo value. Explain your answer. from its\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\no\nΔH . Define enthalpy change of solution, (c)\nsol\n...................................................................................................................................................\n............................................................................................................................................. [1]\nSome relevant energy changes for AgNO are shown in Table 4.1. (d)\n3\nTable 4.1\nmol–1 energy change value / kJ\nenthalpy change of solution of AgNO (s) +22.6\n3\nenthalpy change of hydration of silver ions –475\nenthalpy change of hydration of nitrate ions –314\nComplete the energy cycle in Fig. 4.1 to show the relationship between the lattice energy, (i)\no\nΔH , of AgNO (s) and the energy changes shown in Table 4.1.\n3 latt\nInclude state symbols for all the species.\nAgNO (s)\n3\nFig. 4.1\n[2]\no\nΔH , of AgNO (s). Calculate the lattice energy, (ii)\n3 latt\no\nmol–1 ΔH = .............................. kJ [1]\nlatt\nSuggest the trend in the magnitude of the lattice energies of the metal nitrates, NaNO (s), (e)\n3\n) (s) and RbNO (s). Mg(NO\n3 2 3\nExplain your answer.\n.......................................... .......................................... ..........................................\nmost exothermic least exothermic\n...................................................................................................................................................\n...................................................................................................................................................\n.....................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-mj-43-q04-d4bf056780.pdf" }, { "id": "9701-2024-mj-43-q05", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-43-q05-p01-487fa19f7a.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-mj-43-q05-p02-572d9bac95.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q05", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "2–, In aqueous solution, persulfate ions, S O react with iodide ions, as shown in reaction 1. 5 (a)\n2 8\n2I– 2– 2– I O + 2SO + reaction 1 S\n2 8 4 2\nThe rate of reaction 1 is investigated.\n2– O is mixed with a large excess of iodide ions of known concentration. The A sample of S\n2 8\ngraph in Fig. 5.1 shows the results obtained.\n0.900\n0.800\n0.700\n0.600\n0.500\ndm–3 2–] [S O / mol 0.400\n2 8\n0.300\n0.200\n0.100\n0.000\n0 25 50 75 100 125 150 175 200\n/ min time\nFig. 5.1\nUse Fig. 5.1 to determine the initial rate of reaction 1. Show your working. (i)\n–3 min–1 [1] rate = .............................. mol dm\n[I–]. 2–] O The rate equation for reaction 1 is rate = k [S (ii)\n2 8\nSuggest why a large excess of iodide ions allows the rate constant to be determined\nfrom the half-life in this investigation.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nFe2+ 2–, The reaction of persulfate ions, S O with iodide ions is catalysed by ions. (b)\n2 8\nFe2+ catalyses reaction 1. Write equations to show how two\nequation 1 .................................................................................................................................\nequation 2 .................................................................................................................................\n[2]\nDescribe the effect of an increase in temperature on the rate constant and the rate of (c)\nreaction 1.\n...................................................................................................................................................\n............................................................................................................................................. [1]\n2–, O react with hydrogen ions, as shown in reaction 2. In aqueous solution, thiosulfate ions, S (d)\n2 3\n2H+ 2– O + SO + S + H O reaction 2 S\n2 3 2 2\n[H+] 2–] O and zero order with respect to The rate of reaction is first order with respect to [S\n2 3\nunder certain conditions.\n10–2 s–1. × The rate constant, k, for this reaction is 1.58\n, for reaction 2. Calculate the half-life, t\n1\n2\n= .............................. s [1] t\n1\n2\nThe compound nitrosyl bromide, NOBr, can be formed as shown in reaction 3. (e)\nreaction 3 2NO(g) + Br (g) 2NOBr(g)\n2\n]. The rate is first order with respect to [NO] and first order with respect to [Br\n2\nThe reaction mechanism has two steps.\nSuggest equations for the steps of this mechanism. State which is the rate-determining two\nstep.\nstep 1 ........................................................................................................................................\nstep 2 ..............................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-mj-43-q05-8f0848e278.pdf" }, { "id": "9701-2024-mj-43-q06", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2024-mj-43-q06-p01-18ef9a94a1.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-43-q06-p02-7fa24cd084.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-43-q06-p03-dfb53ff02f.png", "9701-topic-30-hydrocarbons/assets/9701-2024-mj-43-q06-p04-45424c40de.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q06", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "State what is meant by partition coefficient, K . 6 (a) (i)\npc\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\n, for a compound, X, between carbon disulfide, CS , and The partition coefficient, K (ii)\npc 2\nwater is 10.5.\ncm3 in a volumetric flask. 1.85 g of is dissolved in water and made up to 100.0 X\ncm3 cm3 of this aqueous solution is shaken with 25.0 of CS . 40.0\n2\nThe mixture is left to reach equilibrium.\nlayer. Calculate the mass of X, in g, extracted into the CS\n2\nmass of = .............................. g [2] X\nH has many structural isomers. Four suggested structures of C H are The compound C (b)\n6 6 6 6\nshown in Fig. 6.1.\nKekulé benzene Dewar benzene Ladenburg benzene delocalised benzene\nFig. 6.1\nsp2 Using Fig. 6.1, complete Table 6.1 to predict the number of carbon atoms that have sp,\nsp3 hybridisation in Kekulé benzene, Dewar benzene and Ladenburg benzene. and\nTable 6.1\nsp2 sp3 C H structure sp hybridised hybridised hybridised\n6 6\nKekulé benzene\nDewar benzene\nLadenburg benzene\n[2]\nDescribe the shape of delocalised benzene. (c)\nInclude the geometry of each carbon, the C-C-H bond angle and the type of bond(s) between\nthe carbon atoms and between the carbon and hydrogen atoms.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [2]\nH . Suggest why Dewar benzene and Ladenburg benzene are unstable isomers of C (d)\n6 6\n...................................................................................................................................................\n............................................................................................................................................. [1]\n1H) NMR spectrum for Complete Table 6.2 to predict the number of peaks in the proton ( (e)\nDewar benzene, Ladenburg benzene and delocalised benzene.\nTable 6.2\nnumber of peaks\nDewar benzene\nLadenburg benzene\ndelocalised benzene\n[1]\nThe reaction of phenylethanone with 1,4-dibromobutane, BrCH CH CH CH Br, in th", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2024-mj-43-q06-975b5847fe.pdf" }, { "id": "9701-2024-mj-43-q07", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 18, 19, 20 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-mj-43-q07-p01-c953c75bdc.png", "9701-topic-36-organic-synthesis/assets/9701-2024-mj-43-q07-p02-7d35ffd23b.png", "9701-topic-36-organic-synthesis/assets/9701-2024-mj-43-q07-p03-706c12a1cc.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "Four esters, A, B, and D, with the molecular formula C H O are shown in Fig. 7.1. 7 C\n6 12 2\nA B\nO O\nO O\nC D\nO\nO\nO\nO\nFig. 7.1\nGive the systematic name of ester A. (a)\n............................................................................................................................................. [1]\nA mixture of these esters, A, B, and D, is analysed by gas–liquid chromatography. (b) C\nThe chromatogram produced is shown in Fig. 7.2. The number above each peak represents\nthe area under the peak.\nThe area under each peak is proportional to the mass of the respective ester in the mixture.\nester B\ndetector\nresponse\n52 ester A\nester D 38\n25\n14\nester C\n/ min time\nFig. 7.2\nState what is meant by retention time. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nCalculate the percentage by mass of ester in the original mixture. (ii) D\npercentage by mass of ester = .............................. % [1] D\n(1H) Separate samples of the esters, A, B, and D, are analysed using proton NMR and (c) C\ncarbon-13 NMR spectroscopy.\nComplete Table 7.1 to show the number of peaks in each NMR spectrum for esters (i) B\nand C.\nTable 7.1\nnumber of peaks in number of peaks in\nester\n(1H) NMR spectrum carbon-13 NMR spectrum proton\nB\nC\n[2]\nIdentify of the esters from A, B, and that have at least one triplet peak in their (ii) all C D\n1H) NMR spectrum. proton (\n..................................................................................................................................... [1]\nQuestion 7 continues on page 20.\nCompound F, C H O , shows stereoisomerism and effervesces with Na CO (aq). (d)\n6 8 3 2 3\nI (aq) to form yellow precipitate and compound H. Compound reacts with alkaline G F\n2\nLiAl to form compound J, C H O . Compound reacts with H F\n4 6 12 2\nCl SOCl to form compound K, C H O . Compound reacts with F\n2 6 7 2\nCompound reacts with propan-2-ol to form compound L. K\nDraw the structures of compounds F, G, H, J, and in the boxes in Fig. 7.3. K L\nF, C H O G H\n6 8 3\nalkaline\nI (aq)\n2 +\nSOCl\n2\nLiAl H\n4\nCl K, C H O\n6 7 2\nJ, C H O\n6 12 2\npropan-2-ol\nL\nFig. 7.3\n[6]\n[Total: 12]", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-mj-43-q07-c3fb7ed0dd.pdf" }, { "id": "9701-2024-mj-43-q08", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 21, 22 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-43-q08-p01-0d5335a2f0.png", "9701-topic-34-nitrogen-compounds/assets/9701-2024-mj-43-q08-p02-1efee5409c.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Neotame is an artificial sweetener added to some foods. 8\nneotame\nH O\nO N\nN\nO O H\nOH\nFig. 8.1\nState the number of chiral carbon atoms in a molecule of neotame. (a) (i)\n..................................................................................................................................... [1]\nNeotame contains the arene functional group. (ii)\nIdentify all the functional groups present in neotame. other\n...........................................................................................................................................\n..................................................................................................................................... [2]\nNeotame reacts with an excess of hot NaOH(aq) to form three organic products. (b)\nState the types of reaction that occur when neotame reacts with hot NaOH(aq). (i) two\n1 .........................................................................................................................................\n2 .........................................................................................................................................\n[2]\nneotame\nH O\nO N\nN\nO O H\nOH\nFig. 8.1\nDraw the structures of the organic products formed from the reaction of neotame (ii) three\nwith an excess of hot NaOH(aq).\n[3]\n[Total: 8]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2024-mj-43-q08-49c4132bee.pdf" }, { "id": "9701-2024-mj-43-q09", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_43.pdf?download=true", "source_pages": [ 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_43.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-43-q09-p01-7e323f6ade.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-43-q09-p02-41b8ad7799.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-43-q09-p03-9d77054569.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-43-q09-p04-263930e0a9.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-mj-43-q09-p05-ac45e38efc.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-43-q09", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Samples of phenol, C H OH, are reacted separately with sodium and with dilute nitric acid. 9 (a)\n6 5\nphenol\nOH\nFig. 9.1\nH OH with Na. Write the equation for the reaction of C (i)\n6 5\n..................................................................................................................................... [1]\nDraw the structures of the major isomeric organic products formed in the reaction of (ii) two\n. phenol with dilute HNO\n3\n[1]\nSalicylic acid can be synthesised from phenol. (b)\nsalicylic acid\nCOOH\nOH\nFig. 9.2\nOne of the steps in this synthesis is the electrophilic substitution reaction of carbon dioxide\nO–. H with the phenoxide ion, C\n6 5\nO– H with CO . Complete the mechanism in Fig. 9.3 for the reaction of C\n6 5 2\nInclude all relevant curly arrows, dipoles and charges. Draw the structure of the organic\nintermediate.\norganic intermediate\nO\nC\nO\nO–\nCOO–\nO– + ............\nFig. 9.3\n[3]\nSome syntheses use Diels–Alder reactions, which normally involve a diene and an alkene (c)\nreacting together to form a cyclohexene.\nDraw curly arrows in Fig. 9.4 to complete the mechanism for the Diels–Alder (i) three\nreaction between buta-1,3-diene and ethene.\nethene buta-1,3-diene cyclohexene\n+\nFig. 9.4\n[1]\nAnother Diels–Alder reaction of buta-1,3-diene is shown in Fig. 9.5. (ii)\nPredict the product formed in this reaction.\n+\nFig. 9.5\n[1]\n[Total: 7]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n104 mol–1 × Faraday constant F = 9.65 C\n1023 mol–1 × Avogadro constant L = 6.022\n10–19 × electronic charge e = –1.60 C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n10–14 mol2 dm–6 × °C)) = 1.00 (at 298 K (25 ionic product of water K\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eH eN nR eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 9.621 0.571 enidoi 0.91 5.53 9.97 uL 71 lC 301 sT rB 711 tA rL 71 53 35 58 17 F I – – – 9\nmuiromrevil muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib muiluht cinesra 8.121 0.902 9.861 mT dM cM bS 0.41 0.13 9.47 sA 51 101 511 iB N P 51 33 15 38 96 – – 7\nmuinamreg muivorelf muimref nobrac muibre 2.702 3.761 7.811 mF nocilis eG nS bP 0.21 1.82 6.27 41 001 rE 411 dael lF iS C 28 41 23 05 86 nit 6 – –\nmuinietsnie muinimula muinohin muimloh muillaht muillag 4.402 9.461 muidni 8.411 aG norob hN oH 8.01 0.72 7.96 sE 31 nI 311 lA lT 18 31 13 94 B 76 99 5 – –\nmuicinrepoc muisorpsyd muinrofilac muimdac yrucrem 6.002 5.261 4.211 dC gH nC yD 4.56 nZ 21 fC 211 cniz 08 84 03 89 66 – –\nmuinegtneor stnemelE muilekreb muibret reppoc 9.701 0.791 9.851 uC gR gA uA 5.36 bT kB revlis 11 dlog 111 74 97 79 92 56 – –\nmuitdatsmrad muinilodag muidallap m", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2024-mj-43-q09-094720c5fa.pdf" }, { "id": "9701-2024-mj-51-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-51-q01-p01-ea23fb8bcf.png", "9701-experimental-skills/assets/9701-2024-mj-51-q01-p02-bdd1d5bef6.png", "9701-experimental-skills/assets/9701-2024-mj-51-q01-p03-023d5d06c6.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Titration can be used to determine the concentration of dissolved oxygen in samples of river water. 1\nThe procedure for the experiment is given.\n3 cm3 graduated syringes, A, B, C, and E, to collect five separate 30.0 Use five 50 cm D step 1\nsamples of river water.\ncm3 dm–3 manganese(II) of 0.220 mol sulfate, In the laboratory, carefully add 5.0 step 2\n(aq), into syringe and mix well. MnSO A\n4\ncm3 of alkaline aqueous potassium iodide into syringe and mix well. Add 5.0 A step 3\ncm3 of dilute sulfuric acid into syringe and mix well. Add 10.0 A step 4\ncm3 conical flask. Rinse syringe using Transfer the contents of syringe into a 150 A step 5 A\ncm3 of distilled water and add washings to the conical flask. 10\ndm–3 Carry out accurate titration of all the contents in the conical flask with 0.00200 mol step 6 one\nS O (aq), using starch indicator. aqueous sodium thiosulfate, Na\n2 2 3\nRepeat steps 2–6 for the samples in syringes B–E.\nAqueous sodium thiosulfate can be prepared from Na S O •5H O(s). (a)\n2 2 3 2\ncm3 S O •5H O(s) required to prepare 500.0 of Determine the mass, in g, of Na (i)\n2 2 3 2\ndm–3 Na S O (aq). 0.00200 mol\n2 2 3\nmass of Na S O •5H O(s) = .............................. g [1]\n2 2 3 2\ncm3 of Identify the piece of apparatus that should be used to prepare 500.0 (ii)\ndm–3 Na S O (aq) after the required mass of Na S O •5H O(s) has been 0.00200 mol\n2 2 3 2 2 3 2\nweighed out.\n..................................................................................................................................... [1]\n3. The graduations on each syringe are every 1.0 cm (b)\ncm3 of alkaline aqueous Calculate the percentage error in the measurement of 5.0 (i)\npotassium iodide by the syringe.\nShow your working.\npercentage error = .............................. [1]\n✓ Place tick ( ) in each row in Table 1.1 to show the effect, if any, of using a larger (ii) one\nvolume of alkaline aqueous potassium iodide.\nTable 1.1\ngreater effect no effect smaller effect\nuncertainty of the\nmeasurement\npercentage error of\nthe measurement\n[1]\nThe sample in the conical flask and the prepared solution of sodium thiosulfate are provided. (c)\nDescribe the following procedures for the experiment using syringe A.\nPreparing the clean burette before taking any readings. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nCarrying out the accurate titration in step 6. (ii) one\n..............................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-51-q01-83d3946d6d.pdf" }, { "id": "9701-2024-mj-51-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_51.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 11, 12 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-51-q02-p01-3e6e02f702.png", "9701-experimental-skills/assets/9701-2024-mj-51-q02-p02-c07ef7e654.png", "9701-experimental-skills/assets/9701-2024-mj-51-q02-p03-35546e04a4.png", "9701-experimental-skills/assets/9701-2024-mj-51-q02-p04-8844ab3f49.png", "9701-experimental-skills/assets/9701-2024-mj-51-q02-p05-8dcf6aa47b.png", "9701-experimental-skills/assets/9701-2024-mj-51-q02-p06-775d04f5ad.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "HCl The activation energy, E , for the reaction between dilute hydrochloric acid, (aq), and aqueous 2\nA\nS O (aq), can be determined by an initial rates method. sodium thiosulfate, Na\n2 2 3\n2NaCl 2HCl S O (aq) (aq) + H O(l) + S(s) + SO (g) (aq) + Na\n2 2 3 2 2\nThe solid sulfur formed is seen as a white suspension in the reaction mixture. The reactants are\nmixed and the time, t, for a fixed quantity of sulfur to be formed is recorded.\n1\n. A measure of the initial rate of the reaction is\nt\ndm–3 dm–3 HCl Na S O (aq) and 0.500 mol (aq) are supplied. Standard solutions of 0.100 mol\n2 2 3\nMeasurements are taken for a series of temperatures using the following procedure.\nA thermostatically controlled water bath is set up. step 1\n3 cm3 conical flask is labelled and a second 100 conical flask is labelled B. A 100 cm A step 2\ncm3 dm–3 of 0.100 mol Na S O (aq) is added to flask A. Flask is placed in the 10.00 A step 3\n2 2 3\nwater bath.\ncm3 dm–3 HCl of 0.500 mol (aq) is added to flask B. Flask is placed in the same 10 B step 4\nwater bath.\nWait for 10 minutes. step 5\nFlask is removed from the water bath and placed on a tile marked with a black cross. step 6 A\nThe contents of flask are added to flask and a timer started. step 7 B A\nThe timer is stopped when the black cross is no longer visible. The time is recorded. step 8\nSuggest a reason why it is necessary to wait for 10 minutes in step 5. (a)\n............................................................................................................................................. [1]\nThe procedure does not mention how a value for the temperature of the mixture during the (b)\nreaction is obtained.\nState the temperature measurements that should be taken and at which stage in the (i)\nprocedure they should be taken.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nState how to use the temperature measurements to determine an accurate value for the (ii)\ntemperature of the mixture during the reaction.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nA student carries out the procedure at three different temperatures and records the (c)\nmeasurements in Table 2.1.\nComplete Table 2.1. Record values for temperature to the nearest whole number and the\n1\nto decimal places. values for four\nt\nTable 2.1\n1\ns–1 °C temperature, T / time, t / s temperature, T / K /\nt\n15 176\n24 92\n32 62\n[2]\nA second student carries out the procedure at six different temperatures and analyses their (d)\ndata to give the results in Table 2.2.\nTable 2.2\n1 1\nK–1 / log\nT t c m\n0.00353 –2.43\n0.00336 ", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-51-q02-2ff38c57c6.pdf" }, { "id": "9701-2024-mj-52-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-52-q01-p01-b0c2f8727b.png", "9701-experimental-skills/assets/9701-2024-mj-52-q01-p02-8bb62511c2.png", "9701-experimental-skills/assets/9701-2024-mj-52-q01-p03-65c4c616b3.png", "9701-experimental-skills/assets/9701-2024-mj-52-q01-p04-6358b641fc.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:5)(cid:10)(cid:8)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Calcium carbonate, CaCO (s), decomposes when heated, as shown.\nSIHT 3\nNI (s) CaO(s) + CO (g) CaCO\n3 2 ETIRW\n, for the thermal decomposition of CaCO (s) cannot be The enthalpy change of reaction, ∆H\nr 3\nTON measured directly. Instead, a procedure involving two experiments is used. In each ex periment,\nthe enthalpy change of a different reaction is determined.\nOD\n∆H. The equation for the reaction in experiment 1 is shown.T he enthalpy change for this reaction is\n1\n(s) + 2HCl (aq) CaCl (aq) + H O(l) + CO (g) experiment 1 CaCO\nNIGRAM 3 2 2 2\n∆H. The equation for the reaction in experiment 2 is shown.T he enthalpy change for this reaction is\n2\nSIHT\nCaCl (aq) + H O(l) experiment 2 CaO(s) + 2HCl (aq)\n2 2 NI\nETIRW\nExperiment 1\nTON\n(s). step 1 Weigh a 0.0500 mol sample of powdered CaCO\n3\nOD\ncm3, dm–3 an excess, of 2.00 mol hydrochloric acid, HCl (aq), into a small step 2 Transfer 50.00\nglass beaker.\nNIGRAM step 3 Start a timer and measure the temperature of the HC (laq) in the beaker every 30 seconds\n1 minutes. for 2\n2\nSIHT\n(s) to the HCl (aq) in the beaker . Continue step 4 After 3 minutes add the sample of CaCO\n3\nmeasuring the temperature of the reaction mixture every 30 seconds for a further NI\nETIRW 5 minutes.\nExperiment 2 TON\nOD\n(s). Repeat experiment 1 using calcium oxide, CaO(s), instead of CaCO\n3\n(a) Suggest why the enthalpy change of reaction for the thermal decomposition of calcium\ncarbonate cannot be measured directly.\nNIGRAM\n............................................................................................................................................. [1]\nSIHT\n(s) to be weighed using a two-decimal-place balance (b) (i) Calculate the mass, in g, of CaCO\n3\nNI in step 1.\nETIRW\nTON\nOD\nNIGRAM\nmass of CaCO (s) = .............................. g [1]\n3\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(ii) Outline how a student should weigh by dif ference using a weighing boat in order to\nSIHT\n(s) added to HCl (aq) in the beaker. Draw a results determine the exact mass of CaCO\n3\nNI table, with appropriate headings, ready for the student to complete.\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n[2]\n(c) Identify which piece of apparatus should be used to measure the volume of HCl (aq) in step 2\nNIGRAM and give a reason for your choice.\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1] NI\nETIRW\n(d) Without making any changes to the ap", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-52-q01-73ef7ffdae.pdf" }, { "id": "9701-2024-mj-52-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-52-q02-p01-9084683d3e.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p02-077fa7a9cd.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p03-70f8a611b4.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p04-bd9fa6fa0b.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p05-9651546c6c.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p06-25f1b40f5b.png", "9701-experimental-skills/assets/9701-2024-mj-52-q02-p07-274bb1425d.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:2)(cid:10)(cid:7)(cid:6)(cid:5)(cid:10)(cid:8)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 This question is about an experiment to investigate the ef fect of temperature on the equilibrium\nSIHT\n, of the reaction shown. constant, K\n1\nNI\nETIRW Fe3+(aq) SCN–(aq) FeSCN2+(aq) +\nTON The data collected is used to determine the value of the enthalpy change of the reaction.\nOD\nFe(NO) (aq), is mixed with aqueous potassium To set up the equilibrium, aqueous iron(III) nitrate,\n3 3\nFeSCN2+(aq), have a red colour. thiocyanate, KSCN(aq). Aqueous iron thiocyanate ions,\nA colorimeter is used to measure the absorbance of the reaction mixture. A calibration graph can\nNIGRAM\nFeSCN2+(aq) in the reaction mixture. then be used to determine the concentration of\nSIHT Table 2.1 shows the solutions for the experiments.\nNI\nTable 2.1\nETIRW\ndm–3 solution ion concentration / mol TON\nOD SCN–(aq) A 0.00920\nSCN–(aq) 0.00200 B\nFe3+(aq) 0.00200 C\nNIGRAM\nFe3+(aq) 0.500 D\nSIHT\ncm3 of solution B from solution A. (a) Describe how you would prepare 100.0\nNI\nETIRW\nInclude a calculation of the volume of solution A required for the preparation of solution B.\nGive the name and capacity of any key apparatus that should be used.\nTON\nOD W rite your answer as a series of numbered steps.\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Before starting the experiment, solutions B and D are used to produce a calibration graph.\nSIHT\nKnown volumes of each solution are added together and the absorbance for each mixture is\nNI recorded. The calibration graph is shown in Fig. 2.1.\nETIRW\nThe concentration of solution D is much greater than the concentration of solution B in order\nTON that solution D is in excess. Suggest a reason why solution D is in excess.\nOD\n............................................................................................................................................. [1]\n1.2\nNIGRAM\nSIHT\n1.0\nNI\nETIRW\nTON 0.8\nOD\nrela", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-52-q02-b78a9e91a8.pdf" }, { "id": "9701-2024-mj-53-q01", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-53-q01-p01-ea23fb8bcf.png", "9701-experimental-skills/assets/9701-2024-mj-53-q01-p02-bdd1d5bef6.png", "9701-experimental-skills/assets/9701-2024-mj-53-q01-p03-023d5d06c6.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Titration can be used to determine the concentration of dissolved oxygen in samples of river water. 1\nThe procedure for the experiment is given.\n3 cm3 graduated syringes, A, B, C, and E, to collect five separate 30.0 Use five 50 cm D step 1\nsamples of river water.\ncm3 dm–3 manganese(II) of 0.220 mol sulfate, In the laboratory, carefully add 5.0 step 2\n(aq), into syringe and mix well. MnSO A\n4\ncm3 of alkaline aqueous potassium iodide into syringe and mix well. Add 5.0 A step 3\ncm3 of dilute sulfuric acid into syringe and mix well. Add 10.0 A step 4\ncm3 conical flask. Rinse syringe using Transfer the contents of syringe into a 150 A step 5 A\ncm3 of distilled water and add washings to the conical flask. 10\ndm–3 Carry out accurate titration of all the contents in the conical flask with 0.00200 mol step 6 one\nS O (aq), using starch indicator. aqueous sodium thiosulfate, Na\n2 2 3\nRepeat steps 2–6 for the samples in syringes B–E.\nAqueous sodium thiosulfate can be prepared from Na S O •5H O(s). (a)\n2 2 3 2\ncm3 S O •5H O(s) required to prepare 500.0 of Determine the mass, in g, of Na (i)\n2 2 3 2\ndm–3 Na S O (aq). 0.00200 mol\n2 2 3\nmass of Na S O •5H O(s) = .............................. g [1]\n2 2 3 2\ncm3 of Identify the piece of apparatus that should be used to prepare 500.0 (ii)\ndm–3 Na S O (aq) after the required mass of Na S O •5H O(s) has been 0.00200 mol\n2 2 3 2 2 3 2\nweighed out.\n..................................................................................................................................... [1]\n3. The graduations on each syringe are every 1.0 cm (b)\ncm3 of alkaline aqueous Calculate the percentage error in the measurement of 5.0 (i)\npotassium iodide by the syringe.\nShow your working.\npercentage error = .............................. [1]\n✓ Place tick ( ) in each row in Table 1.1 to show the effect, if any, of using a larger (ii) one\nvolume of alkaline aqueous potassium iodide.\nTable 1.1\ngreater effect no effect smaller effect\nuncertainty of the\nmeasurement\npercentage error of\nthe measurement\n[1]\nThe sample in the conical flask and the prepared solution of sodium thiosulfate are provided. (c)\nDescribe the following procedures for the experiment using syringe A.\nPreparing the clean burette before taking any readings. (i)\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\nCarrying out the accurate titration in step 6. (ii) one\n..............................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-53-q01-4c5a20d17d.pdf" }, { "id": "9701-2024-mj-53-q02", "subject": "9701", "year": 2024, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-may-june/9701_s24_qp_53.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 11, 12 ], "local_pdf": "_source-pdfs/2024-May-June/qp/9701_s24_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-mj-53-q02-p01-3e6e02f702.png", "9701-experimental-skills/assets/9701-2024-mj-53-q02-p02-c07ef7e654.png", "9701-experimental-skills/assets/9701-2024-mj-53-q02-p03-35546e04a4.png", "9701-experimental-skills/assets/9701-2024-mj-53-q02-p04-8844ab3f49.png", "9701-experimental-skills/assets/9701-2024-mj-53-q02-p05-8dcf6aa47b.png", "9701-experimental-skills/assets/9701-2024-mj-53-q02-p06-775d04f5ad.png" ], "answer": { "status": "pending", "id": "9701-2024-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "HCl The activation energy, E , for the reaction between dilute hydrochloric acid, (aq), and aqueous 2\nA\nS O (aq), can be determined by an initial rates method. sodium thiosulfate, Na\n2 2 3\n2NaCl 2HCl S O (aq) (aq) + H O(l) + S(s) + SO (g) (aq) + Na\n2 2 3 2 2\nThe solid sulfur formed is seen as a white suspension in the reaction mixture. The reactants are\nmixed and the time, t, for a fixed quantity of sulfur to be formed is recorded.\n1\n. A measure of the initial rate of the reaction is\nt\ndm–3 dm–3 HCl Na S O (aq) and 0.500 mol (aq) are supplied. Standard solutions of 0.100 mol\n2 2 3\nMeasurements are taken for a series of temperatures using the following procedure.\nA thermostatically controlled water bath is set up. step 1\n3 cm3 conical flask is labelled and a second 100 conical flask is labelled B. A 100 cm A step 2\ncm3 dm–3 of 0.100 mol Na S O (aq) is added to flask A. Flask is placed in the 10.00 A step 3\n2 2 3\nwater bath.\ncm3 dm–3 HCl of 0.500 mol (aq) is added to flask B. Flask is placed in the same 10 B step 4\nwater bath.\nWait for 10 minutes. step 5\nFlask is removed from the water bath and placed on a tile marked with a black cross. step 6 A\nThe contents of flask are added to flask and a timer started. step 7 B A\nThe timer is stopped when the black cross is no longer visible. The time is recorded. step 8\nSuggest a reason why it is necessary to wait for 10 minutes in step 5. (a)\n............................................................................................................................................. [1]\nThe procedure does not mention how a value for the temperature of the mixture during the (b)\nreaction is obtained.\nState the temperature measurements that should be taken and at which stage in the (i)\nprocedure they should be taken.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nState how to use the temperature measurements to determine an accurate value for the (ii)\ntemperature of the mixture during the reaction.\n...........................................................................................................................................\n..................................................................................................................................... [1]\nA student carries out the procedure at three different temperatures and records the (c)\nmeasurements in Table 2.1.\nComplete Table 2.1. Record values for temperature to the nearest whole number and the\n1\nto decimal places. values for four\nt\nTable 2.1\n1\ns–1 °C temperature, T / time, t / s temperature, T / K /\nt\n15 176\n24 92\n32 62\n[2]\nA second student carries out the procedure at six different temperatures and analyses their (d)\ndata to give the results in Table 2.2.\nTable 2.2\n1 1\nK–1 / log\nT t c m\n0.00353 –2.43\n0.00336 ", "pdf_path": "9701-experimental-skills/print/9701-2024-mj-53-q02-165372a3ae.pdf" }, { "id": "9701-2024-on-41-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2024-on-41-q01-p01-2bb0527963.png", "9701-topic-25-equilibria/assets/9701-2024-on-41-q01-p02-91815db93f.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q01", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n+) 2–), 1 (a) Disodium phosphate, (Na (HPO reacts with an acid to form monosodium phosphate,\nSIHT 2 4\nNa+(H –). PO\n2 4\nNI\nETIRW\n(i) Identify the ions that are a conjugate acid–base pair in this reaction, using the formulae\nof the species involved.\nTON\nconjugate acid conjugate base\nOD\n.................................................................... ....................................................................\n[1]\nNIGRAM\n(ii) Define buffer solution.\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [2]\nETIRW\n(Na+) Na+(H 2–) –) (HPO and PO can act (iii) Write two equations to show how a mixture of\n2 4 2 4 TON\nas a buffer solution.\nOD\nequation 1 .........................................................................................................................\nequation 2 .........................................................................................................................\nNIGRAM [2]\n(iv) Identify one inorganic ion that acts as a buffer in blood.\nSIHT\n..................................................................................................................................... [1] NI\nETIRW\n(b) Compound E is the hydroxide of a Group 2 element. Compound E is a strong alkali.\nTON\ncm3 of solution F. Solution F has a pH of 13.09 2.63 g of E is dissolved in water to make 250\nOD\nat 298 K.\ndm–3. (i) Show that the concentration of hydroxide ions in solution F is 0.123 mol\nNIGRAM\nSIHT\n[2]\nNI\nETIRW\ndm–3. (ii) Explain why the concentration of compound E in solution F is 0.0615 mol\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(iii) Use the concentration given in (ii) to identify compound E.\nNIGRAM\nSIHT\nNI\nETIRW\ncompound E ................................................................................................................ [1]\nTON\nNIGRAM\n(c) Compound E is much more soluble than magnesium hydroxide.\nSIHT\n0–4 dm–3 NI mol A saturated solution of magnesium hydroxide in water has a concentratioofn 1 .40 ×1\nETIRW\nat 298 K.\nTON , of magnesium hydroxide. Include units. Calculate the solubility product, K\nsp\nOD\nNIGRAM\nSIHT\nK = .............................. units .............................. [3]\nsp NI\nETIRW\n(d) Explain why compound E is much more soluble than magnesium hydroxide.\nTON\n...................................................................................................................................................\nOD\n.............", "pdf_path": "9701-topic-25-equilibria/print/9701-2024-on-41-q01-da2523b0a1.pdf" }, { "id": "9701-2024-on-41-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 4, 5, 6 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-on-41-q02-p01-a259759750.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-41-q02-p02-21e2983599.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-41-q02-p03-3e63048474.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n–, –, – 2 (a) Predict and explain the variation in enthalpy change of hydration for the ions F Cl Br\nSIHT\nI–. and\nNI\nETIRW\n...................................................................................................................................................\nTON ...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\n. (b) Fig. 2.1 shows an incomplete energy cycle involving calcium fluoride, CaF\n2\nNIGRAM\nCa2+(g) 2F–(g) + line B:\nSIHT\nprocess 1: enthalpy change of\nCa2+(g) formation of plus NI\nprocess 2: enthalpy change of\nETIRW twice the enthalpy change of\nhydration of calcium ions plus\nF–(g), formation of\ntwice the enthalpy change of\nCa2+(g) F–(g) + 2ΔH ΔH TON\nf f hydration of fluoride ions,\nCa2+(g) F–(g) OD ΔH + 2ΔH\n(g) line A: Ca(s) + F hyd hyd\n2\nprocess 3: enthalpy change of line D: NIGRAM\nformation of calcium fluoride,\nCaF (s) ΔH\nf 2\nSIHT\nNI process 4: enthalpy change of line C: CaF (s)\n2 ETIRW\nsolution of calcium fluoride,\nCaF (s) ΔH\nsol 2\nTON\nOD\nFig. 2.1\n(i) Complete line D. Include state symbols. [1]\nNIGRAM\n(ii) The value of the enthalpy change for process 1 can be calculated using the v alues of\nfive other enthalpy changes which are not referred to in Fig. 2.1.\nSIHT\nCa2+(g) 2F–(g) (g) + process 1: Ca(s) + F\n2\nNI\nETIRW\nIdentify these five other enthalpy changes, using either names or symbols.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ..................................................................................................................................... [2]\nNI\nETIRW\nTON\nNIGRAM\n(iii) Define lattice energy, ΔH .\nSIHT latt\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nof calcium (iv) Complete the expression to give the mathematical relationship between ΔH\nlatt\nfl", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-on-41-q02-eb2a8a652b.pdf" }, { "id": "9701-2024-on-41-q03", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-on-41-q03-p01-0e57666e91.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-on-41-q03-p02-283d2b1633.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-on-41-q03-p03-34494edce1.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n3 (a) A and B react together to give product AB.\nSIHT\nNI AB A + B\nETIRW\ndm–3, the rate of formation of AB When the concentrations of A and B are both 0.0100 mol\nTON 10–4 dm–3 s–1. dm–3, mol When the concentrations of A and B are both 0.0200 mol is 7.62 ×\n10–3 dm–3 s–1. mol the rate of formation of AB is 3.05 ×\nOD\n(i) Complete the three possible rate equations that are consistent with these data.\nrate = .................................................................................................................................\nNIGRAM\nrate = .................................................................................................................................\nSIHT\nrate = .................................................................................................................................\nNI\n[2]\nETIRW\n(ii) Choose one of the rate equations you have written in (i), and calculate the value of the\nTON\nrate constant, k. Include the units of k.\nOD\nNIGRAM\nk = .............................. units .............................. [2]\nSIHT\n, of this reaction (iii) Explain why it is not possible to calculate a value for the half-life, t NI 1\nETIRW 2\nusing the value of the rate constant k calculated in (ii) and the equation k = 0.693 / t .\n1\n2\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Catalysts may be homogeneous or heterogeneous.\nSIHT\nNI from the (i) Identify two metals that act as heterogeneous catalysts in the removal of NO\n2\nETIRW\nexhaust gases of car engines.\nTON ............................................................... and .............................................................. [1]\nOD\n(ii) Iron acts as a heterogeneous catalyst in the Haber process.\nDescribe the mode of action of this iron catalyst.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [2]\nETIRW\nFe2+ I–(aq) 2–(aq). ions act as a homogeneous catalyst in the reaction between and S O (iii)\n2 8 TON\n2+(aq) OD is added to a mixture of Write equations for the two reactions that occur when Fe\nI–(aq) 2–(aq). and S O\n2 8\n2– O + .................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-on-41-q03-0fef55d7aa.pdf" }, { "id": "9701-2024-on-41-q04", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-41-q04-p01-f7195c9f4a.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-41-q04-p02-12ae10cbe3.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n4 Transition metal atoms and transition metal ions form complexes by combining with ligands.\nSIHT\nNI (a) Explain why transition elements form complex ions.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nCo2+ ions form complex ion G. (b)\n2+ ions, both of which are octahedrally coordinated. Each G ion contains two Co\nNIGRAM\nCo2+ molecule, which donates one pair of electrons to each ion, Each G ion contains one O\n2\nCo2+ – ion, which donates one pair of electrons to each ion. and one NH SIHT\n2\nNI\nmolecules. The remaining ligands are NH\nETIRW 3\n(i) Deduce the formula of complex ion G. Include its overall charge.\nTON\nOD\nformula of G ......................................................... [2]\nNIGRAM\n2+ ions present in complex ion G are split. State the number of (ii) The d-orbitals of the Co\nd-orbitals that are at a higher energy level and the number of d-orbitals that are at a\nSIHT\nCo2+ ion. lower energy level in each\nNI\nETIRW\nnumber of d-orbitals at a higher energy level\nnumber of d-orbitals at a lower energy level TON\n[1]\nOD\nCo2+ ions form a different complex ion, M. (iii)\nCo2+ ions, both of which are octahedrally coordinated, but the Each M ion contains two\nNIGRAM\nligands are different from the ligands in G.\nExplain why G and M have different colours. SIHT\nNI\n...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n........................................................................................................................................... OD\n...........................................................................................................................................\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n]2+. (c) Cadmium forms complex ion X, [Cd(NH )\nSIHT 3 4\nCN– NI ions is added to an aqueous solution of X, a ligand exchange W hen a solution containing\nETIRW\nligands and no H O ligands. reaction takes place, forming complex ion Y. Y contains no NH\n3 2\nTON Y is in a much higher concentration in the mixture than X.\nOD\nThe oxidation state and coordination number of cadmium do not change in this reaction.\n(i) Write an ionic equation for this reaction, using the f", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-41-q04-3b5d9b5a15.pdf" }, { "id": "9701-2024-on-41-q05", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 12 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-41-q05-p01-7d7bdac057.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n5 The shapes of four different complexes, P, Q, R and S, are shown in Table 5.1.\nSIHT\nNI The symbol J represents an atom or ion of a transition element.\nETIRW\nThe symbol L is used to represent a monodentate ligand.\nTON\nTable 5.1\nOD\nP Q\nL\nL\nNIGRAM\nL J L\nJ\nSIHT\nL\nL L NI\nL\nETIRW\nR S\nTON\nL\nL OD\nL J L\nL J L\nL\nNIGRAM L\nSIHT\n(a) Label one bond angle on each of complexes P, Q, R and S, and identify the size of the angle\nNI in degrees. [2]\nETIRW\n(b) Identify the shapes of complexes P, Q, R and S.\nTON\nP ...............................................................................................................................................\nOD\nQ ...............................................................................................................................................\nR ...............................................................................................................................................\nNIGRAM\nS ...............................................................................................................................................\nSIHT [2]\nNI\n(c) Two L ligands are exchanged with two different monodentate ligands X and Y in each of\nETIRW\ncomplexes P, Q, R and S.\nTON\nIdentify all the complexes which form new complexes that show geometrical isomerism.\nOD\n............................................................................................................................................. [1]\n(d) Three L ligands are exchanged with three different monodentate ligands X, Y and Z in each\nNIGRAM of complexes P, Q and R.\nIdentify all the complexes which form new complexes that show optical isomerism.\nSIHT\n............................................................................................................................................. [1] NI\nETIRW\n[Total: 6]\nTON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-41-q05-767da81f4b.pdf" }, { "id": "9701-2024-on-41-q06", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2024-on-41-q06-p01-e85909270b.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-41-q06-p02-72616953aa.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-41-q06-p03-026f80a184.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-41-q06-p04-700ffe5e08.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n6 Benzene, C H , reacts with chloroethane, C H Cl, in the presence of a suitable catalyst to form\nSIHT 6 6 2 5\n+ H C H . In the presence of the catalyst, the ion C H is formed. This ion reacts ethylbenzene, C\n6 5 2 5 2 5\nNI with benzene.\nETIRW\n+ H Cl with this catalyst to form C H as one (a) Complete the equation for the reaction of C\n2 5 2 5\nTON product.\nOD\n+ C H H Cl + ....................................... + ....................................... [1] C\n2 5 2 5\nH Cl, forming a mixture containing 1,2-diethylbenzene and (b) Ethylbenzene reacts with more C\n2 5\n1,4-diethylbenzene.\nNIGRAM\n(i) Draw the structures of 1,2-diethylbenzene and 1,4-diethylbenzene.\nSIHT\n1,2-diethylbenzene 1,4-diethylbenzene\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\n[1]\nNI\nETIRW\n(ii) Explain why there is very little 1,3-diethylbenzene in the product mixture.\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) 1,2-diethylbenzene can be oxidised to benzene-1,2-dioic acid, C H (COOH) .\nSIHT 6 4 2\nbenzene-1,2-dioic acid NI\nETIRW\nCOOH\nTON\nOD COOH\n(i) State the reagent and conditions used for this reaction.\nNIGRAM\n..................................................................................................................................... [1]\n(ii) Complete the overall equation for this reaction.\nSIHT\nNI An atom of oxygen from the oxidising agent is represented as [O].\nETIRW\nAll of the atoms in the two ethyl groups are fully oxidised in this reaction.\nTON\nOD\nC H (COOH) + ................................ + ................................ ................................. + ................. [O]\n6 4 2\n(1,2-diethylbenzene)\n[2]\nNIGRAM\n(iii) Predict the number of peaks in the carbon-13 NMR spectrum of benzene-1,2-dioic acid.\nSIHT ..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(1H) (d) The proton NMR spectra of ethylbenzene, C H C H , in CDCl and of benzene-1,2-dioic\nSIHT 6 5 2 5 3\nH (COOH) , in CDCl are shown. They have not been identified. acid, C\n6 4 2 3\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\n4 3 2 1 0 11 10 9 8 7 6 5\nOD\n/ ppm δ\nFig. 6.1\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n16 14 12 10 8 6 4 2 0\nδ / ppm\nTON\nOD Fig. 6.2\n, instead of CHCl , as the solvent when obtaining these spectra. (i) Explain the use of CDCl\n3 3\nNIGRAM ..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(ii) Identify the substanc", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2024-on-41-q06-e4e30ea910.pdf" }, { "id": "9701-2024-on-41-q07", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-on-41-q07-p01-7600c820bd.png", "9701-topic-36-organic-synthesis/assets/9701-2024-on-41-q07-p02-bd03fd8dca.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 A reaction scheme is shown in Fig. 7.1.\nSIHT\nNI The reagents needed for reaction 2 and reaction 3 are stated.\nETIRW\nH NH is mixed with compound V. No special conditions are Reaction 5 takes place when C\n2 5 2\nTON required.\nOD\nreaction 1\ncompound U CH COOH\n3\nNIGRAM\nreaction 3 reaction 2\nSIHT reagent = SOCl reagent = LiAl H\n4 2\nNI\nETIRW\nTON compound W C H NH compound V\n2 5 2\nOD\nreaction 4 reaction 5\nNIGRAM\nreaction 6 SIHT\nC H NHC H C H NHCOCH\n2 5 2 5 2 5 3\nNI\nETIRW\nTON Fig. 7.1\nOD\n(a) Identify compound U which contains only three elements.\n............................................................................................................................................. [1]\nNIGRAM\n(b) Describe the reagents and conditions for reaction 1.\n............................................................................................................................................. [1] SIHT\nNI\n(c) Identify compound V.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD (d) Complete the equation for reaction 3.\n...................................................................................................... [1] COOH + SOCl CH\n3 2\nNIGRAM (e) Identify compound W.\n............................................................................................................................................. [1]\nSIHT\n(f) Describe the conditions for reaction 4. NI\nETIRW\n............................................................................................................................................. [1]\nTON\nNIGRAM\n(g) Suggest the reagent needed for reaction 6.\nSIHT\nNI ............................................................................................................................................. [1]\nETIRW\n(h) Complete Table 7.1 by adding the reaction numbers, 1, 2, 3, 4, 5 and 6, to the right-hand\nTON column. Use the reaction numbers given in Fig. 7.1.\nOD\nEach of the numbers 1, 2, 3, 4, 5 and 6 should be used once only.\nTable 7.1\nNIGRAM\ntype of reaction reaction number(s)\nhydrolysis SIHT\naddition NI\nETIRW\nreduction\nTON\nsubstitution\nOD [4]\nH NHCOCH , C H NHC H and NH . (i) Compare the basicities of C\n2 5 3 2 5 2 5 3\nNIGRAM Explain your answer.\n............................................ ................................. ........... ............................................\nSIHT\nmost basic least basic\nNI\nETIRW ...................................................................................................................................................\n................................................................................................................................................... TON\nOD\n.....................................................................................................", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-on-41-q07-41807ab8b5.pdf" }, { "id": "9701-2024-on-41-q08", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_41.pdf?download=true", "source_pages": [ 20, 23, 24 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_41.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-41-q08-p01-89118748be.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-41-q08-p02-4c2a89a02a.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-41-q08-p03-139933076e.png" ], "answer": { "status": "pending", "id": "9701-2024-on-41-q08", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n8 (a) An aqueous solution of phenol, C H OH, is acidic at 298 K.\nSIHT 6 5\nNI Explain why phenol is more acidic than water .\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\n(aq). (b) (i) Name the two products formed when phenol reacts with an excess of Br\nNIGRAM 2\n............................................................... and ............................................................... [1]\nSIHT\n= 139, that are formed (ii) Draw the structures of the two isomeric organic products, with M\nr NI\n(aq) at room temperature. when phenol reacts with HNO\nETIRW 3\nTON\nOD\nNIGRAM\nSIHT\nNI\n[1] ETIRW\nH OH, and sodium metal. (iii) Write the equation for the reaction between phenol, C\nTON 6 5\nOD ..................................................................................................................................... [1]\n(c) Phenol can be produced from phenylamine in a two-step synthesis.\nNIGRAM step one step two\nintermediate compound phenol phenylamine\nSIHT\nDescribe the reagents and conditions needed in each step.\nNI\nETIRW step one:\nTON reagents ....................................................................................................................................\nOD\nconditions .................................................................................................................................\nstep two:\nNIGRAM\nreagents ....................................................................................................................................\nconditions ................................................................................................................................. SIHT\n[2]\nNI\nETIRW\n[Total: 7]\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.022 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas V\nm\ndm3 mol–1 V = 24.0 at room conditions\nNIGRAM m\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nSIHT\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nSIHT\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eN nR eH eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nNI\nETIRW\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 0.571 9.6", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2024-on-41-q08-8c542554da.pdf" }, { "id": "9701-2024-on-42-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-on-42-q01-p01-cd954adad3.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-on-42-q01-p02-7e177e659a.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q01", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) The equation for reaction 1 is shown.\nSIHT\nNI 2Y reaction 1 X\nETIRW\n, Reaction 1 is first order with respect to the concentration of X. The half-life of the reaction, t\n1\n2 TON is 900 s at 20 °C.\nOD\ndm–3 is prepared at 20 °C. Calculate the (i) A solution of X with a concentration of 0.180 mol\naverage rate of reaction 1 over the first 1800 s.\nNIGRAM\naverage rate of reaction 1 = .............................. [2]\nSIHT\n(ii) Complete the rate equation for reaction 1.\nNI\nETIRW\nrate = ........................................................................................................................... [1]\nTON\n10–4 s–1 at 20 °C. (iii) Show that the rate constant, k, is 7.70 ×\nOD\n[1]\nNIGRAM\ndm–3. (iv) Calculate the initial rate of reaction 1 when the concentration of X is 0.150 mol\nSIHT\nInclude units.\nNI\nETIRW\nrate = .............................. units .............................. [2] TON\nOD\n(b) Catalysts may be homogeneous or heterogeneous.\n(i) Platinum is a transition element. Explain why transition elements behave as catalysts.\nNIGRAM\n...........................................................................................................................................\n...........................................................................................................................................\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\n(ii) Name the metal catalyst in the Haber process and explain why it is a heterogeneous\nTON\ncatalyst.\nOD\nmetal .........................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Platinum acts as a heterogeneous catalyst in the removal of nitrogen dioxide, NO , from\nSIHT 2\nthe exhaust gases of car engines.\nNI\nETIRW\nDescribe the mode of action of a platinum catalyst in this process.\nTON ...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [2]\nacts as a homogeneous catalyst in the oxidation of atmospheric sulfur dioxide, SO. SIHT (iv) NO\n2 2\nNI\nWrite equations for the two reactions that occur.\nETIRW\nequation 1 ....................................................................................................................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-on-42-q01-f28b4e82e6.pdf" }, { "id": "9701-2024-on-42-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 4, 5, 6 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-on-42-q02-p01-2a199cbf20.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-42-q02-p02-ba147323d1.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-42-q02-p03-321d814312.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n+, Mg2+ 2 (a) Predict and explain the variation in enthalpy change of hydration for the ions Na\nSIHT\n3 +. and Al\nNI\nETIRW\n...................................................................................................................................................\nTON ...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [3]\n(b) Fig. 2.1 shows an incomplete energy cycle. SIHT\nNI\nMg2+(g) –(g) + 2Cl line B: ETIRW\nchange 2: TON\nchange 1: lattice energy\nof magnesium chloride, OD\nMgCl (s) ΔH\nlatt 2\nNIGRAM\n(s) line A: MgCl\n2\nSIHT\nchange 3: enthalpy change of\nNI\nsolution of magnesium chloride,\nline C: ETIRW\nMgCl (s) ΔH\nsol 2\nTON\nFig. 2.1\nOD\n(i) Complete line C on Fig. 2.1. Include state symbols. [1]\n(ii) Use both words and symbols to identify change 2 on Fig. 2.1.\nNIGRAM\nUse changes 1 and 3 as examples of how this should be done.\nSIHT [2]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Calculate a value for the lattice energy of magnesium chloride, ΔH MgCl (s), by\nSIHT latt 2\nselecting and using appropriate data from Table 2.1.\nNI\nETIRW\nTable 2.1\nTON\nmo–l1 energy change value / kJ\nOD\nenthalpy change of solution of magnesium chloride –155\nenthalpy change of formation of magnesium chloride –642\nfirst ionisation energy of magnesium +736 NIGRAM\nsecond ionisation energy of magnesium +1450\nSIHT\nelectron affinity of chlorine –349\nNI\nMg2+ –1920 enthalpy change of hydration of\nETIRW\n– –364 enthalpy change of hydration of Cl\nTON\nOD\nNIGRAM\nSIHT\nmol–1 MgCl (s) = .............................. kJ [3] ΔH\nNI latt 2\nETIRW\n(c) Define entropy.\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\nmo–l1. The entropy change (d) At 25 °C the enthalpy change of solution of compound Z is +26 kJ\nNIGRAM K–1 mol–1. of solution of Z at the same temperature is +52 J\nCalculate the value of the Gibbs free energy change, ΔG, for the solution of Z at 25 °C.\nSIHT\nNI\nETIRW\nmol–1 TON [2] ΔG = .............................. kJ\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(e) (i) Use your answer to (d) to predict whether or not Z is soluble in water at 25 °C. Explain\nSIHT\nyour answer.\nNI\nETIRW\n........", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-on-42-q02-524b6e6b38.pdf" }, { "id": "9701-2024-on-42-q03", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2024-on-42-q03-p01-10c4267921.png", "9701-topic-25-equilibria/assets/9701-2024-on-42-q03-p02-fa4cbfeb49.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n3 (a) The pH of a saturated solution of calcium hydroxide is 12.35 at 298 K.\nSIHT\nNI (i) Show that the concentration of hydroxide ions in a saturated solutiono f calcium hydroxide\nETIRW dm–3 at 298 K. is 0.0224 mol\nTON\nOD\n[2]\n, of calcium hydroxide at 298K . (ii) Use data given in (i) to calculate the solubility product, K\nNIGRAM sp\nin your answer. Include the units of K\nsp\nSIHT\nNI\nETIRW\nK = .............................. units .............................. [3]\nsp TON\nOD (iii) A spatula measure of solid calcium chloride is stirred into a sample of saturated\ncalcium hydroxide solution. All of the calcium chloride dissolves.\nDescribe one other observation that would be made and give an estimated value of the\nNIGRAM pH of the solution obtained.\nExplain both your answers.\nSIHT\nobservation ........................................................................................................................ NI\nETIRW\npH of solution .................................\nTON\nexplanation ........................................................................................................................\nOD\n...........................................................................................................................................\n[3]\nNIGRAM\n(iv) Calcium hydroxide reacts with dilute sulfuric acid to form calcium sulfate. Barium hydroxide\nbehaves in a similar way, forming barium sulfate.\nSIHT\nExplain why calcium sulfate is more soluble in water than barium sulfate.\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [3]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Some solid calcium is added to an excess of aqueous ethanoic acid, CHCOOH, and left until\nSIHT 3\nall the calcium has reacted. The resulting mixture, mixture D, contains no undissolved solids.\nNI\nETIRW\nCOOH. (i) Write an equation for the reaction of calcium with CH\n3\nTON ..................................................................................................................................... [1]\nOD\n(ii) Use formulae of molecules and ions to identify two conjugate acid–base pairs present in\nmixture D.\nPair 1 should consist of organic species.\nNIGRAM\npair 1: ............................................ .......................", "pdf_path": "9701-topic-25-equilibria/print/9701-2024-on-42-q03-e0ee0064f6.pdf" }, { "id": "9701-2024-on-42-q04", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-42-q04-p01-284aa607e9.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-42-q04-p02-3c9907bb74.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n4 Transition metal atoms and transition metal ions form complexes by combining with species called\nSIHT\nligands.\nNI\nETIRW ]2+ O) a precipitation (a) When NaOH(aq) is added to an aqueous solution containing [Co(H\n2 6\nreaction occurs accompanied by a colour change.\nTON\n+ H+ OH– ion. The ions are gained by In this reaction two of the water ligands each lose one H\nOD\nions from the NaOH(aq).\n(i) State the colour change seen in this precipitation reaction.\nNIGRAM\nfrom ............................................................. to ............................................................. [1]\n(ii) Complete the ionic equation for this precipitation reaction. SIHT\nNI\n]2+ O) + ................................. ................................. + ................................. [Co(H\nETIRW 2 6\n[1]\nTON\n(iii) This precipitation reaction can also be described as a different type of reaction.\nOD\nName this type of reaction.\n..................................................................................................................................... [1]\nNIGRAM\n(b) L is an uncharged tridentate ligand. L donates three lone pairs to a metal atom or ion.\nSIHT\nCobalt forms an octahedral complex ion, E, with L. Complex ion E has a 2+ charge.\nNI\nETIRW (i) Give the formula of E.\n..................................................................................................................................... [1] TON\nOD\n(ii) Identify the oxidation state of cobalt in E.\n..................................................................................................................................... [1]\nNIGRAM\n(iii) The d-orbitals of the cobalt atom or ion present in E are split in energy.\nState the number of d-orbitals that are at a higher energy level and the number of\nSIHT\nd-orbitals that are at a lower energy level.\nNI\nETIRW\nnumber of d-orbitals at a higher energy level\nTON number of d-orbitals at a lower energy level\nOD [1]\n(iv) Define the term non-degenerate d-orbitals.\nNIGRAM ...........................................................................................................................................\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The mineral chromite contains a compound which has the formula FeCr O . The oxidation\nSIHT n 4\nO is +2. state of iron in FeCr\nn 4\nNI\nETIRW\nO is dissolved in an excess of sulfuric acid. The resulting solution A sample of 4.18 g of FeCr\nn 4\ncm3. This is solution F. is made up to 250\nTON\n2+ cm3 3+ cm3 ions in 25.0 of solution F are oxidised to Fe ions by exactly 18.7 of All the Fe\nOD\ndm–3 KMnO . 0.0200 mol\n4\nFe2+ – ion reacts with five ions. Assume no other oxidation reaction occurs. One MnO\n4\nNIGRAM\nFe2+ – ions with MnO ions in acid solution. (i) Write an equation ", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-42-q04-4c7be853e6.pdf" }, { "id": "9701-2024-on-42-q05", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-42-q05-p01-37681cd9d6.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-42-q05-p02-3d5e417a1c.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\nNi2+ ]2+, ]2+ 5 ions form a number of different complex ions, including [Ni(H O) [Ni(NH ) and\nSIHT 2 6 3 6\n]2+. [Ni(en)\n3\nNI\nETIRW\nThe abbreviation en represents 1,2-diaminoethane. The numerical values of two stability\n, are given in Table 5.1. constants, K\nstab\nTON\nTable 5.1\nOD\ncomplex K\nstab\n]2+ 107 [Ni(NH ) 4.8 ×\nNIGRAM 3 6\n]2+ 1018 [Ni(en) 2.0 ×\n3\nSIHT\n]2+. (a) Complete the expression for the K of [Ni(en)\nstab 3\nNI\nETIRW\nK =\nstab TON\nOD\n[1]\n]2+ dm–3 (b) A solution of [Ni(H O) is added to a solution that contains 0.10 mol NH and\n2 6 3\ndm–3 en. 0.10 mol NIGRAM\n]2+ ]2+, ) or [Ni(en) is present in the resulting mixture (i) Predict which complex ion, [Ni(NH\n3 6 3\nSIHT in the highest concentration. Explain your answer.\nNI\ncomplex ion present in largest concentration = ............................................ ETIRW\nexplanation ........................................................................................................................\nTON\n[1]\nOD\n(ii) Complete the equation for the ligand exchange reaction occurring in (i).\n]2+ ................................. + ................................. O) + ................................. [Ni(H\n2 6\nNIGRAM [1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n]2+. (c) Complete Fig. 5.1 to show the three-dimensional structures of the two isomers of [Ni(en)\nSIHT 3\nNI\nN N to represent the en ligand. Use ETIRW\nName the type of isomerism shown.\nTON\nOD\nNIGRAM\nNi Ni\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 5.1\ntype of isomerism shown ..........................................................................................................\n[3]\nNIGRAM\n[Total: 6]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-42-q05-d78fb26c15.pdf" }, { "id": "9701-2024-on-42-q06", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2024-on-42-q06-p01-1daa0fe16a.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2024-on-42-q06-p02-1f6a257f72.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q06", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n6 Fig. 6.1 shows two reactions of ethanedioic acid, HOOCCOOH.\nSIHT\nNI G\nan excess ETIRW\nof SOCl\n2\nTON\nHOOCCOOH\nOD\nNIGRAM\n2CO + H O SIHT\n2 2\nNI\nETIRW Fig. 6.1\nTON (a) (i) Draw the organic product G in the box in Fig. 6.1.\n[1]\nOD\nis given as the reagent that reacts with HOOCCOOH to produce G. (ii) In Fig. 6.1, SOCl\n2\nIdentify a different reagent that also reacts with HOOCCOOH to produce G.\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\n(b) Identify two different reagents that oxidise HOOCCOOH to form carbon dioxide and water.\nNI\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [2]\nOD\n(c) HOOCCOOH ionises as shown.\nHOOCCOO– H+ + HOOCCOOH\nNIGRAM\nHOOCCOOH is a much stronger acid than methanoic acid, HCOOH.\nSIHT\nSuggest an explanation for this dif ference in acidity.\nNI\n................................................................................................................................................... ETIRW\n................................................................................................................................................... TON\nOD\n............................................................................................................................................. [2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Benzene-1,4-dicarboxylic acid, HOOCC H COOH, can be made from benzene, C H , in two\nSIHT 6 4 6 6\nsteps as shown in Fig. 6.2.\nNI\nETIRW\nJ\nTON\nstep 1 step 2\nOD HOOC COOH\nbenzene-1,4-dicarboxylic acid\nNIGRAM\nFig. 6.2\nSIHT\n(i) Suggest the identity of J by drawing its structure in the box in Fig. 6.2.\nNI\n[1]\nETIRW\n(ii) Identify the reagents and conditions for step 1 and step 2.\nTON\nstep 1 ................................................................................................................................ OD\nstep 2 ................................................................................................................................\n[2]\nNIGRAM\n(iii) Draw the structure of exactly one repeat unit of the polymer formed when\nCH OH. The linkage benzene-1,4-dicarboxylic acid reacts with ethane-1,2-diol, HOCH\n2 2 SIHT\nformed between the monomers should be shown fully displayed.\nNI\nETIRW\nTON\nOD\n[2]\n(iv) State the type of polymerisation that occurs when benzene-1,4-dicarboxylic acid reacts\nNIGRAM\nwith ethane-1,2-diol and name the linkage formed between the monomers.\ntype of polymerisation .......................................................................................................\nSIHT\nNI linkage ...................................", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2024-on-42-q06-37174b1792.pdf" }, { "id": "9701-2024-on-42-q07", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2024-on-42-q07-p01-467c4436d3.png", "9701-topic-30-hydrocarbons/assets/9701-2024-on-42-q07-p02-52c0f9953d.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q07", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n7 Benzene reacts with chlorine gas to form chlorobenzene. This reaction can be described as the\nSIHT\n+ + ions. The Cl ions are formed by adding a suitable reaction between benzene molecules and Cl\nNI catalyst to the chlorine gas.\nETIRW\n(a) Give the name or formula of a catalyst that can be used for this reaction.\nTON\n............................................................................................................................................. [1]\nOD\n(b) The mechanism for this reaction is shown.\n+ Cl NIGRAM y H x\nCl step 1 step 2\nCl\n+ SIHT\nNI\nETIRW\ndiagram 3 diagram 1 diagram 2\nTON\n(i) The movement of a pair of electrons is represented by x in diagram 1.\nOD\n• State where this pair of electrons is before step 1 takes place.\n....................................................................................................................................\nNIGRAM\n• State where this pair of electrons is after step 1 has taken place.\nSIHT\n....................................................................................................................................\nNI [2]\nETIRW\n(ii) The movement of another pair of electrons is represented by y in diagram 2.\nTON\n• State where this pair of electrons is before step 2 takes place.\nOD\n....................................................................................................................................\n• State where this pair of electrons is after step 2 has taken place.\nNIGRAM\n....................................................................................................................................\nSIHT [2]\nNI\n(c) There are six carbon atoms in diagram 2.\nETIRW\n2 sp3 hybridised, and hybridised. State how many of these carbon atoms are sp hybridised, sp\nTON\nOD sp hybridised .................................\n2 hybridised ................................. sp\n3 NIGRAM hybridised ................................. sp\n[1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Complete the equation for this reaction between benzene and chlorine.\nSIHT\nNI H + ................................. ................................. + ................................. C\n6 6\nETIRW\n[1]\nTON (e) The mechanism for this reaction is electrophilic substitution.\nOD\nComplete the following sentence. W rite formulae in the gaps provided.\nDuring this reaction, the electrophile is ................................. and a ................................. atom\nNIGRAM\nin benzene is substituted by a ................................. a tom.\n[1]\nSIHT\n(f) Chloroethane reacts with NaOH(aq). Chlorobenzene does not.\nNI\nETIRW\n(i) Name the mechanism of the reaction that chloroethane undergoes with NaOH(aq), and\nidentify the major organic product that is formed.\nTON\nOD mechanism ........................................................................................................................\nmajor organic product ....", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2024-on-42-q07-33fc23c1f8.pdf" }, { "id": "9701-2024-on-42-q08", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 29, "topic": "An introduction to A Level organic chemistry", "topic_slug": "9701-topic-29-an-introduction-to-a-level-organic-chemistry", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_42.pdf?download=true", "source_pages": [ 18, 19, 20, 23, 24 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_42.pdf", "image_paths": [ "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2024-on-42-q08-p01-5a372bfd62.png", "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2024-on-42-q08-p02-f0f0964579.png", "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2024-on-42-q08-p03-229fc42c14.png", "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2024-on-42-q08-p04-c5e8ebf77c.png", "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2024-on-42-q08-p05-7b54d2631d.png" ], "answer": { "status": "pending", "id": "9701-2024-on-42-q08", "html": "9701-topic-29-an-introduction-to-a-level-organic-chemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n8 The amino acid serine, HOCH CH(NH )COOH, exists in two optically active forms. These optical\nSIHT 2 2\nisomers, isomer P and isomer Q, are shown in Fig. 8.1.\nNI\nETIRW isomer P isomer Q\nCH OH CH OH\n2 2 TON\nOD\nC C\nH H\nCOOH HOOC\nH N NH\n2 2\nNIGRAM\nFig. 8.1\nSIHT\n(a) Isomer P and isomer Q have identical physical and chemical properties, with the exception of\nNI\ntwo specific properties. One of these two properties is their differing effect on plane polarised ETIRW\nlight.\nTON\nState the other property by which they dif fer.\nOD\n...................................................................................................................................................\n............................................................................................................................................. [1]\nNIGRAM\n(b) A solution of pure isomer P of a particular concentration rotates plane polarised light by 5.0°\nin a clockwise direction.\nSIHT\nDescribe how a solution of pure isomer Q of the same concentration affects plane polarised NI\nETIRW light.\nTON ...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\n(c) State another term, in addition to stereoisomers, optical isomers and non-superim posable\nmirror images, which can be used to describe this pair of chiral compounds, isomer P and\nNIGRAM\nisomer Q.\n............................................................................................................................................. [1] SIHT\nNI\n(d) Give the term used to describe a mixture containing equal amounts of isomer P and isomer Q.\nETIRW\n............................................................................................................................................. [1]\nTON\n(e) Describe one way in which a single pure optical isomer of serine can be produced, instead of OD\nmaking a mixture of isomer P and isomer Q.\n............................................................................................................................................. [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n1H) (f) Complete Table 8.1 to describe the peaks seen in the proton ( NMR spectrum of\nSIHT\nCH(NH )COOH dissolved in D O. HOCH\n2 2 2\nNI\nETIRW\nUse as many rows in Table 8.1 as you need to, leaving the other rows blank.\nTON Table 8.1\nOD\ngroup responsible name of splitting pattern\nexplanation for splitting pattern\nfor peak shown by peak\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n[3]\nNIGRAM\n(g) Proline is a naturally occurring amino acid. The skeletal formula of proline is shown.\nSIHT proline\nNI O\nETIRW\nOH\nTON\nNH\nOD\n13C) State the number of peaks in the carbon-13 ( NMR spectrum of proline.\nNIGRAM .........", "pdf_path": "9701-topic-29-an-introduction-to-a-level-organic-chemistry/print/9701-2024-on-42-q08-915943985b.pdf" }, { "id": "9701-2024-on-43-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2024-on-43-q01-p01-2bb0527963.png", "9701-topic-25-equilibria/assets/9701-2024-on-43-q01-p02-91815db93f.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q01", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n+) 2–), 1 (a) Disodium phosphate, (Na (HPO reacts with an acid to form monosodium phosphate,\nSIHT 2 4\nNa+(H –). PO\n2 4\nNI\nETIRW\n(i) Identify the ions that are a conjugate acid–base pair in this reaction, using the formulae\nof the species involved.\nTON\nconjugate acid conjugate base\nOD\n.................................................................... ....................................................................\n[1]\nNIGRAM\n(ii) Define buffer solution.\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [2]\nETIRW\n(Na+) Na+(H 2–) –) (HPO and PO can act (iii) Write two equations to show how a mixture of\n2 4 2 4 TON\nas a buffer solution.\nOD\nequation 1 .........................................................................................................................\nequation 2 .........................................................................................................................\nNIGRAM [2]\n(iv) Identify one inorganic ion that acts as a buffer in blood.\nSIHT\n..................................................................................................................................... [1] NI\nETIRW\n(b) Compound E is the hydroxide of a Group 2 element. Compound E is a strong alkali.\nTON\ncm3 of solution F. Solution F has a pH of 13.09 2.63 g of E is dissolved in water to make 250\nOD\nat 298 K.\ndm–3. (i) Show that the concentration of hydroxide ions in solution F is 0.123 mol\nNIGRAM\nSIHT\n[2]\nNI\nETIRW\ndm–3. (ii) Explain why the concentration of compound E in solution F is 0.0615 mol\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(iii) Use the concentration given in (ii) to identify compound E.\nNIGRAM\nSIHT\nNI\nETIRW\ncompound E ................................................................................................................ [1]\nTON\nNIGRAM\n(c) Compound E is much more soluble than magnesium hydroxide.\nSIHT\n0–4 dm–3 NI mol A saturated solution of magnesium hydroxide in water has a concentratioofn 1 .40 ×1\nETIRW\nat 298 K.\nTON , of magnesium hydroxide. Include units. Calculate the solubility product, K\nsp\nOD\nNIGRAM\nSIHT\nK = .............................. units .............................. [3]\nsp NI\nETIRW\n(d) Explain why compound E is much more soluble than magnesium hydroxide.\nTON\n...................................................................................................................................................\nOD\n.............", "pdf_path": "9701-topic-25-equilibria/print/9701-2024-on-43-q01-7db7af7df5.pdf" }, { "id": "9701-2024-on-43-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 4, 5, 6 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2024-on-43-q02-p01-a259759750.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-43-q02-p02-21e2983599.png", "9701-topic-23-chemical-energetics/assets/9701-2024-on-43-q02-p03-3e63048474.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n–, –, – 2 (a) Predict and explain the variation in enthalpy change of hydration for the ions F Cl Br\nSIHT\nI–. and\nNI\nETIRW\n...................................................................................................................................................\nTON ...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\n. (b) Fig. 2.1 shows an incomplete energy cycle involving calcium fluoride, CaF\n2\nNIGRAM\nCa2+(g) 2F–(g) + line B:\nSIHT\nprocess 1: enthalpy change of\nCa2+(g) formation of plus NI\nprocess 2: enthalpy change of\nETIRW twice the enthalpy change of\nhydration of calcium ions plus\nF–(g), formation of\ntwice the enthalpy change of\nCa2+(g) F–(g) + 2ΔH ΔH TON\nf f hydration of fluoride ions,\nCa2+(g) F–(g) OD ΔH + 2ΔH\n(g) line A: Ca(s) + F hyd hyd\n2\nprocess 3: enthalpy change of line D: NIGRAM\nformation of calcium fluoride,\nCaF (s) ΔH\nf 2\nSIHT\nNI process 4: enthalpy change of line C: CaF (s)\n2 ETIRW\nsolution of calcium fluoride,\nCaF (s) ΔH\nsol 2\nTON\nOD\nFig. 2.1\n(i) Complete line D. Include state symbols. [1]\nNIGRAM\n(ii) The value of the enthalpy change for process 1 can be calculated using the v alues of\nfive other enthalpy changes which are not referred to in Fig. 2.1.\nSIHT\nCa2+(g) 2F–(g) (g) + process 1: Ca(s) + F\n2\nNI\nETIRW\nIdentify these five other enthalpy changes, using either names or symbols.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ..................................................................................................................................... [2]\nNI\nETIRW\nTON\nNIGRAM\n(iii) Define lattice energy, ΔH .\nSIHT latt\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nof calcium (iv) Complete the expression to give the mathematical relationship between ΔH\nlatt\nfl", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2024-on-43-q02-18694925a5.pdf" }, { "id": "9701-2024-on-43-q03", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 7, 8, 9 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2024-on-43-q03-p01-0e57666e91.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-on-43-q03-p02-283d2b1633.png", "9701-topic-26-reaction-kinetics/assets/9701-2024-on-43-q03-p03-34494edce1.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n3 (a) A and B react together to give product AB.\nSIHT\nNI AB A + B\nETIRW\ndm–3, the rate of formation of AB When the concentrations of A and B are both 0.0100 mol\nTON 10–4 dm–3 s–1. dm–3, mol When the concentrations of A and B are both 0.0200 mol is 7.62 ×\n10–3 dm–3 s–1. mol the rate of formation of AB is 3.05 ×\nOD\n(i) Complete the three possible rate equations that are consistent with these data.\nrate = .................................................................................................................................\nNIGRAM\nrate = .................................................................................................................................\nSIHT\nrate = .................................................................................................................................\nNI\n[2]\nETIRW\n(ii) Choose one of the rate equations you have written in (i), and calculate the value of the\nTON\nrate constant, k. Include the units of k.\nOD\nNIGRAM\nk = .............................. units .............................. [2]\nSIHT\n, of this reaction (iii) Explain why it is not possible to calculate a value for the half-life, t NI 1\nETIRW 2\nusing the value of the rate constant k calculated in (ii) and the equation k = 0.693 / t .\n1\n2\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Catalysts may be homogeneous or heterogeneous.\nSIHT\nNI from the (i) Identify two metals that act as heterogeneous catalysts in the removal of NO\n2\nETIRW\nexhaust gases of car engines.\nTON ............................................................... and .............................................................. [1]\nOD\n(ii) Iron acts as a heterogeneous catalyst in the Haber process.\nDescribe the mode of action of this iron catalyst.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [2]\nETIRW\nFe2+ I–(aq) 2–(aq). ions act as a homogeneous catalyst in the reaction between and S O (iii)\n2 8 TON\n2+(aq) OD is added to a mixture of Write equations for the two reactions that occur when Fe\nI–(aq) 2–(aq). and S O\n2 8\n2– O + .................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2024-on-43-q03-a3aa6aefc8.pdf" }, { "id": "9701-2024-on-43-q04", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-43-q04-p01-f7195c9f4a.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-43-q04-p02-12ae10cbe3.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q04", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n4 Transition metal atoms and transition metal ions form complexes by combining with ligands.\nSIHT\nNI (a) Explain why transition elements form complex ions.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nCo2+ ions form complex ion G. (b)\n2+ ions, both of which are octahedrally coordinated. Each G ion contains two Co\nNIGRAM\nCo2+ molecule, which donates one pair of electrons to each ion, Each G ion contains one O\n2\nCo2+ – ion, which donates one pair of electrons to each ion. and one NH SIHT\n2\nNI\nmolecules. The remaining ligands are NH\nETIRW 3\n(i) Deduce the formula of complex ion G. Include its overall charge.\nTON\nOD\nformula of G ......................................................... [2]\nNIGRAM\n2+ ions present in complex ion G are split. State the number of (ii) The d-orbitals of the Co\nd-orbitals that are at a higher energy level and the number of d-orbitals that are at a\nSIHT\nCo2+ ion. lower energy level in each\nNI\nETIRW\nnumber of d-orbitals at a higher energy level\nnumber of d-orbitals at a lower energy level TON\n[1]\nOD\nCo2+ ions form a different complex ion, M. (iii)\nCo2+ ions, both of which are octahedrally coordinated, but the Each M ion contains two\nNIGRAM\nligands are different from the ligands in G.\nExplain why G and M have different colours. SIHT\nNI\n...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n........................................................................................................................................... OD\n...........................................................................................................................................\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n]2+. (c) Cadmium forms complex ion X, [Cd(NH )\nSIHT 3 4\nCN– NI ions is added to an aqueous solution of X, a ligand exchange W hen a solution containing\nETIRW\nligands and no H O ligands. reaction takes place, forming complex ion Y. Y contains no NH\n3 2\nTON Y is in a much higher concentration in the mixture than X.\nOD\nThe oxidation state and coordination number of cadmium do not change in this reaction.\n(i) Write an ionic equation for this reaction, using the f", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-43-q04-487fd93099.pdf" }, { "id": "9701-2024-on-43-q05", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 12 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2024-on-43-q05-p01-7d7bdac057.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n5 The shapes of four different complexes, P, Q, R and S, are shown in Table 5.1.\nSIHT\nNI The symbol J represents an atom or ion of a transition element.\nETIRW\nThe symbol L is used to represent a monodentate ligand.\nTON\nTable 5.1\nOD\nP Q\nL\nL\nNIGRAM\nL J L\nJ\nSIHT\nL\nL L NI\nL\nETIRW\nR S\nTON\nL\nL OD\nL J L\nL J L\nL\nNIGRAM L\nSIHT\n(a) Label one bond angle on each of complexes P, Q, R and S, and identify the size of the angle\nNI in degrees. [2]\nETIRW\n(b) Identify the shapes of complexes P, Q, R and S.\nTON\nP ...............................................................................................................................................\nOD\nQ ...............................................................................................................................................\nR ...............................................................................................................................................\nNIGRAM\nS ...............................................................................................................................................\nSIHT [2]\nNI\n(c) Two L ligands are exchanged with two different monodentate ligands X and Y in each of\nETIRW\ncomplexes P, Q, R and S.\nTON\nIdentify all the complexes which form new complexes that show geometrical isomerism.\nOD\n............................................................................................................................................. [1]\n(d) Three L ligands are exchanged with three different monodentate ligands X, Y and Z in each\nNIGRAM of complexes P, Q and R.\nIdentify all the complexes which form new complexes that show optical isomerism.\nSIHT\n............................................................................................................................................. [1] NI\nETIRW\n[Total: 6]\nTON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2024-on-43-q05-d279d3cc88.pdf" }, { "id": "9701-2024-on-43-q06", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2024-on-43-q06-p01-e85909270b.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-43-q06-p02-72616953aa.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-43-q06-p03-026f80a184.png", "9701-topic-37-analytical-techniques/assets/9701-2024-on-43-q06-p04-700ffe5e08.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n6 Benzene, C H , reacts with chloroethane, C H Cl, in the presence of a suitable catalyst to form\nSIHT 6 6 2 5\n+ H C H . In the presence of the catalyst, the ion C H is formed. This ion reacts ethylbenzene, C\n6 5 2 5 2 5\nNI with benzene.\nETIRW\n+ H Cl with this catalyst to form C H as one (a) Complete the equation for the reaction of C\n2 5 2 5\nTON product.\nOD\n+ C H H Cl + ....................................... + ....................................... [1] C\n2 5 2 5\nH Cl, forming a mixture containing 1,2-diethylbenzene and (b) Ethylbenzene reacts with more C\n2 5\n1,4-diethylbenzene.\nNIGRAM\n(i) Draw the structures of 1,2-diethylbenzene and 1,4-diethylbenzene.\nSIHT\n1,2-diethylbenzene 1,4-diethylbenzene\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\n[1]\nNI\nETIRW\n(ii) Explain why there is very little 1,3-diethylbenzene in the product mixture.\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) 1,2-diethylbenzene can be oxidised to benzene-1,2-dioic acid, C H (COOH) .\nSIHT 6 4 2\nbenzene-1,2-dioic acid NI\nETIRW\nCOOH\nTON\nOD COOH\n(i) State the reagent and conditions used for this reaction.\nNIGRAM\n..................................................................................................................................... [1]\n(ii) Complete the overall equation for this reaction.\nSIHT\nNI An atom of oxygen from the oxidising agent is represented as [O].\nETIRW\nAll of the atoms in the two ethyl groups are fully oxidised in this reaction.\nTON\nOD\nC H (COOH) + ................................ + ................................ ................................. + ................. [O]\n6 4 2\n(1,2-diethylbenzene)\n[2]\nNIGRAM\n(iii) Predict the number of peaks in the carbon-13 NMR spectrum of benzene-1,2-dioic acid.\nSIHT ..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(1H) (d) The proton NMR spectra of ethylbenzene, C H C H , in CDCl and of benzene-1,2-dioic\nSIHT 6 5 2 5 3\nH (COOH) , in CDCl are shown. They have not been identified. acid, C\n6 4 2 3\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\n4 3 2 1 0 11 10 9 8 7 6 5\nOD\n/ ppm δ\nFig. 6.1\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n16 14 12 10 8 6 4 2 0\nδ / ppm\nTON\nOD Fig. 6.2\n, instead of CHCl , as the solvent when obtaining these spectra. (i) Explain the use of CDCl\n3 3\nNIGRAM ..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(ii) Identify the substanc", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2024-on-43-q06-55fce4a4cb.pdf" }, { "id": "9701-2024-on-43-q07", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2024-on-43-q07-p01-7600c820bd.png", "9701-topic-36-organic-synthesis/assets/9701-2024-on-43-q07-p02-bd03fd8dca.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 A reaction scheme is shown in Fig. 7.1.\nSIHT\nNI The reagents needed for reaction 2 and reaction 3 are stated.\nETIRW\nH NH is mixed with compound V. No special conditions are Reaction 5 takes place when C\n2 5 2\nTON required.\nOD\nreaction 1\ncompound U CH COOH\n3\nNIGRAM\nreaction 3 reaction 2\nSIHT reagent = SOCl reagent = LiAl H\n4 2\nNI\nETIRW\nTON compound W C H NH compound V\n2 5 2\nOD\nreaction 4 reaction 5\nNIGRAM\nreaction 6 SIHT\nC H NHC H C H NHCOCH\n2 5 2 5 2 5 3\nNI\nETIRW\nTON Fig. 7.1\nOD\n(a) Identify compound U which contains only three elements.\n............................................................................................................................................. [1]\nNIGRAM\n(b) Describe the reagents and conditions for reaction 1.\n............................................................................................................................................. [1] SIHT\nNI\n(c) Identify compound V.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD (d) Complete the equation for reaction 3.\n...................................................................................................... [1] COOH + SOCl CH\n3 2\nNIGRAM (e) Identify compound W.\n............................................................................................................................................. [1]\nSIHT\n(f) Describe the conditions for reaction 4. NI\nETIRW\n............................................................................................................................................. [1]\nTON\nNIGRAM\n(g) Suggest the reagent needed for reaction 6.\nSIHT\nNI ............................................................................................................................................. [1]\nETIRW\n(h) Complete Table 7.1 by adding the reaction numbers, 1, 2, 3, 4, 5 and 6, to the right-hand\nTON column. Use the reaction numbers given in Fig. 7.1.\nOD\nEach of the numbers 1, 2, 3, 4, 5 and 6 should be used once only.\nTable 7.1\nNIGRAM\ntype of reaction reaction number(s)\nhydrolysis SIHT\naddition NI\nETIRW\nreduction\nTON\nsubstitution\nOD [4]\nH NHCOCH , C H NHC H and NH . (i) Compare the basicities of C\n2 5 3 2 5 2 5 3\nNIGRAM Explain your answer.\n............................................ ................................. ........... ............................................\nSIHT\nmost basic least basic\nNI\nETIRW ...................................................................................................................................................\n................................................................................................................................................... TON\nOD\n.....................................................................................................", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2024-on-43-q07-b740496bee.pdf" }, { "id": "9701-2024-on-43-q08", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_43.pdf?download=true", "source_pages": [ 20, 23, 24 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_43.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-43-q08-p01-89118748be.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-43-q08-p02-4c2a89a02a.png", "9701-topic-32-hydroxy-compounds/assets/9701-2024-on-43-q08-p03-139933076e.png" ], "answer": { "status": "pending", "id": "9701-2024-on-43-q08", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n8 (a) An aqueous solution of phenol, C H OH, is acidic at 298 K.\nSIHT 6 5\nNI Explain why phenol is more acidic than water .\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\n(aq). (b) (i) Name the two products formed when phenol reacts with an excess of Br\nNIGRAM 2\n............................................................... and ............................................................... [1]\nSIHT\n= 139, that are formed (ii) Draw the structures of the two isomeric organic products, with M\nr NI\n(aq) at room temperature. when phenol reacts with HNO\nETIRW 3\nTON\nOD\nNIGRAM\nSIHT\nNI\n[1] ETIRW\nH OH, and sodium metal. (iii) Write the equation for the reaction between phenol, C\nTON 6 5\nOD ..................................................................................................................................... [1]\n(c) Phenol can be produced from phenylamine in a two-step synthesis.\nNIGRAM step one step two\nintermediate compound phenol phenylamine\nSIHT\nDescribe the reagents and conditions needed in each step.\nNI\nETIRW step one:\nTON reagents ....................................................................................................................................\nOD\nconditions .................................................................................................................................\nstep two:\nNIGRAM\nreagents ....................................................................................................................................\nconditions ................................................................................................................................. SIHT\n[2]\nNI\nETIRW\n[Total: 7]\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.022 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas V\nm\ndm3 mol–1 V = 24.0 at room conditions\nNIGRAM m\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nSIHT\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nSIHT\nnossenago\nnotpyrk 3.131 muileh nonex gO nogra nodar eN nR eH eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nNI\nETIRW\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 0.571 9.6", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2024-on-43-q08-ec7c009830.pdf" }, { "id": "9701-2024-on-51-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-51-q01-p01-bc7dbb664e.png", "9701-experimental-skills/assets/9701-2024-on-51-q01-p02-a194a774f8.png", "9701-experimental-skills/assets/9701-2024-on-51-q01-p03-472e07b132.png", "9701-experimental-skills/assets/9701-2024-on-51-q01-p04-463501ce76.png" ], "answer": { "status": "pending", "id": "9701-2024-on-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 A student uses the following method to determine the percentage by mass of the painkiller aspirin,\nSIHT\nH O (s), in some tablets. C\n9 8 4\nNI\nETIRW\nstep 1 Grind five tablets into a powder.\nTON step 2 Use a weighing boat to accurately weigh by dif ference approximately 0.4 g of powdered\ntablets into a pear‑shaped flask containing anti‑bumping granules.\nOD\ncm3 dm–3 of aqueous 1 mol sodium hydroxide, NaOH(aq), to the pear‑shaped step 3 Add 25\nflask, forming mixture A.\nNIGRAM\nstep 4 Reflux mixture A for 20 minutes.\nstep 5 Allow mixture A to cool and then filter into a small beaker. Label the filtrate solution B. SIHT\nNI\ncm3 of alkaline aqueous iodine to solution B and leave to stand for 1 hour . A step 6 Add 30\nETIRW\nH I O) (s), will form. precipitate, C, (C\n6 2 2 2\nTON\nstep 7 Filter the resulting mixture under reduced pressure. W ash the residue, C, with a small\nOD volume of cold distilled water.\nstep 8 Allow solid C to dry.\nNIGRAM step 9 Weigh solid C and record its mass.\nAlkaline aqueous iodine is irritating to the skin and eyes.\nSIHT\n(a) Identify an appropriate precaution, other than eye protection and a lab coat, that the student NI\nETIRW should take when using alkaline aqueous iodine.\n................................................................................................................................................... TON\nOD\n............................................................................................................................................. [1]\n(b) Describe how the student should carry out step 2. Include a results table, with appropriate\nheadings, for the student to fill in.\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\nNIGRAM\n(c) Complete Fig. 1.1 to show how step 4 is carried out in the laboratory.\nSIHT\nLabel your diagram fully . NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\npear-shaped flask\nmixture A\nNIGRAM + anti-bumping granules\nSIHT\nheat NI\nETIRW\nFig. 1.1\nTON [2]\nOD\n(d) (i) The student uses a measuring cylinder to measure the volume of alkaline aqueous\niodine in step 6. Suggest why this is a suitable piece of apparatus to use.\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\n(ii) Suggest why the student lea", "pdf_path": "9701-experimental-skills/print/9701-2024-on-51-q01-a11e62566e.pdf" }, { "id": "9701-2024-on-51-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_51.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 12, 13, 15, 16 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-51-q02-p01-8d1a1694a4.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p02-cef6a6c7e9.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p03-543d643d2a.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p04-e8645f72bc.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p05-9b6d395983.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p06-04f2166689.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p07-db053d9cba.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p08-eb36207ef7.png", "9701-experimental-skills/assets/9701-2024-on-51-q02-p09-9447f3dc70.png" ], "answer": { "status": "pending", "id": "9701-2024-on-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 Crystal violet, C H N Cl (s), is a purple dye.\nSIHT 25 30 3\nNI H N Cl (aq). Some light is absorbed when it passes through C\n25 30 3\nETIRW\nAbsorbance is the proportion of light absorbed at a particular wavelength. This is measured using\nTON a colorimeter.\nOD\nH N Cl (aq) is shown in Fig. 2.1. A graph of absorbance against wavelength for C\n25 30 3\nNIGRAM\necnabrosba\nSIHT\nNI\nETIRW\n400 450 500 550 600 650 700\nTON\n/ nm wavelength\nOD\nFig. 2.1\nA student investigates how to determine the concentration of aqueous crystal violet, NIGRAM\nH N Cl (aq), using colorimetry. C\n25 30 3\nSIHT (a) Suggest the best wavelength of light to use in the colorimeter when m easuring the\nH N Cl (aq). concentration of C\nNI 25 30 3\nETIRW\nwavelength = .............................. nm [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 10–2 dm–3 (b) Solution D is 500.0 of 2.50 × mol C H N Cl (aq).\nSIHT 25 30 3\nNI H N Cl (s) needed to prepare solution D. (i) Calculate the mass of C\n25 30 3\nETIRW\nGive your answer to three significant figures.\nTON\n: C H N Cl (s), 407.5] [M\nOD r 25 30 3\nNIGRAM\nH N Cl (s) = .............................. g [1] mass of C SIHT\n25 30 3\nNI\nH N Cl (s) calculated (ii) The student is given a small beaker containing the mass of C\nETIRW 25 30 3\nin (i).\nTON\ncm3 of solution D. Describe how the student should prepare 500.0\nOD\nInclude the name and capacity of the key apparatus which should be used and describe\ncm3. how the student should ensure the volume is exactly 500.0\nNIGRAM ...........................................................................................................................................\n...........................................................................................................................................\nSIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n– 4 dm–3 (c) A small sample of solution D was diluted to form solution E, 2.50 × 10 mol\nSIHT\nH N Cl(aq). C\n25 30 3\nNI\nETIRW\nThe student prepares solutions 2 to 6 as shown in Table 2.1.\nTON cm3. The total volume needed for each of solutions 2 to 6 is 20.00\nOD\nEach solution is placed into a colorimeter and the absorb", "pdf_path": "9701-experimental-skills/print/9701-2024-on-51-q02-74501d2654.pdf" }, { "id": "9701-2024-on-52-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-52-q01-p01-221db28912.png", "9701-experimental-skills/assets/9701-2024-on-52-q01-p02-2d8ba0c0d6.png", "9701-experimental-skills/assets/9701-2024-on-52-q01-p03-26fb3a6f2b.png", "9701-experimental-skills/assets/9701-2024-on-52-q01-p04-597c40ba51.png" ], "answer": { "status": "pending", "id": "9701-2024-on-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Solution X is dilute hydrochloric acid of unknown concentration. A student uses titration with\nSIHT\nCO (aq), to determine the concentration of solution X. aqueous sodium carbonate, Na\n2 3\nNI\nETIRW cm3 dm–3 of 0.500 mol aqueous sodium carbonate, The student plans to prepare 250.0\nCO (aq). Na\n2 3\nTON\ncm3 dm–3 CO (s) needed to make 250.0 of 0.500 mol (a) (i) Calculate the mass of Na\nOD 2 3\nCO (aq), using a two decimal place balance. Na\n2 3\nNIGRAM\nCO (s) = .............................. g [1] mass of Na SIHT\n2 3\nNI\ncm3 dm–3 of 0.500 mol Na CO (aq) starting (ii) Describe how the student should make 250.0\nETIRW 2 3\ncm3 CO (s) calculated in (i) supplied in a 50 beaker. from the mass of Na\n2 3\nTON\nGive the name and size of any key apparatus to be used.\nOD\nWrite your answer using a series of numbered steps.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW ...........................................................................................................................................\n........................................................................................................................................... TON\nOD\n...........................................................................................................................................\n..................................................................................................................................... [3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 (b) The student incorrectly makes up the 250.0 of Na CO (aq) and the concentration is not\nSIHT 2 3\ndm–3. The student calls this solution Y. 0.500 mol\nNI\nETIRW\nThe student uses the following method to determine both the concentration of solution X and\nthe concentration of solution Y.\nTON\ncm3 of solution Y into a conical flask using a volumetric pipette. Add a step 1 Transfer 25.0\nOD\nfew drops of methyl orange.\nstep 2 Titrate the sample in the conical flask with solution X.\nNIGRAM\ncm3 portion of solution Y into a second conical flask, but do not step 3 Transfer a fresh 25.0\nadd methyl orange.\nSIHT\nstep 4 Use the burette to add the volume of solution X used in step 2 to the second conical\nNI\nflask.\nETIRW\nstep 5 Measure and record the mass of a dry evaporating basin.\nTON\nOD step 6 Transfer the contents of the second conical flask into the evaporating basin.\nstep 7 Use a water bath to heat the solution in the evaporating basin until all the water is\nevaporated and only solid remains.\nNIGRAM\nst", "pdf_path": "9701-experimental-skills/print/9701-2024-on-52-q01-ca6cfd7419.pdf" }, { "id": "9701-2024-on-52-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 12 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-52-q02-p01-6ea169d398.png", "9701-experimental-skills/assets/9701-2024-on-52-q02-p02-c6d1b83af2.png", "9701-experimental-skills/assets/9701-2024-on-52-q02-p03-287f386f5d.png", "9701-experimental-skills/assets/9701-2024-on-52-q02-p04-d80b58b785.png", "9701-experimental-skills/assets/9701-2024-on-52-q02-p05-01fea22b5c.png", "9701-experimental-skills/assets/9701-2024-on-52-q02-p06-7e72400d48.png" ], "answer": { "status": "pending", "id": "9701-2024-on-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 A group of students uses the following method to investigate the change in mass that takes place\nSIHT\nwhen metal M combines with sulfur to form a metal sulfide.\nNI\nETIRW\nstep 1 Weigh a clean crucible and lid using a balance. Record the mass.\nTON step 2 Place a coiled length of metal wire into the crucible and weigh the crucible, lid and wire.\nOD\nstep 3 Cover the metal wire in the crucible with a large quantity of powdered sulfur and replace\nthe lid.\nstep 4 Heat the crucible in a fume hood until the crucible glows red. Continue heating strongly\nNIGRAM\nuntil no more sulfur can be seen.\nstep 5 Allow the apparatus to cool and weigh the crucible, lid and residue. SIHT\nNI\nlid coiled length of metal wire\nETIRW\ncovered with sulfur\ncrucible\nTON\nOD\ntripod\nheat NIGRAM\nSIHT\nNI\nETIRW\nFig. 2.1\nTON\n(a) (i) Fig. 2.1 shows how the apparatus is set up when heating the crucible in step 4.\nOD\nIdentify the missing piece of apparatus used to support the crucible during heating.\n..................................................................................................................................... [1]\nNIGRAM\n(ii) Suggest why the students heat their crucibles in a fume hood in step 4.\nSIHT\n...........................................................................................................................................\nNI\nETIRW ..................................................................................................................................... [1]\n(iii) Suggest why a large quantity of powdered sulfur is used in step 3. TON\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Five students each use a different mass of M.\nSIHT\nNI Their results are shown in Table 2.1.\nETIRW\nComplete Table 2.1 by inserting values for the mass of M and the mass of sulfur which reacts\nTON for each student.\nOD\nTable 2.1\nstudent 1 student 2 student 3 student 4 student 5\nNIGRAM\nmass of crucible and lid / g 34.15 38.28 35.68 33.70 36.84\nSIHT\nmass of crucible, lid and M / g 35.58 39.42 36.54 34.27 37.13\nNI\nETIRW\nmass of crucible, lid and\n36.04 39.70 36.74 34.42 37.19\nresidue after heating / g\nTON\nOD mass of M / g\nmass of sulfur which reacts / g\nNIGRAM\n[1]\nSIHT\n(c) Identify the independent variable in this experiment.\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) (i) Plot a graph on the grid in Fig. 2.2 to show the relationship between mass of sulfur which\nSIHT\nreacts and mass of M.\nNI\nETIRW\nUse a cross (×) to p", "pdf_path": "9701-experimental-skills/print/9701-2024-on-52-q02-761106339c.pdf" }, { "id": "9701-2024-on-53-q01", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-53-q01-p01-bc7dbb664e.png", "9701-experimental-skills/assets/9701-2024-on-53-q01-p02-a194a774f8.png", "9701-experimental-skills/assets/9701-2024-on-53-q01-p03-472e07b132.png", "9701-experimental-skills/assets/9701-2024-on-53-q01-p04-463501ce76.png" ], "answer": { "status": "pending", "id": "9701-2024-on-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 A student uses the following method to determine the percentage by mass of the painkiller aspirin,\nSIHT\nH O (s), in some tablets. C\n9 8 4\nNI\nETIRW\nstep 1 Grind five tablets into a powder.\nTON step 2 Use a weighing boat to accurately weigh by dif ference approximately 0.4 g of powdered\ntablets into a pear‑shaped flask containing anti‑bumping granules.\nOD\ncm3 dm–3 of aqueous 1 mol sodium hydroxide, NaOH(aq), to the pear‑shaped step 3 Add 25\nflask, forming mixture A.\nNIGRAM\nstep 4 Reflux mixture A for 20 minutes.\nstep 5 Allow mixture A to cool and then filter into a small beaker. Label the filtrate solution B. SIHT\nNI\ncm3 of alkaline aqueous iodine to solution B and leave to stand for 1 hour . A step 6 Add 30\nETIRW\nH I O) (s), will form. precipitate, C, (C\n6 2 2 2\nTON\nstep 7 Filter the resulting mixture under reduced pressure. W ash the residue, C, with a small\nOD volume of cold distilled water.\nstep 8 Allow solid C to dry.\nNIGRAM step 9 Weigh solid C and record its mass.\nAlkaline aqueous iodine is irritating to the skin and eyes.\nSIHT\n(a) Identify an appropriate precaution, other than eye protection and a lab coat, that the student NI\nETIRW should take when using alkaline aqueous iodine.\n................................................................................................................................................... TON\nOD\n............................................................................................................................................. [1]\n(b) Describe how the student should carry out step 2. Include a results table, with appropriate\nheadings, for the student to fill in.\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\nNIGRAM\n(c) Complete Fig. 1.1 to show how step 4 is carried out in the laboratory.\nSIHT\nLabel your diagram fully . NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\npear-shaped flask\nmixture A\nNIGRAM + anti-bumping granules\nSIHT\nheat NI\nETIRW\nFig. 1.1\nTON [2]\nOD\n(d) (i) The student uses a measuring cylinder to measure the volume of alkaline aqueous\niodine in step 6. Suggest why this is a suitable piece of apparatus to use.\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\n(ii) Suggest why the student lea", "pdf_path": "9701-experimental-skills/print/9701-2024-on-53-q01-f04c1cbfcc.pdf" }, { "id": "9701-2024-on-53-q02", "subject": "9701", "year": 2024, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2024-oct-nov/9701_w24_qp_53.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 12, 13, 15, 16 ], "local_pdf": "_source-pdfs/2024-Oct-Nov/qp/9701_w24_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2024-on-53-q02-p01-8d1a1694a4.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p02-cef6a6c7e9.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p03-543d643d2a.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p04-e8645f72bc.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p05-9b6d395983.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p06-04f2166689.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p07-db053d9cba.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p08-eb36207ef7.png", "9701-experimental-skills/assets/9701-2024-on-53-q02-p09-9447f3dc70.png" ], "answer": { "status": "pending", "id": "9701-2024-on-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 Crystal violet, C H N Cl (s), is a purple dye.\nSIHT 25 30 3\nNI H N Cl (aq). Some light is absorbed when it passes through C\n25 30 3\nETIRW\nAbsorbance is the proportion of light absorbed at a particular wavelength. This is measured using\nTON a colorimeter.\nOD\nH N Cl (aq) is shown in Fig. 2.1. A graph of absorbance against wavelength for C\n25 30 3\nNIGRAM\necnabrosba\nSIHT\nNI\nETIRW\n400 450 500 550 600 650 700\nTON\n/ nm wavelength\nOD\nFig. 2.1\nA student investigates how to determine the concentration of aqueous crystal violet, NIGRAM\nH N Cl (aq), using colorimetry. C\n25 30 3\nSIHT (a) Suggest the best wavelength of light to use in the colorimeter when m easuring the\nH N Cl (aq). concentration of C\nNI 25 30 3\nETIRW\nwavelength = .............................. nm [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 10–2 dm–3 (b) Solution D is 500.0 of 2.50 × mol C H N Cl (aq).\nSIHT 25 30 3\nNI H N Cl (s) needed to prepare solution D. (i) Calculate the mass of C\n25 30 3\nETIRW\nGive your answer to three significant figures.\nTON\n: C H N Cl (s), 407.5] [M\nOD r 25 30 3\nNIGRAM\nH N Cl (s) = .............................. g [1] mass of C SIHT\n25 30 3\nNI\nH N Cl (s) calculated (ii) The student is given a small beaker containing the mass of C\nETIRW 25 30 3\nin (i).\nTON\ncm3 of solution D. Describe how the student should prepare 500.0\nOD\nInclude the name and capacity of the key apparatus which should be used and describe\ncm3. how the student should ensure the volume is exactly 500.0\nNIGRAM ...........................................................................................................................................\n...........................................................................................................................................\nSIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n– 4 dm–3 (c) A small sample of solution D was diluted to form solution E, 2.50 × 10 mol\nSIHT\nH N Cl(aq). C\n25 30 3\nNI\nETIRW\nThe student prepares solutions 2 to 6 as shown in Table 2.1.\nTON cm3. The total volume needed for each of solutions 2 to 6 is 20.00\nOD\nEach solution is placed into a colorimeter and the absorb", "pdf_path": "9701-experimental-skills/print/9701-2024-on-53-q02-dba692a650.pdf" }, { "id": "9701-2025-m-42-q01", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-m-42-q01-p01-3a7731ab36.png", "9701-topic-23-chemical-energetics/assets/9701-2025-m-42-q01-p02-b2e531e219.png", "9701-topic-23-chemical-energetics/assets/9701-2025-m-42-q01-p03-5e5bad1545.png", "9701-topic-23-chemical-energetics/assets/9701-2025-m-42-q01-p04-95aa0c68f3.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Silver, Ag, is a metal in the d-block of the Periodic Table.\nSIHT\nAg+ Ag2+ NI or ions. (a) Silver can form compounds containing either\nETIRW\nExplain why silver is a transition element.\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\nsilver(I) fluoride, AgF. (b) Table 1.1 gives data relevant to the Born–Haber cycle for\nNIGRAM\nTable 1.1\nSIHT\nmo–l1 standard energy change value / kJ NI\nETIRW\nfirst ionisation energy of silver +732\nTON\nenthalpy change of atomisation of silver +289\nOD\nenthalpy change of atomisation of fluorine +79\nsilver(I) –203 fluoride enthalpy change of formation of\nNIGRAM silver(I) –955 fluoride lattice energy of\n(i) Write equations for the standard enthalpy changes described. SIHT\nInclude state symbols.\nNI\nETIRW\n• standard enthalpy change of atomisation of silver\nTON\n...........................................................................................................................................\nOD\n• silver(I) standard enthalpy change of formation of fluoride\n...........................................................................................................................................\n[2] NIGRAM\n(ii) Define lattice energy.\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Calculate the first electron affinity, EA , of fluorine, using data from Table 1.1.\nSIHT 1\nNI It may be helpful to draw a labelled energy cycle as part of the working for your answer.\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nmol–1 = .............................. kJ [2] EA\n1\nSIHT\n, of AgF(s). (c) (i) Use the data in Table 1.2 to calculate the enthalpy change of solution, ΔH\nsol\nNI\nTable 1.2 ETIRW\nTON mo–l1 energy change at 298 K value / kJ\nOD\nlattice energy of AgF(s) –955\nAg+(g) –464 enthalpy change of hydration of\nF–(g) NIGRAM –506 enthalpy change of hydration of\nSIHT\nNI\nETIRW\nTON\nOD\nmol–1 ΔH of AgF(s) = .............................. kJ [1]\nsol\nNIGRAM (ii) Use your answer to (c)(i) to suggest whether AgF is soluble in water at 298 K. Explain\nyour answer.\nSIHT\n...........................................................................................................................................\nNI\nETIRW ................................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-m-42-q01-ed6ebb602b.pdf" }, { "id": "9701-2025-m-42-q02", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 6, 7, 8, 9 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-m-42-q02-p01-17c67ddc13.png", "9701-topic-25-equilibria/assets/9701-2025-m-42-q02-p02-4351ce61a6.png", "9701-topic-25-equilibria/assets/9701-2025-m-42-q02-p03-478aee379d.png", "9701-topic-25-equilibria/assets/9701-2025-m-42-q02-p04-94659bad35.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 Propanone, CH COCH , is a common organic solvent and reagent.\nSIHT 3 3\nNI OH, under acidic conditions to form compound A, as (a) Propanone reacts with methanol, CH\n3\nETIRW\nshown by reaction 1.\nA TON\nCH O OCH OD\n3 3 H+\n+ H C O reaction 1 CH COCH + 2CH OH\n2 3 3 3 C CH H\n3 3\nNIGRAM\nFig. 2.1\nThe overall order of reaction 1 can be found by studying experimental data. SIHT\nNI\n[H+] OH] and are varied. In T able 2.1 shows how the initial rate of reaction changes as [CH\nETIRW 3\nCOCH is used. each experiment, a large excess of CH\n3 3\nTON\nTable 2.1\nOD\n[H+] [CH OH] relative initial\nexperiment 3\ndm–3 dm–3 / mol / mol rate of reaction\nNIGRAM 1 0.010 0.010 1.00\n2 0.015 0.015 2.25\nSIHT\n3 0.015 0.020 3.00\nNI\nETIRW\nCOCH is used in each experiment. (i) Explain why a large excess of CH\n3 3\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nCHOH and (ii) Use the data in Table 2.1 to determine the order of reaction 1 with respect to\n3\nH+ ions. Explain your answers. to\nSIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nH+ (iii) In a separate experiment, a large excess of CH OH and ions are added to a solution\nSIHT 3\nCOCH . containing a known concentration of CH\n3 3\nNI\nETIRW\nCOCH ] varies over time. Fig. 2.2 shows how [CH\n3 3\n100 TON\nOD\n90\n80\nNIGRAM\n70\nSIHT\n60\nNI % of the original\nETIRW\n[CH COCH ] 50\n3 3\nremaining\nTON\n40\nOD\n30\n20\nNIGRAM\n10\nSIHT\n0\nNI 0 100 200 300 400 500\nETIRW\n/ s time\nTON\nFig. 2.2\nOD\nUse Fig. 2.2 to show how, under these conditions, reaction 1 is first order with respect to\nCOCH . CH\n3 3\nNIGRAM\n...........................................................................................................................................\n...........................................................................................................................................\nSIHT\nNI ", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-m-42-q02-6823c37a04.pdf" }, { "id": "9701-2025-m-42-q03", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-m-42-q03-p01-a9afdc9ec1.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-m-42-q03-p02-1e03c60494.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-m-42-q03-p03-37dc5c4d49.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q03", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\nFe2+ Fe3+ 3 and ions are able to form a variety of complexes with different species.\nSIHT\nNI (a) (i) Define complex.\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nFe2+ Fe3+. and of (ii) Table 3.1 gives some details of different complexes of\nNIGRAM\nComplete Table 3.1.\nSIHT\nTable 3.1\nNI\nETIRW\ncoordination formula and charge\ncomplex ion ligand\nnumber of complex TON\nOD\nFe2+ NH 6 E\n3\n]2– F [FeCl\n4\nNIGRAM\n]3+ G en [Fe(en)\n3\nSIHT\n[3]\nNI\nETIRW\n(iii) Complete Fig. 3.1 to show the splitting of the d-orbitals in a tetrahedral complex.\nTON\nOD\nNIGRAM\nenergy\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 3.1\nNIGRAM\n[1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nFe3+. (b) Table 3.2 gives details of some complexes of\nSIHT\nNI Table 3.2\nETIRW\ncomplex colour value of K\nstab TON\n]3+ [Fe(H O) violet 1\nOD 2 6\nSCN]2+ 102 O) red 1.40 × [Fe(H\n2 5\nF]2+ 105 [Fe(H O) colourless 2.40 ×\n2 5\nNIGRAM\n]3+ (i) Explain the reason for the dif ference in colour of the two complexes [Fe(H O) and\n2 6\nSCN]2+. O) [Fe(H\n2 5 SIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [2]\nSCN]2+. of [Fe(H O) (ii) Write an expression for K\nstab 2 5 NIGRAM\nK = SIHT\nstab\nNI\nETIRW\n[1]\nTON\n(iii) Use information in Table 3.2 to calculate the value of the equilibrium constant, K , for the\nc\nfollowing reaction. OD\nSCN]2+ F– F]2+ SCN– O) + [Fe(H O) + [Fe(H\n2 5 2 5\nNIGRAM\nSIHT\nNI\nETIRW\nK = .............................. [1]\nc\nTON ]3+(aq), O) followed by a few (iv) A few drops of KF(aq) are added to a solution of [Fe(H\n2 6\ndrops of KSCN(aq).\nOD\nUse information in Table 3.2 to describe any observations after each addition. Explain\nyour answer.\nNIGRAM\n...........................................................................................................................................\nSIHT ...........................................................................................................................................\nNI\n..................................................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-m-42-q03-21e0ba27b2.pdf" }, { "id": "9701-2025-m-42-q04", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-m-42-q04-p01-e7573f9c5c.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-m-42-q04-p02-0c8fdd515d.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-m-42-q04-p03-7181e25a33.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q04", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:4)(cid:44)\n4 (a) State the difference in the basicities of ammonia, NH , propanamide, CH CH CONH , and\nSIHT 3 3 2 2\nCH CH NH . propylamine, CH\n3 2 2 2\nNI\nETIRW\nExplain your answer .\nTON\n.............................................. < .............................................. < .............................................\nOD\nweakest base strongest base\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n................................................................................................................................................... SIHT\nNI\n...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\nOD ...................................................................................................................................................\n[4]\n(b) Fig. 4.1 shows two different ways to synthesise propylamine.\nNIGRAM\nNH\n3\nK CH CH CONH\nM 3 2 2 SIHT\nNI\nCH CH NH CH ETIRW\n3 2 2 2\nM\nTON KCN in ethanol\nCH CH Br L\n3 2 OD\nFig. 4.1\nIdentify compounds K and L and reagent M from Fig. 4.1. NIGRAM\nK ...............................................................................................................................................\nSIHT\nL ...............................................................................................................................................\nNI\nETIRW\nM ...............................................................................................................................................\n[3] TON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Compound N is shown in Fig. 4.2.\nSIHT\nN NI\nETIRW\nO\nH\nTON N\nN\nOD H\nO\nCH O\n3\nNIGRAM\nFig. 4.2\nCompound N is treated with an excess of concentrated HCl (aq). SIHT\nNI\nN undergoes complete hydrolysis to form three organic products.\nETIRW\nThe products are isolated from the reaction mixture at pH 4.\nTON\nDraw the structures of the three organic products at pH 4. OD\nO— group does not react. Assume that the CH\n3\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n[4]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Compound P can be synthesised from 1-methyl-4-nitrobenzene by the route shown in\nSIHT\nFig. 4.3.\nNI\n1-methyl-4-nitrobenzene ETIRW\nCH CH CH\n3 3 3 TON\nOD\nstep 1 step 2\nNIGRAM\nNO ) NH N(CH\n2 2 2 3\nSIHT\nstep 3\nNI\nETIRW\nP\nTON\nO O\nCOOH C\nOD\nstep 4\nNIGRAM\n) N(CH ) N(CH\nSIHT 3 2 3 2\nNI Fig. 4.3\nETIRW\n(i) Step 1 is a reduction reaction.\nTON\nComplete the equation for this reaction", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-m-42-q04-73c9c58f4c.pdf" }, { "id": "9701-2025-m-42-q05", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 16, 17, 18, 19, 20 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2025-m-42-q05-p01-20d0b67a88.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-m-42-q05-p02-1b68d0fee4.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-m-42-q05-p03-46473b9292.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-m-42-q05-p04-6dec905f9a.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-m-42-q05-p05-4d23f5f96b.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q05", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n5 Cumene is an aromatic hydrocarbon used in the synthesis of other useful chemicals.\nSIHT\ncumene NI\nETIRW\nTON\nOD\nFig. 5.1\nNIGRAM\n2 3 and sp hybridised carbon atoms that are (a) Complete Table 5.1 to show the number of sp\npresent in a molecule of cumene. SIHT\nNI\nTable 5.1\nETIRW\nsp2 sp3 type of hybridisation TON\nOD\nnumber of carbon atoms\n[1]\nNIGRAM\n(b) Cumene can be synthesised via a Friedel–Crafts alkylation reaction, as shown in Fig. 5.2.\nSIHT\nNI\n+ HBr\nETIRW +\nBr\nTON\nFig. 5.2 OD\n(i) Name the mechanism involved in the Friedel–Crafts alkylation shown in Fig. 5.2.\n..................................................................................................................................... [1] NIGRAM\nCH+ ) cation. (ii) The first step of the reaction forms the (CH\n3 2 SIHT\nIdentify a suitable reagent for the formation of this cation from 2-bromopropane,\nNI\n) CHBr. (CH ETIRW\n3 2\n..................................................................................................................................... [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nCH+ (iii) Complete Fig. 5.3 to show the mechanism for the reaction of benzene with the (CH)\nSIHT 3 2\ncation.\nNI\nETIRW\nInclude all relevant curly arrows and charges.\nTON\nintermediate\nOD\nCH+ ) (CH\n3 2\n+\n..............\nNIGRAM\nSIHT\nNI\nETIRW\nFig. 5.3 TON\n[3]\nOD\nCH CH Br, also (iv) The Friedel–Crafts alkylation of benzene by 1-bromopropane, CH\n3 2 2\nproduces cumene as the major product.\nNIGRAM\nCH+ + CH CH cation formed in the first step quickly rearranges to form the (CH ) The CH\n3 2 2 3 2\ncation.\nSIHT\nSuggest why this is the case. Explain your answer.\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Cumene oxidises in air to form phenol, C H OH, and propanone, CH COCH .\nSIHT 6 5 3 3\no mo–l1 NI H CH(CH ) + O → C H OH + CH COCH ΔH = –371 kJ reaction 1 C\n6 5 3 2 2 6 5 3 3\nETIRW\nT able 5.2 gives some relevant standard entropies for reaction 1.\nTON\nTable 5.2\nOD\ncompound C H CH(CH ) O C H OH CH COCH\n6 5 3 2 2 6 5 3 3\nstandard entropy,\nNIGRAM\n278 205 146 200\no K–1 mol–1 / J S\nSIHT o , of reaction 1. (i) Calculate the standard entropy change, ΔS\nNI\nETIRW\nTON\nOD\no NIGRAM K–1 mol–1 = .............................. J [1] ΔS\n(ii) Show that reaction 1 is feasible at 25 °C.\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\n[2]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Fig. 5.4 shows two reactions of phenol.\nSIHT\nNI\nQ\nETIRW\nTON\nOD Br\n2\nphenol\nreaction 2\nNIGRAM\nOH\nR and\nS", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2025-m-42-q05-5c32a9d970.pdf" }, { "id": "9701-2025-m-42-q06", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_42.pdf?download=true", "source_pages": [ 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p01-b1fe27db57.png", "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p02-59f91c3367.png", "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p03-3f457432a1.png", "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p04-e70ba15e6d.png", "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p05-120c46d48e.png", "9701-topic-37-analytical-techniques/assets/9701-2025-m-42-q06-p06-8a22956f2e.png" ], "answer": { "status": "pending", "id": "9701-2025-m-42-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n6 (a) Maleic anhydride is an unsaturated cyclic compound used in the formation of several\nSIHT\npolymers.\nNI\nETIRW\nMaleic anhydride can be used to form maleic acid and tartaric acid.\nmaleic anhydride maleic acid tartaric acid TON\nOD\nHO OH\nreaction 1 reaction 2\nHOOC COOH\nHOOC COOH O O\nNIGRAM O\nFig. 6.1 SIHT\nNI\n(i) Maleic acid reacts with ethane-1,2-diol to form a condensation polymer.\nETIRW\nDraw a section of this polymer, showing only one repeat unit.\nTON\nThe new functional group formed should be shown fully displayed. OD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\n(ii) Identify a suitable reagent and the conditions for reaction 2.\nOD\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Compound U can be formed from tartaric acid in two steps, as shown in Fig. 6.2.\nSIHT\ntartaric acid T U NI\nETIRW\nCOCH CH\n3 3 TON OH HO\nH+ and\nO O O O\nOD\nstep 2 step 1\nHOOC COOH\n–OOC COO– COOH HOOC\nNIGRAM\nFig. 6.2\n(i) Suggest the type of reaction that occurs in step 1. SIHT\nNI\n..................................................................................................................................... [1]\nETIRW\n(ii) U can act as a bidentate ligand.\nTON\nExplain what is meant by a bidentate ligand. OD\n...........................................................................................................................................\n..................................................................................................................................... [2] NIGRAM\n(iii) Complete the three-dimensional diagrams in Fig. 6.3 to show both stereoisomers of\nSIHT ]4–. [Cu(U)\n3\nNI\nETIRW O O UOse to represent ligand U. O\nTON\nOD\nNIGRAM\nCu Cu Cu Cu\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 6.3\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) A student analyses an aromatic compound, X, C H O , using NMR spectroscopy.\nSIHT 8 8 3\nNI O. Fig. 6.4 shows the carbon-13 NMR spectrum of a sample of X dissolved in D\n2\nETIRW\nTON\nOD\nNIGRAM\nSIHT\n240 220 200 180 160 140 120 100 80 60 40 20 0\nNI\nETIRW / ppm chemical shift δ\nTON Fig. 6.4\nOD\n1H) NMR spectroscopy. Separate samples of X were analysed using proton (\nT able 6.1 gives information obtained from this analysis.\nNIGRAM\nTable 6.1\nSIHT\nnumber of signals in\nsolvent\n(1H) NMR spectrum proton NI\nETIRW\n6 CDCl\n3\nTON\nO 4 D\n2\nOD\n(i) Identify the number of different carbon environments present in X.\n..................................................................................................................................... [1]\nNIGRAM\n(1H) O before obtaining its proton NMR spectrum. (ii) Explain why X is dissolved in D\n2\nSIHT\n...........................................................................................................................................\nNI\nETIRW ..............................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-m-42-q06-c2e021e9ad.pdf" }, { "id": "9701-2025-m-52-q01", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-m-52-q01-p01-aeb9f2b218.png", "9701-experimental-skills/assets/9701-2025-m-52-q01-p02-3fcfbd5c8c.png", "9701-experimental-skills/assets/9701-2025-m-52-q01-p03-9885a5a22b.png", "9701-experimental-skills/assets/9701-2025-m-52-q01-p04-a205c2e1a8.png" ], "answer": { "status": "pending", "id": "9701-2025-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Brass is an alloy of copper and zinc.\nSIHT\nAn experiment is completed to find the percentage by mass of copper in a sample of brass.\nNI\nETIRW\n. In the experiment, the sample of brass is reacted with an excess of concentrated nitric acid, HNO\n3\nCu2+(aq) Cu2+(aq) ions. The amount of ions formed is determined This forms a solution containing\nTON by titration.\nOD\nA student uses the following method.\nstep 1 Weigh a glass beaker and record the mass.\nNIGRAM\nstep 2 Add approximately 1.00 g of powdered brass to the beaker and record the mass of the\nbeaker and the brass.\nSIHT\n. step 3 Transfer the brass into conical flask A which contains excess concentrated HNO\n3 NI\nETIRW\nstep 4 Reweigh the glass beaker and record the mass.\nTON\nCO (aq), dropwise to flask A until a precipitate of step 5 Add aqueous sodium carbonate, Na\n2 3\ncopper(II) OD carbonate, CuCO (s), appears. Then add dilute ethanoic acid dropwise until\n3\nthe precipitate is fully dissolved.\ncm3 volumetric flask and make up to the step 6 Transfer all the contents of flask A to a 100.0\nNIGRAM mark with distilled water. This is solution B.\ncm3 of solution B into conical flask C. step 7 Transfer 10.0\nSIHT\ncm3, an excess, of aqueous potassium iodide, KI(aq), to flask C. step 8 Add 10 NI\nETIRW\ndm–3 sodium thiosulfate, Na S O (aq), step 9 Titrate the contents of flask C against 0.0600 mol\n2 2 3\nusing starch solution as an indicator. TON\nOD\nstep 10 Repeat steps 7 to 9 until concordant results are obtained.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(a) Both copper and zinc in brass react with concentrated HNO in step 3.\nSIHT 3\nNI (aq) Zn(NO ) (aq) + 2NO (g) + 2H O(l) reaction 1 Zn(s) + 4HNO\n3 3 2 2 2\nETIRW\n(aq) Cu(NO ) (aq) + 2NO (g) + 2H O(l) reaction 2 Cu(s) + 4HNO\n3 3 2 2 2\nTON\nSuggest why step 3 in the experiment should be completed in a fume cupboard.\nOD\n............................................................................................................................................. [1]\n(b) Explain why the glass beaker is reweighed in step 4.\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1]\nNI\nETIRW\ncm3 of solution B in step 7. (c) Name a suitable piece of apparatus to transfer the 10.0\nTON\n............................................................................................................................................. [1]\nOD\n(d) Identify the substance used to rinse the burette before step 9 is done for the first time.\n............................................................................................................................................. [1]\nNIGRAM\ndm–3 Na S O (aq) is used. (e", "pdf_path": "9701-experimental-skills/print/9701-2025-m-52-q01-7dc517b60e.pdf" }, { "id": "9701-2025-m-52-q02", "subject": "9701", "year": 2025, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-march/9701_m25_qp_52.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 15, 16 ], "local_pdf": "_source-pdfs/2025-March/qp/9701_m25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-m-52-q02-p01-7d9f33c683.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p02-1a2de8ba51.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p03-eaae46d245.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p04-574d3bb569.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p05-e92b519f62.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p06-76b7054a49.png", "9701-experimental-skills/assets/9701-2025-m-52-q02-p07-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 Ester X has the formula CH COOR.\nSIHT 3\nH . R is an alkyl group with the general formula C\nn 2n+1\nNI Ester X undergoes alkaline hydrolysis with aqueous potassium hydroxide, KOH(aq).\nETIRW\nThe resulting mixture is acidified with dilute hydrochloric acid, HCl (aq).\nCOOH, and an The organic products of the hydrolysis after acidification are ethanoic acid, CH\n3\nTON alcohol, ROH. Once the identity of ROH is found, the structure of ester X can then be determined.\nOD\nA student uses the following steps.\nstep 1 Equal molar quantities of ester X and KOH(aq) are placed in a round‑bottomed flask.\nNIGRAM\nstep 2 A few drops of a suitable indicator are added to show whether a reaction has occurred.\nstep 3 A substance is added to promote smooth boiling.\nSIHT\nNI step 4 The reaction mixture is set up for reflux and heated for 30 minutes.\nETIRW\nstep 5 After 30 minutes, the reaction mixture in the round‑bottomed flask is acidified by adding\nTON HCl (aq) dropwise.\nOD\nstep 6 Thin‑layer chromatography is carried out on the reaction mixture.\n(a) (i) Complete the diagram in Fig. 2.1 to show the apparatus used for reflux in step 4. Label\nthe diagram.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nheat NIGRAM\nFig. 2.1\nSIHT\n[2]\nNI\nETIRW (ii) Suggest the type of substance added to promote smooth boiling in step 3.\n..................................................................................................................................... [1] TON\nNIGRAM\n(b) As the reaction proceeds in step 4, the indicator changes colour.\nSIHT\nNI T able 2.1 shows the colours of three different indicators at pH 1.0 and at pH 14.0 and the pH\nETIRW\nrange over which the indicators change colour.\nTable 2.1 TON\nOD\ncolour at pH range over which it colour at\nindicator\npH 1.0 changes colour pH 14.0\nthymolphthalein colourless 9.5 –10.5 blue\nNIGRAM\nmethyl orange red 3.0 – 4.5 yellow\nbromocresol green yellow 4.0 – 5.5 blue\nSIHT\nNI\nUse the table to identify a suitable indicator .\nETIRW\nExplain your choice.\nTON\nindicator ....................................................................................................................................\nOD\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n[2]\nSIHT\n(c) In step 6, a small sample of the reaction mixture is analysed along with samples of ester X\nNI\nand ethanoic acid.\nETIRW\nFig. 2.2 shows the chromatogram produced.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nester X reaction ethanoic\nmixture acid\nNIGRAM\nFig. 2.2\nSIHT\nState what feature of", "pdf_path": "9701-experimental-skills/print/9701-2025-m-52-q02-eee6d40553.pdf" }, { "id": "9701-2025-mj-41-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 3 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-mj-41-q01-p01-092596ceba.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 Both calcium carbonate, CaCO , and barium carbonate, BaCO , decompose when heated to form\nSIHT 3 3\nthe metal oxide and a gas.\nNI\nETIRW\n. (a) Write an equation for the thermal decomposition of CaCO\n3\nTON\n............................................................................................................................................. [1]\nOD\n(b) State which of CaCO and BaCO decomposes at a lower temperature.\n3 3\nExplain your answer.\nNIGRAM\nThe compound that decomposes at a lower temperature is ................................................... .\nSIHT\nexplanation ...............................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM [2]\n(c) Calcium oxide, CaO, reacts with water to form compound A.\nSIHT\nBarium oxide, BaO, reacts with water to form compound B. NI\nETIRW\n(i) Identify A.\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Explain why A is less soluble than B.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [3]\n[Total: 7]\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-27-group-2/print/9701-2025-mj-41-q01-61dbcea223.pdf" }, { "id": "9701-2025-mj-41-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-41-q02-p01-7f18b0fa7d.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-41-q02-p02-ceb634fade.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n2 Three experiments are carried out to investigate the reaction of nitrogen oxide, NO, with chlorine.\nSIHT\nNI 2NOCl 2NO + Cl\n2\nETIRW\nThe rate equation for this reaction is shown.\nTON\n[NO]2[Cl ] rate = k\nOD 2\n(a) Under the conditions used in experiments 1 and 2, the value of k is 26.4.\ndm–3 s–1. State the units of k. (i) The rate of the reaction is measured in mol\nNIGRAM\nunits of k = .............................. [1] SIHT\nNI\n(ii) In experiment 1, the initial concentrations of NO and Cl are equal.\nETIRW 2\n10–6 dm–3 s–1. mol The initial rate of the reaction in experiment 1 is 2.57 ×\nTON\nOD Calculate the initial concentration of NO.\nShow your working.\nNIGRAM\nSIHT\nNI\ndm–3 ETIRW [2] initial concentration of NO = .............................. mol\nare both ten times greater than (iii) In experiment 2, the initial concentrations of NO and Cl TON\n2\nthe initial concentrations used in experiment 1.\nOD\nCalculate the initial rate of the reaction in experiment 2.\nNIGRAM\nSIHT\nNI dm–3 s–1 [1] initial rate of reaction in experiment 2 = .............................. mol\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Experiment 3 uses a large excess of NO.\nSIHT\n10– 4 dm–3. NI is 2.00 × mol The initial concentration of Cl\n2\nETIRW\n] against time shows that the reaction has a constant half-life, t . (i) The graph of [Cl\n2 ½\nTON\nExplain this observation.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\n(ii) Under the conditions used in experiment 3, the value of the rate constant is 105.6.\nSIHT\n10–3 of [Cl ] is 6.56 × s under these conditions. Show that t\n½ 2 NI\nETIRW\nTON\n[1]\nOD\n10–5 dm–3 ] to fall to 1.25 × mol in experiment 3. (iii) Calculate the time taken, in s, for [Cl\n2\nNIGRAM\ntime = .............................. s [1]\nSIHT\n, reacts very slowly with oxygen in the atmosphere, forming sulfur trioxide, (c) Sulfur dioxide, SO NI\n2\nETIRW . This reaction is much faster in the presence of NO. SO\n3\nExplain the role of NO in this process. TON\nOD\nInclude chemical equations in your answer .\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n...................................................................................................................................................\nSIHT\nNI ............................................................................................................................................. [3]\nETIRW\n[Total: 10]\nTON\nOD\nNIGRAM\nSIHT\nN", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-mj-41-q02-d095187372.pdf" }, { "id": "9701-2025-mj-41-q03", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-mj-41-q03-p01-10c578e60a.png", "9701-topic-25-equilibria/assets/9701-2025-mj-41-q03-p02-43deed138b.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\nChromium(III) 3 (a) hydroxide, Cr(OH) , is only slightly soluble in water. The value of the solubility\nSIHT 3\n10–33 , of Cr(OH) is 1.0 × at 298 K. product, K\nsp 3\nNI\nETIRW\nof Cr(OH) . Include the units. (i) Complete the expression for K\nsp 3\nTON\nK =\nOD sp\nunits = ..............................\nNIGRAM\n[2]\ndm–3, SIHT of Cr(OH) in pure water at 298 K. (ii) Calculate the solubility, in g\n3\nNI\nShow your working.\nETIRW\nTON\nOD\ndm–3 [3] solubility = .............................. g\nNIGRAM\ndm–3 is less soluble in 0.100 mol NaOH than it is in pure water. (iii) Cr(OH)\n3\nSIHT\nExplain this observation.\nNI\nETIRW ...........................................................................................................................................\n..................................................................................................................................... [1] TON\nOD\n, of butanoic acid, CH CH CH COOH, is (b) The value of the acid dissociation constant, K\na 3 2 2\n10–5 at 298 K. 1.51 ×\ndm–3 CH CH CH COOH at 298 K. (i) Calculate the pH of 0.100 mol\n3 2 2 NIGRAM\nShow your working.\nSIHT\nNI\nETIRW\nTON\npH = .............................. [2] OD\ndm–3 NaOH at 298 K. (ii) Calculate the pH of 0.100 mol\nNIGRAM\nSIHT\nNI\npH = .............................. [1] ETIRW\nTON\nNIGRAM\ncm3 dm–3 cm3 dm–3 (iii) 5.00 of 0.100 mol NaOH is added to 10.00 of 0.100 mol\nSIHT\nCH CH COOH. CH\n3 2 2\nNI\nETIRW\nCalculate the pH of the resulting solution.\nTON Show your working.\nOD\nNIGRAM\npH = .............................. [2]\nSIHT\ncm3 of an aqueous solution containing 0.704 g of CH CH CH COOH is shaken with (c) 80.0\n3 2 2 NI\ncm3 of benzene, C H . 100\nETIRW 6 6\ncm3 CH CH COOH in the 100 of C H at equilibrium. There is 0.556 g of CH\n3 2 2 6 6 TON\nOD , of CH CH CH COOH between C H and water. Calculate the partition coef ficient, K\npc 3 2 2 6 6\nShow your working.\nNIGRAM\nSIHT\nNI\nETIRW\nK = .............................. [2] TON\npc\nOD\n[Total: 13]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-mj-41-q03-d308a55f12.pdf" }, { "id": "9701-2025-mj-41-q04", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-mj-41-q04-p01-da38ac678d.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-41-q04-p02-45ced07146.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\nF–, K+ Ca2+. 4 Table 4.1 gives the enthalpy changes of hydration, ΔH , of three ions, and\nSIHT hyd\nNI Table 4.1\nETIRW\nmo–l1 ion ΔH / kJ\nhyd TON\nF– –506\nOD\nK+ –322\nCa2+ –1650\nNIGRAM\n(a) (i) Define enthalpy change of hydration.\nSIHT\n...........................................................................................................................................\nNI\nETIRW ...........................................................................................................................................\n..................................................................................................................................... [1] TON\nOD\nK+ Ca2+. and (ii) Explain the relative magnitudes of the enthalpy changes of hydration of\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI ..................................................................................................................................... [2]\nETIRW\n(iii) Define lattice energy.\nTON\n........................................................................................................................................... OD\n..................................................................................................................................... [1]\nmo–l1. , of calcium fluoride, CaF , is –2602 kJ (iv) The lattice energy, ΔH NIGRAM\nlatt 2\nmol–1, , in kJ of CaF . Calculate the enthalpy change of solution, ΔH\nsol 2\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nmol–1 ΔH of CaF = .............................. kJ [2]\nsol 2\nTON\nNIGRAM\n(b) The formation of CaF at 298 K is shown.\nSIHT 2\nΔHo mo–l1 NI (g) CaF (s) = –1214 kJ Ca(s) + F\n2 2\nETIRW ΔGo mo–l1 = –1162 kJ\nTON o, K–1 mol–1, Calculate the entropy change, ΔS in J for this reaction.\nOD\nNIGRAM\nSIHT\nΔSo K–1 mol–1 = .............................. J [2]\nNI\nETIRW\n[Total: 8]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-mj-41-q04-f16a7e7fab.pdf" }, { "id": "9701-2025-mj-41-q05", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-mj-41-q05-p01-8110c6e438.png", "9701-topic-24-electrochemistry/assets/9701-2025-mj-41-q05-p02-8362894e24.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q05", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n5 Copper is a transition element.\nSIHT\nCu+ Cu2+ NI ion and a ion. (a) (i) Complete the electronic configurations of a\nETIRW\nCu+ ion: [Ar] ..............................\nTON\nCu2+ ion: [Ar] ..............................\nOD\n[1]\n(ii) Explain why transition elements have variable oxidation states.\nNIGRAM\n...........................................................................................................................................\n..................................................................................................................................... [1] SIHT\nNI\n]2+ copper(II) sulfate, CuSO , contains the [Cu(H O) complex ion. (b) Aqueous\nETIRW 4 2 6\n(aq) are added to CuSO (aq). (i) A few drops of NH\n3 4 TON\nOD Describe any observations made.\n..................................................................................................................................... [1]\nNIGRAM (ii) Write an equation for the reaction taking place.\n..................................................................................................................................... [1]\nSIHT\n(aq) is added to CuSO (aq). (c) (i) An excess of NH NI\n3 4\nETIRW\nDescribe any further observations made.\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Write an equation for the reaction taking place.\n..................................................................................................................................... [1]\nNIGRAM\n(iii) State the name for the type of reaction taking place.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Copper metal can be oxidised by acidified KMnO . The relevant half-equations and their\nSIHT 4\nEo, are shown. standard electrode potentials,\nNI\nETIRW 2+ 2e– Eo + Cu = +0.34 V Cu\nTON 8H+ 5e– Mn2+ Eo – + + + 4H O = +1.52 V MnO\n4 2\nOD\n–/Mn2+ dm–3 dm–3 Mn2+ –, electrode is constructed using 0.0020m ol MnO 1.0 mol (i) A MnO\n4 4\ndm–3 H+. The temperature used is 298 K. and 1.0 mol\n–/Mn2+ electrode is +1.49V . Use the Nernst equation to show that the E value for this MnO\nNIGRAM 4\nSIHT\nNI\nETIRW\n[2]\nTON\n2+/Cu electrode and the (ii) An electrochemical cell is constructed using a standard Cu\n–/Mn2+ OD electrode described in (d)(i). MnO\n4\n. Calculate the value of E\ncell\nNIGRAM\n= .............................. V [1] E\ncell\n(iii) Write an equation for the reaction taking place in the electrochemical cell described in\nSIHT\n(d)(ii).\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\n(iv) Complete the sentences for the electrochemical cell described in (d)(ii).\nOD\nThe ...", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-mj-41-q05-97df56b9aa.pdf" }, { "id": "9701-2025-mj-41-q06", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-41-q06-p01-4e920f6e3c.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-41-q06-p02-6d18db19de.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\nCN–. 6 (a) Iron forms complex ions with the monodentate ligand,\nSIHT\nFe3+ CN– NI ion and six ligands. (i) Complex ion A contains one\nETIRW\nFe2+ CN– ion and six ligands. Complex ion B contains one\nTON\nState the formulae of these two complex ions. Include the overall charge of eachc omplex\nOD\nion.\ncomplex ion A .................................................\nNIGRAM\ncomplex ion B .................................................\n[1]\nSIHT\n(ii) Explain why a solution containing complex ion A and a solutionc ontaining complex ion B\nNI\nare different colours.\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [2]\nCN– Fe3+ ligand bonds to the ion. (iii) In complex ion A, the carbon atom of each\nNIGRAM\nState the type of bonding involved.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Complex ions have different geometries.\nSIHT\nNI Complex ion A is octahedral.\nETIRW\n+ ions form a linear complex with ammonia. Ag\nTON\nNi atoms form a tetrahedral complex with carbon monoxide molecules. The carbon atom in\nOD\nthe monodentate carbon monoxide ligand bonds to the nickel atom.\n2+ ions form a square planar complex with chloride ions. Pd\nNIGRAM\nComplete Fig. 6.1 to show the geometry of each of these four ions, using three-dimensional\nbonds where necessary. Label one bond angle on each complex ion.\nSIHT\nAg+ with ammonia complex ion A\nNI\nETIRW\nTON\nOD\nAg Fe\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nPd2+ Ni with carbon monoxide with chloride\nOD\nNIGRAM\nNi Pd\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 6.1\nNIGRAM [4]\n[Total: 8]\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-mj-41-q06-37680e9c0b.pdf" }, { "id": "9701-2025-mj-41-q07", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-mj-41-q07-p01-451679c085.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-41-q07-p02-35dc5cf439.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-41-q07-p03-405e738c98.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-41-q07-p04-16c237b938.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q07", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n7 A hydrocarbon is known to be either compound D or compound E.\nSIHT\nD E NI\nETIRW\nCH CH CH CH\n2 3 2 3\nTON\nOD\nCH CH\n2 3\nCH CH\n2 3\nNIGRAM\nFig. 7.1\nSIHT\n(a) Give the systematic name of E.\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\n(1H) NMR spectra of D and E are compared. They are very similar. (b) The proton\nOD 1H) NMR spectrum of D is shown in Fig. 7.2. The proton (\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n2 1 0 10 9 8 7 6 5 4 3\nNIGRAM\n/ ppm chemical shift δ\nSIHT\nFig. 7.2\nNI\n(i) Suggest a suitable solvent for obtaining the spectrum in Fig. 7.2. ETIRW\n..................................................................................................................................... [1] TON\nOD\n1H) NMR spectrum of E is obtained twice, once before and once after (ii) The proton (\nO. shaking with D\n2\nDescribe any differences between these two spectra. Explain your answer.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nNIGRAM\n(1H) (iii) Complete Table 7.1 for the proton NMR spectrum of D.\nSIHT\nNI Table 7.1\nETIRW\n1H chemical shift number of atoms group responsible\nsplitting pattern TON\nδ / ppm responsible for the peak for the peak\nOD\n1.3\n2.7\nNIGRAM\n7.1\nSIHT\n[3]\nNI\nETIRW\nTable 7.2\nTON\nchemical shift range\nenvironment of proton example\nδ / ppm OD\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\nNIGRAM\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\nSIHT 3 2 2\nattached to alkene =CHR 4.5–6.0\nNI\nETIRW\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5 TON\nOD alcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nNIGRAM\nalkyl amine R–NH– 1.0–5.0\n3.0–6.0 aryl amine Ar–NH SIHT\n2\namide RCONHR 5.0–12.0 NI\nETIRW\n(iv) Compounds D and E can be distinguished by carbon-13 NMR spectroscopy.\nTON\nState the number of peaks in each spectrum. OD\nThe carbon-13 NMR spectrum of D has .............................. peaks.\nThe carbon-13 NMR spectrum of E has .............................. peaks. NIGRAM\n[1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Compound D can be oxidised to compound F by alkaline KMnO followed by dilute acid.\nSIHT 4\nF D NI\nETIRW\nCH CH COOH\n2 3\nTON\nOD\nCH CH COOH\n2 3\nFig. 7.3 NIGRAM\n(i) Write an equation for this reaction using molecular formulae for D and F. The products of\nSIHT\nthis reaction are F, water and carbon dioxide.\nNI\nUse [O] to represent one atom of oxygen from the oxidising agent. ETIRW\nTON\n.....................................................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-mj-41-q07-5c1ae17893.pdf" }, { "id": "9701-2025-mj-41-q08", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2025-mj-41-q08-p01-e87835a1c0.png", "9701-topic-30-hydrocarbons/assets/9701-2025-mj-41-q08-p02-09ab882927.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q08", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n8 Bromine reacts with methylbenzene in the dark in the presence of a suitable catalyst to form HBr\nSIHT\nH Br. L is one of three isomers that can form in this reaction. and compound L, C\n7 7\nNI\nETIRW Br+ ion. This ion (a) (i) The mechanism for the reaction involves methylbenzene reacting with a\nis produced when bromine reacts with the catalyst.\nTON\nwith the catalyst. Complete the equation for the reaction of Br\nOD 2\nBr+ + .............................. + .............................. [1] Br\n2\n(ii) One of the isomers of L forms in much smaller amounts than the other two isomers.\nNIGRAM\nDraw the structure of this isomer and explain why it forms in the smallest amount.\nSIHT\nNI\nETIRW\nTON\nOD ...........................................................................................................................................\n...........................................................................................................................................\n[2]\nNIGRAM\n(iii) Complete the mechanism in Fig. 8.1 for the reaction between methylbenzene and the\nBr+ ion.\nSIHT\nInclude all relevant curly arrows and charges. NI\nETIRW\nintermediate\nTON\nCH\n3\nOD\n+ ........ Br+\nNIGRAM\nSIHT\nNI\nETIRW\nFig. 8.1\nTON [3]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Chlorobutane and chlorobenzene are added separately to samples of warm aqueous AgNO .\nSIHT 3\nNI One of the chloro-compounds reacts slowly and the other does not react.\nETIRW\n(i) Identify the chloro-compound that reacts and describe any observations.\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(ii) Write two equations to explain any observations in (b)(i).\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [2]\nNI\nETIRW\n(iii) Explain the dif ference in reactivity of chlorobutane and chlorobenzene with warm\n. aqueous AgNO\n3 TON\nOD ...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM ...........................................................................................................................................\n..................................................................................................................................... [2]\nSIHT\n[Total: 11] NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\n", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2025-mj-41-q08-4cf42e7a08.pdf" }, { "id": "9701-2025-mj-41-q09", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 20, 21 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-41-q09-p01-29e09fb462.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-41-q09-p02-1a9cf39fa2.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n9 (a) Phenylamine, C H NH , and propylamine, CH CH CH NH , can be produced by dif ferent\nSIHT 6 5 2 3 2 2 2\nreduction reactions.\nNI\nETIRW H NH by a reduction (i) Identify an organic compound that can be converted into C\n6 5 2\nreaction. State the reagents and conditions for this reaction.\nTON\norganic compound .............................................................................................................\nOD\nreagents ............................................................................................................................\nconditions ..........................................................................................................................\nNIGRAM\n[2]\nCH CH NH by a reduction (ii) Identify an organic compound that can be converted into CH\nSIHT 3 2 2 2\nreaction. State the reagent for this reaction.\nNI\nETIRW\norganic compound .............................................................................................................\nTON reagent ..............................................................................................................................\n[2]\nOD\nH NH and CH CH CH NH by (iii) Identify a single test that will distinguish between C\n6 5 2 3 2 2 2\nproducing a white precipitate with only one of these amines.\nNIGRAM\nDraw the structure of the compound that is precipitated.\ntesting reagent ..................................................................................................................\nSIHT\nNI amine that gives a precipitate ...........................................................................................\nETIRW\nstructure of the compound that is precipitated:\nTON\nOD\nNIGRAM\nSIHT\nNI\n[2] ETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Describe the relative basicities of C H NH , CH CH CH NH and NH .\nSIHT 6 5 2 3 2 2 2 3\nExplain your answer. NI\nETIRW\n.............................................. < .............................................. < ..............................................\nleast basic most basic TON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\n[4] ETIRW\n[Total: 10]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-mj-41-q09-3f41b0e080.pdf" }, { "id": "9701-2025-mj-41-q10", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 10, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_41.pdf?download=true", "source_pages": [ 22, 23, 24 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-41-q10-p01-be58134788.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-41-q10-p02-72cc2d514b.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-41-q10-p03-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-41-q10", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n10 Propanoic acid, methanoic acid and ethanedioic acid are all weak acids.\nSIHT\nNI (a) Draw the displayed formula of ethanedioic acid.\nETIRW\nTON\nOD\n[1]\n(b) The three acids, propanoic acid, methanoic acid and ethanedioic acid, can be distinguished\nusing a combination of two chemical tests. Neither testing reagent is an acid–base indicator.\nNIGRAM\nIdentify two suitable testing reagents and complete Table 10.1 to show the observations from\neach test. SIHT\nNI\nreagent 1 ........................................................ reagent 2 ........................................................\nETIRW\nTable 10.1\nTON\nOD\nobservation when treated observation when treated\nwith reagent 1 with reagent 2\nNIGRAM\npropanoic acid\nSIHT\nNI\nETIRW\nmethanoic acid\nTON\nOD\nethanedioic acid\nNIGRAM\n[4]\nSIHT\n(c) When propanoic acid is treated with chlorine gas in the presence of ultraviolet light, a mixture\nNI\nof products is formed. One of these products is 2,2-dichloropropanoic acid.\nETIRW\nExplain why 2,2-dichloropropanoic acid is stronger than propanoic acid. Refer to the structure\nTON\nof each compound in your answer.\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [2]\nNI\nETIRW [Total: 7]\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.02 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm NIGRAM\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nkg–1 K–1 g–1 K–1) SIHT (4.18 J specific heat capacity of water c = 4.18 kJ\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nSIHT\nnossenago\nnotpyrk 3.131 muileh nonex gO nodar nogra nR eN eH eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nNI\nETIRW\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 9.621 0.571 enidoi 5.53 9.97 0.91 uL 71 lC 301 sT rB 711 tA rL 53 35 71 58 17 F I – – – 9\nTON\nmuiromrevil OD muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib muiluht cinesra 8.121 0.902 9.861 mT dM", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-mj-41-q10-0cc05233e1.pdf" }, { "id": "9701-2025-mj-42-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 2 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-mj-42-q01-p01-19520db2c9.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) (i) Calcium nitrate, Ca(NO ) , decomposes on heating.\nSIHT 3 2\nNI Write an equation for the decomposition of calcium nitrate.\nETIRW\nTON ..................................................................................................................................... [1]\nOD\n(ii) Describe the trend in the decomposition temperature of the Group 2 nitrates.\nExplain your answer.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\nOD ..................................................................................................................................... [3]\n(b) A sample of 0.333 g of strontium oxide, SrO, is completely dissolved in distilled water to form\n. a solution of strontium hydroxide, Sr(OH)\n2\nNIGRAM\ncm3 with distilled The resulting solution is added to a volumetric flask and made up to 250.0\nwater.\nSIHT\nCalculate the pH of this solution at 298 K. Give your answer to two decimal places. NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI pH = .............................. [4]\nETIRW\n[Total: 8]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-27-group-2/print/9701-2025-mj-42-q01-621c236e0a.pdf" }, { "id": "9701-2025-mj-42-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-mj-42-q02-p01-9273bbc7dd.png", "9701-topic-24-electrochemistry/assets/9701-2025-mj-42-q02-p02-25d0582916.png", "9701-topic-24-electrochemistry/assets/9701-2025-mj-42-q02-p03-822dd747b7.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q02", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\ncobalt(II) 2 (a) When sulfate, CoSO , is dissolved in distilled water, solution A is formed.\nSIHT 4\nNI The reaction scheme in Fig. 2.1 shows some reactions of solution A.\nETIRW\nexcess\n(aq) NH NaOH(aq) TON\n3\nsolution A solid B solution C\nOD\nNIGRAM\n]2– [CoCl\n4\nSIHT\nFig. 2.1\nNI\nETIRW\n(i) Complete Table 2.1 to show the formula and colour of each of the cobalt-containing\nspecies present in A, B and C. Identify the type of reaction forming each of B and C.\nTON\nOD\nTable 2.1\nformula of colour of\ntype of reaction\ncobalt-containing species cobalt-containing species NIGRAM\nA\nSIHT\nB\nNI\nC\nETIRW\n[4]\nTON\n]2– from solution A. (ii) Suggest a suitable reagent for the formation of [CoCl\n4 OD\n..................................................................................................................................... [1]\n]2– has tetrahedral geometry. (b) The complex ion [CoCl\n4 NIGRAM\n2+ ion are degenerate. The 3d orbitals in an isolated Co\nSIHT\nCo2+ ion (i) Complete Fig. 2.2 to show the relative energies of the 3d orbitals in an isolated\nNI Co2+ in a tetrahedral complex. and in\nETIRW\nenergy\nTON\nOD\nNIGRAM\nCo2+ Co2+ isolated ion in a tetrahedral complex\nSIHT\nNI Fig. 2.2\nETIRW\n[2]\nTON\nNIGRAM\n]2–. (ii) Draw a three-dimensional diagram to show the structure of the complex ion [CoCl\nSIHT 4\nNI\nETIRW\nTON\nOD\n[1]\nNIGRAM\nO can act as an oxidising agent or a reducing agent when reacting with species that (c) H\n2 2\ncontain manganese. SIHT\nNI o , for some electrode reactions. T able 2.2 shows electrode potentials, E\nETIRW\nTable 2.2\nTON\nOD o / V E electrode reaction\n2e– 2OH– –0.04 MnO + 2H O + Mn(OH) +\n2 2 2\n4H+ 2e– 2+ +1.22 + + Mn + 2H O MnO\nNIGRAM\n2 2\n2H+ 2e– +1.78 O + + 2H O H\n2 2 2\nSIHT\nOH– 2e– – +0.88 O + + 3OH H\n2 2\nNI\n2H+ 2e– +0.68 + + H O O\nETIRW 2 2 2\nUse only the species listed in Table 2.2 to suggest: TON\n• one reaction in which H O acts as an oxidising agent and\n2 2 OD\n• one reaction in which H O acts as a reducing agent.\n2 2\no , and an overall equation for each Include the value of the standard cell potential, E\ncell\nreaction.\nNIGRAM\nO acting as an oxidising agent ............................................................................................ H\n2 2\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON ...................................................................................................................................................\nOD\nO acting as a reducing agent .............................................................................................. H\n2 2\n........................................................................................................", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-mj-42-q02-007fb71f52.pdf" }, { "id": "9701-2025-mj-42-q03", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-mj-42-q03-p01-ac41c12033.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-42-q03-p02-121377a3ae.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n3 (a) Define entropy.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n............................................................................................................................................. [1]\nTON\n(b) Fig. 3.1 shows how the entropy, S, of a pure substance changes with temperature, T.\nOD\nentropy, S\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nT T\n1 2\ntemperature, T NIGRAM\nFig. 3.1\nSIHT\nNI and T . (i) Identify the process occurring at each of the temperatures T\n1 2 ETIRW\n.................................................. T .................................................. [1] T\n1 2\nTON\nis bigger than the entropy change at T . (ii) Explain why the entropy change, ∆S, at T\nOD 2 1\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\niron(III) (c) The equation for the reduction of oxide by carbon monoxide at 450 °C is shown.\nSIHT\nmo–l1 NI O (s) + 3CO(g) 2Fe(s) + 3CO (g) ∆G = –36.2 kJ Fe\n2 3 2 ETIRW\nT able 3.1 shows the enthalpy of formation, ∆H , and the entropy, S , for some substances.\nf\nTON\nTable 3.1\nOD\nFe O (s) CO(g) Fe(s) CO (g)\n2 3 2\nmo–l1 –824.2 –110.5 0.0 –393.5 / kJ ∆H\nf NIGRAM\nK–1 mol–1 / J 87.4 to be calculated 27.3 213.8 S\nSIHT\n, of carbon monoxide at 450 °C. Use the data in Table 3.1 to calculate the entropy, S\nNI\nETIRW\nShow your working.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON K–1 mol–1 S of CO(g) = .............................. J [3]\nOD\nIron(II) oxide can also be reduced to iron by carbon monoxide, as shown. (d)\nmo–l1 Fe(s) + CO (g) ∆H = –11.1 kJ FeO(s) + CO(g)\n2\nK–1 mol–1 NIGRAM ∆S = –15.2 J\nState the ef fect of increasing temperature on the feasibility of this reaction.\nSIHT\nExplain your answer . NI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n............................................................................................................................................. [2]\nNIGRAM\n[Total: 8]\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-mj-42-q03-8fae0b482d.pdf" }, { "id": "9701-2025-mj-42-q04", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 8, 9, 10 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-42-q04-p01-da8a424190.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-42-q04-p02-f3e7da0e32.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-42-q04-p03-bf00049fba.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q04", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n4 (a) In aqueous solution, iodide ions react with acidified hydrogen peroxide, as shown in reaction 1.\nSIHT\n– 2H+ NI + H O + I + 2H O reaction 1 2I\n2 2 2 2\nETIRW\nThe rate equation for reaction 1 is shown.\nTON\n[I–][H O ] rate = k\nOD 2 2\n(i) Explain what is meant by order of reaction.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n(ii) Complete Table 4.1.\nTON\nTable 4.1\nOD\n[H+] the order of reaction with respect to\n[I–] the order of reaction with respect to\nNIGRAM\nO ] the order of reaction with respect to [H\n2 2\noverall order of the reaction\nSIHT\n[2]\nNI\nETIRW\n[I–] and time. (iii) Sketch a line on Fig. 4.1 to show the relationship between\nTON\n[I–]\nOD\nNIGRAM\nSIHT\n0\ntime\nNI\nETIRW\nFig. 4.1\nTON [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Nitrogen dioxide, NO , reacts with ozone, O , as shown in reaction 2.\nSIHT 2 3\nNI + O O + N O reaction 2 2NO\n2 3 2 2 5\nETIRW\nThe rate equation for reaction 2 is shown.\nTON\n][O ] rate = k [NO\nOD 2 3\n(i) Two experiments are carried out to measure the rate of reaction 2.\nIn the first experiment, the initial rate is measured starting with known concentrations\nNIGRAM\nand O . In the second experiment, the concentrations of NO and O are both of NO\n2 3 2 3\nincreased by a factor of four.\nSIHT\nPredict how the initial rate for reaction 2 would change.\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) The reaction mechanism for reaction 2 has two steps.\nOD\nDefine rate-determining step.\n..................................................................................................................................... [1]\nNIGRAM\n(iii) Suggest equations for the two steps of the reaction mechanism for reaction 2.\nSIHT\nstep 1 ................................................................................................................................\nNI\nETIRW step 2 ................................................................................................................................\n[2]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Dinitrogen pentoxide, N O , can decompose to NO and O .\nSIHT 2 5 2 2\nNI The rate equation for this decomposition is shown.\nETIRW\nO ] rate = k [N\n2 5\nTON\nO ] for this decomposition. Fig. 4.2 shows the graph of rate against [N\nOD 2 5\n16.0\n14.0\n12.0 NIGRAM\n10.0\nrate\n8.0\n10–4 dm–3 s–1 / mol SIHT\n6.0\nNI 4.0\nETIRW\n2.0\n0.0\nTON\n0.0000 0.0100 0.0200 0.0300 0.0500 0.0400\nOD\ndm–3 [N ", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-mj-42-q04-8bcd0ffa7a.pdf" }, { "id": "9701-2025-mj-42-q05", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 11, 12 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-mj-42-q05-p01-9d753591f7.png", "9701-topic-25-equilibria/assets/9701-2025-mj-42-q05-p02-6eb8234af2.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q05", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:2)(cid:44)\nChloric(I) 5 (a) acid, HCl O, is a weak Brønsted–Lowry acid.\nSIHT\nI) NI acid is added to aqueous sodium hydroxide, an acid–base reaction takes When chloric(\nETIRW\nplace, as shown.\nTON NaCl O + H O HCl O + NaOH\n2\nOD\n(i) Identify the two conjugate acid–base pairs in this reaction.\nI I HCl O conjugate base of acid ................ acid\nNIGRAM\nII II ................ conjugate base of acid ................ acid\n[1]\nSIHT\n10–8. , of HCl O(aq) is 3.70 × (ii) The value for the acid dissociation constant, K\na NI\nETIRW\ndm–3, of HCl O(aq) at a pH of 4.51. Calculate the concentration, in mol\nTON\nOD\nNIGRAM\nSIHT\nNI\ndm–3 [2] concentration of HCl O = ............................. mol\nETIRW\nchloric(V) acid and a strong acid not containing (iii) When a solution of HCl O(aq) is heated,\nTON\noxygen are formed as the only products.\nOD\nWrite an equation for this reaction.\n..................................................................................................................................... [1] NIGRAM\n(b) (i) Define a buffer solution.\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Suggest a substance that could be added to aqueous ethanoic acid to form a buf fer\nOD\nsolution.\nExplain your answer.\nNIGRAM\n...........................................................................................................................................\n...........................................................................................................................................\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\nTON\nNIGRAM\n(c) Some fertilisers contain calcium dihydrogenphosphate, Ca(H PO ) .\nSIHT 2 4 2\n–, NI PO can act as a buf fer An aqueous solution containing dihydrogenphosphate ions, H\n2 4\nETIRW\nsolution.\nTON – PO ions can act as a buffer. W rite two equations to show how H\n2 4\nOD\nequation 1 .................................................................................................................................\nequation 2 .................................................................................................................................\n[2]\nNIGRAM\n10–7 dm–3 (PO ) , is 1.14 × mol at 25 °C. (d) The solubility of calcium phosphate, Ca\n3 4 2\nSIHT\n, of Ca (PO ) is shown. (i) The expression for the solubility product, K\nsp 3 4 2 NI\nETIRW\n[Ca2+]3[PO 3–]2 = K\nsp 4\nTON\nCalculate the value of K for Ca (PO ) . Include units.\nsp 3 4 2\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD = ............................. units ............................. K\nsp\n[3]\n(PO ) . (ii) Some solid sodi", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-mj-42-q05-7fbfcc0229.pdf" }, { "id": "9701-2025-mj-42-q06", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2025-mj-42-q06-p01-2845ac4739.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-mj-42-q06-p02-146e69bc19.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-mj-42-q06-p03-67819772f9.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q06", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:4)(cid:44)\n+. 6 (a) Methylbenzene reacts readily with nitronium ions, NO\nSIHT 2\n+ NI ions are generated by the reaction between concentrated nitric acid and concentrated NO\n2\nETIRW\nsulfuric acid.\nTON + ion. (i) Write an equation for the formation of the NO\n2\nOD\n..................................................................................................................................... [1]\n(ii) Complete the mechanism in Fig. 6.1 for the nitration of methylbenzene to form\n1-methyl-2-nitrobenzene.\nNIGRAM\nInclude all relevant curly arrows and charges.\nSIHT\norganic intermediate 1-methyl-2-nitrobenzene\nNI\nETIRW\nCH CH\n3 3\nTON NO\n2\n+\nOD NO\n+ ............. 2\nNIGRAM\nSIHT\nFig. 6.1\n[3]\nNI\nETIRW\n(b) Phenol can be nitrated with dilute nitric acid.\nTON\nExplain why the nitration of phenol occurs under milder conditions than the nitration of\nOD benzene.\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n................................................................................................................................................... NI\nETIRW\n............................................................................................................................................. [2]\nTON\n(c) A sample of 2-nitrophenol is reacted with sodium.\nOD\nComplete the equation in Fig. 6.2 for the reaction of 2-nitrophenol with sodium.\nOH\nNIGRAM\nNO\n2\nSIHT\n+ Na\nNI\nETIRW\nFig. 6.2\n[1] TON\nNIGRAM\n(d) 2-nitrophenol can undergo different reactions as shown in Fig. 6.3.\nSIHT\n2-nitrophenol NI\nETIRW\nOH OH\nTON\nNH NO\nCH COCl 2 2 OD 3\nreaction 2 reaction 1\nNIGRAM\nSIHT\nFig. 6.3\nNI\nETIRW\n(i) Suggest reagents and conditions for reaction 1.\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Name the type of reaction for reaction 1.\n..................................................................................................................................... [1]\nNIGRAM\n(iii) Reaction 2 is carried out at room temperature.\nSIHT\nDraw the structure of the organic product from reaction 2 in Fig. 6.3. [1]\nNI\nETIRW (iv) Name the mechanism for reaction 2.\nTON ..................................................................................................................................... [1]\nOD\ngroup in 2-nitrophenol is electron withdrawing. (e) The NO\n2\nSuggest the relative acidities of ethanol, 2-nitrophenol, phenol and water .\nNIGRAM\nExplain your answer .\n............", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2025-mj-42-q06-f79126caf9.pdf" }, { "id": "9701-2025-mj-42-q07", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q07-p01-57d69b199b.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q07-p02-84b31e3702.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n7 (a) 2-aminobutane, CH CH(NH )CH CH , exists as a mixture of two enantiomers.\nSIHT 3 2 2 3\nNI Define enantiomers.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\n(b) (i) Explain why an aqueous solution of 2-aminobutane has a pH greater than 7.\nInclude an equation in your answer.\nNIGRAM\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\ndm–3 solution of diethylamine, (CH CH ) NH, has a higher pH than a (ii) A 0.10 mol\n3 2 2\ndm–3 solution of 2-aminobutane, CH CH(NH )CH CH . 0.10 mol\n3 2 2 3\nNIGRAM Suggest why.\n...........................................................................................................................................\nSIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nCH ) NH reacts with ethanoic acid, CH COOH. (iii) (CH\n3 2 2 3\nComplete the equation for this reaction.\nNIGRAM\n(CH .................................................................................. [1] CH ) NH + CH COOH SIHT\n3 2 2 3\nNI\nCH ) NH reacts with ethanoyl chloride, CH COCl. (iv) (CH\nETIRW 3 2 2 3\nComplete the equation for this reaction.\nTON\nOD\n(CH CH ) NH + CH COCl .................................................................................... [1]\n3 2 2 3\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Table 7.1 shows monomers that can undergo polymerisation.\nSIHT\nNI (i) Complete Table 7.1.\nETIRW\nTable 7.1\nTON\nOD monomer type of polymerisation\nC(CH )COOH CH\n2 3\nO NIGRAM\nCl OH SIHT\nNI\nCH CH(NH )COOH\nETIRW 3 2\n[1]\nTON\nHNCH CH CH NH , (ii) Ethanedioic acid, HOOCCOOH, can react with propane-1,3-diamine,\n2 2 2 2 2 OD\nto form polymer W.\nDraw a section of polymer W showing only one repeat unit.\nNIGRAM\nThe new functional group formed should be displayed.\nSIHT\nNI\nETIRW\nTON\nOD\n[2]\nNIGRAM\n(iii) Poly(alkenes) biodegrade very slowly. Explain why.\nSIHT\n........................................................................................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-mj-42-q07-c7866fea90.pdf" }, { "id": "9701-2025-mj-42-q08", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-mj-42-q08-p01-0dc2e95e73.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-42-q08-p02-72ddd6c516.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n(1H) 8 (a) Compound A is analysed by carbon-13 NMR and proton NMR spectroscopy.\nSIHT\nA NI\nETIRW\nO\nTON\nO OD\nO\nFig. 8.1 NIGRAM\nState the reference substance and a solvent that can be used in NMR spectroscopy.\nSIHT\nreference ..................................................................................................................................\nNI\nETIRW\nsolvent ......................................................................................................................................\n[1]\nTON\nOD\n(b) Predict the number of peaks in the carbon-13 NMR spectrum of A.\n............................................................................................................................................. [1]\nNIGRAM (1H) NMR spectrum of A shows peaks in four different chemical environments. (c) The proton\n(1H) NMR spectrum of A. Complete Table 8.1 for the proton\nSIHT\nNI Table 8.1\nETIRW\n1H chemical shift number of protons on number of atoms\nsplitting pattern TON\nδ / ppm adjacent carbon atoms responsible for the peak\nOD\n1.10\n1.50 6\nNIGRAM\n2.85\nSIHT\nNI 3.75\nETIRW\n[4]\nTON\n[Total: 6]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nTable 8.2\nSIHT\nNI chemical shift range\nenvironment of proton example ETIRW\nδ / ppm\n, –CH –, >CH– 0.9–1.7 alkane –CH TON\n3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH OD\n3 2\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nNIGRAM\nattached to alkene =CHR 4.5–6.0\nattached to aromatic ring H–Ar 6.0–9.0\nSIHT\naldehyde HCOR 9.3–10.5\nNI\nETIRW\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0 TON\nOD carboxylic acid RCOOH 9.0–13.0\nalkyl amine R–NH– 1.0–5.0\n3.0–6.0 aryl amine Ar–NH\n2\nNIGRAM\namide RCONHR 5.0–12.0\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-mj-42-q08-a0e52bac48.pdf" }, { "id": "9701-2025-mj-42-q09", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_42.pdf?download=true", "source_pages": [ 20, 21, 23, 24 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q09-p01-01bc9e0b73.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q09-p02-58cee9baad.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q09-p03-51ec7b9905.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-42-q09-p04-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n9 (a) The structures of the amino acids serine and lysine are shown in Fig. 9.1.\nSIHT\nserine lysine NI\nETIRW\nCH OH CH CH CH CH NH\n2 2 2 2 2 2\nTON\nH N C COOH H N C COOH\n2 2 OD\nH H\nFig. 9.1\nNIGRAM\nH N O . Draw the structure for the dipeptide, ser–lys, with molecular formula C\n9 19 3 4\nSIHT The peptide functional group formed should be displayed.\nNI\nETIRW\nTON\nOD\n[2]\nNIGRAM (b) The isoelectric point of serine is 5.7 and of lysine is 9.7.\n(i) State what is meant by isoelectric point.\nSIHT\n........................................................................................................................................... NI\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) A mixture of serine, lysine and ser–lys is analysed by electrophoresis using a buf fer at\nOD\npH 5.7.\n– NIGRAM +\nSIHT\nmixture applied here\nNI\nETIRW\nFig. 9.2\nTON\nDraw and label three spots on Fig. 9.2 to indicate the predicted position of each of these\nOD\nthree species, serine, lysine and ser–lys, after electrophoresis.\nExplain your answer.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n..................................................................................................................................... [3]\nTON\nNIGRAM\n(c) Fig. 9.3 shows the synthesis of compound R from compound P.\nSIHT\nNI\nH NO Q, C\nETIRW 6 13 3\nP\nTON\nO\nOD\nH\nstep 1\nN\nNIGRAM\nOH\nSIHT\nNI\nETIRW\nstep 2 TON\nOD\nR\nO\nNIGRAM\nO\nSIHT\nNH\n2\nNI\nETIRW\nFig. 9.3\nTON\nOD\n(i) Draw the structure of Q in Fig. 9.3. [1]\n(ii) State the reagents and conditions for steps 1 and 2 in Fig. 9.3.\nNIGRAM\nstep 1 ................................................................................................................................\nSIHT\nstep 2 ................................................................................................................................\n[2]\nNI\nETIRW\n[Total: 9]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.02 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 V = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm NIGRAM\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ SIHT\nNI\nETIRW\nTON\nOD\nNIG", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-mj-42-q09-f566fe7616.pdf" }, { "id": "9701-2025-mj-43-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 3 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-mj-43-q01-p01-bbade27cfa.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 Both calcium carbonate, CaCO , and barium carbonate, BaCO , decompose when heated to form\nSIHT 3 3\nthe metal oxide and a gas.\nNI\nETIRW\n. (a) Write an equation for the thermal decomposition of CaCO\n3\nTON\n............................................................................................................................................. [1]\nOD\n(b) State which of CaCO and BaCO decomposes at a lower temperature.\n3 3\nExplain your answer.\nNIGRAM\nThe compound that decomposes at a lower temperature is ................................................... .\nSIHT\nexplanation ...............................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM [2]\n(c) Calcium oxide, CaO, reacts with water to form compound A.\nSIHT\nBarium oxide, BaO, reacts with water to form compound B. NI\nETIRW\n(i) Identify A.\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Explain why A is less soluble than B.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [3]\n[Total: 7]\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-27-group-2/print/9701-2025-mj-43-q01-03dc6e6126.pdf" }, { "id": "9701-2025-mj-43-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-43-q02-p01-4ce53e38a7.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-mj-43-q02-p02-2cd473721a.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n2 Three experiments are carried out to investigate the reaction of nitrogen oxide, NO, with chlorine.\nSIHT\nNI 2NOCl 2NO + Cl\n2\nETIRW\nThe rate equation for this reaction is shown.\nTON\n[NO]2[Cl ] rate = k\nOD 2\n(a) Under the conditions used in experiments 1 and 2, the value of k is 26.4.\ndm–3 s–1. State the units of k. (i) The rate of the reaction is measured in mol\nNIGRAM\nunits of k = .............................. [1] SIHT\nNI\n(ii) In experiment 1, the initial concentrations of NO and Cl are equal.\nETIRW 2\n10–6 dm–3 s–1. mol The initial rate of the reaction in experiment 1 is 2.57 ×\nTON\nOD Calculate the initial concentration of NO.\nShow your working.\nNIGRAM\nSIHT\nNI\ndm–3 ETIRW [2] initial concentration of NO = .............................. mol\nare both ten times greater than (iii) In experiment 2, the initial concentrations of NO and Cl TON\n2\nthe initial concentrations used in experiment 1.\nOD\nCalculate the initial rate of the reaction in experiment 2.\nNIGRAM\nSIHT\nNI dm–3 s–1 [1] initial rate of reaction in experiment 2 = .............................. mol\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Experiment 3 uses a large excess of NO.\nSIHT\n10– 4 dm–3. NI is 2.00 × mol The initial concentration of Cl\n2\nETIRW\n] against time shows that the reaction has a constant half-life, t . (i) The graph of [Cl\n2 ½\nTON\nExplain this observation.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\n(ii) Under the conditions used in experiment 3, the value of the rate constant is 105.6.\nSIHT\n10–3 of [Cl ] is 6.56 × s under these conditions. Show that t\n½ 2 NI\nETIRW\nTON\n[1]\nOD\n10–5 dm–3 ] to fall to 1.25 × mol in experiment 3. (iii) Calculate the time taken, in s, for [Cl\n2\nNIGRAM\ntime = .............................. s [1]\nSIHT\n, reacts very slowly with oxygen in the atmosphere, forming sulfur trioxide, (c) Sulfur dioxide, SO NI\n2\nETIRW . This reaction is much faster in the presence of NO. SO\n3\nExplain the role of NO in this process. TON\nOD\nInclude chemical equations in your answer .\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n...................................................................................................................................................\nSIHT\nNI ............................................................................................................................................. [3]\nETIRW\n[Total: 10]\nTON\nOD\nNIGRAM\nSIHT\nN", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-mj-43-q02-3fb76c01e1.pdf" }, { "id": "9701-2025-mj-43-q03", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-mj-43-q03-p01-086e60c4f6.png", "9701-topic-25-equilibria/assets/9701-2025-mj-43-q03-p02-b1bb29aa08.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\nChromium(III) 3 (a) hydroxide, Cr(OH) , is only slightly soluble in water. The value of the solubility\nSIHT 3\n10–33 , of Cr(OH) is 1.0 × at 298 K. product, K\nsp 3\nNI\nETIRW\nof Cr(OH) . Include the units. (i) Complete the expression for K\nsp 3\nTON\nK =\nOD sp\nunits = ..............................\nNIGRAM\n[2]\ndm–3, SIHT of Cr(OH) in pure water at 298 K. (ii) Calculate the solubility, in g\n3\nNI\nShow your working.\nETIRW\nTON\nOD\ndm–3 [3] solubility = .............................. g\nNIGRAM\ndm–3 is less soluble in 0.100 mol NaOH than it is in pure water. (iii) Cr(OH)\n3\nSIHT\nExplain this observation.\nNI\nETIRW ...........................................................................................................................................\n..................................................................................................................................... [1] TON\nOD\n, of butanoic acid, CH CH CH COOH, is (b) The value of the acid dissociation constant, K\na 3 2 2\n10–5 at 298 K. 1.51 ×\ndm–3 CH CH CH COOH at 298 K. (i) Calculate the pH of 0.100 mol\n3 2 2 NIGRAM\nShow your working.\nSIHT\nNI\nETIRW\nTON\npH = .............................. [2] OD\ndm–3 NaOH at 298 K. (ii) Calculate the pH of 0.100 mol\nNIGRAM\nSIHT\nNI\npH = .............................. [1] ETIRW\nTON\nNIGRAM\ncm3 dm–3 cm3 dm–3 (iii) 5.00 of 0.100 mol NaOH is added to 10.00 of 0.100 mol\nSIHT\nCH CH COOH. CH\n3 2 2\nNI\nETIRW\nCalculate the pH of the resulting solution.\nTON Show your working.\nOD\nNIGRAM\npH = .............................. [2]\nSIHT\ncm3 of an aqueous solution containing 0.704 g of CH CH CH COOH is shaken with (c) 80.0\n3 2 2 NI\ncm3 of benzene, C H . 100\nETIRW 6 6\ncm3 CH CH COOH in the 100 of C H at equilibrium. There is 0.556 g of CH\n3 2 2 6 6 TON\nOD , of CH CH CH COOH between C H and water. Calculate the partition coef ficient, K\npc 3 2 2 6 6\nShow your working.\nNIGRAM\nSIHT\nNI\nETIRW\nK = .............................. [2] TON\npc\nOD\n[Total: 13]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-mj-43-q03-5b66f7655d.pdf" }, { "id": "9701-2025-mj-43-q04", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-mj-43-q04-p01-b708f83cff.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-43-q04-p02-398f52ea11.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\nF–, K+ Ca2+. 4 Table 4.1 gives the enthalpy changes of hydration, ΔH , of three ions, and\nSIHT hyd\nNI Table 4.1\nETIRW\nmo–l1 ion ΔH / kJ\nhyd TON\nF– –506\nOD\nK+ –322\nCa2+ –1650\nNIGRAM\n(a) (i) Define enthalpy change of hydration.\nSIHT\n...........................................................................................................................................\nNI\nETIRW ...........................................................................................................................................\n..................................................................................................................................... [1] TON\nOD\nK+ Ca2+. and (ii) Explain the relative magnitudes of the enthalpy changes of hydration of\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI ..................................................................................................................................... [2]\nETIRW\n(iii) Define lattice energy.\nTON\n........................................................................................................................................... OD\n..................................................................................................................................... [1]\nmo–l1. , of calcium fluoride, CaF , is –2602 kJ (iv) The lattice energy, ΔH NIGRAM\nlatt 2\nmol–1, , in kJ of CaF . Calculate the enthalpy change of solution, ΔH\nsol 2\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nmol–1 ΔH of CaF = .............................. kJ [2]\nsol 2\nTON\nNIGRAM\n(b) The formation of CaF at 298 K is shown.\nSIHT 2\nΔHo mo–l1 NI (g) CaF (s) = –1214 kJ Ca(s) + F\n2 2\nETIRW ΔGo mo–l1 = –1162 kJ\nTON o, K–1 mol–1, Calculate the entropy change, ΔS in J for this reaction.\nOD\nNIGRAM\nSIHT\nΔSo K–1 mol–1 = .............................. J [2]\nNI\nETIRW\n[Total: 8]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-mj-43-q04-098204a568.pdf" }, { "id": "9701-2025-mj-43-q05", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-mj-43-q05-p01-3def6100e0.png", "9701-topic-24-electrochemistry/assets/9701-2025-mj-43-q05-p02-36e4b68f85.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q05", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n5 Copper is a transition element.\nSIHT\nCu+ Cu2+ NI ion and a ion. (a) (i) Complete the electronic configurations of a\nETIRW\nCu+ ion: [Ar] ..............................\nTON\nCu2+ ion: [Ar] ..............................\nOD\n[1]\n(ii) Explain why transition elements have variable oxidation states.\nNIGRAM\n...........................................................................................................................................\n..................................................................................................................................... [1] SIHT\nNI\n]2+ copper(II) sulfate, CuSO , contains the [Cu(H O) complex ion. (b) Aqueous\nETIRW 4 2 6\n(aq) are added to CuSO (aq). (i) A few drops of NH\n3 4 TON\nOD Describe any observations made.\n..................................................................................................................................... [1]\nNIGRAM (ii) Write an equation for the reaction taking place.\n..................................................................................................................................... [1]\nSIHT\n(aq) is added to CuSO (aq). (c) (i) An excess of NH NI\n3 4\nETIRW\nDescribe any further observations made.\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Write an equation for the reaction taking place.\n..................................................................................................................................... [1]\nNIGRAM\n(iii) State the name for the type of reaction taking place.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Copper metal can be oxidised by acidified KMnO . The relevant half-equations and their\nSIHT 4\nEo, are shown. standard electrode potentials,\nNI\nETIRW 2+ 2e– Eo + Cu = +0.34 V Cu\nTON 8H+ 5e– Mn2+ Eo – + + + 4H O = +1.52 V MnO\n4 2\nOD\n–/Mn2+ dm–3 dm–3 Mn2+ –, electrode is constructed using 0.0020m ol MnO 1.0 mol (i) A MnO\n4 4\ndm–3 H+. The temperature used is 298 K. and 1.0 mol\n–/Mn2+ electrode is +1.49V . Use the Nernst equation to show that the E value for this MnO\nNIGRAM 4\nSIHT\nNI\nETIRW\n[2]\nTON\n2+/Cu electrode and the (ii) An electrochemical cell is constructed using a standard Cu\n–/Mn2+ OD electrode described in (d)(i). MnO\n4\n. Calculate the value of E\ncell\nNIGRAM\n= .............................. V [1] E\ncell\n(iii) Write an equation for the reaction taking place in the electrochemical cell described in\nSIHT\n(d)(ii).\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\n(iv) Complete the sentences for the electrochemical cell described in (d)(ii).\nOD\nThe ...", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-mj-43-q05-0c4dda7d97.pdf" }, { "id": "9701-2025-mj-43-q06", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-43-q06-p01-3f4d2e5648.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-43-q06-p02-a6e41a4e0e.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\nCN–. 6 (a) Iron forms complex ions with the monodentate ligand,\nSIHT\nFe3+ CN– NI ion and six ligands. (i) Complex ion A contains one\nETIRW\nFe2+ CN– ion and six ligands. Complex ion B contains one\nTON\nState the formulae of these two complex ions. Include the overall charge of eachc omplex\nOD\nion.\ncomplex ion A .................................................\nNIGRAM\ncomplex ion B .................................................\n[1]\nSIHT\n(ii) Explain why a solution containing complex ion A and a solutionc ontaining complex ion B\nNI\nare different colours.\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [2]\nCN– Fe3+ ligand bonds to the ion. (iii) In complex ion A, the carbon atom of each\nNIGRAM\nState the type of bonding involved.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Complex ions have different geometries.\nSIHT\nNI Complex ion A is octahedral.\nETIRW\n+ ions form a linear complex with ammonia. Ag\nTON\nNi atoms form a tetrahedral complex with carbon monoxide molecules. The carbon atom in\nOD\nthe monodentate carbon monoxide ligand bonds to the nickel atom.\n2+ ions form a square planar complex with chloride ions. Pd\nNIGRAM\nComplete Fig. 6.1 to show the geometry of each of these four ions, using three-dimensional\nbonds where necessary. Label one bond angle on each complex ion.\nSIHT\nAg+ with ammonia complex ion A\nNI\nETIRW\nTON\nOD\nAg Fe\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nPd2+ Ni with carbon monoxide with chloride\nOD\nNIGRAM\nNi Pd\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 6.1\nNIGRAM [4]\n[Total: 8]\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-mj-43-q06-8cd9c1d23d.pdf" }, { "id": "9701-2025-mj-43-q07", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-mj-43-q07-p01-2effe01011.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-43-q07-p02-43f23baec5.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-43-q07-p03-8a2d176dca.png", "9701-topic-37-analytical-techniques/assets/9701-2025-mj-43-q07-p04-ad7a65562f.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q07", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n7 A hydrocarbon is known to be either compound D or compound E.\nSIHT\nD E NI\nETIRW\nCH CH CH CH\n2 3 2 3\nTON\nOD\nCH CH\n2 3\nCH CH\n2 3\nNIGRAM\nFig. 7.1\nSIHT\n(a) Give the systematic name of E.\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\n(1H) NMR spectra of D and E are compared. They are very similar. (b) The proton\nOD 1H) NMR spectrum of D is shown in Fig. 7.2. The proton (\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n2 1 0 10 9 8 7 6 5 4 3\nNIGRAM\n/ ppm chemical shift δ\nSIHT\nFig. 7.2\nNI\n(i) Suggest a suitable solvent for obtaining the spectrum in Fig. 7.2. ETIRW\n..................................................................................................................................... [1] TON\nOD\n1H) NMR spectrum of E is obtained twice, once before and once after (ii) The proton (\nO. shaking with D\n2\nDescribe any differences between these two spectra. Explain your answer.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nNIGRAM\n(1H) (iii) Complete Table 7.1 for the proton NMR spectrum of D.\nSIHT\nNI Table 7.1\nETIRW\n1H chemical shift number of atoms group responsible\nsplitting pattern TON\nδ / ppm responsible for the peak for the peak\nOD\n1.3\n2.7\nNIGRAM\n7.1\nSIHT\n[3]\nNI\nETIRW\nTable 7.2\nTON\nchemical shift range\nenvironment of proton example\nδ / ppm OD\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\nNIGRAM\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\n–O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\nSIHT 3 2 2\nattached to alkene =CHR 4.5–6.0\nNI\nETIRW\nattached to aromatic ring H–Ar 6.0–9.0\naldehyde HCOR 9.3–10.5 TON\nOD alcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nNIGRAM\nalkyl amine R–NH– 1.0–5.0\n3.0–6.0 aryl amine Ar–NH SIHT\n2\namide RCONHR 5.0–12.0 NI\nETIRW\n(iv) Compounds D and E can be distinguished by carbon-13 NMR spectroscopy.\nTON\nState the number of peaks in each spectrum. OD\nThe carbon-13 NMR spectrum of D has .............................. peaks.\nThe carbon-13 NMR spectrum of E has .............................. peaks. NIGRAM\n[1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Compound D can be oxidised to compound F by alkaline KMnO followed by dilute acid.\nSIHT 4\nF D NI\nETIRW\nCH CH COOH\n2 3\nTON\nOD\nCH CH COOH\n2 3\nFig. 7.3 NIGRAM\n(i) Write an equation for this reaction using molecular formulae for D and F. The products of\nSIHT\nthis reaction are F, water and carbon dioxide.\nNI\nUse [O] to represent one atom of oxygen from the oxidising agent. ETIRW\nTON\n.....................................................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-mj-43-q07-fe996fbf57.pdf" }, { "id": "9701-2025-mj-43-q08", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2025-mj-43-q08-p01-f00c431d78.png", "9701-topic-30-hydrocarbons/assets/9701-2025-mj-43-q08-p02-32fa38657e.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q08", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n8 Bromine reacts with methylbenzene in the dark in the presence of a suitable catalyst to form HBr\nSIHT\nH Br. L is one of three isomers that can form in this reaction. and compound L, C\n7 7\nNI\nETIRW Br+ ion. This ion (a) (i) The mechanism for the reaction involves methylbenzene reacting with a\nis produced when bromine reacts with the catalyst.\nTON\nwith the catalyst. Complete the equation for the reaction of Br\nOD 2\nBr+ + .............................. + .............................. [1] Br\n2\n(ii) One of the isomers of L forms in much smaller amounts than the other two isomers.\nNIGRAM\nDraw the structure of this isomer and explain why it forms in the smallest amount.\nSIHT\nNI\nETIRW\nTON\nOD ...........................................................................................................................................\n...........................................................................................................................................\n[2]\nNIGRAM\n(iii) Complete the mechanism in Fig. 8.1 for the reaction between methylbenzene and the\nBr+ ion.\nSIHT\nInclude all relevant curly arrows and charges. NI\nETIRW\nintermediate\nTON\nCH\n3\nOD\n+ ........ Br+\nNIGRAM\nSIHT\nNI\nETIRW\nFig. 8.1\nTON [3]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Chlorobutane and chlorobenzene are added separately to samples of warm aqueous AgNO .\nSIHT 3\nNI One of the chloro-compounds reacts slowly and the other does not react.\nETIRW\n(i) Identify the chloro-compound that reacts and describe any observations.\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(ii) Write two equations to explain any observations in (b)(i).\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [2]\nNI\nETIRW\n(iii) Explain the dif ference in reactivity of chlorobutane and chlorobenzene with warm\n. aqueous AgNO\n3 TON\nOD ...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM ...........................................................................................................................................\n..................................................................................................................................... [2]\nSIHT\n[Total: 11] NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\n", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2025-mj-43-q08-669e762c4d.pdf" }, { "id": "9701-2025-mj-43-q09", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 20, 21 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-43-q09-p01-946eff5e38.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-mj-43-q09-p02-356559f239.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n9 (a) Phenylamine, C H NH , and propylamine, CH CH CH NH , can be produced by dif ferent\nSIHT 6 5 2 3 2 2 2\nreduction reactions.\nNI\nETIRW H NH by a reduction (i) Identify an organic compound that can be converted into C\n6 5 2\nreaction. State the reagents and conditions for this reaction.\nTON\norganic compound .............................................................................................................\nOD\nreagents ............................................................................................................................\nconditions ..........................................................................................................................\nNIGRAM\n[2]\nCH CH NH by a reduction (ii) Identify an organic compound that can be converted into CH\nSIHT 3 2 2 2\nreaction. State the reagent for this reaction.\nNI\nETIRW\norganic compound .............................................................................................................\nTON reagent ..............................................................................................................................\n[2]\nOD\nH NH and CH CH CH NH by (iii) Identify a single test that will distinguish between C\n6 5 2 3 2 2 2\nproducing a white precipitate with only one of these amines.\nNIGRAM\nDraw the structure of the compound that is precipitated.\ntesting reagent ..................................................................................................................\nSIHT\nNI amine that gives a precipitate ...........................................................................................\nETIRW\nstructure of the compound that is precipitated:\nTON\nOD\nNIGRAM\nSIHT\nNI\n[2] ETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Describe the relative basicities of C H NH , CH CH CH NH and NH .\nSIHT 6 5 2 3 2 2 2 3\nExplain your answer. NI\nETIRW\n.............................................. < .............................................. < ..............................................\nleast basic most basic TON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\n[4] ETIRW\n[Total: 10]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-mj-43-q09-76f023dbb3.pdf" }, { "id": "9701-2025-mj-43-q10", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 10, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_43.pdf?download=true", "source_pages": [ 22, 23, 24 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-43-q10-p01-0f5edf357b.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-43-q10-p02-cdb15369a8.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-43-q10-p03-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-43-q10", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n10 Propanoic acid, methanoic acid and ethanedioic acid are all weak acids.\nSIHT\nNI (a) Draw the displayed formula of ethanedioic acid.\nETIRW\nTON\nOD\n[1]\n(b) The three acids, propanoic acid, methanoic acid and ethanedioic acid, can be distinguished\nusing a combination of two chemical tests. Neither testing reagent is an acid–base indicator.\nNIGRAM\nIdentify two suitable testing reagents and complete Table 10.1 to show the observations from\neach test. SIHT\nNI\nreagent 1 ........................................................ reagent 2 ........................................................\nETIRW\nTable 10.1\nTON\nOD\nobservation when treated observation when treated\nwith reagent 1 with reagent 2\nNIGRAM\npropanoic acid\nSIHT\nNI\nETIRW\nmethanoic acid\nTON\nOD\nethanedioic acid\nNIGRAM\n[4]\nSIHT\n(c) When propanoic acid is treated with chlorine gas in the presence of ultraviolet light, a mixture\nNI\nof products is formed. One of these products is 2,2-dichloropropanoic acid.\nETIRW\nExplain why 2,2-dichloropropanoic acid is stronger than propanoic acid. Refer to the structure\nTON\nof each compound in your answer.\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [2]\nNI\nETIRW [Total: 7]\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.02 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) V molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm NIGRAM\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nkg–1 K–1 g–1 K–1) SIHT (4.18 J specific heat capacity of water c = 4.18 kJ\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nSIHT\nnossenago\nnotpyrk 3.131 muileh nonex gO nodar nogra nR eN eH eX 2.02 9.93 8.38 noen 81 rA rK 811 0.4 81 63 45 68 01 2 – –\nNI\nETIRW\nmuicnerwal enissennet enimorb enitatsa muitetul enirolhc eniroulf 9.621 0.571 enidoi 5.53 9.97 0.91 uL 71 lC 301 sT rB 711 tA rL 53 35 71 58 17 F I – – – 9\nTON\nmuiromrevil OD muibretty muilebon muinolop muineles muirullet negyxo 6.721 1.371 oN eS oP bY ruflus 0.61 1.23 0.97 eT vL 61 201 611 O 07 S 61 43 25 48 8 – – –\nmuivelednem surohpsohp muivocsom ynomitna negortin htumsib muiluht cinesra 8.121 0.902 9.861 mT dM", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-mj-43-q10-5b1d625652.pdf" }, { "id": "9701-2025-mj-44-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-44-q01-p01-f2eab5a6ee.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-44-q01-p02-ba015f3397.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-mj-44-q01-p03-de3ab65a76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 (a) (i) Describe the trend in the thermal stabilities of the carbonates of the Group 2 elements.\nSIHT\nExplain your answer. NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [3]\nCopper(II) SIHT carbonate decomposes on heating in a similar way to the carbonates of (ii)\nGroup 2.\nNI\nETIRW\ncopper(II) carbonate. Write an equation for the decomposition of\nTON\n..................................................................................................................................... [1]\nOD\n(b) (i) Complete the electrons in boxes diagram in Fig. 1.1 to show the electronic configuration\ncopper(II) ion. of a\n3d 4s 4p\nNIGRAM\n[Ar]\nSIHT\nNI\nFig. 1.1\nETIRW\n[1]\nTON\n(ii) There are five different 3d orbitals.\nOD\norbital in Fig. 1.2. Sketch the shape of a 3d\n2 z\nz\ny\nNIGRAM\nx\nSIHT\nNI\nETIRW\nTON\nFig. 1.2\n[1]\nOD\n(iii) Copper can form stable complexes in the +1 and +2 oxidation states.\nExplain why transition elements have variable oxidation states.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nNIGRAM\n(c) (i) 1,2-diaminoethane, H NCH CH NH , en, can act as a bidentate ligand.\nSIHT 2 2 2 2\nNI Explain what is meant by a bidentate ligand.\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [2]\n]2+ O) (en) exists as stereoisomers. (ii) The complex [Cu(H\nNIGRAM 2 2 2\nComplete the three-dimensional diagrams in Fig. 1.3 to show the three dif ferent\n]2+. O) (en) stereoisomers of [Cu(H SIHT\n2 2 2\nNI\nETIRW\nN N The en ligand can be represented using .\nTON\nisomer 1 isomer 2\nOD\nNIGRAM\nCu Cu\nSIHT\nNI\nETIRW\nTON\nisomer 3 OD\nNIGRAM\nCu\nSIHT\nNI\nETIRW\nTON\nFig. 1.3 OD\n[3]\n]2+. O) (en) (iii) State", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-mj-44-q01-e972ae76f9.pdf" }, { "id": "9701-2025-mj-44-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-mj-44-q02-p01-b9fb53bca3.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-44-q02-p02-582ebd77ad.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 (a) Anhydrous barium chloride can be obtained from the hydrated salt, as shown in reaction 1.\nSIHT\nNI •2H O(s) + 2SOCl (l) BaCl (s) + 2SO (g) + 4HCl (g) reaction 1 BaCl\n2 2 2 2 2\nETIRW\n(i) Describe one observation when reaction 1 is carried out.\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(ii) Define the term entropy, S.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\no K–1 mol–1. , for reaction 1 at 25 °C is +768 J (iii) The entropy change, ΔS\nTON\no has a large positive value. Explain why ΔS\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\no\n, for the compounds in (iv) Table 2.1 shows the enthalpy changes of formation, ΔH\nf\nreaction 1.\nSIHT\nTable 2.1 NI\nETIRW\no\nmo–l1 compound / kJ ΔH\nf\nTON\nBaCl (s) –859\n2 OD\n•2H O(s) –1460 BaCl\n2 2\n(l) –246 SOCl\n2\nNIGRAM\n(g) –297 SO\n2\nHCl (g) –92 SIHT\nNI\no ETIRW mol–1, Calculate the standard Gibbs free energy change, ΔG , in kJ for reaction 1\nat 25 °C.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\no mol–1 ΔG = .............................. kJ [3]\nTON\nNIGRAM\n(b) When aqueous solutions of BaCl and Na Cr O are mixed, a yellow precipitate of BaCrO (s)\nSIHT 2 2 2 7 4\nis produced and an acidic solution remains.\nNI\nETIRW\n(i) Write the ionic equation for this reaction.\nTON ..................................................................................................................................... [1]\nOD\n(s) is coloured. (ii) Explain why BaCrO\n4\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\nOD .......................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-mj-44-q02-383a0a136e.pdf" }, { "id": "9701-2025-mj-44-q03", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 8, 9, 10 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-mj-44-q03-p01-d8e31062da.png", "9701-topic-25-equilibria/assets/9701-2025-mj-44-q03-p02-fbd80233b9.png", "9701-topic-25-equilibria/assets/9701-2025-mj-44-q03-p03-c68b362627.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\nNickel(II) 3 (a) iodate(V), Ni(IO ) , is sparingly soluble in water. The concentration of its saturated\nSIHT 3 2\n10–2 dm–3 mol at 298 K. solution is 2.30 ×\nNI\nETIRW\n, of Ni(IO ) . Include the units. (i) Complete the expression for the solubility product, K\nsp 3 2\nTON\nK = OD\nsp\nunits = ..............................\n[2]\nNIGRAM\nof Ni(IO ) at 298 K. (ii) Calculate the numerical value for K\nsp 3 2\nSIHT\nNI\nETIRW\nK = .............................. [1] TON\nsp\nOD\n(b) An electrochemical cell is set up as shown in Fig. 3.1.\nV\nNIGRAM\nPt(s)\nCu(s) SIHT\n) (aq) and I (aq) Ni(IO\nNI 3 2 2\nETIRW\n(aq) CuCl ) (s) Ni(IO\n2 3 2\nTON\nFig. 3.1\nOD\no , for this electrochemical cell are shown. The relevant standard electrode potentials, E\n1 o 6H+(aq) 5e– –(aq) + + I (aq) + 3H O(l) E = +1.19 V IO\nNIGRAM 2 3 2 2\no Cu2+(aq) 2e– + Cu(s) E = +0.34 V\nSIHT\no\n. State which electrode is positive. (i) Use this information to calculate the value of E\ncell\nNI\nETIRW\nTON o\nE = .............................. positive electrode is ..............................\ncell\n[1] OD\no\nof this cell compares to the E under standard (ii) Suggest how the measured E\ncell cell\nconditions.\nNIGRAM\nExplain your answer.\nSIHT\n...........................................................................................................................................\nNI\n..................................................................................................................................... [1] ETIRW\nTON\nNIGRAM\n(iii) Complete Table 3.1 by placing one tick (3) to indicate how the E of this cell changes\nSIHT cell\n(aq) is added to the beaker containing Ni(IO ) (aq) and when a small amount of NiSO\n4 3 2\nNI (aq) in Fig. 3.1. I\n2 ETIRW\nExplain your answer.\nTON\nTable 3.1\nOD\nchange in E\ncell\nless positive no change more positive\nNIGRAM\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n[2]\niodic(V) acid, HIO , ionises as shown. (c) In solution,\n3\nNIGRAM H+(aq) –(aq) (aq) IO + HIO\n3 3\ndm–3 solution of HIO is 0.47. The pH of a 1.0 mol\nSIHT 3\nNI [H+(aq)], dm–3, dm–3 in mol in a 1.0 mol solution of HIO . (i) Calculate\n3 ETIRW\nTON\nOD\n+(aq)] dm–3 [H = .............................. mol [1]\n(aq) and (ii) Use your answer from (c)(i) to calculate the equilibrium concentrations of HIO\n3\ndm–3, dm–3 –(aq), in mol in a 1.0 mol solution of HIO . IO NIGRAM\n3 3\nSIHT\nNI\ndm–3 [HIO (aq)] = .............................. mol ETIRW\n3\ndm–3 –(aq)] [IO = .............................. mol\nTON 3\n[1]\nOD\ndm–3, , in mol of HIO . (iii) Use your ", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-mj-44-q03-b4bcfe89f3.pdf" }, { "id": "9701-2025-mj-44-q04", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 4, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2025-mj-44-q04-p01-29e5524189.png", "9701-topic-35-polymerisation/assets/9701-2025-mj-44-q04-p02-731a2f5708.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q04", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n4 Table 4.1 shows the structures of sections of three polymers, X, Y and Z.\nSIHT\nNI Each polymer is made from only one type of monomer.\nETIRW\nTable 4.1\nTON\npolymer structure of section of polymer\nOD\nO\nO\nH H H O H\n2 2 2 H H H H C C C C N H2 H2 H2 NIGRAM H X C C C C N 2 2 2 C N C C C C C C C N\nC N C C C H H H H\nC2 N C2 C2 C H H H H\nH2 H2 H2 H O SIHT\n2 2 2 O\nO\nNI\nCOOCH COOCH COOCH COOCH COOCH\n3COOCH 3COOCH 3COOCH 3COOCH 3 ETIRW COOCH\nCOOCH3 COOCH3 COOCH3 COOCH3 COOCH3\n3 3 3 3 3\nCH CH CH CH CH\nTON CH CH CH CH CH Y\nC C C C CH CH CH CH CH\nC C C C OD H H H H\nC C C C 2 2 2 2 H H H H\nH2 H2 H2 H2\n2 2 2 2\nO O CH\n3 O O CH\nCH3 O O\n3 NIGRAM O O CH C C\nO O CH C C\nO CH CH C O O CH C C\nO CH CH C Z\nO CH CH C\nSIHT\nO CH CH\nO 3 3 CH CH\nNI O CH3 CH3\n3 3 ETIRW\nTON (a) Complete Table 4.2 to state the type of polymerisation and draw the structure of the monomer\nfor each polymer, X, Y and Z.\nOD\nTable 4.2\npolymer type of polymerisation structure of monomer\nNIGRAM\nSIHT\nX\nNI\nETIRW\nTON\nOD\nY\nNIGRAM\nSIHT Z\nNI\nETIRW\n[4]\nTON\nNIGRAM\n(b) Amino acids can act as monomers.\nSIHT\nNI State what is meant by the isoelectric point of an amino acid.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\n(c) Electrophoresis can be used to separate and identify amino acids.\nT able 4.3 shows information about the three amino acids glycine, lysine and glutamic acid.\nNIGRAM\nTable 4.3\nSIHT\namino acid structural formula of amino acid isoelectric point\nNI\nETIRW\nNCH COOH 6.0 glycine (gly) H\n2 2\nTON NCH(CH CH CH CH NH )COOH 9.7 lysine (lys) H\n2 2 2 2 2 2\nOD\nNCH(CH CH COOH)COOH 3.2 glutamic acid (glu) H\n2 2 2\n(i) A mixture containing these three amino acids is analysed in a buffer solution of pH 6.0.\nNIGRAM\nDraw and label three spots on Fig. 4.1 to indicate the predicted position of each of these\namino acids, gly, lys and glu, after electrophoresis.\nSIHT\nNI\nETIRW\n– +\nTON\nOD\nmixture applied here\nFig. 4.1\nNIGRAM [2]\n(ii) Electrophoresis is repeated using a buffer solution of pH 11.\nSIHT\nPredict how the position of glycine will change, if at all, after electrophoresis. NI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [1]\nOD\n[Total: 8]\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-35-polymerisation/print/9701-2025-mj-44-q04-8fe7777f93.pdf" }, { "id": "9701-2025-mj-44-q05", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 5, "topic_number": 29, "topic": "An introduction to A Level organic chemistry", "topic_slug": "9701-topic-29-an-introduction-to-a-level-organic-chemistry", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2025-mj-44-q05-p01-807306270b.png", "9701-topic-29-an-introduction-to-a-level-organic-chemistry/assets/9701-2025-mj-44-q05-p02-673f7b950e.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q05", "html": "9701-topic-29-an-introduction-to-a-level-organic-chemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n5 A group of drugs known as statins are used to lower cholesterol in blood. A commonly used statin\nSIHT\nis atorvastatin.\nNI\nETIRW\natorvastatin\nTON\nOD\nOH OH O\nNH\nOH N\nNIGRAM\nO\nSIHT\nNI\nETIRW\nTON\nF\nOD\nFig. 5.1\n(a) Statins can break down in the acid found in the stomach. NIGRAM\n(i) Draw a line through the bond in the atorvastatin structure in Fig. 5.1 that could be broken\nSIHT\nunder acid conditions. [1]\nNI\n(ii) By referring to the structure, explain why atorvastatin dissolves in water. ETIRW\n........................................................................................................................................... TON\nOD\n..................................................................................................................................... [1]\n(iii) Complete the molecular formula of atorvastatin.\nNIGRAM\nC H N O F\n35\n[1]\nSIHT\n(iv) Atorvastatin contains chiral carbon atoms. NI\nETIRW\nCircle all chiral carbon atoms in Fig. 5.1. [1]\nTON\n(v) The synthetic preparation of atorvastatin requires the production of a single optical\nOD\nisomer.\nSuggest why.\nNIGRAM\n...........................................................................................................................................\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(1H) (b) (i) The proton NMR spectrum of atorvastatin dissolved in CDCl is recorded.\nSIHT 3\nUse Table 5.1 to deduce the number of hydrogen atoms that could produce peaks in the NI\nETIRW region δ = 6.5–13.0 ppm.\n..................................................................................................................................... [1] TON\nOD (1H) NMR spectrum of atorvastatin dissolved in D O is recorded. (ii) The proton\n2\nPredict the number of hydrogen atoms that would not show a peak in this spectrum.\nExplain your answer. NIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [2]\nTON Table 5.1\nOD\nchemical shift range\nenvironment of proton example\nδ / ppm\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\nNIGRAM\nalkyl next to C=O CH –C=O, –CH –C=O, >CH–C=O 2.2–3.0\n3 2\nalkyl next to aromatic ring CH –Ar, –CH –Ar, >CH–Ar 2.3–3.0\n3 2\nSIHT\nalkyl next to electronegative atom CH –O, –CH –O, –CH –Cl 3.2–4.0\n3 2 2\nNI\nattached to alkene =CHR 4.5–6.0\nETIRW\nattached to aromatic ring H–Ar 6.0–9.0\nTON\naldehyde HCOR 9.3–10.5\nOD\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0\ncarboxylic acid RCOOH 9.0–13.0\nNIGRAM\nalkyl", "pdf_path": "9701-topic-29-an-introduction-to-a-level-organic-chemistry/print/9701-2025-mj-44-q05-432fbebf76.pdf" }, { "id": "9701-2025-mj-44-q06", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 6, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 17, 18, 19 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2025-mj-44-q06-p01-898e5fce0a.png", "9701-topic-36-organic-synthesis/assets/9701-2025-mj-44-q06-p02-d0cc735ff0.png", "9701-topic-36-organic-synthesis/assets/9701-2025-mj-44-q06-p03-3a27368ee6.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q06", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:8)(cid:44)\n6 (a) A list of tests for different organic groups is given in Table 6.1.\nSIHT\nNI Complete Table 6.1 to identify an organic functional group, in aliphatic compounds, that\nETIRW\nproduces a positive result in each test.\nTON Table 6.1\nOD\ntest\nwarm with I (aq)\nsodium 2\nCO (aq) 2,4-DNPH (aq) Fehling’s Br Na +\nmetal 2 3 2 NIGRAM\nOH–(aq) reagent\nSIHT\nNI\n[4] ETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Lavandulol is an aliphatic organic compound and the major component of lavender oil.\nSIHT\nFig. 6.1 shows a reaction scheme involving lavandulol, A.\nNI\nETIRW\nlavandulol, A (C H O)\n10 18\nTON\nOD\nB (C H O)\n10 16\nNIGRAM\nSIHT\nheat with concentrated acidified KMnO\n4 NI\nETIRW\nTON\nH O ) D (C C (C H O)\n6 8 5 3 6 + + CO\n2 OD\nNIGRAM\nSIHT\nNI\nETIRW\nNaBH\n4\nTON\nE (C H O ) F (C H O ) OD\n6 10 5 6 8 4\nheat with\nNIGRAM\nconcentrated\nH SO\n2 4\nSIHT\nNI\nETIRW\nheat with concentrated\nacidified KMnO TON\n4\nOD\nG (C H O ) H (C H O )\n4 4 5 2 4 2\n+\nNIGRAM\nSIHT\nNI\nETIRW\nFig. 6.1 TON\nNIGRAM\nT able 6.2 shows the results obtained when the tests in Table 6.1 are carried out on the eight\nSIHT\norganic compounds, A–H, in the reaction scheme in Fig. 6.1.\nNI\nETIRW\nTable 6.2\nTON test\nOD letter of\nwarm with I (aq)\nsodium 2 compound\nCO (aq) 2,4-DNPH (aq) Fehling’s Br Na +\nmetal 2 3 2\nOH–(aq) reagent\nA 3 ✗ ✗ ✗ ✗ 3 NIGRAM\nB ✗ ✗ 3 ✗ 3 3\nSIHT\nC 3 3 3 3 ✗ ✗\nNI\nD ✗ ✗ 3 3 ✗ ✗ ETIRW\nE 3 3 ✗ 3 ✗ ✗\nTON\nF 3 3 ✗ ✗ ✗ 3\nOD\nG 3 3 3 ✗ ✗ ✗\nH 3 3 ✗ ✗ ✗ ✗\nNIGRAM\n(i) Deduce the functional group present in compound A using both the molecular formulae\nof A and B and the reaction of B with Fehling’s reagent.\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\n(ii) Name the type of reaction that occurs in each of the following conversions.\nTON\n• A B ..............................\nOD\n• C E ..............................\n• E F ..............................\nNIGRAM\n[3]\nSIHT (iii) Use the information in Table 6.2 and the molecular form ulae to deduce structures for G\nand H. Draw your structures in Fig. 6.1. [2]\nNI\nETIRW\n(iv) Use the information in Table 6.2, the molecular formulae and your answer to (b)(iii) to\ndeduce structures for A, C, D, E and F. Draw your structures in Fig. 6.1. [5]\nTON\nOD [Total: 15]\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2025-mj-44-q06-b28c59c806.pdf" }, { "id": "9701-2025-mj-44-q07", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 7, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 20, 21 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-44-q07-p01-f91701a3f4.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-mj-44-q07-p02-7282652dcd.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q07", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n7 (a) State the relative acidities of benzoic acid, C H COOH, ethanol, CH CH OH, and phenol,\nSIHT 6 5 3 2\nH OH, in aqueous solution. Explain your answer. C\n6 5\nNI\nETIRW\n........................................... ........................................... ...........................................\nmost acidic least acidic\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\n[3]\nTON\nOD (b) Draw the major products from the nitration of benzoic acid and phenol in the boxes in Fig. 7.1.\nThe molecular formula for each major product is given in the boxes.\nH NO H NO major product from phenol, C major product from benzoic acid, C\n7 5 4 6 5 3 NIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\n[2]\nFig. 7.1\nSIHT\nNI (c) Ethanol reacts with propanoyl chloride, C H COCl, to form ester W.\n2 5 ETIRW\nW\nTON\nO\nOD\nO\nNIGRAM\nFig. 7.2\nSIHT (i) Give the systematic name for ester W.\nNI\n..................................................................................................................................... [1] ETIRW\nTON\nNIGRAM\n(ii) Complete the mechanism in Fig. 7.3 for the reaction between C H COCl and ethanol.\nSIHT 2 5\nNI R–OH represents ethanol.\nETIRW\nInclude all relevant lone pairs of electrons, curly arrows, charges and partial charges.\nTON\nOD\norganic intermediate\nO\nNIGRAM products C H C\n2 5\nCl\nSIHT\nNI\nETIRW\nR O\nTON\nH\nOD\nFig. 7.3\n[4]\nNIGRAM\n(iii) Name the mechanism for the reaction shown in Fig. 7.3.\n..................................................................................................................................... [1] SIHT\nNI\n[Total: 11]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-mj-44-q07-c3a4c0d6db.pdf" }, { "id": "9701-2025-mj-44-q08", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 8, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_44.pdf?download=true", "source_pages": [ 22, 23, 24 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_44.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-mj-44-q08-p01-d8e1c37e6f.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-44-q08-p02-2ac38b8612.png", "9701-topic-23-chemical-energetics/assets/9701-2025-mj-44-q08-p03-4709b7d6fb.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-44-q08", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n8 (a) (i) Define lattice energy, ΔH .\nSIHT latt\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [2]\nTON\n. (ii) Define enthalpy change of solution, ΔH\nOD sol\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\n. (b) The enthalpy change of hydration can be represented by ΔH\nhyd\nSIHT\n(Na+) of NaCl in terms of ΔH (NaCl ), ΔH W rite the mathematical expression for the ΔH\nsol latt hyd NI\n– (Cl ). and ΔH\nETIRW hyd\n(NaCl ) = ...................................................................................................................... [1] ΔH\nsol TON\nOD (c) Complete the Born–Haber cycle in Fig. 8.1 for the ionic solid NaCl.\nInclude state symbols of relevant species.\n........................................................ NIGRAM\nΔH\nNa+(g) –(g) + Cl ea1\nSIHT ΔH\ni1\n..................................\nNI\nETIRW\nΔH\nTON at\n...............................\nOD\nΔH\nat\n.........................................\nNIGRAM\nΔH\nf\nNaCl (s)\nSIHT\nNI\nETIRW\nKey\nΔH first ionisation energy\nTON i1\nΔH first electron affinity\nOD ea1\nFig. 8.1\n[3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n– –, (d) Predict which of the ions, Cl or NO has the more negative enthalpy change of hydration.\nSIHT 3\nNI Explain your answer .\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [2]\nSIHT\n[Total: 9]\nNI\nETIRW\nImportant values, constants and standards\nTON\nK–1 mol–1 molar gas constant R = 8.31 J\nOD\n104 mo–l1 Faraday constant F = 9.65 C ×\n1023 mol–1 Avogadro constant L = 6.02 ×\nNIGRAM\n10–19 electronic charge e = –1.60 C ×\ndm3 mol–1 molar volume of gas V = 22.4 at s.t.p. (101 kPa and 273 K)\nm SIHT\ndm3 mol–1 V = 24.0 at room conditions\nm\nNI\n10–14 mol2 dm–6 ionic product of water K = 1.00 × (at 298 K (25 °C)) ETIRW\nw\nkg–1 K–1 g–1 K–1) specific heat ca", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-mj-44-q08-fe47a23e28.pdf" }, { "id": "9701-2025-mj-51-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_51.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-51-q01-p01-07e8f9b2d1.png", "9701-experimental-skills/assets/9701-2025-mj-51-q01-p02-07c39a51b7.png", "9701-experimental-skills/assets/9701-2025-mj-51-q01-p03-6e196ff17f.png", "9701-experimental-skills/assets/9701-2025-mj-51-q01-p04-9281f0299f.png", "9701-experimental-skills/assets/9701-2025-mj-51-q01-p05-a22b3acdad.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Grignard reagents have the general formula RMgX, where R is a hydrocarbon group and X is a\nSIHT\nH MgBr is used as an intermediate in the reaction between halogen. The Grignard reagent C\n6 5\nNI H Br, and ethanal, CH CHO, to prepare 1-phenylethanol, C H CH(OH)CH . bromobenzene, C\n6 5 3 6 5 3\nETIRW\nAn organic solvent, ethoxyethane, is used.\nTON The equations for the three reactions that take place during the preparation are shown.\nOD\nH Br → C H MgBr reaction 1 Mg + C\n6 5 6 5\nH MgBr + CH CHO → C H CH(CH )OMgBr reaction 2 C\n6 5 3 6 5 3\nNIGRAM\nH+ Mg2+ – H CH(CH )OMgBr + → C H CH(OH)CH + + Br reaction 3 C\n6 5 3 6 5 3\nThe preparation involves the following steps. SIHT\nNI\nstep 1 Set up the apparatus shown in Fig. 1.1 with approximately 1.25 g of Mg powder and\nETIRW\ncm3 of ethoxyethane in the round-bottomed flask. 5\nTON\nH Br to the round-bottomed flask dropwise using the tap step 2 Add 0.0500 mol of liquid C\n6 5\nOD funnel. Leave until reaction 1 is complete.\ncm3 cm3 of CH CHO in 15 of ethoxyethane and add this solution to the step 3 Dissolve 3.00\n3\nround-bottomed flask using the tap funnel. Leave until reaction 2 is complete.\nNIGRAM\nstep 4 Remove the condenser, tube Y and the tap funnel from the round-bottomed flask.\nSIHT\ncm3 of dilute hydrochloric acid, HCl (aq), to the round-bottomed flask so that step 5 Add 40\nreaction 3 takes place. NI\nETIRW\nstep 6 Transfer the contents of the round-bottomed flask to a separating funnel.A llow the liquids\nto settle so that two layers are formed. TON\nOD\nstep 7 Open the tap of the separating funnel and run the lower layer into a beaker labelled A.\nRun the upper layer into a beaker labelled B.\nH CH(OH)CH . step 8 Allow the ethoxyethane to evaporate from the beaker containing C\n6 5 3 NIGRAM\nsolid Z\nSIHT\nNI tube Y\nETIRW\ncondenser\nTON\nOD\ntap funnel\nNIGRAM\nround-bottomed\nflask\nSIHT\nNI\nETIRW\nFig. 1.1 TON\nNIGRAM\nSome relevant data are shown in Table 1.1.\nSIHT\nNI Table 1.1\nETIRW\ndensity boiling point\nsubstance hazard TON\ncm–3 / g / °C\nOD\nbromobenzene 1.50 156 flammable, toxic, skin irritant\ndistilled water 1.00 100 non-hazardous\nethoxyethane 0.714 35 flammable, toxic NIGRAM\nethanal 0.788 21 flammable, eye and respiratory irritant\nSIHT\n1-phenylethanol 1.01 204 flammable, toxic, eye irritant\nNI\nETIRW\n(a) Use the information in Table 1.1 to suggest why the following safety precautions are used.\nTON • wearing chemically resistant gloves\nOD\n....................................................................................................................................\n• using a fume hood\nNIGRAM\n....................................................................................................................................\n[2]\nSIHT\n(b) Dry apparatus and reagents are essential for steps 1–3.\nNI\nETIRW\n(i) Suggest how the glassware shown in Fig. 1.1 should be dried before use in step 1.\nTON\n..........................", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-51-q01-d45824ab10.pdf" }, { "id": "9701-2025-mj-51-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_51.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-51-q02-p01-cd18d7b6c7.png", "9701-experimental-skills/assets/9701-2025-mj-51-q02-p02-2e04815b4a.png", "9701-experimental-skills/assets/9701-2025-mj-51-q02-p03-2a501a30cf.png", "9701-experimental-skills/assets/9701-2025-mj-51-q02-p04-f92b4ea145.png", "9701-experimental-skills/assets/9701-2025-mj-51-q02-p05-8eaf79a281.png", "9701-experimental-skills/assets/9701-2025-mj-51-q02-p06-a6521df17f.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 An experiment is carried out to determine the rate constant, k, for the hydrolysis of ethyl ethanoate,\nSIHT\nCOOC H , using a hydrochloric acid, HCl (aq), catalyst. CH\n3 2 5\nNI\nETIRW\nThe equation for the reaction is shown.\nTON + H\nCH COOC H + H O CH COOH + C H OH\n3 2 5 2 3 2 5 OD\nThe rate equation for this reaction is shown.\nCOOC H ] rate of reaction = k [CH\n3 2 5 NIGRAM\nThe progress of the reaction is followed by determining how the concentration of acid changes\nwith time.\nSIHT\nA portion of the reaction mixture is removed every 5 minutes and titrated with sodium hydroxide,\nNI NaOH(aq). A final titration is carried out after 180 minutes.\nETIRW\nA student carries out the following steps.\nTON\ncm3 of iced water to seven separate small conical flasks. Add a few drops of step 1 Add 70 OD\nphenolphthalein indicator to each flask. Phenolphthalein is pink in alkaline conditions\nand colourless in acidic conditions.\ncm3 dm–3 of 0.200 mol HCl (aq) into a large step 2 Use a measuring cylinder to transfer 100 NIGRAM\nconical flask.\nSIHT cm3 of CH COOC H to the large conical flask and swirl the flask to mix the step 3 Add 5.00\n3 2 5\ncontents. Start a stopwatch.\nNI\nETIRW\ncm3 of reaction mixture to one of the small conical flasks containing the step 4 Transfer 10.00\niced water and indicator. Record the time. Shake the small flask.\nTON\nOD dm–3 step 5 Carry out a single titration of the mixture in the small conical flask using 0.15 mol\nNaOH(aq).\nstep 6 Repeat steps 4 and 5 at the times shown in Table 2.1 using a different small conical flask\nNIGRAM for each titration.\n(a) Give two reasons that explain why the use of iced water in step 4 decreases the rate of\nSIHT\nreaction.\nNI\nETIRW reason 1 ....................................................................................................................................\nTON reason 2 ....................................................................................................................................\n[2]\nOD\n(b) Describe the observation that is used to determine the end-point of the titrations.\n............................................................................................................................................. [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The results of the experiment are shown in Table 2.1.\nSIHT\nis the titre at a given time, t. V\nt\nNI is the final titre at t = 180 min when the reaction is assumed to be complete. V\n∞\nETIRW\nTable 2.1\nTON\nOD 1 2 3 4\ncm3 cm3 cm3] / (V – V ) / log[(V – V ) / time, t / min titre, V\nt ∞ t ∞ t\n0 12.00\nNIGRAM\n5 16.40\n10 22.15\nSIHT\n15 23.45 NI\nETIRW\n20 26.30\nTON 25 28.70\nOD 180 45.70\n(i) Complete Table 2.1.\nGive your answers in column 3 to two decimal places and your answers in column 4 to\nNIGRAM\nfour significant figures. [2]\ncm3] – V ) / (ii) Plot a graph on the grid in Fig. 2.1 to show the relationship between log[(V SIHT\n∞ t\nand", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-51-q02-fda7774602.pdf" }, { "id": "9701-2025-mj-52-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 20, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-52-q01-p01-be0a010048.png", "9701-experimental-skills/assets/9701-2025-mj-52-q01-p02-94aa0ccdbf.png", "9701-experimental-skills/assets/9701-2025-mj-52-q01-p03-5afd11baed.png", "9701-experimental-skills/assets/9701-2025-mj-52-q01-p04-a28241971f.png", "9701-experimental-skills/assets/9701-2025-mj-52-q01-p05-a3ecb370ac.png", "9701-experimental-skills/assets/9701-2025-mj-52-q01-p06-4397da1a4f.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Activated carbon is a form of carbon with the ability to adsorb solutes from solutions. The\nSIHT\n, from dilute ethanedioic acid, (COOH) (aq), adsorption of ethanedioic acid molecules, (COOH)\n2 2\nNI onto the surface of activated carbon is studied in a series of experiments.\nETIRW\ncm3 dm–3 of 0.139 mol (COOH) (aq), solution X, is made. Before beginning the experiment, 500.0\n2\nTON The activated carbon is placed in an oven at 120 °C for three hours.\nOD\nThe experimental procedure involves the following steps.\ncm3 dm–3 of 0.00556 mol (COOH) (aq) from solution X. step 1 Prepare 100.0\n2\nNIGRAM\ncm3 dm–3 of the 0.00556 mol (COOH) (aq) into a conical flask. step 2 Transfer 50.0\n2\nstep 3 Add 0.500 g of activated carbon to the conical flask and start a stopwatch. SIHT\nNI\ncm3 sample from the flask. Determine the step 4 Shake the flask and immediately remove a 5.0\nETIRW\nin the sample using chromatography. mass of non-adsorbed (COOH)\n2\nTON\nstep 5 Repeat step 4 at suitable time intervals until there is no further change in the mass of\nOD in the sample. non-adsorbed (COOH)\n2\n•2H O. (a) Solid ethanedioic acid has the formula (COOH)\n2 2\nm3 dm–3 NIGRAM •2H O(s) required to prepare 500.0c of 0.139 mol (i) Calculate the mass of (COOH)\n2 2\n(aq), solution X. (COOH)\n2\nSIHT\nNI\nETIRW\nTON\nOD\nmass = .............................. g [1]\ncm3 •2H O(s) calculated in (a)(i) is placed into a 100 beaker. (ii) The mass of (COOH)\n2 2\ncm3 dm–3 of 0.139 mol (COOH) (aq). Describe the steps taken to prepare 500.0\n2 NIGRAM\nGive the name and capacity of any apparatus used.\nSIHT\nWrite your answer using a series of numbered steps.\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ...........................................................................................................................................\nNI\n..................................................................................................................................... [3] ETIRW\nTON\nNIGRAM\n(b) (COOH) •2H O(s) is corrosive. Other than wearing eye protection and a lab coat, state one\nSIHT 2 2\n•2H O(s). safety precaution that should be taken when using (COOH)\n2 2\nNI\nETIRW\n..............................................................", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-52-q01-138b54af08.pdf" }, { "id": "9701-2025-mj-52-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_52.pdf?download=true", "source_pages": [ 8, 9, 11, 12 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-52-q02-p01-d14c4540bf.png", "9701-experimental-skills/assets/9701-2025-mj-52-q02-p02-5c7e23211f.png", "9701-experimental-skills/assets/9701-2025-mj-52-q02-p03-fdd9999139.png", "9701-experimental-skills/assets/9701-2025-mj-52-q02-p04-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n2 The enthalpy change of combustion, ∆H , of butane, C H , can be determined using the\nSIHT c 4 10\napparatus shown in Fig. 2.1.\nNI\nETIRW\nthermometer\nTON metal can\nOD\nwater\ngas burner\ntripod\nNIGRAM\ntap\nSIHT\ngas container\nof butane NI\nETIRW\nFig. 2.1\nTON\nThe following steps are carried out. OD\ncm3 cm3 measuring cylinder to transfer 320 of water into a metal can. step 1 Use a 500\nstep 2 Place a thermometer into the water . Record the initial temperature of the water in the NIGRAM\nmetal can.\nSIHT\nstep 3 Weigh the gas container with burner and record the initial mass.\nNI\nstep 4 Set up the apparatus as shown in Fig. 2.1. ETIRW\nstep 5 Light the burner and allow the flame to heat the water in the metal can for three minutes.\nTON\nOD\nstep 6 Switch off the burner and record the maximum temperature reached.\nstep 7 When cool, reweigh the gas container with burner and record the final mass.\nNIGRAM\nThe results are shown in Table 2.1.\nTable 2.1\nSIHT\nNI\ninitial maximum change in initial mass of final mass of mass of\nETIRW\ntemperature temperature temperature of gas container gas container butane\nof water / °C of water / °C water, ∆T / °C with burner / g with burner / g burned / g\nTON\n19.3 76.6 183.56 181.46\nOD\n(a) Complete Table 2.1. Record your answers to the appropriate number of decimal places. [2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Use the relationship q = mc∆T to calculate the energy, q, in J, gained by the water.\nSIHT\n3 of water has a mass of 1.00 g. 1.00 cm\nNI\nETIRW\nTON\nOD\nq = .............................. J [1]\nmol–1. , of butane, in kJ (c) Calculate the enthalpy change of combustion, ∆H\nNIGRAM c\nGive your answer to three significant figures.\nSIHT\nNI\nETIRW\nTON\nOD\nmol–1 = .............................. kJ [2] ∆H\nc\n(d) Without changing the apparatus, suggest what should be done in step 6 before recording the\nNIGRAM maximum temperature reached to improve the experimental procedure.\n............................................................................................................................................. [1]\nSIHT\ncm3 cm3. measuring cylinder has graduations every 5 (e) The 500 NI\nETIRW Calculate the percentage error in the measurement of the volume of water .\nShow your working.\nTON\nOD\npercentage error = .............................. % [1]\nNIGRAM\n(f) A student suggests that the value calculated in (c) is dif ferent from the actual value of ∆H\nc\nof butane because of heat lost during the experiment. Suggest one change to the apparatus SIHT\nthat would reduce the heat lost.\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\n(g) The experiment was repeated but the burner was switched off after only two minutes.\nOD\nof butane. (i) Suggest why this might contribute to a reduction in the accuracy of ∆H\nc\n............................", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-52-q02-acc1cc6b9e.pdf" }, { "id": "9701-2025-mj-53-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_53.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-53-q01-p01-07e8f9b2d1.png", "9701-experimental-skills/assets/9701-2025-mj-53-q01-p02-07c39a51b7.png", "9701-experimental-skills/assets/9701-2025-mj-53-q01-p03-6e196ff17f.png", "9701-experimental-skills/assets/9701-2025-mj-53-q01-p04-9281f0299f.png", "9701-experimental-skills/assets/9701-2025-mj-53-q01-p05-a22b3acdad.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Grignard reagents have the general formula RMgX, where R is a hydrocarbon group and X is a\nSIHT\nH MgBr is used as an intermediate in the reaction between halogen. The Grignard reagent C\n6 5\nNI H Br, and ethanal, CH CHO, to prepare 1-phenylethanol, C H CH(OH)CH . bromobenzene, C\n6 5 3 6 5 3\nETIRW\nAn organic solvent, ethoxyethane, is used.\nTON The equations for the three reactions that take place during the preparation are shown.\nOD\nH Br → C H MgBr reaction 1 Mg + C\n6 5 6 5\nH MgBr + CH CHO → C H CH(CH )OMgBr reaction 2 C\n6 5 3 6 5 3\nNIGRAM\nH+ Mg2+ – H CH(CH )OMgBr + → C H CH(OH)CH + + Br reaction 3 C\n6 5 3 6 5 3\nThe preparation involves the following steps. SIHT\nNI\nstep 1 Set up the apparatus shown in Fig. 1.1 with approximately 1.25 g of Mg powder and\nETIRW\ncm3 of ethoxyethane in the round-bottomed flask. 5\nTON\nH Br to the round-bottomed flask dropwise using the tap step 2 Add 0.0500 mol of liquid C\n6 5\nOD funnel. Leave until reaction 1 is complete.\ncm3 cm3 of CH CHO in 15 of ethoxyethane and add this solution to the step 3 Dissolve 3.00\n3\nround-bottomed flask using the tap funnel. Leave until reaction 2 is complete.\nNIGRAM\nstep 4 Remove the condenser, tube Y and the tap funnel from the round-bottomed flask.\nSIHT\ncm3 of dilute hydrochloric acid, HCl (aq), to the round-bottomed flask so that step 5 Add 40\nreaction 3 takes place. NI\nETIRW\nstep 6 Transfer the contents of the round-bottomed flask to a separating funnel.A llow the liquids\nto settle so that two layers are formed. TON\nOD\nstep 7 Open the tap of the separating funnel and run the lower layer into a beaker labelled A.\nRun the upper layer into a beaker labelled B.\nH CH(OH)CH . step 8 Allow the ethoxyethane to evaporate from the beaker containing C\n6 5 3 NIGRAM\nsolid Z\nSIHT\nNI tube Y\nETIRW\ncondenser\nTON\nOD\ntap funnel\nNIGRAM\nround-bottomed\nflask\nSIHT\nNI\nETIRW\nFig. 1.1 TON\nNIGRAM\nSome relevant data are shown in Table 1.1.\nSIHT\nNI Table 1.1\nETIRW\ndensity boiling point\nsubstance hazard TON\ncm–3 / g / °C\nOD\nbromobenzene 1.50 156 flammable, toxic, skin irritant\ndistilled water 1.00 100 non-hazardous\nethoxyethane 0.714 35 flammable, toxic NIGRAM\nethanal 0.788 21 flammable, eye and respiratory irritant\nSIHT\n1-phenylethanol 1.01 204 flammable, toxic, eye irritant\nNI\nETIRW\n(a) Use the information in Table 1.1 to suggest why the following safety precautions are used.\nTON • wearing chemically resistant gloves\nOD\n....................................................................................................................................\n• using a fume hood\nNIGRAM\n....................................................................................................................................\n[2]\nSIHT\n(b) Dry apparatus and reagents are essential for steps 1–3.\nNI\nETIRW\n(i) Suggest how the glassware shown in Fig. 1.1 should be dried before use in step 1.\nTON\n..........................", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-53-q01-45c2aa4035.pdf" }, { "id": "9701-2025-mj-53-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_53.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-53-q02-p01-cd18d7b6c7.png", "9701-experimental-skills/assets/9701-2025-mj-53-q02-p02-2e04815b4a.png", "9701-experimental-skills/assets/9701-2025-mj-53-q02-p03-2a501a30cf.png", "9701-experimental-skills/assets/9701-2025-mj-53-q02-p04-f92b4ea145.png", "9701-experimental-skills/assets/9701-2025-mj-53-q02-p05-8eaf79a281.png", "9701-experimental-skills/assets/9701-2025-mj-53-q02-p06-a6521df17f.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 An experiment is carried out to determine the rate constant, k, for the hydrolysis of ethyl ethanoate,\nSIHT\nCOOC H , using a hydrochloric acid, HCl (aq), catalyst. CH\n3 2 5\nNI\nETIRW\nThe equation for the reaction is shown.\nTON + H\nCH COOH + C H OH CH COOC H + H O\n3 2 5 3 2 5 2 OD\nThe rate equation for this reaction is shown.\nCOOC H ] rate of reaction = k [CH\n3 2 5 NIGRAM\nThe progress of the reaction is followed by determining how the concentration of acid changes\nwith time.\nSIHT\nA portion of the reaction mixture is removed every 5 minutes and titrated with sodium hydroxide,\nNI NaOH(aq). A final titration is carried out after 180 minutes.\nETIRW\nA student carries out the following steps.\nTON\ncm3 of iced water to seven separate small conical flasks. Add a few drops of step 1 Add 70 OD\nphenolphthalein indicator to each flask. Phenolphthalein is pink in alkaline conditions\nand colourless in acidic conditions.\ncm3 dm–3 of 0.200 mol HCl (aq) into a large step 2 Use a measuring cylinder to transfer 100 NIGRAM\nconical flask.\nSIHT cm3 of CH COOC H to the large conical flask and swirl the flask to mix the step 3 Add 5.00\n3 2 5\ncontents. Start a stopwatch.\nNI\nETIRW\ncm3 of reaction mixture to one of the small conical flasks containing the step 4 Transfer 10.00\niced water and indicator. Record the time. Shake the small flask.\nTON\nOD dm–3 step 5 Carry out a single titration of the mixture in the small conical flask using 0.15 mol\nNaOH(aq).\nstep 6 Repeat steps 4 and 5 at the times shown in Table 2.1 using a different small conical flask\nNIGRAM for each titration.\n(a) Give two reasons that explain why the use of iced water in step 4 decreases the rate of\nSIHT\nreaction.\nNI\nETIRW reason 1 ....................................................................................................................................\nTON reason 2 ....................................................................................................................................\n[2]\nOD\n(b) Describe the observation that is used to determine the end-point of the titrations.\n............................................................................................................................................. [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The results of the experiment are shown in Table 2.1.\nSIHT\nis the titre at a given time, t. V\nt\nNI is the final titre at t = 180 min when the reaction is assumed to be complete. V\n∞\nETIRW\nTable 2.1\nTON\nOD 1 2 3 4\ncm3 cm3 cm3] / (V – V ) / log[(V – V ) / time, t / min titre, V\nt ∞ t ∞ t\n0 12.00\nNIGRAM\n5 16.40\n10 22.15\nSIHT\n15 23.45 NI\nETIRW\n20 26.30\nTON 25 28.70\nOD 180 45.70\n(i) Complete Table 2.1.\nGive your answers in column 3 to two decimal places and your answers in column 4 to\nNIGRAM\nfour significant figures. [2]\ncm3] – V ) / (ii) Plot a graph on the grid in Fig. 2.1 to show the relationship between log[(V SIHT\n∞ t\nand", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-53-q02-6ebce7aebb.pdf" }, { "id": "9701-2025-mj-54-q01", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_54.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-54-q01-p01-53c199e917.png", "9701-experimental-skills/assets/9701-2025-mj-54-q01-p02-a1c2b252e5.png", "9701-experimental-skills/assets/9701-2025-mj-54-q01-p03-307e63ec85.png", "9701-experimental-skills/assets/9701-2025-mj-54-q01-p04-a96e1b7a08.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-54-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 The relative molecular mass, M, of an unknown volatile liquid, Y, can be determined experimenta.lly\nSIHT r\nNI A student uses the following method to determine the volume of a conical flask.\nETIRW\nstep 1 Weigh a dry conical flask.\nTON\nstep 2 Fill the conical flask completely with distilled water.\nOD\nstep 3 Weigh the conical flask when filled with distilled water.\nstep 4 Use a thermometer to measure the temperature of the distilled water in the conical flask.\nNIGRAM\nThe student collects the results shown in Table 1.1.\nSIHT\nTable 1.1\nNI\nETIRW\nmass of dry flask / g 31.022\nTON\nmass of flask filled with water / g 161.175\nOD\ntemperature of water in flask / °C 23.0\nlaboratory atmospheric pressure / kPa 99.0\nNIGRAM\n(a) Fig. 1.1 shows the variation of the density of water with temperature.\n1.000\nSIHT\nNI\nETIRW\n0.999\nTON\nOD\n0.998\nNIGRAM density\ncm–3 / g\nSIHT 0.997\nNI\nETIRW\nTON 0.996\nOD\n0.995\n16 18 20 22 24 26 28 30\nNIGRAM\n/ °C temperature\nSIHT\nFig. 1.1\nNI\nETIRW\nTON\nNIGRAM\n(i) Use Fig. 1.1 to determine the density of water at 23.0 °C.\nSIHT\nGive your answer to four decimal places.\nNI\nETIRW\ncm–3 density of water = .............................. g [1]\nTON\n(ii) Calculate the volume of the flask, using the density of water determined in (a)(i).\nOD\nNIGRAM\ncm3 [2] volume of flask = ..............................\nSIHT\ncm3. This (b) Another student determines the volume of a dif ferent conical flask to be 129.56\nNI\nof unknown volatile liquid Y. conical flask is used to determine the M\nETIRW r\nThe following method is used.\nTON\nOD step 1 Cover the opening of the dry conical flask with aluminium foil and secure using a\nrubber band.\nstep 2 Weigh the conical flask, aluminium foil and rubber band. Record the mass.\nNIGRAM\nstep 3 Use a syringe with a needle to make a small hole in the alum inium foil and inject\ncm3 of Y into the conical flask. Remove the syringe. approximately 5\nSIHT\nstep 4 Place the conical flask in a water-bath containing boiling water. NI\nETIRW\nstep 5 Allow all of Y to evaporate. Keep the conical flask containing vaporised Y in the boiling\nwater for a further 3 minutes. TON\nOD\nstep 6 Carefully remove the conical flask from the boiling water and dry the outside surface\nthoroughly.\nstep 7 Weigh the conical flask, aluminium foil, rubber band and contents. Record this mass.\nNIGRAM\n(i) Suggest why the conical flask containing vaporised Y is kept in boiling water for 3 minutes\nin step 5.\nSIHT\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Suggest why it is not necessary to determine the m ass of liquid Y injected into the OD\nconical flask by the syringe in step 3.\n.......................................", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-54-q01-93888af201.pdf" }, { "id": "9701-2025-mj-54-q02", "subject": "9701", "year": 2025, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-may-june/9701_s25_qp_54.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-May-June/qp/9701_s25_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-mj-54-q02-p01-85ea0756d8.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p02-c2dbc22dbe.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p03-1222d2be8b.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p04-692552a45b.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p05-7b67431c68.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p06-f3d8257ab7.png", "9701-experimental-skills/assets/9701-2025-mj-54-q02-p07-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-mj-54-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\nn+(aq), 2 A student carries out an experiment to determine the charge of an aqueous ion, M of\nSIHT\nmetal M.\nNI\nETIRW cm3 dm–3 copper(II) of 1.00 mol aqueous nitrate, Cu(NO ) (aq), to The student prepares 100.0\n3 2\nuse in the experiment.\nTON\ncm3 dm–3 ) •3H O(s) required to prepare 100.0 of 1.00 mol (a) Calculate the mass of Cu(NO\nOD 3 2 2\n) (aq). Cu(NO\n3 2\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nmass = .............................. g [1]\nOD\ncm3 dm–3 of 1.00 mol (b) Describe the steps the student should take to prepare 100.0\n) (aq) starting from the mass calculated in (a) supplied in a small beaker. Cu(NO\n3 2\nNIGRAM Give the name and capacity of any apparatus used.\nW rite your answer using a series of numbered steps.\nSIHT\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [3]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The student sets up the electrochemical cell shown in Fig. 2.1 to investigate the ef fect of\nSIHT\nMn+(aq) on the measured cell potential, E . changing the concentration of\ncell\nNI\nETIRW high-resistance voltmeter\nV\nTON\nOD\nA\nCu(s) electrode M(s) electrode\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\ndm–3 1.00 mol Mn+(aq)\nCu(NO ) (aq)\n3 2\nNIGRAM\nFig. 2.1\nSIHT\nSuggest the function of the item labelled A in Fig. 2.1.\nNI\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) The student uses the apparatus in Fig. 2.1 to measure the cell potentials, using six solutions\nSIHT\nMn+(aq). each with a different concentration of\nNI\nETIRW\nT able 2.1 shows the results obtained by the student.\nTON Table 2.1\nOD\nelectrode\nconcentration\npotential of cell potential,\nM", "pdf_path": "9701-experimental-skills/print/9701-2025-mj-54-q02-43335c8d10.pdf" }, { "id": "9701-2025-on-41-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-on-41-q01-p01-ef4a5d8daf.png", "9701-topic-27-group-2/assets/9701-2025-on-41-q01-p02-239f681ab7.png", "9701-topic-27-group-2/assets/9701-2025-on-41-q01-p03-835d89cc79.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 (a) Solutions of Group 2 hydrogencarbonates, M(HCO ) , decompose on heating to give the\nSIHT 3 2\ncorresponding metal carbonate, carbon dioxide and water.\nNI\nETIRW\n) . (i) Write an equation for the decomposition of strontium hydrogencarbonate, Sr(HCO\n3 2\nTON ..................................................................................................................................... [1]\nOD\n(ii) The thermal stability of Group 2 carbonates increases down the group.\nExplain this trend.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n..................................................................................................................................... [2]\nTON\nOD (b) The hydroxides and fluorides of Group 2 elements show similar trends in solubility.\nDescribe the trend in the solubility of the fluorides of calcium, strontium and barium.\nNIGRAM Explain your answer.\n.................................... .................................... .....................................\nSIHT\nleast soluble most soluble\nNI\nETIRW explanation ...............................................................................................................................\n................................................................................................................................................... TON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n...................................................................................................................................................\nSIHT\nNI ............................................................................................................................................. [4]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) (i) Define enthalpy change of hydration, ΔH .\nSIHT hyd\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n.", "pdf_path": "9701-topic-27-group-2/print/9701-2025-on-41-q01-315aa1c67d.pdf" }, { "id": "9701-2025-on-41-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-41-q02-p01-9d75c691c1.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-41-q02-p02-1a58f33a15.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 (a) Iron can form stable ions in the +2 and +3 oxidation states.\nSIHT\nNI Explain why transition elements have variable oxidati on states.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\n]2+. iron(II) salts contain the complex ion [Fe(H O) (b) Aqueous solutions of\n2 6\nDefine complex ion.\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1]\nNI\nETIRW\n]2+ O) can be converted into [Fe(H O) (OH) ]. (c) [Fe(H\n2 6 2 4 2\nTON\n(i) Suggest a suitable reagent for this conversion. State the type of reaction.\nOD\nreagent ..............................................................................................................................\ntype of reaction ..................................................................................................................\nNIGRAM [1]\nO) (OH) ] is a green precipitate that turns brown on standing in air. (ii) [Fe(H\n2 4 2 SIHT\nTable 2.1 shows electrode potentials for some electrode reactions. NI\nETIRW\nTable 2.1\nTON\no electrode reaction E / V OD\ne– OH– –0.56 O) (OH) + H O + Fe(H O) (OH) + Fe(H\n2 3 3 2 2 4 2\n4e– 4OH– +0.40 + 2H O + O\n2 2\nNIGRAM\nO) (OH) ] turns brown on standing Use the information in Table 2.1 to explain why [Fe(H\n2 4 2\nin air. SIHT\nInclude an equation for this reaction.\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ..................................................................................................................................... [3]\nNI\nETIRW\nTON\nNIGRAM\n]2+ (d) The complex [Co(NH ) reacts with hydrogen peroxide as shown.\nSIHT 3 6\no ]2+ ]3+ 2OH– NI ) + H O 2[Co(NH ) + E = +1.67 V reaction 1 2[Co(NH\ncell 3 6 2 2 3 6\nETIRW\no TON mol–1, Calculate ΔG , in kJ for reaction 1.\nOD\nNIGRAM\no mol–1 = ......", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-41-q02-0637938b7b.pdf" }, { "id": "9701-2025-on-41-q03", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-on-41-q03-p01-0ffb9634b2.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-on-41-q03-p02-7acf56ee1a.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\nmanganese(IV) 3 (a) Solid oxide, MnO , catalyses the decomposition of hydrogen peroxide.\nSIHT 2\nNI O (aq) 2H O(l) + O (g) 2H\n2 2 2 2 ETIRW\nState the type of catalysis for this reaction. Explain your answer .\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\n(b) Hydrogen peroxide reacts with iodide ions in acidic conditions as shown.\nNIGRAM\n2I– 2H+ 2H O + I O + + H\n2 2 2 2\nSIHT\nI– H+. The initial rate of this reaction is investigated with dif ferent concentrations of H O , and\n2 2 NI\nThe results obtained are shown in Table 3.1.\nETIRW\nTable 3.1\nTON\nOD\n[H+] dm–3 dm–3 s–1 dm–3 [I–] dm–3 / mol initial rate / mol experiment [H O ] / mol / mol\n2 2\n10–3 1 0.0450 0.0300 0.0125 2.42 ×\n10–3 NIGRAM 2 0.0225 0.0600 0.0125 2.42 ×\n10–3 3 0.0225 0.120 0.0125 4.84 ×\nSIHT\n10–3 4 0.0450 0.120 0.0500 9.68 ×\nNI\nETIRW\n(i) Use the information in Table 3.1 to deduce the rate equation for this reaction.\nTON\nExplain your reasoning.\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW ...........................................................................................................................................\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [4]\n(ii) Use your rate equation from (b)(i) and the data from Experiment 1 to calculate the rate\nconstant, k, for this reaction. Include the units of k.\nNIGRAM\nSIHT\nNI\nETIRW\nk = .............................. units .............................. [2]\nTON\nNIGRAM\n(c) The rate of the thermal decomposition of azomethane, CH N=NCH , is investigated.\nSIHT 3 3\nNI N=NCH N + C H CH\n3 3 2 2 6\nETIRW\nFig. 3.1 shows the results obtained. The reaction is first order with respect to CH N=NCH .\n3 3\nTON\n0.06\nOD\n0.05\n0.04 NIGRAM\ndm–3 N=NCH ] / mol [CH\n0.03 3 3\nSIHT\nNI 0.02\nETIRW\n0.01\nTON\n0 OD\n0 50 100 150 200 250 300 350 400\ntime / s\nNIGRAM\nFig. 3.1\n, to show that the reaction is first order. t (i) Use Fig. 3.1 to calc", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-on-41-q03-b2dd3ea737.pdf" }, { "id": "9701-2025-on-41-q04", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-on-41-q04-p01-90eeda0d52.png", "9701-topic-24-electrochemistry/assets/9701-2025-on-41-q04-p02-d7eba8e505.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q04", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\no 4 (a) Define standard cell potential, E . Include a description of standard conditions.\nSIHT cell\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [2]\nOD\n2+(aq) / Cu(s) electrode and a (b) The Daniell cell is an electrochemical cell consisting of a Cu\nZn2+(aq) / Zn(s)e lectrode.\nNIGRAM\n(i) Draw a labelled diagram of this electrochemical cell.\nSIHT Include all necessary substances and relevant pieces of apparatus needed to measure\no . the E\ncell NI\nETIRW\nIt is not necessary to state the conditions used.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\n[3]\nSIHT\n(ii) State the charge carriers that transfer current through the solutions and through the wire.\nNI\nETIRW\nthe solutions .............................. the wire .............................. [1]\nTON o Zn2+(aq) , for the / Zn(s)e lectrode is –0.76 V. (iii) The standard electrode potential, E\nOD\nZn2+(aq) / Zn(s)e lectrode. Water is added to a standard\nZn2+(aq) dm–3. is 0.25 mol The new concentration of\nNIGRAM\nZ2+n(aq) / Zn(s) Use the Nernst equation to calculate the electrode potential, E, for this new\nelectrode.\nSIHT\nNI\nETIRW\n(Zn2+(aq) / Zn(s)) = .............................. V [2] E\nTON\nNIGRAM\n(c) An electrochemical cell consists of a ZnO / Zn electrode and a MnO / MnO electrode in an\nSIHT 2 2 3\nalkaline electrolyte.\nNI\nETIRW o , for this cell is +1.47 V. The standard cell potential, E\ncell\nTON The half-equation at each electrode when this cell is discharging is shown.\nOD\n2e– 2OH– ZnO + H O + Zn +\n2\n2e– 2OH– 2MnO + H O + Mn O +\n2 2 2 3\nNIGRAM\n(i) Use this information to determine the change in oxidation state of manganese when this\ncell is discharging.\nSIHT\nfrom .............................. to .............................. [1]\nNI\nETIRW\n(ii) Write the equation for the overall reaction that occurs when this cell is discharging.\nTON\n..................................................................................................................................... [1]\nOD\no for the ZnO / Zn electrode is –1.28 V. (iii) The E\no , for the MnO / MnO electrode. Calculate the standard electrode potential, E\n2 2 3\nNIGRAM\nSIHT\nNI\no ETIRW (MnO / MnO ) = .............................. V [1] E\n2 2 3\n[Total: 11] TON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-on-41-q04-fef0da7e86.pdf" }, { "id": "9701-2025-on-41-q05", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 12, 13, 14 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-41-q05-p01-565602ee31.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-41-q05-p02-406c481b37.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-41-q05-p03-70aea4f7b2.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n5 (a) Copper shows typical properties of transition elements, including its behaviour as a catalyst.\nSIHT\nNI Complete Table 5.1 to show the total number of unpaired electrons in the 3d and 4s orbitals\nETIRW Cu2+ ion. of an isolated gaseous Cu atom and a\nTON Table 5.1\nOD\nnumber of unpaired electrons\nspecies\n3d 4s\nNIGRAM\nCu\nCu2+\nSIHT\n[1]\nNI\nETIRW\nCu2+ ion are degenerate. (b) The 3d orbitals in an isolated\nTON\n2+ ion Complete the diagram to show the relative energies of the 3d orbitals in an isolated Cu\nCu2+ in a tetrahedral complex. and in OD\nNIGRAM\nenergy\nSIHT\nNI\nETIRW\nTON\nCu2+ Cu2+ isolated ion in a tetrahedral complex OD\n[2]\n(c) Explain why transition elements behave as catalysts.\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [2]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nCN– (d) is a monodentate ligand.\nSIHT\nCN– NI ions as ligands. T able 5.2 shows information about two complex ions that contain only\nETIRW\nComplete T able 5.2.\nTON\nTable 5.2\nOD\nmetal ion coordination number formula of complex ion charge of complex ion\nAg+ 2 NIGRAM\nFe2+ 4–\nSIHT\n[2]\nNI\n]– Br displays geometrical (cis / trans) isomerism. (e) The complex ion [Au(CN) ETIRW\n2 2\n]–. Br State its shape and the Br-Au-Br bond angle. Draw the structure of trans-[Au(CN)\nTON\n2 2\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON shape .............................. Br-Au-Br bond angle = ..............................\n[2]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nvanadium(V) (f) An impure sample of a compound of mass 0.250g is dissolved in aqueous acid.\nSIHT\n– ions. This solution contains VO\n3\nNI\nETIRW V2+ – ions are reduced to ions and Zn An excess of zinc is added to this solution. All the VO\n3\nZn2+ ions. atoms are oxidised to\nTON\n–. The unreacted zinc is removed and the resulting solution is titrated with acidified MnO\nOD 4\ncm3 moldm–3 – of 0.0750 MnO is added. The end-point is reached when 22.5\n4\nV2+ –. reacts forming VO A redox reaction takes place and all the\nNIGRAM 3\n5V2+ 3Mn2+ 6H+ – – + + 3H O + 5VO + 3MnO\n4 2 3\nSIHT\n(i) Calculate the percentage by mass of vanadium in the 0.250 g of impure sample.\nNI\nETIRW\nAssume the impurities do not contain any vanadium ions.\nTON\nShow your working.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\npercentage of vanadium = .............................. [3]\n– ions and Zn metal. (ii) Complete the equation for the reaction between acidified VO\n3\nNIGRAM\nV2+ Zn2+ – ...... + ...... + .............. + ...... Zn + ............ ...... VO\n3\n[2]\nSIHT\n[Total: 14]\nNI\nE", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-41-q05-bdd04a7048.pdf" }, { "id": "9701-2025-on-41-q06", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-on-41-q06-p01-2b9c6a35e6.png", "9701-topic-37-analytical-techniques/assets/9701-2025-on-41-q06-p02-ade82af5ce.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n6 (a) Thin-layer and gas / liquid chromatography can be used to separate mixtures into their\nSIHT\nindividual components.\nNI\nETIRW\n(i) Define the following terms used in chromatography.\nTON value ............................................................................................................................. R\nf\nOD\n...........................................................................................................................................\nretention time ....................................................................................................................\nNIGRAM\n...........................................................................................................................................\n[2]\nSIHT\n(ii) Each type of chromatography makes use of a stationary phase and a mobile phase.\nNI\nETIRW\nComplete Table 6.1 with a description of each of these.\nTON\nTable 6.1\nOD\nstationary phase mobile phase\nthin-layer chromatography NIGRAM\nSIHT\ngas / liquidc hromatography\nNI\nETIRW\n[1]\nTON\n(b) A mixture of two substances A and B is analysed by thin-layer chromatography.\nOD\nvalue of substance A is larger than that of substance B. The R\nf\nvalue. Suggest why substance A has a larger R\nf\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(1H) (c) The two isomeric compounds Y and Z are analysed by proton NMR spectroscopy.\nSIHT\nNI\nY Z\nETIRW\nO O\nTON\nOD\nO O\n1H) NIGRAM (i) Complete Table 6.2 to predict the number of peaks observed in the proton ( NMR\nspectra for Y and Z.\nSIHT\nTable 6.2\nNI\nETIRW\ncompound number of peaks observed\nY TON\nOD Z\n[1]\n1H) NMR spectra for Y (ii) Name all the different splitting patterns observed in the proton (\nNIGRAM\nand Z.\nY ........................................................................................................................................\nSIHT\nNI Z ........................................................................................................................................\nETIRW\n[2]\nTON [Total: 7]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-on-41-q06-41f03f148b.pdf" }, { "id": "9701-2025-on-41-q07", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 18, 19, 20 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-41-q07-p01-f89da991c5.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-41-q07-p02-c9e5d53f6b.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-41-q07-p03-734188d460.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q07", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 (a) State the relative acidities of bromoethanoic acid, BrCH COOH, chloroethanoic acid,\nSIHT 2\nCOOH, ethanoic acid, CH COOH and ethanol, CH CH OH. Cl CH\n2 3 3 2\nNI\nETIRW\nExplain your answer.\nTON .................................. .................................. .................................. ..................................\nmost acidic least acidic\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n[4]\nNIGRAM . (b) Fig. 7.1 shows the reaction of methylbenzene and ethanedioic acid with KMnO\n4\nPredict the major carbon-containing product for each of these reactions.\nSIHT\nNI\nmethylbenzene\nETIRW\nhot alkaline KMnO\nTON 4\nOD\nethanedioic acid NIGRAM\nO\nSIHT\nhot acidified KMnO\n4\nOH\nNI\nETIRW\nHO\nTON\nO\nOD\nFig. 7.1\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Polyamide X can be synthesised from ethanedioic acid and benzene-1,4-diamine.\nSIHT\nNI\nbenzene-1,4-diamine\nETIRW\nTON\nN NH H\n2 2\nOD\n(i) Draw the repeat unit of polyamide X in the box.\nNIGRAM\nThe new functional group formed should be shown displayed.\nSIHT\npolyamide X\nNI\nETIRW\nTON\nOD\nNIGRAM\n[2]\nSIHT\n(ii) Benzene-1,4-diamine can be formed by reduction of 1,4-dinitrobenzene.\nNI\nETIRW\nComplete the equation for this reduction.\nTON\n[H] represents one atom of hydrogen from a reducing agent.\nOD\n+ .......... [H] H N NH + .....................\n2 2\nNIGRAM\n..........................................................\n[1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Fig. 7.2 shows the two-step synthesis of the azo compound W.\nSIHT\nNI\nV C H N Cl\n6 4 4 2 ETIRW\nstep 1 TON\nH N NH\nOD 2 2\nNIGRAM\nSIHT\nOH\nstep 2\nNI\nETIRW\nand NaOH(aq)\nTON\nOD\nW C H N O\n18 14 4 2\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 7.2\nNIGRAM\n(i) Suggest structures for compounds V and W and draw them in the boxes in Fig. 7.2. [2]\nSIHT (ii) Give the reagents and conditions for step 1.\nNI\n...........................................................", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-on-41-q07-151bc6c942.pdf" }, { "id": "9701-2025-on-41-q08", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 22, 23 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-41-q08-p01-8837bc0233.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-41-q08-p02-132ce98123.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q08", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n8 (a) In the electrophilic substitution of arenes, dif ferent substituents can direct to dif ferent ring\nSIHT\npositions.\nNI\nETIRW\ngroup. Explain your answer. (i) Describe the directing effect of the –NO\n2\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nand concentrated H SO to (ii) The nitration of arenes uses a mixture of concentrated HNO\n3 2 4\n+ electrophile. generate the NO\nNIGRAM 2\n+ electrophile. Write an equation for the formation of the NO\n2\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n(b) Carbon-carbon bond formation is an important reaction in organic synthesis.\nTON\nFig. 8.1 shows the synthesis of compound Q from benzene in two reaction steps.\nOD\ncompound Q\ncompound P O\nNIGRAM\nreaction 1 reaction 2\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 8.1\nNIGRAM\n(i) Draw the structure of compound P in the box in Fig. 8.1. [1]\n(ii) Suggest reagents and conditions for reactions 1 and 2 in Fig. 8.1. SIHT\nNI\nreaction 1 ..........................................................................................................................\nETIRW\nreaction 2 ..........................................................................................................................\nTON\n[2]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Separate samples of C H Br and C H CH Br are added to warm AgNO (aq).\nSIHT 6 5 6 5 2 3\nNI State the expected observations, if any . Explain your answer.\nETIRW\nH Br with AgNO (aq) ................................................ C\n6 5 3\nTON\nH CH Br with AgNO (aq) ................................................ C\nOD 6 5 2 3\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\n[3]\nETIRW\nO. (d) Acyl bromides, RCOBr, react readily with H\n2 TON\nOD O with acyl chlorides, The mechanism of this reaction is similar to that of the reaction of H\n2\nRCOCl.\n(i) Name the mechanism of this reaction.\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\nO. (ii) Complete the mechanism in ", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-on-41-q08-1fd85843bb.pdf" }, { "id": "9701-2025-on-41-q09", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_41.pdf?download=true", "source_pages": [ 24, 25, 26, 27, 28 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-41-q09-p01-70bb31a8fb.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-41-q09-p02-84487f4dd0.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-41-q09-p03-f5e64c8d82.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-41-q09-p04-c9cf758a1e.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-41-q09-p05-71956466d1.png" ], "answer": { "status": "pending", "id": "9701-2025-on-41-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:5)(cid:44)\n9 (a) Explain why amides are much weaker bases than amines.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\nH CH CH NH , by three dif ferent (b) Fig. 9.1 shows the preparation of 2-phenylethylamine, C\nNIGRAM 6 5 2 2 2\nroutes.\nSIHT NH\n2\nNI\nETIRW\nreaction 1\nO\nTON\nOD\n2-phenylethylamine\nM\nNH\nH /Ni 2\n2\nNIGRAM\nSIHT\nNI NH\n3 ETIRW\nN\nTON\nOD\nNIGRAM\nFig. 9.1\n(i) Suggest structures for compounds M and N and draw them in the boxes in Fig. 9.1. [2] SIHT\nNI\n(ii) Give the reagents and conditions for reaction 1.\nETIRW\n..................................................................................................................................... [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Fig. 9.2 shows compound H which is a useful starting material in organic synthesis.\nSIHT\nNI\nH\nETIRW\nO\nN\nTON\nOD\nH\nFig. 9.2\nNIGRAM\nH contains an alkene and an amine functional group.\nSIHT\nName the other functional group and give the classification of the amine group in H.\nNI\nETIRW\nother functional group in H ................................................\nTON\nclassification of amine ................................................\n[1] OD\n, as (d) Ozonolysis involves the oxidative cleavage of a C=C bond in alkenes using ozone, O\n3\nshown in Fig. 9.3.\nNIGRAM\nR R R\nR 3 1 3\n1 O\nSIHT 3\nO + O\nNI\nR ETIRW R 2 R R\n4 2 4\nTON\nFig. 9.3\nOD\nFig. 9.4 shows the first step in this reaction which involves the formation of an ozonide\nintermediate.\nNIGRAM\nozonide\nR R\n3 SIHT R R 2\n1 3 R\n1 R\nNI 4\nETIRW\nO O R R\nTON 2 4\nO\nOD\n-\nO O\nO\nNIGRAM +\nFig. 9.4 SIHT\nNI\n(i) On Fig. 9.4, draw three curly arrows to complete the mechanism of this step. [2]\nETIRW\nTON\nNIGRAM\n(ii) L is formed from alkene K, C H , by a similar reaction to that shown in Fig. 9.3.\nSIHT 8 14\nNI\nL\nETIRW\nO O\nTON\nOD\nSuggest the structure of K.\nNIGRAM\nK C H\n8 14\nSIHT\nNI\nETIRW\nTON\nOD\n[1]\n[Total: 9]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.02 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas V\nm\ndm3 mol–1 V = 24.0 at room conditions\nNIGRAM m\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product o", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-on-41-q09-c25f73b5f1.pdf" }, { "id": "9701-2025-on-42-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 3 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-on-42-q01-p01-8fec78c0b3.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 Magnesium nitrate, Mg(NO ) , and strontium nitrate, Sr(NO ) , both decompose when heated to\nSIHT 3 2 3 2\nform the metal oxide and a mixture of gases.\nNI\nETIRW\n) . (a) Write an equation for the thermal decomposition of Mg(NO\n3 2\nTON ............................................................................................................................................. [1]\nOD\n) or Sr(NO ) decomposes at a lower temperature. (b) State which of Mg(NO\n3 2 3 2\nExplain your answer .\nNIGRAM\ncompound that decomposes at a lower temperature ...............................................................\nexplanation ............................................................................................................................... SIHT\nNI\n...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\nOD ...................................................................................................................................................\n...................................................................................................................................................\n[2]\nNIGRAM\n(c) Magnesium oxide, MgO, and strontium oxide, SrO, both react with dilute sulfuric acid.\nSIHT\nMgO forms a soluble salt, A.\nNI\nETIRW SrO forms an insoluble salt, B.\n(i) Identify the products formed when MgO reacts with dilute sulfuric acid. TON\nOD\n..................................................................................................................................... [1]\n(ii) Explain why A is more soluble than B.\nNIGRAM\n...........................................................................................................................................\n...........................................................................................................................................\nSIHT\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n........................................................................................................................................... OD\n..................................................................................................................................... [3]\n[Total: 7] NIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-27-group-2/print/9701-2025-on-42-q01-38ddb48370.pdf" }, { "id": "9701-2025-on-42-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-on-42-q02-p01-412bb40a44.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-on-42-q02-p02-8f2321e666.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q02", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n2 Ethanal, CH CHO, reacts with nitrogen dioxide, NO . The products of the first step of this reaction\nSIHT 3 2\n•\nare a CH C=O radical and a molecule of nitrous acid, HNO .\n3 2 NI\nETIRW •\nCHO + NO CH C=O + HNO CH\n3 2 3 2\nTON\n(a) (i) Use two words to complete the sentence.\nOD\nThis reaction involves ........................................ ........................................ of the single\nCHO. covalent bond between a hydrogen atom and a carbon atom in CH\n3\n[1]\nNIGRAM\n(ii) The hydrogen atom mentioned in (a)(i) forms a covalent bond with one of the oxygen\nmolecule. An NO molecule has a single, unpaired electron on the atoms of an NO\n2 2 SIHT\nmolecule. nitrogen atom. All electrons are paired in an HNO\n2\nNI\nETIRW and HNO in the boxes. Show outer shell electrons Draw dot-and-cross diagrams of NO\n2 2\nonly.\nTON\nOD\nNIGRAM\nSIHT\nNI\nHNO NO ETIRW\n2 2\n[1]\nTON\nmolecule. (iii) Use VSEPR theory to predict the bond angle at the nitrogen atom in an HNO OD\n2\nbond angle = .............................. [1]\nCHO and NO is shown. (b) The rate equation for the reaction between CH NIGRAM\n3 2\nCHO][NO ] rate = k [CH\n3 2\nSIHT\ndm–3, CHO and NO are 0.200 mol Under certain conditions, when the concentrations of both CH\nNI 2 3\n10–4 dm–3 s–1. mol the rate of the reaction is 1.53 × ETIRW\nCalculate the value of the rate constant, k, under these conditions. Give the units of k.\nTON\nOD\nNIGRAM\nk = .............................. units .............................. [2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The reaction mixture described in (b) is monitored over a period of time.\nSIHT\nNI ] against time shows a constant half-life. Predict whether the graph of [NO\n2\nETIRW\nExplain your answer .\nTON\nprediction ..................................................................................................................................\nOD\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nNIGRAM\n[1]\nalso reacts with ozone, O . (d) NO SIHT\n2 3\nNI\nThe rate equation is shown.\nETIRW\n[NO ] rate = k\n1 2 TON\ns–1. OD is 0.0848 Under certain conditions, the value of k\n1\nThe reaction has a constant half-life under these conditions.\nNIGRAM Calculate the half-life in seconds.\nSIHT\nNI\nETIRW\nhalf-life = .............................. s [1] TON\nOD\nis present in the exhaust gases of cars. It can react with carbon monoxide, CO, on the (e) NO\n2\nsurface of a heterogeneous catalyst in the car’s catalytic converter.\nDescribe the mode of action of this heterogeneous catalyst.\nNIGRAM\n...................................................................................................................................................\nSIHT\n.....................................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-on-42-q02-268210bde4.pdf" }, { "id": "9701-2025-on-42-q03", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 6, 7, 8 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2025-on-42-q03-p01-8699da113d.png", "9701-topic-25-equilibria/assets/9701-2025-on-42-q03-p02-da6ce9ee2f.png", "9701-topic-25-equilibria/assets/9701-2025-on-42-q03-p03-3b1f3bcea1.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n3 (a) (i) Define conjugate acid–base pair.\nSIHT\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Give the formulas of the conjugate acid and the conjugate base of the hydrogen\nOD\n2–. phosphate ion, HPO\n4\n2– .............................. conjugate acid of HPO\n4\nNIGRAM\n2– .............................. conjugate base of HPO\n4\n[1]\nSIHT\n10–5 dm–3 of propanoic acid, CH CH COOH, is 1.35 × mol at 298 K. (b) The K\na 3 2 NI\nETIRW\nCH COOH with a pH of 3.60 at 298 K. Solution C is a solution of CH\n3 2\nTON\nCH COOH in solution C. (i) Calculate the concentration of CH\n3 2\nOD\nNIGRAM\ndm–3 CH COOH] = .............................. mol [2] [CH\n3 2\nSIHT\n(ii) Calculate the concentration of hydroxide ions in solution C.\nNI\nETIRW\nTON\n–] dm–3 = .............................. mol [1] [OH\nOD\n(iii) Calculate the concentration of a solution of hydrochloric acid with the same pH as\nsolution C.\nNIGRAM\nSIHT\ndm–3 [1] concentration = .............................. mol\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iv) Table 3.1 shows three possible values of the K of dimethylpropanoic acid, (CH) CCOOH.\nSIHT a 3 3\nNI Place a tick in Table 3.1 to show the correct value. Explain your answer.\nETIRW\nTable 3.1\nTON\nOD value of K place one tick (✓)\na\ndm–3 in this column / mol\n10–6 9.33 ×\nNIGRAM\n10–5 1.35 ×\nSIHT\n10–5 3.35 ×\nNI\nETIRW\nexplanation ........................................................................................................................\nTON\n........................................................................................................................................... OD\n...........................................................................................................................................\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [3]\nSIHT\ncm3 dm–3 cm3 of 0.100 mol CH CH COOH and 100 of (c) Solution D is made by mixing 100 NI\n3 2\ndm–3 NaCl. 0.100 mol ETIRW\nSO (aq) are added to it, and when The pH of solution D is measured as small amounts of H TON\n2 4\nsmall amounts of NaOH(aq) are added to it.\nOD\nSolution D only acts as a buf fer solution when one of these solutions is added to it.\n(i) Complete the sentence and write an equation for the reaction that occurs.\nNIGRAM\nSolution D acts as a buffer when ................................................................ is added to it.\nSIHT\nequation .................................................", "pdf_path": "9701-topic-25-equilibria/print/9701-2025-on-42-q03-f143bf29a6.pdf" }, { "id": "9701-2025-on-42-q04", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 9 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-on-42-q04-p01-2b27f98180.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:10)(cid:44)\n4 (a) Define enthalpy change of atomisation, ΔH .\nSIHT at\nNI ...................................................................................................................................................\nETIRW\n............................................................................................................................................. [1]\nTON\n(b) Define first electron affinity, EA.\nOD\n...................................................................................................................................................\n............................................................................................................................................. [1]\nNIGRAM\n(c) Explain why the first electron af finity of chlorine is more exothermic than the first electron\nSIHT affinity of iodine.\nNI\n...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\nOD ...................................................................................................................................................\n............................................................................................................................................. [2]\n–(g) mo–l1. 2e– NIGRAM 2Cl is – 486 kJ (g) + (d) The enthalpy change for the reaction Cl\n2\nmol–1. The first electron af finity of chlorine is –364 kJ\nSIHT\nCalculate the enthalpy change of atomisation of chlorine. NI\nETIRW\nTON\nOD\nNIGRAM\nmol–1 ΔH of chlorine = .............................. kJ [2]\nat\n[Total: 6]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-on-42-q04-4fb9af3066.pdf" }, { "id": "9701-2025-on-42-q05", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-on-42-q05-p01-c5c7fe6e96.png", "9701-topic-24-electrochemistry/assets/9701-2025-on-42-q05-p02-cde6bb1574.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q05", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n2+ Co3+ Cobalt(II) 5 Cobalt is a transition element which forms compounds containing Co and ions.\nSIHT\n]2+ O) complex ion. sulfate dissolves in water to form a solution containing the [Co(H\n2 6\nNI\nETIRW Co2+ Co3+ ion and a ion. (a) (i) Complete the electronic configurations of a\nTON Co2+ = [Ar] ..............................\nOD\nCo3+ = [Ar] ..............................\n[1]\n(ii) Explain why transition elements can form complex ions.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n]2+. O) (iii) An excess of concentrated HCl is added to a solution containing [Co(H\n2 6\nTON\nDescribe the colour change observed and the state of the cobalt-containing product.\nOD\nThe colour changes from .............................. to .............................. .\nThe state of the cobalt-containing product is .............................. .\nNIGRAM [2]\n(iv) Write an equation for the reaction occurring in (a)(iii).\nSIHT\n..................................................................................................................................... [1] NI\nETIRW\n(v) Name the type of reaction occurring in (a)(iii).\nTON\n..................................................................................................................................... [1]\nOD\n(vi) Write an equation for the reaction that occurs when an excess of NaOH(aq) is added to\n]2+. O) a solution containing [Co(H\n2 6\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Cobalt metal can be oxidised by acidified K Cr O . The relevant half-equations, and their\nSIHT 2 2 7\no– values, are shown. E\nNI\nETIRW 2+ 2e– o– + Co E = –0.28 V Co\n14H+ 6e– 2Cr3+ o– 2– O + + + 7H O E = +1.33 V Cr\n2 7 2\nTON\nCo2+/Co [Co2+] dm–3 electrode is constructed in which is 0.020 mol at 298 K. (i) A\nOD\nCo2+ / Coe lectrode is –0.33 V. Use the Nernst equation to show that the E value for this\nNIGRAM\n[2] SIHT\nNI\n2+ / Co electrode described in (b)(i) (ii) An electrochemical cell is constructed using the Co\nETIRW\nCr3+ 2– O / electrode in which all conditions are standard. and a Cr\n2 7\nTON\n. Calculate the value of E\ncell\nOD\nE = .............................. [1]\ncell\nNIGRAM\n(iii) A current is drawn from the electrochemical cell described in (b)(ii).\nSIHT\nWrite an equation for the reaction taking place in the cell.\nNI\nETIRW ..................................................................................................................................... [1]\n(iv) Complete the sentences to identify the negative electrode and the ", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-on-42-q05-9e58ebfc5c.pdf" }, { "id": "9701-2025-on-42-q06", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 12 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-42-q06-p01-f4034d9f60.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n6 (a) Nickel forms complexes.\nSIHT\nNI (i) Give the formula and charge of the tetrahedral complex formed by Ni atoms with carbon\nETIRW\nmonoxide molecules. Carbon monoxide is a monodentate ligand. This is complex E.\nTON E = ............................................................................................................................... [1]\nOD\n2+ ions with (ii) Give the formula and charge of the octahedral complex formed by Ni\nethanedioate ions. This is complex F.\nF = ............................................................................................................................... [2]\nNIGRAM\n(iii) Identify which complex, E or F, exists as a mixture of two stereoisomers and the type of\nstereoisomerism involved. SIHT\nNI\nThe complex which exists as a mixture of two stereoisomers is .............................. .\nETIRW\nThe type of stereoisomerism involved is .............................. .\nTON\n[1]\nOD\nNH , and 1,2-diaminoethane, en. The (b) Cadmium forms complexes with methylamine, CH\n3 2\n, of these complex ions are given in Table 6.1. values of the stability constants, K\nstab\nNIGRAM Table 6.1\ncomplex K SIHT\nstab\n]2+ 106 [Cd(CH NH ) 3.5 × NI\n3 2 4\nETIRW\n]2+ 1010 [Cd(en) 4.0 ×\n2\nTON\n(i) Explain, by reference to its structure, why CH NH acts as a monodentate ligand.\nOD 3 2\n..................................................................................................................................... [1]\n2+(aq) is added to a solution containing equal concentrations of CH NH (ii) Some Cd\nNIGRAM 3 2\nand en.\nSIHT Predict which of the two complexes in Table 6.1 forms at the higher concentration.\nNI\nExplain your answer.\nETIRW\ncomplex that forms at the higher concentration ................................................................\nTON\nOD explanation ........................................................................................................................\n...........................................................................................................................................\n[1]\nNIGRAM\n]2+. of [Cd(CH NH ) (iii) Complete the expression for the K\nstab 3 2 4\nSIHT\n= K\nstab\nNI\nETIRW [1]\n[Total: 7] TON", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-42-q06-dcdeb44270.pdf" }, { "id": "9701-2025-on-42-q07", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 13, 14, 15 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-on-42-q07-p01-abf185e003.png", "9701-topic-37-analytical-techniques/assets/9701-2025-on-42-q07-p02-eff08f9004.png", "9701-topic-37-analytical-techniques/assets/9701-2025-on-42-q07-p03-263927596e.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q07", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:4)(cid:44)\n7 P, Q, R, S, T, U, and V are the seven structural isomers with molecular formula C H O that have\nSIHT 5 10\na carbonyl group.\nNI\nETIRW\n(CH ) CHO Q CH CH CH(CH )CHO R (CH ) CHCH CHO P CH\n3 2 3 3 2 3 3 2 2\nTON ) CCHO T CH CH CH COCH U CH CH COCH CH S (CH\n3 3 3 2 2 3 3 2 2 3\nOD\nV (CH ) CHCOCH\n3 2 3\n(a) Only one of these seven compounds has stereoisomers.\nNIGRAM\nDraw three-dimensional diagrams of the two stereoisomers of this compound.\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\n(aq) and the product mixture is (b) P, Q, R, S, T, U, and V are treated separately with alkaline I\n2\nacidified. OD\n(aq). (i) Identify the two compounds that give a positive result with alkaline I\n2\n............................................................... and ............................................................... [1] NIGRAM\n(ii) Describe the observations when one of the compounds you have identified in (b)(i) is\nSIHT (aq) and give the structural formulae of the two carbon-containing treated with alkaline I\n2\nproducts of this reaction.\nNI\nETIRW\nobservations ......................................................................................................................\nTON\ntwo carbon-containing products ........................................................................................\nOD\nand ........................................................................................\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nP CH (CH ) CHO Q CH CH CH(CH )CHO R (CH ) CHCH CHO\nSIHT 3 2 3 3 2 3 3 2 2\nNI ) CCHO T CH CH CH COCH U CH CH COCH CH S (CH\n3 3 3 2 2 3 3 2 2 3\nETIRW\nV (CH ) CHCOCH\n3 2 3\nTON\n(1H) (c) The proton NMR spectra of P, Q, R, S, T, U, and V are compared.\nOD\n(i) Identify the only compound that gives a spectrum with two singlets and no other peaks.\n..................................................................................................................................... [1]\nNIGRAM\nFig. 7.1 shows the spectrum obtained from one of the compounds.\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n11 10 9 8 7 6 5 4 3 2 1 0\nδ / ppm\nNIGRAM\nFig. 7.1\nSIHT\nNI (ii) Identify the compound that gives this spectrum.\nETIRW\n..................................................................................................................................... [1]\nTON\n(iii) Name the splitting pattern of the peak at δ = 1.1 in Fig. 7.1.\nOD\nGive the reason for this splitting.\nname ..............................\nNIGRAM\nreason ...............................................................................................................................\n[1] SIHT\nNI\n(iv) Identify the substance that gives the small peak at δ = 0 in Fig. 7.1.\nETIRW\n..................................................................................................................................... [1]\nTON\nNIGRAM\n(d) The carbon-13 NMR spectra of R, S, T and U are compared.", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-on-42-q07-1f92e1090a.pdf" }, { "id": "9701-2025-on-42-q08", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-42-q08-p01-db5cf98f92.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-42-q08-p02-7e05067b74.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-42-q08-p03-4ea646c626.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n8 Asparagine and aspartic acid are two naturally occurring amino acids. Their structures and\nSIHT\nisoelectric points are shown in Table 8.1.\nNI\nETIRW Table 8.1\nTON\namino acid structure isoelectric point\nOD\n)CH CONH 5.41 asparagine HOOCCH(NH\n2 2 2\n)CH COOH 2.77 aspartic acid HOOCCH(NH\n2 2\nNIGRAM\n(a) Define isoelectric point.\n................................................................................................................................................... SIHT\nNI\n............................................................................................................................................. [1]\nETIRW\n(b) Draw the structures of asparagine and aspartic acid at pH 2.\nTON\naspartic acid at pH 2 asparagine at pH 2 OD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n[2]\nNIGRAM\n. (c) Asparagine and aspartic acid are treated separately with an excess of LiAl H\n4\nDraw the structures of the organic products of these reactions.\nSIHT\nNI\nproduct of aspartic acid treated with product of asparagine treated with an\nETIRW\nan excess of LiAl H excess of LiAl H\n4 4\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2] TON\nNIGRAM\n(d) Propanedioic acid, HOOCCH COOH, is treated with an excess of thionyl chloride, SOCl .\nSIHT 2 2\nCOCl , is formed. Propanedioyl chloride, Cl OCCH\n2\nNI\nETIRW\n(i) Write an equation for this reaction.\nTON ..................................................................................................................................... [1]\nOD\n(ii) Propanedioyl chloride reacts with an ex cess of asparagine to form compound G with\nH N O . molecular formula C\n11 16 4 8\nEach molecule of compound G has four amide groups.\nNIGRAM\nDraw the structure of compound G.\nSIHT\nH N O Compound G, C\nNI 11 16 4 8\nETIRW\nTON\nOD\nNIGRAM\n[2]\nSIHT\n(e) Asparagine is hydrolysed with an excess of hot NaOH(aq). NI\nETIRW\nDraw the structure of the organic product of this reaction.\nTON\nOD\nNIGRAM\n[2]\n)CH CONH , as the only monomer. (f) A polymer can form from asparagine, HOOCCH(NH SIHT\n2 2 2\nNI\nDraw a length of the polymer chain containing three monomer residues.\nETIRW\nClearly label the repeat unit of the polymer on your diagram.\nTON\nOD\nNIGRAM\nSIHT [3]\nNI\nETIRW\nTON\nNIGRAM\n(g) Aspartic acid exists in two optically active forms.\nSIHT\nNI (i) Plane polarised light is passed through pure samples of these two optically active forms\nETIRW\nin solutions of the same concentration.\nTON Describe two similarities and one difference in their effect on the plane polarised light.\nOD\nsimilarities .........................................................................................................................\n...........................................................................................................................................\nNIGRAM\ndifference ...........................................................................................................................\n...", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-on-42-q08-ab2f286541.pdf" }, { "id": "9701-2025-on-42-q09", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_42.pdf?download=true", "source_pages": [ 20, 21, 22, 23, 24 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2025-on-42-q09-p01-fb69147301.png", "9701-topic-36-organic-synthesis/assets/9701-2025-on-42-q09-p02-32c622e92d.png", "9701-topic-36-organic-synthesis/assets/9701-2025-on-42-q09-p03-67f3911d3a.png", "9701-topic-36-organic-synthesis/assets/9701-2025-on-42-q09-p04-df43e094fd.png", "9701-topic-36-organic-synthesis/assets/9701-2025-on-42-q09-p05-a22dbb7b76.png" ], "answer": { "status": "pending", "id": "9701-2025-on-42-q09", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n9 Compound X is made from benzene by the route shown in Fig. 9.1.\nSIHT\nNI\nW X\nETIRW\nbenzene\nNO NO NH\n2 2 2\nTON\nOD\nstep 1 step 2 step 3 step 4\nNIGRAM\nCH CH COOH COOH\n3 3\nSIHT\nFig. 9.1\nNI\nETIRW\nH . (a) Describe the bonding in benzene, C\n6 6\nTON\nY our answer should include:\nOD\n• the hybridisation of the six carbon atoms\n• the types of bond between the carbon atoms\n• the orbitals that overlap to produce the bonds between the carbon atoms\nNIGRAM • the type of bond between the carbon atoms and the hydrogen atoms\n• the orbitals that overlap to produce the bonds between the carbon atoms and the\nhydrogen atoms.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [3]\nNI\nETIRW\n(b) Describe the reagents and conditions required for step 1 in Fig. 9.1.\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n+CH (c) In step 1 of Fig. 9.1 benzene reacts with .\nSIHT 3\nNI Complete Fig. 9.2 to show the mechanism for this reaction, including:\nETIRW\n• the movement of electron pairs using curly arrows\nTON • the structure of the intermediate involved.\nOD\nintermediate\nNIGRAM\n+ ................\nSIHT\nNI\n+CH CH ETIRW\n3 3\nTON\nOD\nFig. 9.2\n[3]\nNIGRAM\n(d) Describe the reagents and conditions required for step 2 of Fig. 9.1.\n...................................................................................................................................................\nSIHT\nNI ............................................................................................................................................. [2]\nETIRW\n(e) Identify the reagents required for step 3 of Fig. 9.1. Compound W is the", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2025-on-42-q09-239e9bbdb8.pdf" }, { "id": "9701-2025-on-43-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 15, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2025-on-43-q01-p01-ef4a5d8daf.png", "9701-topic-27-group-2/assets/9701-2025-on-43-q01-p02-239f681ab7.png", "9701-topic-27-group-2/assets/9701-2025-on-43-q01-p03-835d89cc79.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q01", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 (a) Solutions of Group 2 hydrogencarbonates, M(HCO ) , decompose on heating to give the\nSIHT 3 2\ncorresponding metal carbonate, carbon dioxide and water.\nNI\nETIRW\n) . (i) Write an equation for the decomposition of strontium hydrogencarbonate, Sr(HCO\n3 2\nTON ..................................................................................................................................... [1]\nOD\n(ii) The thermal stability of Group 2 carbonates increases down the group.\nExplain this trend.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n..................................................................................................................................... [2]\nTON\nOD (b) The hydroxides and fluorides of Group 2 elements show similar trends in solubility.\nDescribe the trend in the solubility of the fluorides of calcium, strontium and barium.\nNIGRAM Explain your answer.\n.................................... .................................... .....................................\nSIHT\nleast soluble most soluble\nNI\nETIRW explanation ...............................................................................................................................\n................................................................................................................................................... TON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n...................................................................................................................................................\nSIHT\nNI ............................................................................................................................................. [4]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) (i) Define enthalpy change of hydration, ΔH .\nSIHT hyd\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n.", "pdf_path": "9701-topic-27-group-2/print/9701-2025-on-43-q01-248f81a357.pdf" }, { "id": "9701-2025-on-43-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-43-q02-p01-9d75c691c1.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-43-q02-p02-1a58f33a15.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 (a) Iron can form stable ions in the +2 and +3 oxidation states.\nSIHT\nNI Explain why transition elements have variable oxidati on states.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\n]2+. iron(II) salts contain the complex ion [Fe(H O) (b) Aqueous solutions of\n2 6\nDefine complex ion.\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1]\nNI\nETIRW\n]2+ O) can be converted into [Fe(H O) (OH) ]. (c) [Fe(H\n2 6 2 4 2\nTON\n(i) Suggest a suitable reagent for this conversion. State the type of reaction.\nOD\nreagent ..............................................................................................................................\ntype of reaction ..................................................................................................................\nNIGRAM [1]\nO) (OH) ] is a green precipitate that turns brown on standing in air. (ii) [Fe(H\n2 4 2 SIHT\nTable 2.1 shows electrode potentials for some electrode reactions. NI\nETIRW\nTable 2.1\nTON\no electrode reaction E / V OD\ne– OH– –0.56 O) (OH) + H O + Fe(H O) (OH) + Fe(H\n2 3 3 2 2 4 2\n4e– 4OH– +0.40 + 2H O + O\n2 2\nNIGRAM\nO) (OH) ] turns brown on standing Use the information in Table 2.1 to explain why [Fe(H\n2 4 2\nin air. SIHT\nInclude an equation for this reaction.\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ..................................................................................................................................... [3]\nNI\nETIRW\nTON\nNIGRAM\n]2+ (d) The complex [Co(NH ) reacts with hydrogen peroxide as shown.\nSIHT 3 6\no ]2+ ]3+ 2OH– NI ) + H O 2[Co(NH ) + E = +1.67 V reaction 1 2[Co(NH\ncell 3 6 2 2 3 6\nETIRW\no TON mol–1, Calculate ΔG , in kJ for reaction 1.\nOD\nNIGRAM\no mol–1 = ......", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-43-q02-27cbb53b76.pdf" }, { "id": "9701-2025-on-43-q03", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-on-43-q03-p01-0ffb9634b2.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-on-43-q03-p02-7acf56ee1a.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\nmanganese(IV) 3 (a) Solid oxide, MnO , catalyses the decomposition of hydrogen peroxide.\nSIHT 2\nNI O (aq) 2H O(l) + O (g) 2H\n2 2 2 2 ETIRW\nState the type of catalysis for this reaction. Explain your answer .\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\n(b) Hydrogen peroxide reacts with iodide ions in acidic conditions as shown.\nNIGRAM\n2I– 2H+ 2H O + I O + + H\n2 2 2 2\nSIHT\nI– H+. The initial rate of this reaction is investigated with dif ferent concentrations of H O , and\n2 2 NI\nThe results obtained are shown in Table 3.1.\nETIRW\nTable 3.1\nTON\nOD\n[H+] dm–3 dm–3 s–1 dm–3 [I–] dm–3 / mol initial rate / mol experiment [H O ] / mol / mol\n2 2\n10–3 1 0.0450 0.0300 0.0125 2.42 ×\n10–3 NIGRAM 2 0.0225 0.0600 0.0125 2.42 ×\n10–3 3 0.0225 0.120 0.0125 4.84 ×\nSIHT\n10–3 4 0.0450 0.120 0.0500 9.68 ×\nNI\nETIRW\n(i) Use the information in Table 3.1 to deduce the rate equation for this reaction.\nTON\nExplain your reasoning.\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW ...........................................................................................................................................\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [4]\n(ii) Use your rate equation from (b)(i) and the data from Experiment 1 to calculate the rate\nconstant, k, for this reaction. Include the units of k.\nNIGRAM\nSIHT\nNI\nETIRW\nk = .............................. units .............................. [2]\nTON\nNIGRAM\n(c) The rate of the thermal decomposition of azomethane, CH N=NCH , is investigated.\nSIHT 3 3\nNI N=NCH N + C H CH\n3 3 2 2 6\nETIRW\nFig. 3.1 shows the results obtained. The reaction is first order with respect to CH N=NCH .\n3 3\nTON\n0.06\nOD\n0.05\n0.04 NIGRAM\ndm–3 N=NCH ] / mol [CH\n0.03 3 3\nSIHT\nNI 0.02\nETIRW\n0.01\nTON\n0 OD\n0 50 100 150 200 250 300 350 400\ntime / s\nNIGRAM\nFig. 3.1\n, to show that the reaction is first order. t (i) Use Fig. 3.1 to calc", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-on-43-q03-35bb27ce60.pdf" }, { "id": "9701-2025-on-43-q04", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2025-on-43-q04-p01-90eeda0d52.png", "9701-topic-24-electrochemistry/assets/9701-2025-on-43-q04-p02-d7eba8e505.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q04", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\no 4 (a) Define standard cell potential, E . Include a description of standard conditions.\nSIHT cell\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [2]\nOD\n2+(aq) / Cu(s) electrode and a (b) The Daniell cell is an electrochemical cell consisting of a Cu\nZn2+(aq) / Zn(s)e lectrode.\nNIGRAM\n(i) Draw a labelled diagram of this electrochemical cell.\nSIHT Include all necessary substances and relevant pieces of apparatus needed to measure\no . the E\ncell NI\nETIRW\nIt is not necessary to state the conditions used.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\n[3]\nSIHT\n(ii) State the charge carriers that transfer current through the solutions and through the wire.\nNI\nETIRW\nthe solutions .............................. the wire .............................. [1]\nTON o Zn2+(aq) , for the / Zn(s)e lectrode is –0.76 V. (iii) The standard electrode potential, E\nOD\nZn2+(aq) / Zn(s)e lectrode. Water is added to a standard\nZn2+(aq) dm–3. is 0.25 mol The new concentration of\nNIGRAM\nZ2+n(aq) / Zn(s) Use the Nernst equation to calculate the electrode potential, E, for this new\nelectrode.\nSIHT\nNI\nETIRW\n(Zn2+(aq) / Zn(s)) = .............................. V [2] E\nTON\nNIGRAM\n(c) An electrochemical cell consists of a ZnO / Zn electrode and a MnO / MnO electrode in an\nSIHT 2 2 3\nalkaline electrolyte.\nNI\nETIRW o , for this cell is +1.47 V. The standard cell potential, E\ncell\nTON The half-equation at each electrode when this cell is discharging is shown.\nOD\n2e– 2OH– ZnO + H O + Zn +\n2\n2e– 2OH– 2MnO + H O + Mn O +\n2 2 2 3\nNIGRAM\n(i) Use this information to determine the change in oxidation state of manganese when this\ncell is discharging.\nSIHT\nfrom .............................. to .............................. [1]\nNI\nETIRW\n(ii) Write the equation for the overall reaction that occurs when this cell is discharging.\nTON\n..................................................................................................................................... [1]\nOD\no for the ZnO / Zn electrode is –1.28 V. (iii) The E\no , for the MnO / MnO electrode. Calculate the standard electrode potential, E\n2 2 3\nNIGRAM\nSIHT\nNI\no ETIRW (MnO / MnO ) = .............................. V [1] E\n2 2 3\n[Total: 11] TON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2025-on-43-q04-f5479b1b11.pdf" }, { "id": "9701-2025-on-43-q05", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 12, 13, 14 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-43-q05-p01-565602ee31.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-43-q05-p02-406c481b37.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-43-q05-p03-70aea4f7b2.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n5 (a) Copper shows typical properties of transition elements, including its behaviour as a catalyst.\nSIHT\nNI Complete Table 5.1 to show the total number of unpaired electrons in the 3d and 4s orbitals\nETIRW Cu2+ ion. of an isolated gaseous Cu atom and a\nTON Table 5.1\nOD\nnumber of unpaired electrons\nspecies\n3d 4s\nNIGRAM\nCu\nCu2+\nSIHT\n[1]\nNI\nETIRW\nCu2+ ion are degenerate. (b) The 3d orbitals in an isolated\nTON\n2+ ion Complete the diagram to show the relative energies of the 3d orbitals in an isolated Cu\nCu2+ in a tetrahedral complex. and in OD\nNIGRAM\nenergy\nSIHT\nNI\nETIRW\nTON\nCu2+ Cu2+ isolated ion in a tetrahedral complex OD\n[2]\n(c) Explain why transition elements behave as catalysts.\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [2]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nCN– (d) is a monodentate ligand.\nSIHT\nCN– NI ions as ligands. T able 5.2 shows information about two complex ions that contain only\nETIRW\nComplete T able 5.2.\nTON\nTable 5.2\nOD\nmetal ion coordination number formula of complex ion charge of complex ion\nAg+ 2 NIGRAM\nFe2+ 4–\nSIHT\n[2]\nNI\n]– Br displays geometrical (cis / trans) isomerism. (e) The complex ion [Au(CN) ETIRW\n2 2\n]–. Br State its shape and the Br-Au-Br bond angle. Draw the structure of trans-[Au(CN)\nTON\n2 2\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON shape .............................. Br-Au-Br bond angle = ..............................\n[2]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nvanadium(V) (f) An impure sample of a compound of mass 0.250g is dissolved in aqueous acid.\nSIHT\n– ions. This solution contains VO\n3\nNI\nETIRW V2+ – ions are reduced to ions and Zn An excess of zinc is added to this solution. All the VO\n3\nZn2+ ions. atoms are oxidised to\nTON\n–. The unreacted zinc is removed and the resulting solution is titrated with acidified MnO\nOD 4\ncm3 moldm–3 – of 0.0750 MnO is added. The end-point is reached when 22.5\n4\nV2+ –. reacts forming VO A redox reaction takes place and all the\nNIGRAM 3\n5V2+ 3Mn2+ 6H+ – – + + 3H O + 5VO + 3MnO\n4 2 3\nSIHT\n(i) Calculate the percentage by mass of vanadium in the 0.250 g of impure sample.\nNI\nETIRW\nAssume the impurities do not contain any vanadium ions.\nTON\nShow your working.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\npercentage of vanadium = .............................. [3]\n– ions and Zn metal. (ii) Complete the equation for the reaction between acidified VO\n3\nNIGRAM\nV2+ Zn2+ – ...... + ...... + .............. + ...... Zn + ............ ...... VO\n3\n[2]\nSIHT\n[Total: 14]\nNI\nE", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-43-q05-7c79f207c3.pdf" }, { "id": "9701-2025-on-43-q06", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2025-on-43-q06-p01-2b9c6a35e6.png", "9701-topic-37-analytical-techniques/assets/9701-2025-on-43-q06-p02-ade82af5ce.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q06", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n6 (a) Thin-layer and gas / liquid chromatography can be used to separate mixtures into their\nSIHT\nindividual components.\nNI\nETIRW\n(i) Define the following terms used in chromatography.\nTON value ............................................................................................................................. R\nf\nOD\n...........................................................................................................................................\nretention time ....................................................................................................................\nNIGRAM\n...........................................................................................................................................\n[2]\nSIHT\n(ii) Each type of chromatography makes use of a stationary phase and a mobile phase.\nNI\nETIRW\nComplete Table 6.1 with a description of each of these.\nTON\nTable 6.1\nOD\nstationary phase mobile phase\nthin-layer chromatography NIGRAM\nSIHT\ngas / liquidc hromatography\nNI\nETIRW\n[1]\nTON\n(b) A mixture of two substances A and B is analysed by thin-layer chromatography.\nOD\nvalue of substance A is larger than that of substance B. The R\nf\nvalue. Suggest why substance A has a larger R\nf\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [1]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(1H) (c) The two isomeric compounds Y and Z are analysed by proton NMR spectroscopy.\nSIHT\nNI\nY Z\nETIRW\nO O\nTON\nOD\nO O\n1H) NIGRAM (i) Complete Table 6.2 to predict the number of peaks observed in the proton ( NMR\nspectra for Y and Z.\nSIHT\nTable 6.2\nNI\nETIRW\ncompound number of peaks observed\nY TON\nOD Z\n[1]\n1H) NMR spectra for Y (ii) Name all the different splitting patterns observed in the proton (\nNIGRAM\nand Z.\nY ........................................................................................................................................\nSIHT\nNI Z ........................................................................................................................................\nETIRW\n[2]\nTON [Total: 7]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2025-on-43-q06-bd017bbb3b.pdf" }, { "id": "9701-2025-on-43-q07", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 18, 19, 20 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-43-q07-p01-f89da991c5.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-43-q07-p02-c9e5d53f6b.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-43-q07-p03-734188d460.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q07", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 (a) State the relative acidities of bromoethanoic acid, BrCH COOH, chloroethanoic acid,\nSIHT 2\nCOOH, ethanoic acid, CH COOH and ethanol, CH CH OH. Cl CH\n2 3 3 2\nNI\nETIRW\nExplain your answer.\nTON .................................. .................................. .................................. ..................................\nmost acidic least acidic\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n[4]\nNIGRAM . (b) Fig. 7.1 shows the reaction of methylbenzene and ethanedioic acid with KMnO\n4\nPredict the major carbon-containing product for each of these reactions.\nSIHT\nNI\nmethylbenzene\nETIRW\nhot alkaline KMnO\nTON 4\nOD\nethanedioic acid NIGRAM\nO\nSIHT\nhot acidified KMnO\n4\nOH\nNI\nETIRW\nHO\nTON\nO\nOD\nFig. 7.1\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Polyamide X can be synthesised from ethanedioic acid and benzene-1,4-diamine.\nSIHT\nNI\nbenzene-1,4-diamine\nETIRW\nTON\nN NH H\n2 2\nOD\n(i) Draw the repeat unit of polyamide X in the box.\nNIGRAM\nThe new functional group formed should be shown displayed.\nSIHT\npolyamide X\nNI\nETIRW\nTON\nOD\nNIGRAM\n[2]\nSIHT\n(ii) Benzene-1,4-diamine can be formed by reduction of 1,4-dinitrobenzene.\nNI\nETIRW\nComplete the equation for this reduction.\nTON\n[H] represents one atom of hydrogen from a reducing agent.\nOD\n+ .......... [H] H N NH + .....................\n2 2\nNIGRAM\n..........................................................\n[1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Fig. 7.2 shows the two-step synthesis of the azo compound W.\nSIHT\nNI\nV C H N Cl\n6 4 4 2 ETIRW\nstep 1 TON\nH N NH\nOD 2 2\nNIGRAM\nSIHT\nOH\nstep 2\nNI\nETIRW\nand NaOH(aq)\nTON\nOD\nW C H N O\n18 14 4 2\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 7.2\nNIGRAM\n(i) Suggest structures for compounds V and W and draw them in the boxes in Fig. 7.2. [2]\nSIHT (ii) Give the reagents and conditions for step 1.\nNI\n...........................................................", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-on-43-q07-75c711e87c.pdf" }, { "id": "9701-2025-on-43-q08", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 22, 23 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-43-q08-p01-8837bc0233.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-43-q08-p02-132ce98123.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q08", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n8 (a) In the electrophilic substitution of arenes, dif ferent substituents can direct to dif ferent ring\nSIHT\npositions.\nNI\nETIRW\ngroup. Explain your answer. (i) Describe the directing effect of the –NO\n2\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\nand concentrated H SO to (ii) The nitration of arenes uses a mixture of concentrated HNO\n3 2 4\n+ electrophile. generate the NO\nNIGRAM 2\n+ electrophile. Write an equation for the formation of the NO\n2\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n(b) Carbon-carbon bond formation is an important reaction in organic synthesis.\nTON\nFig. 8.1 shows the synthesis of compound Q from benzene in two reaction steps.\nOD\ncompound Q\ncompound P O\nNIGRAM\nreaction 1 reaction 2\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 8.1\nNIGRAM\n(i) Draw the structure of compound P in the box in Fig. 8.1. [1]\n(ii) Suggest reagents and conditions for reactions 1 and 2 in Fig. 8.1. SIHT\nNI\nreaction 1 ..........................................................................................................................\nETIRW\nreaction 2 ..........................................................................................................................\nTON\n[2]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Separate samples of C H Br and C H CH Br are added to warm AgNO (aq).\nSIHT 6 5 6 5 2 3\nNI State the expected observations, if any . Explain your answer.\nETIRW\nH Br with AgNO (aq) ................................................ C\n6 5 3\nTON\nH CH Br with AgNO (aq) ................................................ C\nOD 6 5 2 3\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\n[3]\nETIRW\nO. (d) Acyl bromides, RCOBr, react readily with H\n2 TON\nOD O with acyl chlorides, The mechanism of this reaction is similar to that of the reaction of H\n2\nRCOCl.\n(i) Name the mechanism of this reaction.\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\nO. (ii) Complete the mechanism in ", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-on-43-q08-0f68af695f.pdf" }, { "id": "9701-2025-on-43-q09", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_43.pdf?download=true", "source_pages": [ 24, 25, 26, 27, 28 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-43-q09-p01-70bb31a8fb.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-43-q09-p02-84487f4dd0.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-43-q09-p03-f5e64c8d82.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-43-q09-p04-c9cf758a1e.png", "9701-topic-34-nitrogen-compounds/assets/9701-2025-on-43-q09-p05-71956466d1.png" ], "answer": { "status": "pending", "id": "9701-2025-on-43-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:5)(cid:44)\n9 (a) Explain why amides are much weaker bases than amines.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\nH CH CH NH , by three dif ferent (b) Fig. 9.1 shows the preparation of 2-phenylethylamine, C\nNIGRAM 6 5 2 2 2\nroutes.\nSIHT NH\n2\nNI\nETIRW\nreaction 1\nO\nTON\nOD\n2-phenylethylamine\nM\nNH\nH /Ni 2\n2\nNIGRAM\nSIHT\nNI NH\n3 ETIRW\nN\nTON\nOD\nNIGRAM\nFig. 9.1\n(i) Suggest structures for compounds M and N and draw them in the boxes in Fig. 9.1. [2] SIHT\nNI\n(ii) Give the reagents and conditions for reaction 1.\nETIRW\n..................................................................................................................................... [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Fig. 9.2 shows compound H which is a useful starting material in organic synthesis.\nSIHT\nNI\nH\nETIRW\nO\nN\nTON\nOD\nH\nFig. 9.2\nNIGRAM\nH contains an alkene and an amine functional group.\nSIHT\nName the other functional group and give the classification of the amine group in H.\nNI\nETIRW\nother functional group in H ................................................\nTON\nclassification of amine ................................................\n[1] OD\n, as (d) Ozonolysis involves the oxidative cleavage of a C=C bond in alkenes using ozone, O\n3\nshown in Fig. 9.3.\nNIGRAM\nR R R\nR 3 1 3\n1 O\nSIHT 3\nO + O\nNI\nR ETIRW R 2 R R\n4 2 4\nTON\nFig. 9.3\nOD\nFig. 9.4 shows the first step in this reaction which involves the formation of an ozonide\nintermediate.\nNIGRAM\nozonide\nR R\n3 SIHT R R 2\n1 3 R\n1 R\nNI 4\nETIRW\nO O R R\nTON 2 4\nO\nOD\n-\nO O\nO\nNIGRAM +\nFig. 9.4 SIHT\nNI\n(i) On Fig. 9.4, draw three curly arrows to complete the mechanism of this step. [2]\nETIRW\nTON\nNIGRAM\n(ii) L is formed from alkene K, C H , by a similar reaction to that shown in Fig. 9.3.\nSIHT 8 14\nNI\nL\nETIRW\nO O\nTON\nOD\nSuggest the structure of K.\nNIGRAM\nK C H\n8 14\nSIHT\nNI\nETIRW\nTON\nOD\n[1]\n[Total: 9]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mo–l1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.02 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas V\nm\ndm3 mol–1 V = 24.0 at room conditions\nNIGRAM m\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product o", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2025-on-43-q09-f8f9c0d08e.pdf" }, { "id": "9701-2025-on-44-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 19, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-44-q01-p01-443aee746c.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-44-q01-p02-f6f3f3a3cf.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-44-q01-p03-2f50b77162.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2025-on-44-q01-p04-ebc5e3b3ed.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) Define a transition element.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nCu2+ ion are degenerate. (b) The 3d orbitals in an isolated gaseous\nNIGRAM\n(i) Define the term degenerate.\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [1]\nETIRW\nCu2+. (ii) Complete the electronic configuration of\nTON\n1s2 OD ............................................................................................................................... [1]\ncopper(II) (c) (i) State the colours of the aqueous solutions for the two complex ions shown.\nNIGRAM\n]2+(aq) • [Cu(NH ) (H O) .............................................................................................\n3 4 2 2\nSIHT\n]2–(aq) • [CuCl .............................................................................................................\n4\n[1] NI\nETIRW\n(ii) Explain why aqueous complex ions of transition elements are usually coloured.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [3]\nTON\n]2–(aq), ]2+(aq) (aq) is added to a solution of [CuCl [Cu(NH ) (H O) (d) (i) When an excess of NH OD\n3 4 3 4 2 2\nis formed.\nState the type of reaction.\nComplete the equation for this reaction. State symbols are not required. NIGRAM\ntype of reaction ..................................................................................................................\nSIHT\nequation\nNI\nETIRW\n]2– ]2+ + ..................................... [Cu(NH ) (H O) + ..............", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2025-on-44-q01-13001fd778.pdf" }, { "id": "9701-2025-on-44-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 2, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 6, 7, 8, 9 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q02-p01-7344ddc279.png", "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q02-p02-ef795aeb82.png", "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q02-p03-b04a7584b3.png", "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q02-p04-3852136afa.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q02", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 (a) The Group 2 sulfates and the Group 2 chromates show similar trends in solubility.\nSIHT\nNI Suggest the trend in the solubility of the Group 2 chromates down the group.\nETIRW\nExplain your answer.\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [4]\nTON\nSilver(I) OD chromate, Ag CrO , is sparingly soluble in water. (b)\n2 4\nCrO and its (i) Write an ionic equation to show the equilibrium between solid Ag\n2 4\naqueous solution.\nNIGRAM\nInclude state symbols.\nSIHT\n..................................................................................................................................... [1]\nNI\n10–12 ETIRW , of Ag CrO is 1.12 × at 298 K. (ii) The value of the solubility product, K\nsp 2 4\nAg+, dm–3, in mol in a saturated solution of Calculate the equilibrium concentration of TON\nCrO at 298 K. Ag\n2 4 OD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nAg+ dm–3 equilibrium concentration of = .......................................... mol [3]\nTON\nNIGRAM\n–, – (c) The hydrogenchromate ion, HCrO is a weak acid. The pK of HCrO is 6.49.\nSIHT 4 a 4\ndm–3 – NI HCrO solution. (i) Calculate the pH of a 0.0250 mol\n4\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\npH = ......................................................... [2]\nETIRW\n– can show amphoteric behaviour. (ii) HCrO\n4 TON\nState the formula of: OD\n– • the conjugate acid of HCrO ....................................................................................\n4\n–. • the conjugate base of HCrO .................................................................................. NIGRAM\n4\n[1]\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) Table 2.1 shows some energy changes.\nSIHT\nNI Table 2.1\nETIRW\nmol–1 energy change value / kJ\nTON\nfirst ionisation energy of silver +731\nOD\nsecond ionisation energy of silver +2074\nfirst ionisation energy of sulfur +1000\nNIGRAM\nsecond ionisation energy of sulfur +2251\nfirst electron affinity of sulfur –200\nSIHT\nsecond electron affinity of sulfur +532\nNI\nETIRW enthalpy change of atomisation of ", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-on-44-q02-78e0a1c461.pdf" }, { "id": "9701-2025-on-44-q03", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 3, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q03-p01-be553869c3.png", "9701-topic-23-chemical-energetics/assets/9701-2025-on-44-q03-p02-1237a5afe8.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q03", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n3 (a) Define the term entropy.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\n(b) (i) Place one tick (3) in each row of Table 3.1 to show the sign of the entropy change, ΔS,\nfor each process.\nTable 3.1\nNIGRAM\nprocess ΔS is negative ΔS is positive\nSIHT\nsteam condensing into water NI\nETIRW\nsolid KCl dissolving in water\nTON\n[1]\nOD\n, decomposes on heating into its elements, as shown. (ii) Chlorine trifluoride, Cl F\n3\nCl (g) + 3F (g) (g) reaction 1 2Cl F\n2 2 3 NIGRAM\nStandard entropies are shown in Table 3.2.\nSIHT\nTable 3.2\nNI\nETIRW\nsubstance Cl F (g) Cl (g) F (g)\n3 2 2\nTON K–1 mol–1 / J +281.6 +223.1 +203.0 S⦵\nOD\nK–1 mol–1, ΔS⦵, in J for reaction 1. Calculate the standard entropy change,\nNIGRAM\nSIHT\nK–1 mol–1 ΔS⦵ for reaction 1 = ........................................ J [2]\nNI\nETIRW\n(c) Group 2 carbonates decompose on heating. The decomposition for one of the Group 2\nTON\ncarbonates, MCO , is shown in reaction 2.\n3\nOD\nMO(s) + CO (g) (s) reaction 2 MCO\n2 3\n(i) Predict the sign of the entropy change, ΔS, for reaction 2.\nNIGRAM\nExplain your answer.\nSIHT\n...........................................................................................................................................\nNI\n..................................................................................................................................... [1] ETIRW\nTON\nNIGRAM\n(ii) The Gibbs equation is shown.\nSIHT\nNI = ΔH – TΔS⦵ ΔG⦵ ⦵\nETIRW\nmol–1, Fig. 3.1 shows values of the Gibbs free energy change, ΔG⦵, in kJ at different\nTON temperatures, T, in K, for reaction 2.\nOD\nand ΔS⦵ values for this reaction remain constant over this temperature range. Assume ΔH ⦵\n200\nNIGRAM\n150\nΔG⦵\nSIHT\n100 mol–1 kJ /\nNI\nETIRW 50\nTON 0\n0 200 400 600 800 1000 1200 1400 1600\nOD\n–50\n–100\nNIGRAM T / K\nFig. 3.1\nSIHT\nNI Use the gradient and intercept on the y‑axis in Fig. 3.1 and the Gibbs equation\nETIRW\nto determine:\nTON K–1 mol–1, • ΔS⦵, in J for reaction 2\n• the minimum temperature, T, in K, at which the reaction is feasible\nOD\nmol–1, • ΔH ⦵, in kJ for reaction 2.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nK–1 mol–1 ΔS⦵ for reaction 2 = ............................................. J NIGRAM\nminimum temperature, T = ............................................................ K\nSIHT\nmol–1 for reaction 2 = .................................................. kJ ΔH ⦵ NI\n[4] ETIRW\n[Total: 9] TON", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2025-on-44-q03-0b7aa3789c.pdf" }, { "id": "9701-2025-on-44-q04", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 4, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2025-on-44-q04-p01-eaa264a498.png", "9701-topic-26-reaction-kinetics/assets/9701-2025-on-44-q04-p02-542983b3cf.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q04", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n4 (a) Nitrogen monoxide, NO, reacts with hydrogen, as shown in reaction 3.\nSIHT\nNI N + 2H O reaction 3 2NO + 2H\n2 2 2\nETIRW\n(i) The rate equation for reaction 3 is shown.\nTON\n][NO]2 rate = k[H\nOD 2\nComplete Table 4.1.\nTable 4.1\nNIGRAM\nthe order of reaction with respect to [H ]\n2\nSIHT\nthe order of reaction with respect to [NO]\nNI\nETIRW the overall order of the reaction\n[1]\nTON\n(ii) Predict how the initial rate for reaction 3 changes when the concentration of NO is halved.\nOD\n..................................................................................................................................... [1]\n(iii) Predict how the initial rate for reaction 3 changes when the concentrations of NO and H\nNIGRAM\n2\nare both increased three times.\nSIHT ..................................................................................................................................... [1]\nNI\n(iv) Suggest why reaction 3 is unlikely to proceed by a mechanism involving only a\nETIRW\nsingle step.\nTON\n...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(v) Suggest equations for the three steps of the reaction mechanism for reaction 3.\nNIGRAM\nEach step involves a reaction between two molecules.\nSIHT\n.................................................. step 1 ..................................................\nNI\nN O + ..................................... step 2 ...................... + ...................... ETIRW\n2\n....................... + ....................... O + ..................................... step 3 N TON\n2\n[2]\nOD\nO in this mechanism. (vi) Suggest the role of N\n2\nExplain your reasoning.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nNIGRAM\n2–, (b) Iodine, I , reacts with thiosulfate ions, S O as shown in reaction 4.\nSIHT 2 2 3\n2I– 2– 2– NI O + I S O + reaction 4 2S\n2 3 2 4 6 ETIRW\nReaction 4 is carried out in the presence of a large excess of I . Under these conditions, the\n2\nTON 2–] O and zero order with respect to [I ]. reaction is first order with respect to [S\n2 3 2\nOD\n, for reaction 4 is 720 s under certain conditions. The half‑life, t\n1\n2\nCalculate the value of the rate constant, k, for reaction 4. Include the units of k.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nk = ....................... units ......................... [1]\nOD\nI–(aq), 2–(aq), (c) The reaction between iodide ions, and peroxydisulfate ions, S O is catalysed\n2 8\nCo3+(aq). Fe3+(aq) The mechanism is similar", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2025-on-44-q04-045d963370.pdf" }, { "id": "9701-2025-on-44-q05", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 5, "topic_number": 30, "topic": "Hydrocarbons", "topic_slug": "9701-topic-30-hydrocarbons", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 14, 15 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-30-hydrocarbons/assets/9701-2025-on-44-q05-p01-6b2c1e620f.png", "9701-topic-30-hydrocarbons/assets/9701-2025-on-44-q05-p02-2cf73cbef4.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q05", "html": "9701-topic-30-hydrocarbons/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n5 (a) Describe and explain the shape of benzene.\nSIHT\nNI In your answer, include:\nETIRW\n• the shape and bond angle in the ring\nTON • the hybridisation of the carbon atoms\n• how orbital overlap forms σ and π bonds between the carbon atoms in the ring.\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n............................................................................................................................................. [4]\nNIGRAM\n(b) Fig. 5.1 shows two reactions of benzoic acid.\nSIHT\nCOOH COOH COOH\nNI\nETIRW\nTON reaction 5 reaction 6\nOD\nNIGRAM O\nFig. 5.1\nSIHT\nNI (i) Suggest reagents and conditions for reaction 5 and for reaction 6 in Fig. 5.1.\nETIRW\nreaction 5 ..........................................................................................................................\nTON\nreaction 6 ..........................................................................................................................\nOD\n[2]\n(ii) State the type of reaction for reaction 5 in Fig. 5.1.\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) In the electrophilic substitution of arenes, different substituents can direct to different\nSIHT\nring positions.\nNI\nETIRW\nCH group. (i) Describe the directing effect of the –CH\n2 3\nTON Explain your answer.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nCH Br and FeBr to generate the (ii) The alkylation of arenes uses a mixture of CH\n3 2 3\n+ CH electrophile. CH\n3 2\nSIHT\n+ CH electrophile. Write an equation for the formation of the CH\n", "pdf_path": "9701-topic-30-hydrocarbons/print/9701-2025-on-44-q05-31edc0427a.pdf" }, { "id": "9701-2025-on-44-q06", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 6, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 16, 17 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2025-on-44-q06-p01-7b9d74c3ef.png", "9701-topic-36-organic-synthesis/assets/9701-2025-on-44-q06-p02-3a04721cf9.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q06", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n6 (a) Compound Z is used in organic synthesis.\nSIHT\nZ NI\nETIRW O NH\n2\nTON\nCN\nOD\nN H\n2\nsp2 sp3 Complete Table 6.1 to show the number of sp, and hybridised carbon atoms present\nin one molecule of Z. NIGRAM\nTable 6.1\nSIHT\nsp2 sp3 NI type of hybridisation sp\nETIRW\nnumber of carbon atoms\nTON\n[1]\nOD\n(b) Z can undergo different reactions, as shown in Fig. 6.1.\nNIGRAM\nSIHT\nNI\nexcess HCl (aq)\nETIRW\nheat\nTON reaction 7\nZ\nOD\nO NH\n2\nCH COCl\n3\nCN\nreaction 8\nNIGRAM\nN H\n2\nSIHT\nexcess LiAl H\nNI 4\nETIRW\nreaction 9\nTON\nOD\nFig. 6.1\nNIGRAM\n(i) Name the two types of reaction occurring in reaction 7 in Fig. 6.1.\nSIHT\n.............................................................. and ............................................................... [1]\nNI\nETIRW\n(ii) Draw the structures of the organic products of reactions 7, 8 and 9 in Fig. 6.1. [4]\nTON\nNIGRAM\n(1H) (c) Compound Z is dissolved in D O and analysed by carbon‑13 NMR and proton\nSIHT 2\nNMR spectroscopy.\nNI\nETIRW\n(i) Predict the number of peaks in the carbon‑13 NMR spectrum of Z.\nTON ..................................................................................................................................... [1]\nOD\n(1H) NMR spectrum of Z in D O gives three peaks for the proton environments, (ii) The proton\n2\nlabelled a, b and c, as shown on Fig. 6.2.\nZ\nNIGRAM\nNH O\n2\nCN CH C SIHT\nCH CH N H\n2 2 2 NI\nETIRW\na c b\nTON\nFig. 6.2 OD\n(1H) NMR spectrum of Z in D O. Complete Table 6.2 for the proton\n2\nTable 6.2 NIGRAM\nproton environment a b c\nSIHT\nNI name of splitting pattern\nETIRW\nchemical shift range,\nTON δ / ppm\nOD\n[2]\nTable 6.3\nNIGRAM\nchemical shift\nenvironment of proton example\nrange, δ / ppm\nSIHT\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2\nNI\n–C=O, –CH –C=O, CH ETIRW\n3 2 2.2–3.0 alkyl next to C=O\n>CH–C=O\nTON\n–CN 2.0–3.0 alkyl next to nitrile –CH\n2\nOD\n–O, –CH –O, –CH –N 3.2– 4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nalkyl amine R–NH– 1.0–5.0\nNIGRAM\namide RCONHR 5.0–12.0\nSIHT\n[Total: 9]\nNI\nETIRW\nTON", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2025-on-44-q06-06c42f4ff2.pdf" }, { "id": "9701-2025-on-44-q07", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 7, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2025-on-44-q07-p01-45a321b657.png", "9701-topic-32-hydroxy-compounds/assets/9701-2025-on-44-q07-p02-f1c14f3465.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q07", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 Phenylmethanol and 4‑methylphenol are isomers.\nSIHT\nphenylmethanol 4-methylphenol NI\nETIRW\nTON\nOH CH OH\n2\nOD\n(a) Complete Table 7.1 to show the relative acidities of benzoic acid (C H COOH),\nNIGRAM 6 5\nphenylmethanol, 4‑methylphenol and water.\nExplain your answer. SIHT\nNI\nTable 7.1\nETIRW\nname of compound TON\nOD\nmost acidic\nNIGRAM\nSIHT\nleast acidic\nNI\nETIRW\nexplanation ...............................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD [4]\n(b) 4‑methylphenol reacts readily with sodium.\nNIGRAM\nComplete the equation for this reaction.\nSIHT\nNI OH + ...............\nETIRW\nTON [1]\nNIGRAM\n(c) Under certain conditions, ethane‑1,2‑diol, HOCH CH OH, reacts with propane‑1,3‑dioic acid,\nSIHT 2 2\nCOOH, to form different organic products, as shown in Fig. 7.1. HOOCCH\n2\nNI\nETIRW H O X, C\n5 6 4 reaction 10\nO O\nTON\nHO\nOD +\nOH\nHO OH\nNIGRAM reaction 11\npolymer Y\nSIHT\nFig. 7.1\nNI\nETIRW\n(i) X does not react with Na metal.\nTON\nH O , shown in Fig. 7.1. Draw the structure of the organic product X, C\n5 6 4\nOD\nNIGRAM\n[1]\nSIHT\nNI (ii) Reactions 10 and 11 in Fig. 7.1 are different types of reaction.\nETIRW\nName the type of reaction for reaction 10 and for reaction 11.\nTON\nreaction 10 ........................................................................................................................\nOD\nreaction 11 .........................................................................................................................\n[1]\nNIGRAM\n(iii) Draw a section of polymer Y showing only one repeat unit.\nSIHT The new functional group formed should be displayed.\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW [2]\n[Total: 9] TON", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2025-on-44-q07-530b09dc6c.pdf" }, { "id": "9701-2025-on-44-q08", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 4, "variant": "44", "question_number": 8, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_44.pdf?download=true", "source_pages": [ 20, 21, 22, 23, 24 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_44.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-44-q08-p01-0a1f91c7fc.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-44-q08-p02-b272e32049.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-44-q08-p03-aeb19b1d02.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-44-q08-p04-41d53c2a8c.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2025-on-44-q08-p05-2888ceac98.png" ], "answer": { "status": "pending", "id": "9701-2025-on-44-q08", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n8 (a) Describe the difference in reactivity between ethanoyl chloride and chlorobenzene with water.\nSIHT\nNI Explain your answer.\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n............................................................................................................................................. [2]\nNI\nETIRW\n(b) The structure of compound V is shown.\nTON\nV OD\nCN O\nO\nNIGRAM\nO N\nSIHT\nO H\nNI\nETIRW\n(i) Name all the functional groups in V.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [2]\nNIGRAM\n(ii) Deduce the number of possible optical isomers for V.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW (iii) Suggest one reason, other than better biological activity and lower dosage required, why\nit is beneficial to synthesise a single optical isomer of V for use as a drug.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) A sample of V is hydrolysed with an excess of hot aqueous alkali.\nSIHT\nNI The products are isolated from the reaction mixture at pH 12.\nETIRW\nDraw the structures of the two organic products of the complete alkaline hydrolysis of V\nTON in Fig. 8.1.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 8.1\n[3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) A polypeptide formed from four amino acids, A, ", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2025-on-44-q08-965e16b356.pdf" }, { "id": "9701-2025-on-51-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_51.pdf?download=true", "source_pages": [ 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-51-q01-p01-ebaf29f5ce.png", "9701-experimental-skills/assets/9701-2025-on-51-q01-p02-3e08b3879e.png", "9701-experimental-skills/assets/9701-2025-on-51-q01-p03-c7b4803e27.png", "9701-experimental-skills/assets/9701-2025-on-51-q01-p04-bd6a4080a6.png" ], "answer": { "status": "pending", "id": "9701-2025-on-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 The concentration of aqueous chloride ions can be found by titration with aqueous silver nitrate,\nSIHT\n(aq). AgNO\n3\nNI\nETIRW Ag+(aq) – + Cl (aq) AgCl(s)\nTON chromate(VI), K CrO (aq). The indicator used is aqueous potassium\n2 4\nOD\n(aq) is added to aqueous chloride ions, a white precipitate of AgCl(s) is formed. As AgNO\n3\n(aq) leads to the formation of When all the chloride ions have reacted, further addition of AgNO\n3\nVI), Ag CrO (s). The first appearance of the red precipitate a red precipitate of silver chromate(\nNIGRAM 2 4\nshows the end-point of the titration.\nA student carries out an experiment to determine the number of molecules of water of crystallisation, SIHT\n•xH O(s). x, in hydrated barium chloride, BaCl\n2 2 NI\nETIRW\ncm3 dm–3 of 0.0500 mol AgNO (aq) to use for the titration. (a) The student makes 250.0\n3\nTON\ncm3 (s), needed to make 250.0 of (i) Calculate the mass of solid silver nitrate, AgNO\n3\ndm–3 OD AgNO (aq). 0.0500 mol\n3\nGive your answer to two decimal places.\nNIGRAM\nSIHT\nNI\nETIRW\n(s) = .............................. g [1] mass of AgNO\n3\nTON\ncm3 dm–3 of 0.0500 mol AgNO (aq) starting (ii) Describe how the student should make 250.0\n3 OD\ncm3 (s) calculated in (a)(i) in a 50 beaker. from the mass of AgNO\n3\nGive the name and size of any key apparatus used.\nNIGRAM\nWrite your answer using a series of numbered steps.\n...........................................................................................................................................\nSIHT\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n........................................................................................................................................... OD\n...........................................................................................................................................\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [3]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) The student uses the following method.\nSIHT\ncm3 NI •xH O(s) to form 250 of aqueous solution. Label this step 1 Dissolve 1.58 g of BaCl\n2 2\nETIRW\nsolution A.\nTON cm3 of solution A into a conical flask. step 2 Transfer 20.0\nOD\nSO (aq), to the flask and swirl the mixture to step 3 Add aqueous sodium sulfate, Na\n2 4\nremove barium ions from the solution.\nCrO (aq) indicator to the flask. step 4 Add 2–3 drops of K\nNIGRAM 2 4\ndm–3 AgNO (aq). step 5 Titrate the contents of the flask against 0.0500 mol\n3\nSIH", "pdf_path": "9701-experimental-skills/print/9701-2025-on-51-q01-f609aa5534.pdf" }, { "id": "9701-2025-on-51-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_51.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-51-q02-p01-51dc2f5ec1.png", "9701-experimental-skills/assets/9701-2025-on-51-q02-p02-8f239275f4.png", "9701-experimental-skills/assets/9701-2025-on-51-q02-p03-f6cd26d27c.png", "9701-experimental-skills/assets/9701-2025-on-51-q02-p04-5789d67af5.png", "9701-experimental-skills/assets/9701-2025-on-51-q02-p05-6a9c5ecfd5.png", "9701-experimental-skills/assets/9701-2025-on-51-q02-p06-19d39197c6.png" ], "answer": { "status": "pending", "id": "9701-2025-on-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 Effusion is the process in which a gas escapes through a small hole.\nSIHT\nNI A student investigates the relationship between rate of ef fusion and relative molar mass of a gas\nETIRW\nusing the apparatus shown in Fig. 2.1.\nplunger TON\nOD\ngas syringe\nNIGRAM\ngas being tested\nSIHT\nside-arm tube\nNI\nETIRW\nthree-way tap TON\nOD\naluminium foil with small hole\nNIGRAM\nFig. 2.1\nSIHT\nThe following method is used:\nNI\nETIRW step 1 Turn the tap and remove any gas from the syringe through the side-arm tube, by pushing\nin the plunger.\nTON\ncm3 of the gas being tested to the syringe through the side-arm tube. step 2 Add 50\nOD\nstep 3 Remove the gas from the syringe, through the side-arm tube, by pushing in the plunger.\ncm3 of the gas being tested to the syringe through the side-arm tube. step 4 Add 70\nNIGRAM\nstep 5 Turn the tap to connect the syringe to the tube with the aluminium foil and small hole.\nSIHT\nstep 6 Allow the syringe plunger to fall and start a timer when the volum e of gas in the syringe\nNI\ncm3. reaches 60\nETIRW\ncm3. Record the time step 7 Stop the timer when the volume of gas in the syringe reaches 10\nTON\ntaken.\nOD\nstep 8 Repeat steps 1 to 7 with different gases.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 (a) Suggest why the student adds 50 of the gas being tested to the syringe in step 2 and\nSIHT\nthen removes this gas in step 3.\nNI\nETIRW\n...................................................................................................................................................\nTON ............................................................................................................................................. [1]\nOD\n(b) The student’s results are shown in Table 2.1.\nTable 2.1\nNIGRAM\ngas hydrogen, H helium, He neon, Ne argon, Ar krypton, Kr\n2\nrelative SIHT\nmolar 2.0 4.0 20.2 39.9 83.8\nNI\nmass, M\nETIRW\n1\nTON\nM\nOD\ntime taken\n10.8 15.3 34.5 39.7 70.4\n/ s\nrate of\nNIGRAM\neffusion\ncm3 s–1 /\nSIHT\nvolume of gas NI\nrate of effusion =\nETIRW time taken\nTON\n(i) Complete Table 2.1.\nOD\n1\nto three significant figures. Give the values for\nM\nGive the values for rate of effusion to two decimal places. [2]\nNIGRAM\n(ii) Identify the dependent variable in this experiment.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW (iii) Identify a variable, other than temperature, that is controlled when carrying out this\nexperiment.\nTON\n..................................................................................................................................... [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n1 SIHT (c) Plot a graph on the grid in Fig. 2.2 to show the relationship between rate of effusion and .\nM\nUse a cross (×) to plot each data point. Draw a suitable line of best fit. NI\nETIRW\n5.0\nTON\nOD\n4.5\nNIGRAM\n4.0\nSIHT\nNI\nETIRW\n3.5\nTON\nOD\n3.0\nNIGRAM\n2.5 S", "pdf_path": "9701-experimental-skills/print/9701-2025-on-51-q02-6720e3d68e.pdf" }, { "id": "9701-2025-on-52-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_52.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-52-q01-p01-31c4a61a14.png", "9701-experimental-skills/assets/9701-2025-on-52-q01-p02-4e09a89100.png", "9701-experimental-skills/assets/9701-2025-on-52-q01-p03-e3b4a910f3.png", "9701-experimental-skills/assets/9701-2025-on-52-q01-p04-789f1b8036.png", "9701-experimental-skills/assets/9701-2025-on-52-q01-p05-b94fd72853.png", "9701-experimental-skills/assets/9701-2025-on-52-q01-p06-93e40f82b5.png" ], "answer": { "status": "pending", "id": "9701-2025-on-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\nAg+(aq), 2+(aq). iron(II) 1 Aqueous silver ions, react slowly with aqueous ions, Fe An equilibrium is\nSIHT\nestablished.\nNI\nETIRW Ag+(aq) Fe2+(aq) Fe3+(aq) + Ag(s) +\nTON Ag+(aq) at equilibrium can be determined by titration with a standard solution The concentration of\nof aqueous potassium thiocyanate, KSCN(aq).\nOD\nAg+(aq) –(aq) ions react with SCN ions to form a precipitate of During the titration, the remaining\nAgSCN(s).\nNIGRAM\nAg+(aq) SCN–(aq) + AgSCN(s)\nAg+(aq) SCN–(aq) Fe3+(aq) SIHT ions have been removed from solution, excess ions react with When all\nFeSCN2+(aq), which has a red colour. to form a complex ion,\nNI\nETIRW\nFe3+(aq) SCN–(aq) FeSCN2+(aq) +\nTON\nThe appearance of the red colour indicates the end-point.\nOD\n. A student carries out an experiment to determine the equilibrium constant, K\nc\n[Fe3+(aq)]\neqm\nNIGRAM K =\n[Fe2+(aq)] [Ag+(aq)] c\neqm eqm\nSIHT\ncm3 dm–3 The student makes 250.0 of 0.0200 mol KSCN(aq) to use in the titration.\nNI\ncm3 ETIRW of (a) Calculate the mass of solid potassium thiocyanate, KSCN(s), needed to make 250.0\ndm–3 KSCN(aq). 0.0200 mol\nTON\nOD\nmass of KSCN(s) = ....................................................... g [1] NIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 dm–3 (b) Describe how the student should make 250.0 of 0.0200 mol KSCN(aq) starting from\nSIHT\ncm3 beaker. the mass of KSCN(s) calculated in (a) in a 50\nNI\nETIRW\nGive the name and size of any key apparatus used.\nTON W rite your answer using a series of numbered steps.\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n................................................................................................................................................... SIHT\nNI\n...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\nOD ............................................................................................................................................. [3]\n. (c) The student uses the following method to determine K\nc\nNIGRAM\ncm3 dm–3 of 0.100 mol aqueous silver nitrate, AgNO (aq), into a dry conical step 1 Add 25.0\n3\nflask. Label this flask A.\nSIHT\ncm3 dm–3 iron(II) of 0.100 mol aqueous sulfate, FeSO (aq), into flask A. step 2 Add 25.0 NI\n4\nETIRW\nstep 3 Seal flask A, using a", "pdf_path": "9701-experimental-skills/print/9701-2025-on-52-q01-1541c70938.pdf" }, { "id": "9701-2025-on-52-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_52.pdf?download=true", "source_pages": [ 9, 10, 11, 12, 13, 15, 16 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-52-q02-p01-0fb1e9ca24.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p02-1878a99725.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p03-ef41ce3c3b.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p04-1329166ebf.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p05-970b8ea9a1.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p06-ba226cd480.png", "9701-experimental-skills/assets/9701-2025-on-52-q02-p07-6ef6f04d13.png" ], "answer": { "status": "pending", "id": "9701-2025-on-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:10)(cid:44)\n2 A student carries out an experiment to determine the concentration of aqueous sulfate ions,\nSIHT\n2–(aq), in a sample of lake water. SO\n4\nNI\nETIRW\n(a) The student uses the following method.\nTON cm3 of the lake water sample to a beaker and record its conductivity step 1 Transfer 25.00\nas shown in Fig. 2.1.\nOD\ncm3 dm–3 of 0.100 mol aqueous barium hydroxide, Ba(OH) (aq), to the step 2 Add 5.00\n2\nbeaker.\nNIGRAM\nstep 3 S tir the mixture and record the conductivity of the contents of the beaker as shown in\nFig. 2.1.\nSIHT\ncm3 dm–3 of 0.100 mol Ba(OH) (aq) has step 4 R epeat steps 2 and 3 until a total of 40.00\n2 NI\nbeen added to the beaker.\nETIRW\nconductivity meter\nTON\n0.0\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nFig. 2.1\ncm3 of the lake water sample to (i) Suggest a suitable piece of apparatus to transfer 25.00\nthe beaker in step 1.\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\ndm–3 Ba(OH) (aq) is an irritant to skin and eyes. Other than wearing safety (ii) 0.100 mol\n2 NI\ngoggles, state one safety precaution that the student should take when conducting this\nETIRW\nexperiment.\nTON\n..................................................................................................................................... [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) The student’s results are given in Table 2.1.\nSIHT\nNI A correction can be applied to the conductivity values to take into account dilution of the\nETIRW\nsolution as its volume increases using the following equation.\n(total volume in beaker)\nTON corrected conductivity = measured conductivity ×\n25.00\nOD\nTable 2.1\nvolume of\ndm–3 NIGRAM 0.100 mol measured corrected\ntotal volume in reading\n(aq) conductivity Ba(OH) conductivity\ncm3 beaker / number 2\ncm–1 cm–1 µµS µµS added to / /\nSIHT\ncm3 beaker /\nNI\nETIRW 1 0.00 25.00 37 000 37 000\nTON\n2 5.00 23 000 27 600\nOD\n3 10.00 12 000 16 800\nNIGRAM\n4 15.00 2 300 3 680\nSIHT\n5 20.00 5 000\nNI\nETIRW\n6 25.00 12 000\nTON\n7 30.00 18 000\nOD\n8 35.00 21 000\nNIGRAM\n9 40.00 24 500\nSIHT\n(i) Complete Table 2.1. [2]\nNI\nETIRW\n(ii) Identify the independent variable in this experiment.\nTON\n..................................................................................................................................... [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Plot a graph on the grid in Fig. 2.2 to show the relationship between corrected conductiv ity\nSIHT\ndm–3 Ba(OH) added to beaker. and volume of 0.100 mol\n2\nNI\nETIRW\nUse a cross (×) to plot each data point.\nTON Draw a line of best fit using readings 1 to 4 and another line of best fit using readings 5 to 9.\nExtend the lines so that they intersect.\nOD\n000 70\nNIGRAM\n60 000\nSIHT\nNI\nETIRW\n50 000\nTON\nOD\n40 000\ncorrected\nNIGRAM\nconductivity\ncm–1 / μS\n000 30\nSIHT\nNI\nETIRW\n20 000\nTON\nOD\n10 000\nNIGRAM\nSIHT 0\n0 5 10 15 20 25 30 35 40\nNI", "pdf_path": "9701-experimental-skills/print/9701-2025-on-52-q02-04b89c5f66.pdf" }, { "id": "9701-2025-on-53-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_53.pdf?download=true", "source_pages": [ 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-53-q01-p01-ebaf29f5ce.png", "9701-experimental-skills/assets/9701-2025-on-53-q01-p02-3e08b3879e.png", "9701-experimental-skills/assets/9701-2025-on-53-q01-p03-c7b4803e27.png", "9701-experimental-skills/assets/9701-2025-on-53-q01-p04-bd6a4080a6.png" ], "answer": { "status": "pending", "id": "9701-2025-on-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 The concentration of aqueous chloride ions can be found by titration with aqueous silver nitrate,\nSIHT\n(aq). AgNO\n3\nNI\nETIRW Ag+(aq) – + Cl (aq) AgCl(s)\nTON chromate(VI), K CrO (aq). The indicator used is aqueous potassium\n2 4\nOD\n(aq) is added to aqueous chloride ions, a white precipitate of AgCl(s) is formed. As AgNO\n3\n(aq) leads to the formation of When all the chloride ions have reacted, further addition of AgNO\n3\nVI), Ag CrO (s). The first appearance of the red precipitate a red precipitate of silver chromate(\nNIGRAM 2 4\nshows the end-point of the titration.\nA student carries out an experiment to determine the number of molecules of water of crystallisation, SIHT\n•xH O(s). x, in hydrated barium chloride, BaCl\n2 2 NI\nETIRW\ncm3 dm–3 of 0.0500 mol AgNO (aq) to use for the titration. (a) The student makes 250.0\n3\nTON\ncm3 (s), needed to make 250.0 of (i) Calculate the mass of solid silver nitrate, AgNO\n3\ndm–3 OD AgNO (aq). 0.0500 mol\n3\nGive your answer to two decimal places.\nNIGRAM\nSIHT\nNI\nETIRW\n(s) = .............................. g [1] mass of AgNO\n3\nTON\ncm3 dm–3 of 0.0500 mol AgNO (aq) starting (ii) Describe how the student should make 250.0\n3 OD\ncm3 (s) calculated in (a)(i) in a 50 beaker. from the mass of AgNO\n3\nGive the name and size of any key apparatus used.\nNIGRAM\nWrite your answer using a series of numbered steps.\n...........................................................................................................................................\nSIHT\nNI ...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\n........................................................................................................................................... OD\n...........................................................................................................................................\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [3]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) The student uses the following method.\nSIHT\ncm3 NI •xH O(s) to form 250 of aqueous solution. Label this step 1 Dissolve 1.58 g of BaCl\n2 2\nETIRW\nsolution A.\nTON cm3 of solution A into a conical flask. step 2 Transfer 20.0\nOD\nSO (aq), to the flask and swirl the mixture to step 3 Add aqueous sodium sulfate, Na\n2 4\nremove barium ions from the solution.\nCrO (aq) indicator to the flask. step 4 Add 2–3 drops of K\nNIGRAM 2 4\ndm–3 AgNO (aq). step 5 Titrate the contents of the flask against 0.0500 mol\n3\nSIH", "pdf_path": "9701-experimental-skills/print/9701-2025-on-53-q01-e3983cfe95.pdf" }, { "id": "9701-2025-on-53-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_53.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-53-q02-p01-51dc2f5ec1.png", "9701-experimental-skills/assets/9701-2025-on-53-q02-p02-8f239275f4.png", "9701-experimental-skills/assets/9701-2025-on-53-q02-p03-f6cd26d27c.png", "9701-experimental-skills/assets/9701-2025-on-53-q02-p04-5789d67af5.png", "9701-experimental-skills/assets/9701-2025-on-53-q02-p05-6a9c5ecfd5.png", "9701-experimental-skills/assets/9701-2025-on-53-q02-p06-19d39197c6.png" ], "answer": { "status": "pending", "id": "9701-2025-on-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 Effusion is the process in which a gas escapes through a small hole.\nSIHT\nNI A student investigates the relationship between rate of ef fusion and relative molar mass of a gas\nETIRW\nusing the apparatus shown in Fig. 2.1.\nplunger TON\nOD\ngas syringe\nNIGRAM\ngas being tested\nSIHT\nside-arm tube\nNI\nETIRW\nthree-way tap TON\nOD\naluminium foil with small hole\nNIGRAM\nFig. 2.1\nSIHT\nThe following method is used:\nNI\nETIRW step 1 Turn the tap and remove any gas from the syringe through the side-arm tube, by pushing\nin the plunger.\nTON\ncm3 of the gas being tested to the syringe through the side-arm tube. step 2 Add 50\nOD\nstep 3 Remove the gas from the syringe, through the side-arm tube, by pushing in the plunger.\ncm3 of the gas being tested to the syringe through the side-arm tube. step 4 Add 70\nNIGRAM\nstep 5 Turn the tap to connect the syringe to the tube with the aluminium foil and small hole.\nSIHT\nstep 6 Allow the syringe plunger to fall and start a timer when the volum e of gas in the syringe\nNI\ncm3. reaches 60\nETIRW\ncm3. Record the time step 7 Stop the timer when the volume of gas in the syringe reaches 10\nTON\ntaken.\nOD\nstep 8 Repeat steps 1 to 7 with different gases.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 (a) Suggest why the student adds 50 of the gas being tested to the syringe in step 2 and\nSIHT\nthen removes this gas in step 3.\nNI\nETIRW\n...................................................................................................................................................\nTON ............................................................................................................................................. [1]\nOD\n(b) The student’s results are shown in Table 2.1.\nTable 2.1\nNIGRAM\ngas hydrogen, H helium, He neon, Ne argon, Ar krypton, Kr\n2\nrelative SIHT\nmolar 2.0 4.0 20.2 39.9 83.8\nNI\nmass, M\nETIRW\n1\nTON\nM\nOD\ntime taken\n10.8 15.3 34.5 39.7 70.4\n/ s\nrate of\nNIGRAM\neffusion\ncm3 s–1 /\nSIHT\nvolume of gas NI\nrate of effusion =\nETIRW time taken\nTON\n(i) Complete Table 2.1.\nOD\n1\nto three significant figures. Give the values for\nM\nGive the values for rate of effusion to two decimal places. [2]\nNIGRAM\n(ii) Identify the dependent variable in this experiment.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW (iii) Identify a variable, other than temperature, that is controlled when carrying out this\nexperiment.\nTON\n..................................................................................................................................... [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n1 SIHT (c) Plot a graph on the grid in Fig. 2.2 to show the relationship between rate of effusion and .\nM\nUse a cross (×) to plot each data point. Draw a suitable line of best fit. NI\nETIRW\n5.0\nTON\nOD\n4.5\nNIGRAM\n4.0\nSIHT\nNI\nETIRW\n3.5\nTON\nOD\n3.0\nNIGRAM\n2.5 S", "pdf_path": "9701-experimental-skills/print/9701-2025-on-53-q02-99851a17fa.pdf" }, { "id": "9701-2025-on-54-q01", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "54", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_54.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-54-q01-p01-e3d26a8548.png", "9701-experimental-skills/assets/9701-2025-on-54-q01-p02-2338ceb6fe.png", "9701-experimental-skills/assets/9701-2025-on-54-q01-p03-f2c35834ec.png", "9701-experimental-skills/assets/9701-2025-on-54-q01-p04-ea6f819a4e.png", "9701-experimental-skills/assets/9701-2025-on-54-q01-p05-5aaa5ba407.png" ], "answer": { "status": "pending", "id": "9701-2025-on-54-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 A student uses a technique called the Winkler method to determine the mass of oxygen dissolved\nSIHT\nin a sample of water from a lake.\nNI\nETIRW\nTwo solutions, X and Y, are prepared.\nTON dm–3 manganese(II) aqueous sulfate, MnSO (aq). Solution X is 2.30 mol\n4\nOD\nSolution Y is alkaline aqueous potassium iodide, KI(aq).\nmanganese(II) sulfate, MnSO •H O(s), needed to make (a) Calculate the mass of solid hydrated\n4 2\ncm3 of solution X. 100.0\nNIGRAM\nGive your answer to two decimal places.\nSIHT\nNI\nETIRW\nTON\nOD\n•H O(s) = ...................................................... g [1] mass of MnSO\n4 2\nNIGRAM\n(b) The student is given a small beaker containing the mass of MnSO •H O(s) calculated in (a).\n4 2\ncm3 SIHT of solution X. Describe how the student should prepare exactly 100.0\nNI\nInclude the names and capacities of each piece of key apparatus used.\nETIRW\nWrite your answer using a series of numbered steps.\nTON\nOD ...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [3]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Solution Y is prepared as follows.\nSIHT\ncm3 cm3 NI of distilled water in a 250 beaker. step 1 Place 100\nETIRW\nstep 2 Add about 8 g of solid sodium hydroxide, NaOH(s), and stir to dissolve.\nTON\nstep 3 Cool the solution to room temperature using an ice‑bath.\nOD\nstep 4 Repeat steps 2 and 3 until a total of 32 g of NaOH(s) has been dissolved.\nstep 5 Dissolve about 14 g of potassium iodide, KI(s), into the solution formed in step 4.\nNIGRAM\n(i) Solution Y is corrosive.\nSIHT\nOther than wearing safety goggles, state one safety precaution that the student should\nNI\ntake when preparing solution Y.\nETIRW\n..................................................................................................................................... [1]\nTON\nOD (ii) Suggest why the solution is cooled in step 3.\n.......................................................................", "pdf_path": "9701-experimental-skills/print/9701-2025-on-54-q01-6472d15493.pdf" }, { "id": "9701-2025-on-54-q02", "subject": "9701", "year": 2025, "session": "Oct/Nov", "session_code": "on", "paper": 5, "variant": "54", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2025-oct-nov/9701_w25_qp_54.pdf?download=true", "source_pages": [ 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2025-Oct-Nov/qp/9701_w25_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2025-on-54-q02-p01-d50b0c2770.png", "9701-experimental-skills/assets/9701-2025-on-54-q02-p02-7d0aced4c1.png", "9701-experimental-skills/assets/9701-2025-on-54-q02-p03-55b9fdd9c7.png", "9701-experimental-skills/assets/9701-2025-on-54-q02-p04-c5fc855bdf.png", "9701-experimental-skills/assets/9701-2025-on-54-q02-p05-99258fa4f1.png", "9701-experimental-skills/assets/9701-2025-on-54-q02-p06-2888ceac98.png" ], "answer": { "status": "pending", "id": "9701-2025-on-54-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:8)(cid:44)\n2 A student uses the following method to investigate the kinetics of the reaction between iodine and\nSIHT\ntin(IV) iodide, SnI . tin to produce\n4\nNI\nETIRW\nstep 1 Rinse a block of tin with distilled water and then rinse it with propanone.\nTON cm3 dm–3 of a 0.400 mol solution of iodine dissolved in methylbenzene in a step 2 Place 50\ncm3 beaker. 100\nOD\nstep 3 S uspend the block of tin from a three decimal place balance as shown in Fig. 2.1. Start a\ntimer.\nNIGRAM\nstep 4 Record the balance reading every 100 seconds.\nbalance SIHT\nNI\nETIRW\n4.979\nTON\nOD\nwire\nNIGRAM\nSIHT\niodine dissolved\nNI\nin methylbenzene\nETIRW\nblock of tin\nTON\nOD\nFig. 2.1\nNIGRAM\n(a) (i) Suggest why the student rinses the block of tin with propanone after rinsing it with\ndistilled water in step 1.\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Suggest why water is not used as the solvent for iodine.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Suggest why a three decimal place balance is more suitable than a two decimal place\nSIHT\nbalance for this experiment.\nNI\nETIRW\n..................................................................................................................................... [1]\nTON (iv) Suggest a control experiment that could be used to verify that the loss in mass of tin is\ncaused by reaction with iodine and not any other factor.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\n(b) The student’s results are shown in Table 2.1. SIHT\nNI\nComplete Table 2.1.\nETIRW\nTable 2.1\nTON\nOD\ntotal mass of tin\ntime / s balance reading / g\nreacted / g\n0 4.979 0.000\nNIGRAM\n100 4.910\nSIHT\nNI\n200 4.859\nETIRW\nTON 300 4.761\nOD\n400 4.688\n500 4.620 NIGRAM\n[1]\nSIHT\nNI\n(c) (i) Use the results from Table 2.1 to plot a graph on the grid in Fig. 2.2 to show the\nETIRW\nrelationship between total mass of tin reacted and time.\nTON\nUse a cross (×) to plot each data point. Draw a straight line of best fit.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n0.40\nSIHT\nNI\nETIRW\n0.35\nTON\nOD\n0.30\nNIGRAM\nSIHT 0.25\nNI\nETIRW\ntotal mass\nTON 0.20 of tin\n/ g reacted\nOD\n0.15\nNIGRAM\nSIHT\n0.10\nNI\nETIRW\nTON\n0.05\nOD\n0.00\nNIGRAM 100 200 300 400 500 0\n/ s time\nSIH", "pdf_path": "9701-experimental-skills/print/9701-2025-on-54-q02-f04ceccdd0.pdf" }, { "id": "9701-2026-m-42-q01", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 23, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 3, 4, 5, 6, 7 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2026-m-42-q01-p01-ec270c10ee.png", "9701-topic-23-chemical-energetics/assets/9701-2026-m-42-q01-p02-bc1d52930e.png", "9701-topic-23-chemical-energetics/assets/9701-2026-m-42-q01-p03-7da6e263e5.png", "9701-topic-23-chemical-energetics/assets/9701-2026-m-42-q01-p04-e5ecdc1106.png", "9701-topic-23-chemical-energetics/assets/9701-2026-m-42-q01-p05-ef44157a9b.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:4)(cid:44)\n1 Chromium is a transition element that forms coloured compounds.\nSIHT\nNI (a) (i) Define transition element.\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [1]\nOD\n(ii) Complete the electrons-in-boxes diagram to show the electronic configuration of an\nisolated gaseous chromium atom.\nNIGRAM\n3d 4s 4p\nSIHT [Ar]\nNI [1]\nETIRW\norbital in Figure 1.1. (iii) Sketch the shape of a 3d\nz²\nTON\nz\nOD\ny\nNIGRAM\nx\nSIHT\nNI\nETIRW\nTON\nOD\nFigure 1.1\n[1]\nNIGRAM\n(iv) State two reasons that explain why chromium compounds can behave as catalysts.\nSIHT 1 ........................................................................................................................................\nNI\n........................................................................................................................................... ETIRW\n2 ........................................................................................................................................\nTON\nOD\n...........................................................................................................................................\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(b) Table 1.1 lists standard electrode potentials, E ⦵, for some electrode reactions of chromium\nSIHT\nand other species.\nNI\nETIRW\nTable 1.1\nTON\nelectrode reaction E / V ⦵⦵\nOD\nCr2+(aq) 2e– – 0.91 Cr(s) +\nCr2+(aq) Cr3+(aq) e– – 0.41 +\ne– OH–(aq) –1.26 (s) + Cr(OH) (s) + Cr(OH) NIGRAM\n3 2\n2Cr3+(aq) 14H+(aq) 6e– 2–(aq) +1.33 + 7H O(l) O + + Cr\n2 2 7\nSIHT\n5OH–(aq) 3e– 2–(aq) – 0.13 Cr(OH) (s) + + 4H O(l) + CrO\n3 2 4\nNI\n4H+(aq) 4e– +1.23 (g) + + 2H O(l) O ETIRW\n2 2\n4OH–(aq) 4e– +0.40 (g) + 2H O(l) + O\n2 2 TON\nOD\n⦵, including a description of standard conditions. (i) Define standard electrode potential, E\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n...........................................................................................................................................\nSIHT\nNI ..................................................................................................................................... [2]\nETIRW\nCr2+(aq) need (ii) Explain fully, with reference to relevant data in Table 1.1, why solutions of\nTON to be stored in an atmosphere of argon instead of in air.\nOD\n...........................................................................................................................................\n........................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2026-m-42-q01-7e33fb8457.pdf" }, { "id": "9701-2026-m-42-q02", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 8, 9, 10 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-m-42-q02-p01-3ea5a0a549.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-m-42-q02-p02-b6d359ee27.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-m-42-q02-p03-fd0d24fe1b.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q02", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n–, manganate(VII) is used in chemistry as an oxidising agent. 2 The ion, MnO\nSIHT 4\n– NI as a reagent. Three reactions each involve MnO\n4 ETIRW\n5Fe2+ 8H+ Mn2+ 5Fe3+ – + + + + 4H O reaction 2 MnO\n4 2\nTON\nH CH + 3[O] C H O + H O reaction 3 C\nOD 6 5 3 7 6 2 2\n16H+ 5Mn3+ – + 4Mn(OH) + + 12H O reaction 4 MnO\n2 4 2\nFe2+(aq). Reaction 2 can be used to determine the percentage of (a) Oxygen slowly oxidises\nNIGRAM\nFe2+(aq) that is oxidised over a certain time.\ncm3 SIHT solution using 17.70 g of FeSO •7H O. After one week, the A student prepares a 250\n4 2\ncm3 portions of this solution with acidified KMnO (aq) of concentration student titrates 25.0\n4 NI\ndm–3. 0.0500 mol\nETIRW\ncm3. The average titre is 23.80\nTON\nFe2+ OD ions in the original sample that were oxidised during (i) Calculate the percentage of\none week.\n: FeSO •7H O, 277.9] [M\nr 4 2\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nFe2+ percentage of ions oxidised = ..................................................... % [3]\nTON\n(ii) Explain why an indicator is not needed in this titration.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) Reaction 3 uses hot alkaline KMnO as the reagent. The reaction mixture is then acidified.\nSIHT 4\nNI H O , of reaction 3. Draw the structure of the organic product, C\n7 6 2\nETIRW\nTON\nOD\nNIGRAM\n[1]\nSIHT\n(c) Reaction 4 is called a reverse disproportionation reaction.\nNI\nETIRW\nSuggest the meaning of reverse disproportionation. Use oxidation numbers to explain\nyour reasoning.\nTON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n............................................................................................................................................. [2]\nSIHT\nNI\nETIRW 10–3 dm–3 in water is 3.20 × g at 298 K. (d) The solubility of Mn(OH)\n2\nTON , of Mn(OH) . (i) Write an expression for the solubility product, K\nsp 2\nOD\nK =\nsp\n[1]\nNIGRAM\nof Mn(OH) at 298 K. State its units. (ii) Calculate the value of K\nsp 2\nSIHT\nNI\nETIRW\nTON\nOD\nvalue of K = ...............................................................\nsp NIGRAM\nunits ...............................................................\n[3] SIHT\nNI\nETIRW\nNIGRAM\nMn3+(aq) (e) (i) ions are coloured. Explain why.\nSIHT\nNI ...................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-m-42-q02-8e47f22fe7.pdf" }, { "id": "9701-2026-m-42-q03", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 11, 12, 13 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2026-m-42-q03-p01-09d7a506e4.png", "9701-topic-25-equilibria/assets/9701-2026-m-42-q03-p02-884f9c750c.png", "9701-topic-25-equilibria/assets/9701-2026-m-42-q03-p03-112471bbc3.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q03", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:2)(cid:44)\n3 Figure 3.1 shows a reaction scheme starting from 4-hydroxybutanoic acid.\nSIHT\n4-hydroxybutanoic acid NI\nETIRW\nO\nTON HO\nOH\nOD\nexcess [O]\nH+(aq) H+(aq) NIGRAM\nPCl\n5\nSIHT\nNI\nG H J butanedioic acid\nETIRW\nC H O (C H O ) HOOC(CH ) COOH\n4 6 2 4 6 2 n 2 2\nTON\nOD\nFigure 3.1\n(a) Under acidic conditions, 4-hydroxybutanoic acid exists in equilibrium with compound G,\nH O , and water. G does not react with Na. C\n4 6 2 NIGRAM\n4-hydroxybutanoic acid can also react to form condensation polymer H, which has\nH O ) . formula (C\nSIHT 4 6 2 n\nNI Draw the structures of G and H. Show only one repeat unit of H.\nETIRW\nG, C H O H, (C H O )\nTON 4 6 2 4 6 2 n\nOD\nNIGRAM\nSIHT\nNI\n[2] ETIRW\nTON\n(b) Construct an equation for the reaction of 4-hydroxybutanoic acid with an excess of PCl ,\n5\nOD\nforming J.\nNIGRAM\n............................................................................................................................................. [2]\nSIHT\nNI\nETIRW\nNIGRAM\n10–5 dm–3 (c) 4-hydroxybutanoic acid, HO(CH ) COOH, is a weak acid with K = 1.91 × mol\nSIHT 2 3 a\nat 25 °C.\nNI\nETIRW dm–3 solution of HO(CH ) COOH at 25 °C. (i) Calculate the pH of a 0.150 mol\n2 3\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\npH = ......................................................... [2]\nTON ) COOH(aq) is mixed with its conjugate base, a buffer solution can form. (ii) When HO(CH\n2 3\nOD\nDefine buffer solution.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ..................................................................................................................................... [2]\nNI\n) COOH. (iii) State the structural formula of the conjugate base of HO(CH\nETIRW 2 3\n..................................................................................................................................... [1]\nTON\ncm3 dm–3 OD of 0.150 mol (iv) A student makes a buffer solution by reacting 25.0\ncm3 dm–3 ) COOH with 10.0 of 0.200 mol NaOH(aq). HO(CH\n2 3\nCalculate the pH of this buffer solution.\nNIGRAM\n10–5 dm–3 of HO(CH ) COOH = 1.91 × mol at 25 °C. K\na 2 3\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\npH of buffer solution = ......................................................... [3]\nNI\nETIRW\nTON\nNIGRAM\n(d) 4-hydroxybutanoic acid, HO(CH ) COOH, can be used to produce butanedioic\nSIHT 2 3\n) COOH. acid, HOOC(CH\n2 2\nNI\nETIRW\nSuggest a suitable reagent and conditions for this reaction.\nTON ............................................................................................................................................. [1]\nOD\n, of butanedioic acid (e) A student does an experiment to determine the partition coefficient, K\npc\nbetween the immiscible solvents et", "pdf_path": "9701-topic-25-equilibria/print/9701-2026-m-42-q03-5fe8f6ad50.pdf" }, { "id": "9701-2026-m-42-q04", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 33, "topic": "Carboxylic acids and derivatives", "topic_slug": "9701-topic-33-carboxylic-acids-and-derivatives", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 14, 15, 16 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2026-m-42-q04-p01-b5a8d060dd.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2026-m-42-q04-p02-e4b18e7169.png", "9701-topic-33-carboxylic-acids-and-derivatives/assets/9701-2026-m-42-q04-p03-e4e2e20519.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q04", "html": "9701-topic-33-carboxylic-acids-and-derivatives/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n4 A student performs a series of experiments to investigate the chemistry of the ester\nSIHT\nCOOCH . methyl ethanoate, CH\n3 3\nNI\nETIRW\nCOOCH is hydrolysed under acidic conditions. (a) CH\n3 3\nH+(aq)\nTON COOCH (aq) + H O(l) CH COOH(aq) + CH OH(aq) reaction 5 CH\n3 3 2 3 3\nOD\nThe rate of reaction 5 is investigated.\nH+(aq) is added to a dilute solution of CH COOCH (aq). The graph in A small amount of\n3 3\nCOOCH ] changes with time. Figure 4.1 shows how [CH\nNIGRAM 3 3\n0.25\nSIHT\nNI\nETIRW\n0.20\nTON\nOD\n0.15\n[CH COOCH ]\n3 3 NIGRAM\ndm–3 / mol\n0.10\nSIHT\nNI\nETIRW\n0.05\nTON\nOD\n0.00\n2500 5000 7500 10 000 12 500 15 000 0\nNIGRAM / s time\nFigure 4.1\nSIHT\nNI COOCH ]. (i) Use Figure 4.1 to show that reaction 5 is first order with respect to [CH\n3 3 ETIRW\nShow any working fully and explain your reasoning.\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ndm–3 s–1. (ii) Use Figure 4.1 to calculate the initial rate of reaction in mol\nSIHT\nNI\nETIRW\nTON\nOD\ndm–3 s–1 initial rate of reaction = ..................................... mol [1]\n[H+(aq)]. (iii) Reaction 5 is first order with respect to\nNIGRAM\nUse this statement and information from 4(a)(i) to construct the overall rate equation for\nSIHT the hydrolysis reaction.\nNI\nState the units of the rate constant, k, of this reaction.\nETIRW\nTON\nOD\nrate = ...............................................................\nNIGRAM\nunits of k = ...............................................................\n[2]\nSIHT\nNI COOCH , forms when CH OH reacts with either CH COCl (b) Methyl ethanoate, CH\n3 3 3 3 ETIRW\nCOOH. or CH\n3\nTON\nTable 4.1\nOD\nreaction reactants products\nCOCl (l) and CH OH(l) CH COOCH (l) and HCl (g) 6 CH\n3 3 3 3\nNIGRAM\nCOOH(l) and CH OH(l) CH COOCH (l) and H O(l) 7 CH\n3 3 3 3 2\nSIHT\nCOOCH than reaction 7. (i) Suggest why reaction 6 gives a higher yield of CH\n3 3 NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n.......................................................................................", "pdf_path": "9701-topic-33-carboxylic-acids-and-derivatives/print/9701-2026-m-42-q04-3af5fe04b0.pdf" }, { "id": "9701-2026-m-42-q05", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 18, 19, 20, 21 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2026-m-42-q05-p01-a0b82bbb39.png", "9701-topic-36-organic-synthesis/assets/9701-2026-m-42-q05-p02-2153547ca4.png", "9701-topic-36-organic-synthesis/assets/9701-2026-m-42-q05-p03-f6cc1e5e18.png", "9701-topic-36-organic-synthesis/assets/9701-2026-m-42-q05-p04-dd3b225974.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q05", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n5 (a) 4-methylphenol can be synthesised from methylbenzene in three steps, as shown\nSIHT\nin Figure 5.1.\nNI\nETIRW M methylbenzene\nand conc. HNO\n3 NO\nconc. H SO 2 TON\n2 4\nOD step 1\nH C H C\n3 3\nhot Sn and conc. HCl\nNIGRAM step 2\nthen NaOH\nSIHT\nN 4-methylphenol NI\nETIRW\nNH OH\n2\nTON\nstep 3\nC H C H OD\n3 3\nFigure 5.1\nNIGRAM\n+ electrophile. (i) In step 1, methylbenzene reacts with the NO\n2\n+. Write an equation for the formation of NO SIHT\n2\nNI ..................................................................................................................................... [1]\nETIRW\n+ with methylbenzene. (ii) Draw the mechanism for the reaction, in step 1, of NO\n2 TON\nInclude all relevant curly arrows and charges. Draw the organic intermediate. Include OD\nthe by-product of the reaction on the dotted line.\norganic intermediate\nNIGRAM\nM\nNO\nSIHT 2\nNI\nETIRW\nH C H C\n3 3\nTON\n+ ...................\nOD\n[3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) 1-methyl-4-nitrobenzene, CH C H NO , is reduced in step 2.\nSIHT 3 6 4 2\nNI Write an equation for step 2.\nETIRW\nUse [H] to represent one atom of hydrogen from the reducing agent.\nTON\n..................................................................................................................................... [1]\nOD\n(iv) Step 3 is a two-stage process. Identify the reagents and conditions necessary for the\ntwo stages.\nNIGRAM\n1 ........................................................................................................................................\nSIHT 2 ........................................................................................................................................\n[2]\nNI\nETIRW\n(v) A student suggests an alternative synthesis of 4-methylphenol from nitrobenzene.\nThe student decides to use a Friedel–Crafts alkylation reaction as the first step, as\nTON\nshown in Figure 5.2.\nOD\nnitrobenzene M\nNO NO\n2 2\nNIGRAM\nH C\n3\nSIHT\nFigure 5.2\nNI\nETIRW\nSuggest the reagents for this Friedel–Crafts alkylation reaction.\nTON\nExplain why this reaction will produce a low yield of 1-methyl-4-nitrobenzene.\nOD\nreagents ............................................................................................................................\nexplanation ........................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI [2]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(b) The structures of three different phenols are shown in Figure 5.3.\nSIHT\n4-methylphenol 2-ethylphenol phenol NI\nETIRW\nOH OH OH\nTON\nC H C H OD\n2 5 3\nFigure 5.3\nNIGRAM\nA mixture of these thre", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2026-m-42-q05-bef9ac1ccf.pdf" }, { "id": "9701-2026-m-42-q06", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-42.pdf?download=true", "source_pages": [ 22, 23, 24, 25, 27, 28 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p01-e6bb909f14.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p02-7d42743acf.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p03-001123af33.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p04-a749e7bf31.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p05-a97945b99b.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-m-42-q06-p06-de47825d3e.png" ], "answer": { "status": "pending", "id": "9701-2026-m-42-q06", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:3)(cid:44)\n6 (a) Glutathione is a naturally occurring compound.\nSIHT\nglutathione NI\nETIRW\nSH\nO O O\nTON H\nN\nOD HO OH N\nH\nO NH\n2\nNIGRAM\nGlutathione is hydrolysed to form three amino acids.\nNCH(CH SH)COOH. One of the amino acids is cysteine, H\nSIHT\n2 2\nNI (i) Draw the structures of the two other amino acids that are formed by this hydrolysis.\nETIRW\nTON\nOD\nNIGRAM\nSIHT [2]\nNI\n(ii) Cysteine has an isoelectric point of 5.0.\nETIRW\nExplain what is meant by isoelectric point.\nTON\nOD ...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM (iii) Draw the structure of cysteine at its isoelectric point.\nSIHT\nNI\nETIRW\nTON\nOD\n[1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) X, Y and Z are other amino acids that contain sulfur. Table 6.1 gives some details of these\nSIHT\nthree compounds.\nNI\nETIRW\nTable 6.1\nTON\nZ X Y\nOD\nO O O\namino acid\nCH S\n3 HS OH CH S OH OH\n3\nNIGRAM\nNH NH NH\n2 2 2\nSIHT\nM 135.1 149.1 149.1\nr\nNI\nisoelectric point 6.0 5.7 4.9\nETIRW\nA mixture of these three amino acids, X, Y and Z, is analysed by electrophoresis, using a\nTON\nbuffer solution at pH 5.5.\nOD\n– +\nNIGRAM\nSIHT\nmixture applied here\nNI\nETIRW\nFigure 6.1\nTON\nDraw and label three spots on Figure 6.1 to indicate the predicted position of each of these\nOD three amino acids, X, Y and Z, after electrophoresis at pH 5.5.\nExplain your answer.\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n[3]\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\nZ– (c) Anion is a bidentate ligand.\nSIHT\nNI Z–\nETIRW\nO\nCu2+(aq) octahedral\nTON\ncomplex C\nO– HS\nOD\nNH\n2\n(i) Define bidentate ligand. NIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n.....................................................................................................................................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-m-42-q06-e1001bc463.pdf" }, { "id": "9701-2026-m-52-q01", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 18, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-52.pdf?download=true", "source_pages": [ 2, 3, 4, 5, 6 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-m-52-q01-p01-62b4c5ae27.png", "9701-experimental-skills/assets/9701-2026-m-52-q01-p02-0be4c896ec.png", "9701-experimental-skills/assets/9701-2026-m-52-q01-p03-1135fcd65a.png", "9701-experimental-skills/assets/9701-2026-m-52-q01-p04-f5ac0024fb.png", "9701-experimental-skills/assets/9701-2026-m-52-q01-p05-6b05de7c43.png" ], "answer": { "status": "pending", "id": "9701-2026-m-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "KCl NaCl Solid is a mixture of three salts, potassium chloride, , sodium chloride, , and 1 X\n, only. sodium nitrate, NaNO\n3\nThe mass of each substance in is investigated by two experiments. In each experiment, X\na different ion is precipitated out of an aqueous solution of X. The mass of each precipitate\nis measured.\nA student weighs a sample bottle containing and transfers into a small beaker. (a) X X\nThe student reweighs the sample bottle.\nThe measurements are shown in Table 1.1.\nTable 1.1\nmass of sample bottle and / g 7.235 X\nmass of sample bottle after transfer / g 6.035\nmass of transferred to small beaker / g X\nComplete Table 1.1 to determine the mass of in the small beaker. [1] X\nCalculate the percentage error in the measurement of the mass of the sample bottle (b) (i)\nand shown in Table 1.1. X\nShow your working.\npercentage error = ..................................................... % [1]\nWithout changing any apparatus, suggest how the percentage error calculated in (ii) 1(b)(i)\ncan be reduced.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n3 of an aqueous solution of Describe the steps the student should take to prepare 250.0 cm (c)\nX, starting from the mass of calculated in supplied in the small beaker. X 1(a)\nGive the name and capacity of any apparatus used.\nWrite your answer using a series of numbered steps.\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\nAqueous sodium tetraphenylborate, NaB(C H ) (aq), reacts with aqueous potassium ions to (d)\n6 5 4\nform a precipitate.\nThe ionic equation for this reaction is shown.\nK+(aq) –(aq) H ) + KB(C H ) (s) B(C\n6 5 4 6 5 4\nH ) (s) is an irritant. KB(C\n6 5 4\nFigure 1.1 shows a Gooch crucible with a porous glass disc. The porous glass disc acts as a\nfine filter to separate the precipitate from the aqueous reaction mixture.\nporous\nglass disc\nGooch crucible\nFigure 1.1\nThe solution formed from solid in is labelled solution X. X 1(c)\nIn the first expe", "pdf_path": "9701-experimental-skills/print/9701-2026-m-52-q01-4bccff1000.pdf" }, { "id": "9701-2026-m-52-q02", "subject": "9701", "year": 2026, "session": "March", "session_code": "m", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 12, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-march/9701-chemistry-march-2026-question-paper-52.pdf?download=true", "source_pages": [ 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2026-March/qp/9701_m26_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-m-52-q02-p01-c524a3003d.png", "9701-experimental-skills/assets/9701-2026-m-52-q02-p02-8a14bfba84.png", "9701-experimental-skills/assets/9701-2026-m-52-q02-p03-9d0e0b8111.png", "9701-experimental-skills/assets/9701-2026-m-52-q02-p04-c01af78d19.png", "9701-experimental-skills/assets/9701-2026-m-52-q02-p05-0d2e34a08e.png" ], "answer": { "status": "pending", "id": "9701-2026-m-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "Blood plasma contains a number of different cations. Many of these cations emit a different 2\ncolour of light when placed in a flame.\nFlame emission photometry is a method of determining the concentration of cations in a sample\nusing the intensity of light emitted.\nK+ In an experiment, a sample of blood plasma is placed into a colourless flame. ions in the\nblood plasma absorb energy from the flame and emit light with a lilac colour. The intensity of the\nlight emitted is measured.\nK+ ions in the sample, a calibration graph showing the To determine the concentration of\nK+ ions and light intensity is required. relationship between known concentration of\nKCl A solution of potassium chloride, (aq), is prepared. (a)\nK+, dm–3. in this solution is 0.100 g The concentration of aqueous potassium ions,\nKCl Different volumes of the solution of (aq) are taken and diluted by adding specific\nvolumes of distilled water to prepare solutions of specific concentrations.\n[K+(aq)] Each prepared solution of known is tested using flame emission photometry.\nTable 2.1 shows the relative light intensity measured for each prepared solution.\nTable 2.1\n+ volume of volume of distilled [K (aq)] relative\n3 3 KCl –3 (aq) / cm water added / cm light intensity / g dm\n10–3 × 0.0 0.00 50.00 0.00\n10–3 × 2.1 0.50 1.00\n10–3 × 4.2 1.00 2.00\n10–3 × 6.7 1.50 3.00\n10–3 × 8.8 2.00 4.00\n10–3 × 11.0 2.50 5.00\n10–3 × 11.2 3.00 6.00\n10–3 × 15.7 3.50 7.00\n10–3 × 17.1 4.00 8.00\n10–3 × 17.1 4.50 9.00\n10–3 × 17.1 5.00 10.00\nComplete Table 2.1 to show the volume of distilled water added to make each prepared (i)\n[K+(aq)]. [1] solution of known\nIdentify a suitable piece of apparatus for adding the distilled water. (ii)\n..................................................................................................................................... [1]\nIdentify the dependent variable in this experiment. (iii)\n..................................................................................................................................... [1]\nPlot a calibration graph on the grid in Figure 2.1 to show the relationship between (iv)\n[K+(aq)] and relative light intensity.\nUse a cross (×) to plot each data point.\n[K+(aq)] 10–3 10–3 dm–3. × × Draw line of best fit for from 0.00 to 7.00 g one\n[K+(aq)] 10–3 × from 8.00 to Draw a second line of best fit for\n10–3 dm–3. × g Extend both lines so they meet. 10.00\n18\n16\n14\n12\n10\nrelative\nlight intensity\n8\n6\n4\n2\n0\n8.00 10.00 12.00 0.00 2.00 4.00 6.00\n[K+(aq)] 10–3 dm–3 / g\n[2] Figure 2.1\n[K+(aq)] 10–3 10–3 dm–3 × × Describe how the graph shows that from 0.00 to 7.00 g is (v)\ndirectly proportional to relative light intensity.\n..................................................................................................................................... [1]\nCircle the most anomalous point on your graph in Figure 2.1. Suggest reason to (vi) one\nexplain the anomalous point you have circled.\n......................................................................", "pdf_path": "9701-experimental-skills/print/9701-2026-m-52-q02-9f2f954c5e.pdf" }, { "id": "9701-2026-mj-41-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2026-mj-41-q01-p01-a6b41173ea.png", "9701-topic-23-chemical-energetics/assets/9701-2026-mj-41-q01-p02-bd6777d9b8.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "ΔH Write the equation to represent the lattice energy, , of calcium sulfide, CaS. 1 (a)\nlatt\nInclude state symbols.\n............................................................................................................................................. [2]\nΔH of CaS is negative. Explain why the value of (b)\nlatt\n...................................................................................................................................................\n............................................................................................................................................. [1]\nKCl, ΔH values of CaS, MgO and from most negative to State the order of the (c)\nlatt\nleast negative.\nExplain your answer.\n............................. ............................. .............................\nmost negative least negative\nexplanation ................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[3]\n–(g) Mg2+(g) Cl ΔH , of or is the energy change when one The enthalpy change of formation, (d)\nf\nmole of gaseous ions forms from the element in its standard state at 298 K.\n–(g) mol–1 Cl = –243 kJ enthalpy change of formation of chloride ions,\nMg2+(g) mol–1 enthalpy change of formation of magnesium ions, = +2336 kJ\n–(g) Cl The enthalpy change of formation of can be calculated using two energy (i)\nchanges only.\nIdentify the energy changes. two\n...........................................................................................................................................\n..................................................................................................................................... [1]\nmol–1. MgCl The lattice energy of magnesium chloride, , is –2493 kJ (ii)\n2\nUse this value, and other data given, to calculate the enthalpy change of formation, in\nmol–1, MgCl of (s). kJ\n2\nmol–1 MgCl ΔH of (s) = ............................................ kJ [2]\nf 2\nMagnesium carbonate, MgCO , decomposes when heated. (e)\n3\nK–1 mol–1 ΔS MgO + CO = +175 J MgCO\n3 2\nmol–1 ΔH = +117 kJ\n°C. Predict whether the decomposition of MgCO is feasible at 600\n3\nUse a calculation to explain your answer.\nfeasibility ...............................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2026-mj-41-q01-6fcc0603b0.pdf" }, { "id": "9701-2026-mj-41-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2026-mj-41-q02-p01-c8ecb5c702.png", "9701-topic-25-equilibria/assets/9701-2026-mj-41-q02-p02-da7f71eb4b.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "Define pH mathematically. 2 (a) (i)\npH = ......................................................... [1]\nmathematically. Define K (ii)\nw\n= ......................................................... [1] K\nw\ncm3 dm–3 Solution is 100 of an aqueous solution of 0.105 mol butanoic acid, (b) A\nCH CH COOH. has pH 2.90 at 298 K. CH A\n3 2 2\ndm–3, H+(aq) of in A. Calculate the concentration, in mol (i)\n[H+ dm–3 ] in = .......................................... mol [1] A\nof CH CH CH COOH at 298 K. Calculate the value of K (ii)\na 3 2 2\nK of CH CH CH COOH = ......................................................... [1]\na 3 2 2\ncm3 dm–3 Solution is 100 of an aqueous solution containing 0.450 mol CH CH CH COOH. (c) B\n3 2 2\ncm3 of an aqueous solution containing sodium butanoate, Solution is 200 C\nCH CH COONa. CH\n3 2 2\ncm3 H+ of solution D. The concentration of ions in is is added to to produce 300 D B C\n10–5 dm–3. × mol 6.31\nCH CH COONa in C. Calculate the concentration of CH (i)\n3 2 2\n10–5 × as the value (If you were unable to calculate an answer in 2(b)(ii), then use 3.00\nof CH CH CH COOH. This is the correct answer.) of K not\na 3 2 2\ndm–3 [CH CH CH COONa] in = .......................................... mol [3] C\n3 2 2\nSO (aq) is added to D. Write an equation for the reaction when H (ii)\n2 4\n..................................................................................................................................... [1]\nWrite an equation for the reaction when KOH(aq) is added to D. (iii)\n..................................................................................................................................... [1]\nCCl CH COOH, and butanoic Predict the relative acidities of 2,2-dichlorobutanoic acid, CH (d)\n3 2 2\nCH CH COOH. acid, CH\n3 2 2\nExplain your answer.\nstronger acid .............................................................................................................................\nexplanation ...............................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n[2]\n[Total: 11]", "pdf_path": "9701-topic-25-equilibria/print/9701-2026-mj-41-q02-c89e2f56d7.pdf" }, { "id": "9701-2026-mj-41-q03", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-41-q03-p01-5808188733.png", "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-41-q03-p02-23ddd8e4c1.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "Nitrogen monoxide reacts with hydrogen to produce nitrogen and water. 3\nN + 2H O 2NO + 2H\n2 2 2\nThe rate equation for this reaction is shown.\n2[H ] rate = k [NO]\n2\nTwo experiments are carried out to investigate this reaction.\nComplete Table 3.1. (a)\nTable 3.1\norder with respect to [NO]\n] order with respect to [H\n2\noverall order\n[1]\n10–10 dm–3 s–1 × In experiment 1, the rate of the reaction is 2.80 mol when [NO] is (b)\n10–2 dm–3 10–2 dm–3. × × mol and [H ] is 8.00 mol 5.00\n2\nCalculate the value of the rate constant, k, in experiment 1. State the units of k.\nk = ...............................................................\nunits = ...............................................................\n[2]\nExperiment 2 is carried out under different conditions from experiment 1. The value of k for (c)\n10–5. × experiment 2 is 2.13\n10–3 dm–3. × ] is 1.20 mol In experiment 2, a large excess of NO is used. The initial value of [H\n2\n] against time for experiment 2 shows that the reaction has a A graph of [H (i)\n2\nconstant half-life.\nExplain why the graph shows a constant half-life, referring to:\n• the overall order of the reaction under these conditions\n• the reason why this is the overall order under these conditions.\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [1]\nCalculate the half-life, in s, of the reaction in experiment 2 and state the time taken, in s, (ii)\n10–5 dm–3. × ] to fall to 7.50 mol for the value of [H\n2\nhalf-life = ............................................................. s\n10–5 dm–3 × ] to fall to 7.50 mol = ............................................................. s time taken for [H\n2\n[2]\nThe overall reaction of nitrogen monoxide with hydrogen has a three-step mechanism. (d)\nN + 2H O 2NO + 2H\n2 2 2\nPart of this mechanism is shown.\nN O 2NO step 1\n2 2\n................................. ................................. step 2\nO + H N + H O N step 3\n2 2 2 2\nComplete the mechanism by writing an equation for step 2. [2] (i)\nIt can be deduced that step 1 is the rate-determining step of the reaction. (ii) not\nExplain why.\n...........................................................................................................................................\n..................................................................................................................................... [1]\n[Total: 9]", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2026-mj-41-q03-fffe4e3a1c.pdf" }, { "id": "9701-2026-mj-41-q04", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 4, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2026-mj-41-q04-p01-61174b516c.png", "9701-topic-24-electrochemistry/assets/9701-2026-mj-41-q04-p02-5084c27df7.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q04", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "Some electrode potentials are given in Table 4.1. 4\nTable 4.1\nelectrode reaction E / V\n⦵⦵\n2e– – 2Cl Cl +1.36 +\n2\nCu2+ 2e– +0.34 + Cu\ne– OH– – 0.56 + Fe(OH) + Fe(OH)\n3 2\nFe3+ e– Fe2+ +0.77 +\nV2+ 2e– –1.13 + V\nV3+ e– V2+ – 0.26 +\nComplete the equation that can be used to calculate the standard Gibbs free energy change, (a)\nΔG , for a cell reaction using the standard cell potential, E .\ncell\n⦵ ⦵\nΔG =\n⦵\n[1]\nV3+ V2+ Cu2+ An electrochemical cell is set up using a / electrode and a / Cu electrode, both (b)\nunder standard conditions.\n. Write an equation for the cell reaction that occurs and calculate the value for E\ncell\n⦵\nequation ....................................................................................................................................\n= ............................................................ V E\ncell\n⦵\n[2]\nFe3+ Fe2+ Identify atoms or ions from Table 4.1 that will reduce to under neutral (c) two\nto Fe(OH) under alkaline conditions. conditions, but will reduce Fe(OH) not\n3 2\n.............................................................. and ....................................................................... [2]\nIdentify the strongest oxidising agent and the strongest reducing agent in Table 4.1. (d)\nstrongest oxidising agent ...............................................................\nstrongest reducing agent ...............................................................\n[2]\nA dilute solution of NaOH(aq) is electrolysed using inert electrodes. (e)\nA steady current of 2.40 A is passed for 2.00 hours.\nCalculate the mass, in g, of oxygen that is released at the anode.\nmass of oxygen = ....................................................... g [3]\n[Total: 10]", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2026-mj-41-q04-dd8bfbfbb9.pdf" }, { "id": "9701-2026-mj-41-q05", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-41-q05-p01-4b5fb07d52.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-41-q05-p02-7a15a699d6.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "Co2+ Cobalt is a transition element. It forms a wide range of coloured compounds that contain 5\nCo3+ ions. ions or\nExplain why a transition element, such as cobalt, has variable oxidation states in (a)\nits compounds.\n...................................................................................................................................................\n............................................................................................................................................. [1]\n2+ ion. Complete the electronic configurations of a Co atom and a Co (b)\nCo atom: [Ar] ...............................................................\n2+ ion: [Ar] ............................................................... Co\n[1]\nCo2+ Explain why compounds containing ions are coloured. (c)\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n...................................................................................................................................................\n............................................................................................................................................. [3]\ncobalt(II) chloride paper. A few drops of water are added to a piece of dry (d)\nDescribe the colour change that is seen. Write an equation for the reaction that causes this\ncolour change.\ncolour change: from ....................................................... to ......................................................\nequation ....................................................................................................................................\n[2]\nCopper is a transition element. (e)\n(aq). All the copper forms Cu(NO ) (aq). A piece of copper is added to HNO\n3 3 2\nKI(aq) ) (aq) in a conical flask. All the copper present An excess of is added to the Cu(NO\n3 2\nCuI. forms The equation for the reaction is shown.\n4I– – 2CuI I ) + + + 4NO reaction 1 2Cu(NO\n3 2 2 3\ndm–3 I The formed in this reaction is titrated with 0.200 mol Na S O (aq). The end-point of\n2 2 2 3\ncm3 of Na S O (aq) has been added. The equation for the titration is reached when 37.60\n2 2 3\nthe reaction is shown.\n2I– 2– 2– I O + S O + reaction 2 2S\n2 3 2 4 6\nDescribe observations that can be made about the contents of the conical flask (i) two\nKI(aq) ) (aq). after has been added to Cu(NO\n3 2\nobservation 1 ...............................................................................................................", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-41-q05-05211a3be3.pdf" }, { "id": "9701-2026-mj-41-q06", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-41-q06-p01-e6b8494d3e.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-41-q06-p02-63899f8006.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "2–, Transition elements form complexes with species called ligands. The ethanedioate ion, C O is 6\n2 4\na bidentate ligand.\nExplain what is meant by bidentate ligand. (a)\n...................................................................................................................................................\n............................................................................................................................................. [2]\n3+ 2– ion forms an octahedral complex with three C O ions. One Fe (b)\n2 4\nState the formula and charge of this complex. (i)\n..................................................................................................................................... [1]\nThis complex shows stereoisomerism. (ii)\nDraw three-dimensional diagrams to show all the stereoisomers of this complex.\n2– O ion can be represented using . The C O O\n2 4\n[2]\nState the type or types of stereoisomerism shown by this complex. (iii)\n..................................................................................................................................... [1]\nHg2+ I–, ]2–. [HgI ions and iodide ions, form a complex with the formula (c)\n4\n]2–. [HgI of State its units. Write the expression for K\nstab 4\nK =\nstab\nunits = ...............................................................\n[2]\n[Total: 8]", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-41-q06-934da7c71b.pdf" }, { "id": "9701-2026-mj-41-q07", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 7, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 14, 15, 16 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-41-q07-p01-55238c8a0b.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-41-q07-p02-fa76eebc6d.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-41-q07-p03-d775d0cc5e.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q07", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "Phenol, C H O, can be made from benzene, C H , in a four-step process, as shown in 7 (a)\n6 6 6 6\nFigure 7.1.\nstep 1 step 2 step 3 step 4\nCl H C H NO C H N C H N C H O C\n6 6 6 5 2 6 7 6 5 2 6 6\nFigure 7.1\nState the reagents and conditions for step 1. (i)\n..................................................................................................................................... [1]\nState the reagents and conditions for step 3. (ii)\n..................................................................................................................................... [1]\nCl H N formed in step 3. Name the compound C (iii)\n6 5 2\n..................................................................................................................................... [1]\nPhenol reacts with propanone in the presence of an acid catalyst to form compound G, as (b)\nshown in Figure 7.2.\nG\nOH\nOH\nH+ O\n+\nOH\nFigure 7.2\nsp2 sp3 and hybridised carbon atoms in Complete Table 7.1 to show the number of sp, (i)\npropanone and in G.\nTable 7.1\n2 3 sp sp sp\npropanone\nG\n[1]\nState the number of peaks in the carbon-13 NMR spectrum of G. (ii)\n..................................................................................................................................... [1]\nThe first stage of the mechanism for the reaction in Figure 7.2 involves the formation of (iii)\nion J.\nComplete the mechanism in Figure 7.3 to show the formation of by adding dipoles J\nand curly arrows, as appropriate.\nJ\n+ H\nH O\nO\n+\nFigure 7.3\n[1]\nThe next stage of the mechanism involves the reaction between and phenol to form (iv) J\nintermediate K. A proton is then lost from to produce G. K\nComplete Figure 7.4 to show these stages of the mechanism. Include relevant curly\narrows and charges.\nintermediate G K\nOH\nOH\nH+ H +\nO\n+\nOH\nFigure 7.4\n[3]\nH+(aq). Benzene is mixed with propanone in the presence of (v)\nPredict whether benzene reacts with propanone more readily, as readily or less readily\nthan phenol does under the same conditions.\nExplain your answer.\nBenzene reacts with propanone ....................................................... than phenol does.\nexplanation ........................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n[2]\nreacts with Br (aq) in the dark. The organic product of this reaction is compound H. (c) G\n2\nComplete the equation for this reaction in Figure 7.5. (i)\nH\nG\nOH\n+ 2 Br + .....................\n2\nOH\nFigure 7.5\n[2]\nName the mechanism for this reaction. (ii)\n..................................................................................................................................... [1]\n[Total: 14]", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2026-mj-41-q07-e32a275b70.pdf" }, { "id": "9701-2026-mj-41-q08", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q08-p01-fef60fe3e7.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q08-p02-16fec0b81c.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "Secondary amine can be made by the three-step synthesis shown in Figure 8.1. 8 M\nL\nstep 1 step 2\nCOCl CH COOH CH\n3 3\nstep 3\nM\nCH\n3\nCH CH NH CH\n3 2\nCH\n3\nFigure 8.1\nSOCl COOH with in step 1. Write an equation for the reaction of CH (a) (i)\n3 2\n..................................................................................................................................... [1]\nCOCl COOH to produce CH in step 1. State an alternative reagent that reacts with CH (ii)\n3 3\n..................................................................................................................................... [1]\nCompound is an amide. (iii) L\nDraw the structure of in Figure 8.1. [1] L\nCOCl in step 2. Draw the structure of the reagent added to CH (iv)\n3\n[1]\nName the mechanism of the reaction forming in step 2. (v) L\n..................................................................................................................................... [1]\nSuggest a reagent for step 3. (vi)\n..................................................................................................................................... [1]\n(1H) The proton NMR spectrum of dissolved in D O is obtained. Four of the proton (b) M\n2\nenvironments, r, s, and u, are labelled on the structure of in Figure 8.2. t M\nt\nCH r s 3\nu CH CH NH CH\n3 2\nCH\n3\nt\nFigure 8.2\nComplete Table 8.1 to identify the splitting patterns for proton environments r, s, (i) t\nand u.\nTable 8.1\nproton environment name of splitting pattern\nr\ns\nt\nu\n[2]\n1H) CDCl NMR spectrum of dissolved in is obtained. The proton ( M (ii)\n3\n(1H) NMR spectrum of State and explain how this spectrum differs from the proton M\nO. dissolved in D\n2\n...........................................................................................................................................\n...........................................................................................................................................\n...........................................................................................................................................\n..................................................................................................................................... [2]\n[Total: 10]", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-41-q08-ebe0ed1e15.pdf" }, { "id": "9701-2026-mj-41-q09", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "41", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-41.pdf?download=true", "source_pages": [ 20, 21, 22, 23, 24 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_41.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q09-p01-1793e879ba.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q09-p02-76f7ab6e37.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q09-p03-ea9adc60f9.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q09-p04-35a5b03a03.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-41-q09-p05-91df2e83a6.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-41-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "An amino acid is a compound that has both an amine group and a carboxyl group. 9\nThe structures of three amino acids, P, and R, are shown in Figure 9.1. (a) Q\nP Q R\nCH(CH )COOH NH C(CH )CHCOOH NH CH COOH NH\n2 3 2 3 2 2\nFigure 9.1\nTwo of the amino acids in Figure 9.1 show stereoisomerism.\nDraw the stereoisomers of each of these amino acids in Figure 9.2. Name the type two\nof stereoisomerism shown for each pair of stereoisomers. Use three-dimensional bonds\nwhere appropriate.\ntype of stereoisomerism ................................................................\ntype of stereoisomerism ................................................................\nFigure 9.2\n[3]\nThe structures of amino acids and and their isoelectric points are shown in Table 9.1. (b) T U\nTable 9.1\nT U\nH\nNH\n2\nN\nCOOH structure\nCOOH\n6.3 5.5 isoelectric point\nExplain what is meant by isoelectric point. (i)\n...........................................................................................................................................\n..................................................................................................................................... [1]\nComplete Table 9.2 to show the predominant species formed by amino acids and at (ii) T U\nthe pH values shown.\nTable 9.2\npH 4.0 pH 5.5 pH 8.0\nT\nU\n[3]\nAmino acids P, NH CH(CH )COOH, and R, NH CH COOH, can form tripeptide W, (c)\n2 3 2 2\nH N O . The structure of tripeptide can be represented as P–R–P. C W\n8 15 3 4\nDraw the structure of W. The peptide functional groups formed should be displayed. (i)\n[2]\nreacts under suitable conditions to form two molecules of and one molecule of R. (ii) W P\nName the type of reaction.\n..................................................................................................................................... [1]\nAmino acids and can also form a number of polymers. One of these polymers, X, (iii) P R\n. has a structure that can be represented as —[ P–R — ]\nn\nName the type of polymerisation involved in the formation of X.\n..................................................................................................................................... [1]\n[Total: 11]\nImportant values, constants and standards\nK–1 mol–1 molar gas constant R = 8.31 J\n104 mol–1 × Faraday constant F = 9.65 C\n1023 mol–1 × Avogadro constant L = 6.022\n10–19 × electronic charge e = –1.60 C\ndm3 mol–1 V = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\n10–14 mol2 dm–6 × °C)) ionic product of water K = 1.00 (at 298 K (25\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nPermission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every\nreasonable effort has been made by the publisher (Cambridge University Press & Assessment) to trace copyright holders, but if any items requiring clearance\nhave unwittingly been included, the publisher will be pleased to", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-41-q09-a873f15571.pdf" }, { "id": "9701-2026-mj-42-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 1, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 20, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-42-q01-p01-7c766e35fe.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-42-q01-p02-df44f4dc50.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-42-q01-p03-5282397479.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-42-q01-p04-0cdd0239fe.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q01", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) (i) Transition elements have variable oxidation states and form complex ions.\nSIHT\nNI State two other typical chemical properties of a transition element.\nETIRW\n1 ........................................................................................................................................\nTON\n2 ........................................................................................................................................\nOD\n[1]\n(ii) Explain why transition elements have variable oxidation states.\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [1]\nETIRW\nTON\nCr3+, ]3+ chromium(III) ions, contains the [Cr(H O) complex ion. (b) An aqueous solution of\n2 6\nOD\nCr3+. (i) Complete Figure 1.1 to show the electronic configuration for\n3d 4s\nNIGRAM\n[Ar]\nSIHT\nFigure 1.1\nNI\n[1] ETIRW\nCr3+ ]3+. O and in [Cr(H O) (ii) State the type of bonding that exists between H TON\n2 2 6\nOD\n..................................................................................................................................... [1]\n(c) Explain why transition elements form complex ions.\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\n]3+ O) can be converted into the [Cr(H O) (OH) ] complex. (d) [Cr(H\nOD 2 6 2 3 3\n(i) Suggest a suitable reagent for this conversion. State the type of reaction.\nreagent ..............................................................................................................................\nNIGRAM\ntype of reaction ..................................................................................................................\nSIHT [1]\nNI\nETIRW\nTON\nNIGRAM\n]3+. (ii) [Cr(H O) (OH) ] reacts with an excess of NH (aq) to form [Cr(NH )\nSIHT 2 3 3 3 3 6\nNI Complete the equation for this reaction. State the type of reaction.\nETIRW\nO) (OH) ] + ........................................................................................................... [Cr(H\nTON 2 3 3\nOD type of reaction ..................................................................................................................\n[2]\nNIGRAM O) (OH) ] shows stereoisomeri", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-42-q01-b1d22f4875.pdf" }, { "id": "9701-2026-mj-42-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 2, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2026-mj-42-q02-p01-b4e2d5179c.png", "9701-topic-27-group-2/assets/9701-2026-mj-42-q02-p02-64955e6ed5.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q02", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 Group 2 carbonates decompose on heating to form the corresponding metal oxide and\nSIHT\ncarbon dioxide.\nNI\nETIRW\n(a) The mechanism for this decomposition involves the carbonate ion breaking down to form\ncarbon dioxide and oxide ions.\nTON\nAdd two curly arrows to the carbonate ion in Figure 2.1 to suggest a mechanism for\nOD\nthis decomposition.\nO\nNIGRAM\n2– O C O + O C\nSIHT\n– – O O\nNI\nETIRW\nFigure 2.1\n[1]\nTON\nOD\n(b) The radii of some cations are shown in Table 2.1.\nTable 2.1\nNIGRAM\nCa2+ Cu2+ Pb2+ cation\nradius / nm 0.099 0.073 0.120 SIHT\nNI\nUse the data in Table 2.1 to predict the trend in thermal stability of the metal carbonates ETIRW\ncontaining these cations.\nTON\nExplain your answer.\nOD\n.............................. > .............................. > ..............................\nmost stable least stable\nNIGRAM\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Suggest why the solubility of the Group 2 sulfates decreases down the group.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n...................................................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [3]\nSIHT\nNI\n, is sparingly soluble in water at 298 K. (d) Magnesium hydroxide, Mg(OH)\nETIRW 2\n, of Mg(OH) . State the units for K . (i) Write the expression for the solubility product, K\nsp 2 sp TON\nOD\n= K\nsp\nNIGRAM\nunits ..........................................................", "pdf_path": "9701-topic-27-group-2/print/9701-2026-mj-42-q02-49c5d8d84d.pdf" }, { "id": "9701-2026-mj-42-q03", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 8, 9, 10 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-42-q03-p01-0c9890ac33.png", "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-42-q03-p02-b44c4c0b21.png", "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-42-q03-p03-c264767b7d.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n3 (a) Ethanal, CH CHO, reacts with methanol, CH OH, under acidic conditions to form\nSIHT 3 3\ncompound B, as shown in reaction 1.\nNI\nB ETIRW\nH+\nreaction 1 CH CHO + 2CH OH CH CH(OCH ) + H O\n3 3 3 3 2 2\nTON\nCHO, The initial rate of reaction is investigated using different starting concentrations of CH\nOD 3\nH+. OH and The results obtained are shown in Table 3.1. CH\n3\nTable 3.1\nNIGRAM\n[H+] [CH initial rate [CH OH] CHO]\nexperiment 3 3\ndm–3 s–1 dm–3 dm–3 dm–3 / mol / mol / mol / mol\nSIHT\n10–3 1 0.500 0.040 0.100 2.500 ×\nNI\nETIRW 10–3 2 0.500 0.060 0.100 3.750 ×\n10–2 3 0.250 0.120 0.300 1.125 ×\nTON\n10–2 4 0.250 0.120 0.400 1.500 × OD\n(i) Use the information in Table 3.1 to deduce the rate equation for this reaction.\nNIGRAM Explain your reasoning. State clearly which experiments you use in your explanation.\n...........................................................................................................................................\nSIHT\n........................................................................................................................................... NI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\nrate =\nTON\n[4]\nOD\n(ii) State the units of the rate constant, k, for this reaction.\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Another experiment to investigate reaction 1 is carried out as shown in Table 3.2.\nSIHT\nNI Table 3.2\nETIRW\ndm–3 dm–3 [H+] dm–3 experiment [CH CHO] / mol [CH OH] / mol / mol\n3 3 TON\n5 0.250 0.250 0.250\nOD\nCalculate the initial rate of experiment 5.\nNIGRAM\nSIHT\nNI\ndm–3 s–1 initial rate = ..................................... mol [1] ETIRW\nTON\n(b) The reaction of propanone, CH COCH , with bromine, Br , in the presence of an\n3 3 2 OD\nacid catalyst is shown in reaction 2.\nH+\nCH COCH Br + HBr reaction 2 CH COCH + Br\n3 2 3 3 2 NIGRAM\nCOCH ] and first order with respect to The rate of reaction is first order with respect to [CH\n3 3\n[H+] under certain con", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2026-mj-42-q03-905dbad848.pdf" }, { "id": "9701-2026-mj-42-q04", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 4, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 11 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2026-mj-42-q04-p01-b9bc0fcf80.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q04", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:2)(cid:44)\n4 (a) State what is meant by partition coefficient, K .\nSIHT pc\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nC O , is more soluble in water than in the organic solvent ethoxyethane. (b) Ethanedioic acid, H\n2 2 4\nNIGRAM\ncm3 cm3 of ethoxyethane and 50 of 2.70 g of ethanedioic acid is shaken with a mixture of 50\nwater at 298 K and left until there is no further change in concentrations.\nSIHT\ncm3 dm–3 of 0.200 mol NaOH(aq) for The ethoxyethane layer requires 16.5\nNI\ncomplete neutralisation.\nETIRW\nC O + 2NaOH Na C O + 2H O H\nTON 2 2 4 2 2 4 2\nOD , for ethanedioic acid between ethoxyethane and water. Calculate the partition coefficient, K\npc\nNIGRAM\nSIHT\nNI\nETIRW\nTON\n= ......................................................... [3] K\npc OD\n(c) The formula of ethanedioic acid is HOOCCOOH.\nNIGRAM\nThe formula of butanedioic acid is HOOCCH CH COOH.\n2 2\nBoth acids are soluble in ethoxyethane and in water.\nSIHT\nNI of butanedioic acid between ethoxyethane and water Suggest how the value of K\npc ETIRW\nfor ethanedioic acid between ethoxyethane and water. compares to the value of K\npc\nTON Explain your answer.\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [2]\nSIHT [Total: 6]\nNI\nETIRW", "pdf_path": "9701-topic-25-equilibria/print/9701-2026-mj-42-q04-a63c46f583.pdf" }, { "id": "9701-2026-mj-42-q05", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 5, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2026-mj-42-q05-p01-6d7ef3fb4a.png", "9701-topic-24-electrochemistry/assets/9701-2026-mj-42-q05-p02-f78bae02d6.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q05", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n5 (a) Define standard electrode potential, E ⦵, including a description of standard conditions.\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [2]\nOD\n(b) Table 5.1 shows the standard electrode potentials for three redox systems.\nNIGRAM\nTable 5.1\nSIHT\nredox system electrode reaction E / V ⦵⦵\nNI\nFe2+ Fe3+ e– 1 +0.77 +\nETIRW\n10H+ 8e– + – +0.87 2 NH + 3H O + + NO\n4 2 3\nTON\nZn2+ 2e– –0.76 3 + Zn\nOD\n(i) Use the information in Table 5.1 to write equations for two reactions that are feasible.\nExplain why these reactions are feasible.\nNIGRAM\nSIHT\nequation 1 ......................................................................................................................... NI\nETIRW\nequation 2 .........................................................................................................................\nTON\nexplanation ........................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n[3]\n(ii) Suggest why the feasible reactions in 5(b)(i) may not take place under SIHT\nstandard conditions.\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) An electrochemical cell is set up to measure E for redox system 2 in Table 5.1. ⦵\nSIHT\nNI Complete Figure 5.1 to show a labelled diagram of this electrochemical cell.\nETIRW\nInclude all necessary substances and relevant pieces of apparatus needed to\nTON ⦵. measure E\nOD\nIt is not necessary to state the conditions used.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nFigure 5.1\n[3]\nTON\nOD\n(c) A different electrochemical cell is set up. The cell reaction for this electrochemical cell\nis shown.\nNIGRAM 3Mn3+ 3Mn2+ Cr3+ mol–1 + ΔG⦵ = – 645.6 kJ Cr +\nCalculate the standard cell potential, E , for this cell reaction. ⦵\nSIHT cell\nNI\nETIRW\nTON\nOD\n= ...................................................... V [2] E ⦵\ncell NIGRAM\n[Total: 11]\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2026-mj-42-q05-c80517be79.pdf" }, { "id": "9701-2026-mj-42-q06", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 6, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 14, 15, 16, 17 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-42-q06-p01-76776ff418.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-42-q06-p02-096408b4a6.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-42-q06-p03-9b0c38dcd1.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-42-q06-p04-69b39b288f.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q06", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n6 (a) Phenol reacts with Br (aq).\nSIHT 2\nNI (aq) is added dropwise to a solution (i) State all the expected observations when Br\n2\nETIRW\nof phenol.\nTON ...........................................................................................................................................\nOD\n..................................................................................................................................... [1]\n(ii) Draw the structure of the organic product formed when phenol reacts with an excess\n(aq). of Br\nNIGRAM 2\nSIHT\nNI\nETIRW\nTON\nOD\n[1]\nNIGRAM\n(b) Explain the relative acidities of phenol and water.\nSIHT ...................................................................................................................................................\nNI\n................................................................................................................................................... ETIRW\n...................................................................................................................................................\nTON\nOD ............................................................................................................................................. [2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Compound C can undergo both addition and condensation polymerisation.\nSIHT\nC NI\nETIRW\nOH O\nTON\nOD\nOH\nNIGRAM\nFigure 6.1\nSIHT\n(i) Draw one repeat unit of the addition polymer formed from C.\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI [1]\nETIRW\n(ii) Draw two repeat units of the condensation polymer formed from C.\nTON\nThe new functional group formed should be displayed.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(d) C can react with LiAl H . C can also react with an excess of H (g) with a nickel catalyst.\nSIHT 4 2\nNI Draw the structure of the organic product formed in each reaction in Figure 6.2.\nETIRW\nTON\nOD\nC\nLiAl H OH O\n4 NIGRAM\nSIHT\nOH\nNI\nETIRW\nH (g)/Ni catalyst\n2\nTON heat\nOD\nNIGRAM\nFigure 6.2 SIHT\n[2]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(e) Compound F can be synthesised from phenol in three steps, as shown in Figure 6.3.\nSIHT\nOH NI\nD E\nETIRW\nTON\nstep 1 step 2\nOD\nNIGRAM\nSIHT\nstep 3 NI\nETIRW\nTON\nF\nOD O\nO NIGRAM\nCOOH\nSIHT\nNI\nETIRW\nTON\nFigure 6.3\nOD\n(i) Draw the structures of compounds D and E in the boxes in Figure 6.3. [2]\n(ii) Suggest reagents and conditions for steps 1 to 3 in Figure 6.3.\nNIGRAM\nstep 1 ................................................................................................................................\nSIHT\nstep 2 ................................................................................................................................\nNI\nETIRW\nstep 3 ..............................................................................................................................", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2026-mj-42-q06-38997cfb18.pdf" }, { "id": "9701-2026-mj-42-q07", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 7, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q07-p01-8c43f25a88.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q07-p02-e71e15de7e.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q07", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n7 (a) Alanine, CH CH(NH )COOH, is an amino acid that contains a chiral centre.\nSIHT 3 2\nNI Different synthetic routes to produce alanine can lead to the formation of an optically active\nETIRW\nsample or a racemic mixture.\nTON (i) Describe what is meant by optically active.\nOD\n...........................................................................................................................................\n..................................................................................................................................... [1]\nNIGRAM\n(ii) Describe what is meant by racemic mixture.\n........................................................................................................................................... SIHT\nNI\n..................................................................................................................................... [1]\nETIRW\nTON\n(b) Alanine has an isoelectric point of 6.11.\nOD\n(i) Explain what is meant by isoelectric point.\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\n(ii) Draw the structure of alanine at pH 10.\nNI\nETIRW\nTON\nOD\n[1]\nNIGRAM\n(c) Alanine molecules can react together to form the tripeptide Ala–Ala–Ala.\nSIHT\nDraw the structure for this tripeptide. The functional groups formed should be displayed.\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\nNIGRAM\n(d) Compound J can be synthesised from alanine in three steps, as shown in Figure 7.1.\nSIHT\nNI\nG, C H NO\n5 9 3 ETIRW\nalanine\nTON\nOD step 1\nCOOH H N\n2\nNIGRAM\nSIHT\nNI\nETIRW\nstep 2\nTON\nOD\nJ H, C H NO Cl\n5 8 2\nO\nNIGRAM step 3\nSIHT N\nNI\nETIRW O\nH\nTON\nOD\nFigure 7.1\n(i) Draw the structures of compounds G and H in the boxes in Figure 7.1. [2]\nNIGRAM\n(ii) Suggest reagents and conditions for steps 1 to 3 in Figure 7.1.\nSIHT\nstep 1 ................................................................................................................................\nNI\nETIRW step 2 ................................................................................................................................\nstep 3 ................................................................................................................................ TON\n[3]\nOD\n[Total: 11]\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-42-q07-d073d48c9e.pdf" }, { "id": "9701-2026-mj-42-q08", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 20, 21, 22 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2026-mj-42-q08-p01-672a82972c.png", "9701-topic-37-analytical-techniques/assets/9701-2026-mj-42-q08-p02-38a98355ab.png", "9701-topic-37-analytical-techniques/assets/9701-2026-mj-42-q08-p03-2174cc6e73.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n8 (a) Give the full name of the substance used in NMR spectroscopy as the standard for chemical\nSIHT\nshift measurements.\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\n(1H) NMR spectroscopy in D O. (b) Compound K is analysed by carbon‑13 NMR and proton\nOD 2\nK\nH\nNIGRAM\nN\nSIHT\nCl\nNI\nETIRW\nO\nTON\nFigure 8.1\nOD\n(i) Predict the number of peaks in the carbon‑13 NMR spectrum of K.\n..................................................................................................................................... [1]\nNIGRAM\n(1H) NMR spectrum of K in D O shows four peaks, for the proton (ii) The proton\n2\nenvironments labelled w, x, y and z on the structure of K in Figure 8.2.\nSIHT\nH C H\nNI 3\nw ETIRW\nx z\nCH N CH\nTON\n2 y\nH C\nCH OD 3 Cl 2\nO\nFigure 8.2 NIGRAM\nComplete Table 8.1 to identify the splitting patterns for proton environments w, x, y and z.\nSIHT\nTable 8.1\nNI\nETIRW\nproton environment name of splitting pattern\nTON\nw\nOD\nx\ny\nNIGRAM\nz\nSIHT\n[2]\nNI\nETIRW\nTON\nNIGRAM\n(1H) (iii) A separate sample of K is dissolved in CDCl and analysed using proton\nSIHT 3\nNMR spectroscopy.\nNI\nETIRW (1H) NMR spectrum of K dissolved in CDCl contains one more peak than The proton\n3\nO. the spectrum of K dissolved in D\n2\nTON\nExplain why there is one more peak, and suggest the chemical shift range in which\nOD\nit occurs.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\n........................................................................................................................................... SIHT\nNI\nchemical shift range δ = ........................................................ ppm\nETIRW\n[2]\nTON\nTable 8.2\nOD\nchemical shift\nenvironment of proton example\nδδ / ppm range\n, –CH –, >CH– 0.9–1.7 alkane –CH\nNIGRAM 3 2\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\nSIHT\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\nNI\n–O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2 ETIRW\nattached to alkene =CHR 4.5–6.0\nTON\nattached to aromatic ring H–Ar 6.0–9.0\nOD\naldehyde HCOR 9.3–10.5\nalcohol ROH 0.5–6.0\nphenol Ar–OH 4.5–7.0 NIGRAM\ncarboxylic acid RCOOH 9.0–13.0\nSIHT\nalkyl amine R–NH– 1.0–5.0\nNI\n3.0–6.0 aryl amine Ar–NH\nETIRW 2\namide RCONHR 5.0–12.0\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(c) Compound K reacts with an excess of hot NaOH(aq).\nSIHT\nK NI\nETIRW\nH\nTON\nN\nOD\nCl\nO\nNIGRAM\nFigure 8.3\nSIHT\nThe products are isolated from the reaction mixture at pH 10.\nNI\nETIRW\nDraw the structures of the two organic products of the complete alkaline hydrolysis of K.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n[2]\nTON\n", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2026-mj-42-q08-b33f93cd3d.pdf" }, { "id": "9701-2026-mj-42-q09", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "42", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-42.pdf?download=true", "source_pages": [ 24, 25, 26, 27, 28 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_42.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q09-p01-01f56c18bc.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q09-p02-b1dfc45dff.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q09-p03-38d02cb9e9.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q09-p04-6a7169cfab.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-42-q09-p05-44c86a6716.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-42-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:5)(cid:44)\n9 (a) Compound P and compound Q are isomers.\nSIHT\nP Q NI\nETIRW\nTON\nC H CH NH NH\n3 2 2 2\nOD\nFigure 9.1\nNIGRAM\nState the relative basicities of P, Q and ammonia.\nExplain your answer. SIHT\nNI .............................. > .............................. > ..............................\nETIRW\nmost basic least basic\nTON\nexplanation ...............................................................................................................................\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT ...................................................................................................................................................\nNI\n................................................................................................................................................... ETIRW\n...................................................................................................................................................\nTON\n[4]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) P can be prepared from methylbenzene in two steps, as shown in Figure 9.2.\nSIHT\nNI methylbenzene\nETIRW\nstep 1\nTON\nH C H C NO\n3 3 2 OD\nstep 2\nNIGRAM\nSIHT\nP\nNI\nETIRW\nH C NH TON\n3 2\nOD\nFigure 9.2\n(i) Suggest reagents and conditions for steps 1 and 2 in Figure 9.2. NIGRAM\nstep 1 ................................................................................................................................\nSIHT\nstep 2 ................................................................................................................................\nNI\n[2] ETIRW\n(ii) Complete the equation in Figure 9.3 for step 2.\nTON\nOD\nUse [H] to represent an atom of hydrogen from the reducing agent.\nP\nNIGRAM\nstep 2\nH C + ................. NH + ................. H C NO\n3 2 3 2\nSIHT\nNI\nFigure 9.3\nETIRW\n[1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(c) Figure 9.4 shows a two‑step synthesis of azo dye N.\nSIHT\nP NI\nM ETIRW\nstep 1\nTON\nC H NH\n3 2\nOD\nNIGRAM\nSIHT\nNI\nstep 2\nETIRW\nTON\nN\nOD\nNa+ – SO\n3\nH C N\n3\nNIGRAM\nOH N\nSIHT\nFigure 9.4\nNI\nETIRW\n(i) Draw the structure of compound M in the box in Figure 9.4. [1]\nTON\n(ii) Give the reagents and conditions for steps 1 and 2 in Figure 9.4.\nOD\nstep 1 ................................................................................................................................\nNIGRAM\nSIHT\nstep 2 ........................................................................................................................", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-42-q09-9b669c2bcd.pdf" }, { "id": "9701-2026-mj-43-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 1, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2026-mj-43-q01-p01-c1110e1722.png", "9701-topic-23-chemical-energetics/assets/9701-2026-mj-43-q01-p02-d0e12ab795.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q01", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) Write the equation to represent the lattice energy, ΔH , of calcium sulfide, CaS.\nSIHT latt\nNI Include state symbols.\nETIRW\n............................................................................................................................................. [2]\nTON\nOD\nof CaS is negative. (b) Explain why the value of ΔH\nlatt\n...................................................................................................................................................\nNIGRAM\n............................................................................................................................................. [1]\nSIHT\nvalues of CaS, MgO and KCl, from most negative to (c) State the order of the ΔH\nlatt NI\nleast negative.\nETIRW\nExplain your answer.\nTON\nOD ............................. ............................. .............................\nmost negative least negative\nexplanation ................................................................................................................................\nNIGRAM\n...................................................................................................................................................\nSIHT\n...................................................................................................................................................\nNI\nETIRW ...................................................................................................................................................\n................................................................................................................................................... TON\nOD\n...................................................................................................................................................\n[3]\nNIGRAM\n–(g) Mg2+(g) , of Cl or is the energy change when one (d) The enthalpy change of formation, ΔH\nf\nmole of gaseous ions forms from the element in its standard state at 298 K.\nSIHT\n–(g) mol–1 = –243 kJ enthalpy change of formation of chloride ions, Cl\nNI\nETIRW\nMg2+(g) mol–1 enthalpy change of formation of magnesium ions, = +2336 kJ\nTON –(g) (i) The enthalpy change of formation of Cl can be calculated using two energy\nchanges only. OD\nIdentify the two energy changes.\n........................................................................................................................................... NIGRAM\n..................................................................................................................................... [1]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nmol–1. (ii) The lattice energy of magnesium chloride, MgCl , is –2493 kJ\nSIHT 2\nNI Use this value, and other data given, to calculate the enthalpy change of formation, in\nETIRW mol–1, of MgCl (s). kJ\n2\nTON\nOD\nNIGRAM\nmol–1 of MgCl (s) = ............................................ kJ ", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2026-mj-43-q01-1f29f1fbb5.pdf" }, { "id": "9701-2026-mj-43-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2026-mj-43-q02-p01-dbf7616ed1.png", "9701-topic-25-equilibria/assets/9701-2026-mj-43-q02-p02-cef0156b38.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n2 (a) (i) Define pH mathematically.\nSIHT\nNI pH = ......................................................... [1]\nETIRW\nmathematically. (ii) Define K\nw\nTON\n= ......................................................... [1] K\nOD w\ncm3 dm–3 (b) Solution A is 100 of an aqueous solution of 0.105 mol butanoic acid,\nCH CH COOH. A has pH 2.90 at 298 K. CH\nNIGRAM 3 2 2\ndm–3, H+(aq) of in A. (i) Calculate the concentration, in mol\nSIHT\nNI\nETIRW\nTON\n[H+ dm–3 ] in A = .......................................... mol [1]\nOD\nof CH CH CH COOH at 298 K. (ii) Calculate the value of K\na 3 2 2\nNIGRAM\nSIHT\nNI\nETIRW\nK of CH CH CH COOH = ......................................................... [1]\na 3 2 2\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\ncm3 dm–3 (c) Solution B is 100 of an aqueous solution containing 0.450 mol CH CH CH COOH.\nSIHT 3 2 2\ncm3 NI of an aqueous solution containing sodium butanoate, Solution C is 200\nETIRW\nCH CH COONa. CH\n3 2 2\nTON cm3 H+ of solution D. The concentration of ions in D is B is added to C to produce 300\n10–5 dm–3. mol 6.31 ×\nOD\nCH CH COONa in C. (i) Calculate the concentration of CH\n3 2 2\n10–5 as the value (If you were unable to calculate an answer in 2(b)(ii), then use 3.00 ×\nNIGRAM\nof CH CH CH COOH. This is not the correct answer.) of K\na 3 2 2\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\ndm–3 [CH CH CH COONa] in C = .......................................... mol [3]\nNI 3 2 2\nETIRW\nSO (aq) is added to D. (ii) Write an equation for the reaction when H\n2 4\nTON\n..................................................................................................................................... [1]\nOD\n(iii) Write an equation for the reaction when KOH(aq) is added to D.\n..................................................................................................................................... [1]\nNIGRAM\nCH CCl COOH, and butanoic (d) Predict the relative acidities of 2,2-dichlorobutanoic acid, CH\n3 2 2 SIHT\nCH CH COOH. acid, CH\n3 2 2\nNI\nETIRW Explain your answer.\nstronger acid ............................................................................................................................. TON\nOD\nexplanation ...............................................................................................................................\n...................................................................................................................................................\nNIGRAM\n...................................................................................................................................................\n................................................................................................................................................... SIHT\n[2]\nNI\nETIRW\n[Total: 11]", "pdf_path": "9701-topic-25-equilibria/print/9701-2026-mj-43-q02-b4853ca197.pdf" }, { "id": "9701-2026-mj-43-q03", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-43-q03-p01-b9947d3432.png", "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-43-q03-p02-80519e9ca7.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n3 Nitrogen monoxide reacts with hydrogen to produce nitrogen and water.\nSIHT\nNI N + 2H O 2NO + 2H\n2 2 2\nETIRW\nThe rate equation for this reaction is shown.\nTON\n[NO]2[H ] rate = k\nOD 2\nTwo experiments are carried out to investigate this reaction.\n(a) Complete Table 3.1.\nNIGRAM\nTable 3.1\nSIHT\norder with respect to [NO] NI\nETIRW\n] order with respect to [H\n2\nTON overall order\n[1] OD\n10–10 dm–3 s–1 (b) In experiment 1, the rate of the reaction is 2.80 × mol when [NO] is\n10–2 dm–3 10–2 dm–3. mol and [H ] is 8.00 × mol 5.00 × NIGRAM\n2\nCalculate the value of the rate constant, k, in experiment 1. State the units of k.\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nk = ...............................................................\nSIHT\nunits = ...............................................................\nNI [2]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Experiment 2 is carried out under different conditions from experiment 1. The value of k for\nSIHT\n10–5. experiment 2 is 2.13 ×\nNI\nETIRW 10–3 dm–3. ] is 1.20 × mol In experiment 2, a large excess of NO is used. The initial value of [H\n2\nTON ] against time for experiment 2 shows that the reaction has a (i) A graph of [H\n2\nconstant half-life.\nOD\nExplain why the graph shows a constant half-life, referring to:\n• the overall order of the reaction under these conditions\nNIGRAM\n• the reason why this is the overall order under these conditions.\n........................................................................................................................................... SIHT\nNI\n...........................................................................................................................................\nETIRW\n..................................................................................................................................... [1]\nTON\nOD (ii) Calculate the half-life, in s, of the reaction in experiment 2 and state the time taken, in s,\n10–5 dm–3. ] to fall to 7.50 × mol for the value of [H\n2\nNIGRAM\nSIHT\nhalf-life = ............................................................. s\nNI\nETIRW 10–5 dm–3 ] to fall to 7.50 × mol = ............................................................. s time taken for [H\n2\n[2]\nTON\n(d) The overall reaction of nitrogen monoxide with hydrogen has a three-step mechanism.\nOD\nN + 2H O 2NO + 2H\n2 2 2\nPart of this mechanism is shown.\nNIGRAM\nN O step 1 2NO\n2 2\nSIHT\nstep 2 ................................. .................................\nNI\nETIRW\nN + H O O + H step 3 N\n2 2 2 2\nTON\n(i) Complete the mechanism by writing an equation for step 2. [2]\nOD\n(ii) It can be deduced that step 1 is not the rate-determining step of the reaction.\nExplain why.\nNIGRAM\n...........................................................................................................................................\nSIHT\n..........................................................", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2026-mj-43-q03-eae5dc24cf.pdf" }, { "id": "9701-2026-mj-43-q04", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 4, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2026-mj-43-q04-p01-bc118b4175.png", "9701-topic-24-electrochemistry/assets/9701-2026-mj-43-q04-p02-92325fab4a.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q04", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n4 Some electrode potentials are given in Table 4.1.\nSIHT\nNI Table 4.1\nETIRW\nelectrode reaction E / V ⦵⦵\nTON\n– 2e– +1.36 2Cl + Cl\nOD 2\nCu2+ 2e– +0.34 Cu +\ne– OH– – 0.56 + Fe(OH) + Fe(OH)\n3 2\nNIGRAM\nFe2+ Fe3+ e– +0.77 +\nV2+ 2e– –1.13 + V\nSIHT\nV3+ e– V2+ – 0.26 +\nNI\nETIRW\n(a) Complete the equation that can be used to calculate the standard Gibbs free energy change,\nTON ⦵, for a cell reaction using the standard cell potential, E . ΔG ⦵\ncell\nOD\n= ΔG ⦵\n[1]\nNIGRAM\nV3+ V2+ Cu2+ (b) An electrochemical cell is set up using a / electrode and a / Cu electrode, both\nunder standard conditions.\nSIHT\n. Write an equation for the cell reaction that occurs and calculate the value for E ⦵\ncell NI\nETIRW\nequation ....................................................................................................................................\nTON\nOD\n= ............................................................ V E ⦵\ncell\n[2]\nNIGRAM\nFe3+ Fe2+ (c) Identify two atoms or ions from Table 4.1 that will reduce to under neutral\nSIHT\nto Fe(OH) under alkaline conditions. conditions, but will not reduce Fe(OH)\n3 2\nNI\n.............................................................. and ....................................................................... [2] ETIRW\nTON\n(d) Identify the strongest oxidising agent and the strongest reducing agent in Table 4.1.\nOD\nstrongest oxidising agent ...............................................................\nstrongest reducing agent ...............................................................\nNIGRAM\n[2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(e) A dilute solution of NaOH(aq) is electrolysed using inert electrodes.\nSIHT\nA steady current of 2.40 A is passed for 2.00 hours.\nNI\nETIRW\nCalculate the mass, in g, of oxygen that is released at the cathode.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nmass of oxygen = ....................................................... g [3]\n[Total: 10]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2026-mj-43-q04-25cb608952.pdf" }, { "id": "9701-2026-mj-43-q05", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 5, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-43-q05-p01-48f5e67b63.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-43-q05-p02-9719bbe2f5.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q05", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\nCo2+ 5 Cobalt is a transition element. It forms a wide range of coloured compounds that contain\nSIHT\nCo3+ ions. ions or\nNI\nETIRW\n(a) Explain why a transition element, such as cobalt, has variable oxidation states in\nits compounds.\nTON\n...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\nNIGRAM\nCo2+ ion. (b) Complete the electronic configurations of a Co atom and a\nCo atom: [Ar] ............................................................... SIHT\nNI\nCo2+ ion: [Ar] ...............................................................\nETIRW\n[1]\nTON\nCo2+ OD (c) Explain why compounds containing ions are coloured.\n...................................................................................................................................................\nNIGRAM ...................................................................................................................................................\n...................................................................................................................................................\nSIHT\n................................................................................................................................................... NI\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [3]\nOD\ncobalt(II) chloride paper. (d) A few drops of water are added to a piece of dry\nNIGRAM\nDescribe the colour change that is seen. Write an equation for the reaction that causes this\ncolour change.\nSIHT\ncolour change: from ....................................................... to ......................................................\nNI\nETIRW\nequation ....................................................................................................................................\n[2]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(e) Copper is a transition element.\nSIHT\nNI (aq). All the copper forms Cu(NO ) (aq). A piece of copper is added to HNO\n3 3 2\nETIRW\n) (aq) in a conical flask. All the copper present An excess of KI(aq) is added to the Cu(NO\n3 2\nTON forms CuI. The equation for the reaction is shown.\nOD\n4I– – ) + 2CuI + I + 4NO reaction 1 2Cu(NO\n3 2 2 3\ndm–3 The I formed in this reaction is titrated with 0.200 mol Na S O (aq). The end-point of\n2 2 2 3\ncm3 of Na S O (aq) has been added. The equation for the titration is reached when 37.60\nNIGRAM 2 2 3\nthe reaction is shown.\n2I– 2– 2– SIHT O + I S O + re", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-43-q05-be4d1c7ecc.pdf" }, { "id": "9701-2026-mj-43-q06", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 12, 13 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-43-q06-p01-cf6ff95dcd.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-43-q06-p02-fefa8bdfb8.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n2–, 6 Transition elements form complexes with species called ligands. The ethanedioate ion, C O is\nSIHT 2 4\na bidentate ligand.\nNI\nETIRW\n(a) Explain what is meant by bidentate ligand.\nTON ...................................................................................................................................................\nOD\n............................................................................................................................................. [2]\nFe3+ 2– ion forms an octahedral complex with three C O ions. (b) One\nNIGRAM 2 4\n(i) State the formula and charge of this complex.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n(ii) This complex shows stereoisomerism.\nTON\nDraw three-dimensional diagrams to show all the stereoisomers of this complex.\nOD\n2– ion can be represented using O . The C O O\n2 4\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW [2]\nTON (iii) State the type or types of stereoisomerism shown by this complex.\nOD\n..................................................................................................................................... [1]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nHg2+ I–, ]2–. (c) ions and iodide ions, form a complex with the formula [HgI\nSIHT 4\n]2–. NI of [HgI State its units. Write the expression for K\nstab 4 ETIRW\nTON K =\nstab\nOD\nunits = ............................................................... NIGRAM\n[2]\nSIHT [Total: 8]\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-43-q06-7e97f58271.pdf" }, { "id": "9701-2026-mj-43-q07", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 7, "topic_number": 32, "topic": "Hydroxy compounds", "topic_slug": "9701-topic-32-hydroxy-compounds", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 14, 15, 16 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-43-q07-p01-098629b6b1.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-43-q07-p02-457d93419b.png", "9701-topic-32-hydroxy-compounds/assets/9701-2026-mj-43-q07-p03-f879c84eb0.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q07", "html": "9701-topic-32-hydroxy-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:5)(cid:44)\n7 (a) Phenol, C H O, can be made from benzene, C H , in a four-step process, as shown in\nSIHT 6 6 6 6\nFigure 7.1.\nNI\nETIRW\nstep 1 step 2 step 3 step 4\nH C H NO C H N C H N Cl C H O C\n6 6 6 5 2 6 7 6 5 2 6 6\nTON\nFigure 7.1 OD\n(i) State the reagents and conditions for step 1.\n..................................................................................................................................... [1] NIGRAM\n(ii) State the reagents and conditions for step 3.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nH N Cl formed in step 3. (iii) Name the compound C\n6 5 2\nTON\n..................................................................................................................................... [1]\nOD\n(b) Phenol reacts with propanone in the presence of an acid catalyst to form compound G, as\nshown in Figure 7.2.\nNIGRAM\nG\nSIHT\nOH\nNI OH\nETIRW\nH+ O\n+\nTON\nOD\nOH\nFigure 7.2\nNIGRAM\nsp2 sp3 and hybridised carbon atoms in (i) Complete Table 7.1 to show the number of sp,\nSIHT propanone and in G.\nNI\nTable 7.1\nETIRW\nsp2 sp3 sp TON\nOD propanone\nG\n[1]\nNIGRAM\n(ii) State the number of peaks in the carbon-13 NMR spectrum of G.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nTON\nNIGRAM\n(iii) The first stage of the mechanism for the reaction in Figure 7.2 involves the formation of\nSIHT\nion J.\nNI\nETIRW\nComplete the mechanism in Figure 7.3 to show the formation of J by adding dipoles\nand curly arrows, as appropriate.\nTON\nJ OD\nH+\nH O\nO\nNIGRAM +\nSIHT\nFigure 7.3\nNI [1]\nETIRW\n(iv) The next stage of the mechanism involves the reaction between J and phenol to form\nTON intermediate K. A proton is then lost from K to produce G.\nOD\nComplete Figure 7.4 to show these stages of the mechanism. Include relevant curly\narrows and charges.\nG intermediate K NIGRAM\nOH\nOH\nSIHT\nNI\nETIRW H+ H +\nO\nTON\n+\nOH\nOD\nFigure 7.4\nNIGRAM\n[3]\nH+(aq). (v) Benzene is mixed with propanone in the presence of SIHT\nNI\nPredict whether benzene reacts with propanone more readily, as readily or less readily\nETIRW\nthan phenol does under the same conditions.\nTON\nExplain your answer.\nOD\nBenzene reacts with propanone ....................................................... than phenol does.\nexplanation ........................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\n[2]\nNI\nETIRW\nNIGRAM\n(c) G reacts with Br (aq) in the dark. The organic product of t", "pdf_path": "9701-topic-32-hydroxy-compounds/print/9701-2026-mj-43-q07-bf8058b59a.pdf" }, { "id": "9701-2026-mj-43-q08", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 8, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 18, 19 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q08-p01-43bcb41a21.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q08-p02-8bf76c5806.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q08", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:9)(cid:44)\n8 Secondary amine M can be made by the three-step synthesis shown in Figure 8.1.\nSIHT\nNI\nL\nETIRW step 1 step 2\nCH COOH CH COCl\n3 3\nTON\nOD\nNIGRAM\nstep 3\nSIHT\nNI\nM\nETIRW\nCH\n3 TON\nCH CH NH CH\n3 2 OD\nCH\n3\nFigure 8.1\nNIGRAM\nCOOH with SOCl in step 1. (a) (i) Write an equation for the reaction of CH\n3 2\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\nCOOH to produce CH COCl in step 1. (ii) State an alternative reagent that reacts with CH\n3 3\nTON ..................................................................................................................................... [1]\nOD\n(iii) Compound L is an amide.\nDraw the structure of L in Figure 8.1. [1]\nNIGRAM\nCOCl in step 2. (iv) Draw the structure of the reagent added to CH\n3\nSIHT\nNI\nETIRW\nTON\nOD\n[1]\n(v) Name the mechanism of the reaction forming L in step 2.\nNIGRAM\n..................................................................................................................................... [1]\n(vi) Suggest a reagent for step 3.\nSIHT\nNI ..................................................................................................................................... [1]\nETIRW\nTON\nNIGRAM\n(1H) (b) The proton NMR spectrum of M dissolved in D O is obtained. Four of the proton\nSIHT 2\nenvironments, r, s, t and u, are labelled on the structure of M in Figure 8.2.\nNI\nETIRW\nt\nCH r s TON\n3\nu CH CH NH CH\nOD 3 2\nCH\n3\nt\nNIGRAM\nFigure 8.2\nSIHT (i) Complete Table 8.1 to identify the splitting patterns for proton environments r, s, t\nand u.\nNI\nETIRW\nTable 8.1\nTON\nproton environment name of splitting pattern\nOD\nr\ns\nNIGRAM\nt\nu\nSIHT\n[2]\nNI\nETIRW\n(1H) NMR spectrum of M dissolved in CDCl is obtained. (ii) The proton\n3\nTON (1H) NMR spectrum of M State and explain how this spectrum differs from the proton\nO. dissolved in D\nOD\n2\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [2]\nNI\nETIRW\n[Total: 10]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-43-q08-47c72d2311.pdf" }, { "id": "9701-2026-mj-43-q09", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "43", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-43.pdf?download=true", "source_pages": [ 20, 21, 22, 23, 24 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_43.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q09-p01-4c36f535e3.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q09-p02-425344dfc3.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q09-p03-7751390f41.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q09-p04-687487ddf5.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-43-q09-p05-e39b17506a.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-43-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n9 An amino acid is a compound that has both an amine group and a carboxyl group.\nSIHT\nNI (a) The structures of three amino acids, P, Q and R, are shown in Figure 9.1.\nETIRW\nP Q R\nTON\nCH(CH )COOH NH C(CH )CHCOOH NH CH COOH NH\nOD 2 3 2 3 2 2\nFigure 9.1\nTwo of the amino acids in Figure 9.1 show stereoisomerism.\nNIGRAM\nDraw the two stereoisomers of each of these amino acids in Figure 9.2. Name the type\nof stereoisomerism shown for each pair of stereoisomers. Use three-dimensional bonds SIHT\nwhere appropriate.\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\ntype of stereoisomerism ................................................................\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\ntype of stereoisomerism ................................................................\nNIGRAM Figure 9.2\n[3]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) The structures of amino acids T and U and their isoelectric points are shown in Table 9.1.\nSIHT\nNI Table 9.1\nETIRW\nT U\nTON\nH\nOD\nNH\n2\nN\nCOOH structure\nCOOH\nNIGRAM\nisoelectric point 6.3 5.5\nSIHT\nNI (i) Explain what is meant by isoelectric point.\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [1] OD\n(ii) Complete Table 9.2 to show the predominant species formed by amino acids T and U at\nthe pH values shown.\nNIGRAM\nTable 9.2\nSIHT\npH 4.0 pH 5.5 pH 8.0\nNI\nETIRW\nTON\nT\nOD\nNIGRAM\nSIHT\nU\nNI\nETIRW\nTON\n[3]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(c) Amino acids P, NH CH(CH )COOH, and R, NH CH COOH, can form tripeptide W,\nSIHT 2 3 2 2\nH N O . The structure of tripeptide W can be represented as P–R–P. C\n8 15 3 4\nNI\nETIRW\n(i) Draw the structure of W. The peptide functional groups formed should be displayed.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD [2]\n(ii) W reacts under suitable conditions to form two molecules of P and one molecule of R.\nNIGRAM Name the type of reaction.\n..................................................................................................................................... [1]\nSIHT\nNI (iii) Amino acids P and R can also form a number of polymers. One of these polymers, X,\nETIRW . has a structure that can be represented as —[ P–R — ]\nn\nTON Name the type of polymerisation involved in the formation of X.\nOD\n..................................................................................................................................... [1]\n[Total: 11]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mol–1 Faraday constant F = 9.65 × C\nTON 1023 mol–1 Avogadro constant L = 6.022 ×\nOD 10–19 electronic charge e = –1.60 × C\ndm3 mol–1 V = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas\nm\ndm3 mo", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-43-q09-42f7391bfa.pdf" }, { "id": "9701-2026-mj-44-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 1, "topic_number": 24, "topic": "Electrochemistry", "topic_slug": "9701-topic-24-electrochemistry", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 2, 3 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-24-electrochemistry/assets/9701-2026-mj-44-q01-p01-9f86de1601.png", "9701-topic-24-electrochemistry/assets/9701-2026-mj-44-q01-p02-be3f074ea2.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q01", "html": "9701-topic-24-electrochemistry/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 (a) Dilute sodium hydroxide, NaOH(aq), is electrolysed.\nSIHT\nNI Identify the gas produced at the anode, and write a half-equation for the reaction involved.\nETIRW\ngas produced at the anode .......................................................................................................\nTON\nhalf-equation .............................................................................................................................\nOD\n[2]\n(l), is electrolysed using a current of 2.40 A for 12.0 minutes. (b) Molten lead bromide, PbBr\nNIGRAM 2\n(g), is produced at the anode. Bromine gas, Br\n2\nSIHT\n(g) produced. (i) Calculate the amount, in mol, of Br\n2 NI\nETIRW\nTON\nOD\namount of Br (g) = .................................................. mol [2]\n2\n(g) is collected and its volume is measured at a pressure of 101 kPa and a (ii) The Br\nNIGRAM\n2\ntemperature of 380 °C.\nSIHT (g) collected under Use the ideal gas equation to calculate the volume of Br\n2\nthese conditions.\nNI\nETIRW\ndm3 to three significant figures. Give your answer in\nTON\nShow your working.\nOD\nNIGRAM\nSIHT\nNI\nETIRW\ndm3 (g) = .................................................. [1] volume of Br\n2\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) In a different experiment, molten sodium chloride, NaCl (l), is electrolysed.\nSIHT\nNI 36 000 C of charge is transferred. 8.51 g of sodium metal is produced.\nETIRW\nCalculate a value for the Avogadro constant, L.\nTON\nShow your working.\nOD\nGive your answer to three significant figures.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nmol–1 SIHT [2] L = ...............................................\nNI\n[Total: 7]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-24-electrochemistry/print/9701-2026-mj-44-q01-af29c51c9f.pdf" }, { "id": "9701-2026-mj-44-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 2, "topic_number": 25, "topic": "Equilibria", "topic_slug": "9701-topic-25-equilibria", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-25-equilibria/assets/9701-2026-mj-44-q02-p01-71cb63bcc9.png", "9701-topic-25-equilibria/assets/9701-2026-mj-44-q02-p02-0c6cdcc130.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q02", "html": "9701-topic-25-equilibria/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:5)(cid:44)\n2 (a) Define strong acid and weak acid.\nSIHT\nNI strong acid ................................................................................................................................\nETIRW\nweak acid ..................................................................................................................................\nTON [2]\nOD\ndm–3 solution of NaOH(aq) is slowly added to a solution containing ethanedioic (b) A 1.00 mol\nacid, HOOCCOOH(aq), until the solution is alkaline.\nNIGRAM\nDuring the addition of NaOH(aq), two organic conjugate acid–base pairs are formed in\nthe mixture.\nSIHT\nUse the formulas of the species involved to identify the two different organic conjugate\nNI\nacid–base pairs.\nETIRW\nTON\npair 1: .............................. ..............................\nOD\nconjugate acid conjugate base\npair 2: .............................. .............................. NIGRAM\nconjugate acid conjugate base\n[1] SIHT\nNI\nETIRW\nCOOH(aq), mixed with calcium ethanoate, (c) A solution of ethanoic acid, CH\n3\nCOO) (aq), acts as a buffer solution. Ca(CH\n3 2 TON\n(i) Write an equation for a reaction that has calcium ethanoate as one of the products. OD\n..................................................................................................................................... [2]\n(ii) Define buffer solution. NIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\nCOOH(aq) and (iii) Write two equations to explain how a buffer solution containing CH\n3\nOD COO) (aq) can control pH. Ca(CH\n3 2\n...........................................................................................................................................\nNIGRAM ..................................................................................................................................... [2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(d) The pH of a solution of sodium hydroxide, NaOH, is 11.34.\nSIHT\nNI , of the same concentration. Calculate the pH of a solution of barium hydroxide, Ba(OH)\n2\nETIRW\nTON\nOD\npH = ......................................................... [3] NIGRAM\nSIHT\n(e) (i) Define partition coefficient, K .\npc\nNI\n........................................................................................................................................... ETIRW\n..................................................................................................................................... [1]\nTON\nOD\nCH CH CH OH, and water are added to a separating (ii) Equal volumes of butan", "pdf_path": "9701-topic-25-equilibria/print/9701-2026-mj-44-q02-2ad678221e.pdf" }, { "id": "9701-2026-mj-44-q03", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 3, "topic_number": 26, "topic": "Reaction kinetics", "topic_slug": "9701-topic-26-reaction-kinetics", "marks": 8, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 6, 7 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-44-q03-p01-8e2557506b.png", "9701-topic-26-reaction-kinetics/assets/9701-2026-mj-44-q03-p02-fcb785ed77.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q03", "html": "9701-topic-26-reaction-kinetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n3 Nitrogen dioxide reacts with fluorine as shown.\nSIHT\nNI (g) + F (g) 2NO F(g) 2NO\n2 2 2\nETIRW\nThe rate equation for this reaction is shown.\nTON\n][F ] rate = k[NO\nOD 2 2\n(a) Complete Table 3.1.\nTable 3.1\nNIGRAM\norder of the reaction with respect to [NO ]\n2 SIHT\n] order of the reaction with respect to [F\n2 NI\nETIRW overall order of the reaction\n[1]\nTON\nOD\n(b) Table 3.2 shows data from three experiments. The table is incomplete.\nTable 3.2\nNIGRAM\ndm–3 dm–3 dm–3 s–1 experiment [NO ] / mol [F ] / mol rate / mol\n2 2\nSIHT 10–6 1 0.0250 0.0300 3.45 ×\nNI 10–5 2 0.0250 1.38 ×\nETIRW\n3 0.0125 0.1200\nTON\nin experiment 2 and the rate of the (i) Complete Table 3.2, stating the concentration of F\nOD 2\nreaction in experiment 3. [2]\n(ii) Calculate the rate constant, k, under these conditions. Include the units of k.\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nk = ...............................................................\nunits ...............................................................\nNIGRAM\n[2]\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) The experiment is performed again using a large excess of NO .\nSIHT 2\nNI Under these conditions, the reaction behaves as if it is overall first order. The rate equation\nETIRW\nis shown.\nTON ] rate = k'[F\n2\nOD\n10–5 dm–3 ] is 4.00 × mol and the rate of the reaction is measured When the initial value of [F\n2\ndm–3 s–1, the value of k' is 0.0101. in mol\n, under these conditions. Calculate the half-life of the reaction, t\nNIGRAM 1\n2\nSIHT\nNI\nETIRW\nTON\nOD\nt = ...................................................... s [1]\n1\n2\nNIGRAM (d) Suggest a two-step mechanism for the reaction between nitrogen dioxide and fluorine.\nIdentify which of the two steps is the slower step.\nSIHT\n2NO F(g) (g) + F (g) 2NO NI\n2 2 2\nETIRW\n][F ] rate = k[NO\n2 2\nTON\nOD\nstep 1 ................................... ...................................\nstep 2 ................................... ...................................\nNIGRAM\nslower step ............................................................................................................................... SIHT\n[2]\nNI\nETIRW\n[Total: 8]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW", "pdf_path": "9701-topic-26-reaction-kinetics/print/9701-2026-mj-44-q03-6da9986e2c.pdf" }, { "id": "9701-2026-mj-44-q04", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 4, "topic_number": 23, "topic": "Chemical energetics", "topic_slug": "9701-topic-23-chemical-energetics", "marks": 11, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 8, 9 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-23-chemical-energetics/assets/9701-2026-mj-44-q04-p01-e52350b98e.png", "9701-topic-23-chemical-energetics/assets/9701-2026-mj-44-q04-p02-55e95f6733.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q04", "html": "9701-topic-23-chemical-energetics/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:44)\n4 (a) (i) Define first electron affinity.\nSIHT\nNI ...........................................................................................................................................\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Describe the trend in the first electron affinities of chlorine, bromine and iodine.\nOD\nExplain your answer.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n..................................................................................................................................... [2]\nOD\nmol–1. (b) The lattice enthalpy of potassium bromide, KBr, is – 670 kJ\nmol–1, NIGRAM for the lattice enthalpies of sodium chloride, NaCl, and Predict values, in kJ\nmagnesium oxide, MgO. No calculations are needed.\nSIHT\nExplain your predictions.\nNI\nmol–1 ETIRW lattice enthalpy of NaCl = ................................................. kJ\nexplanation ............................................................................................................................... TON\nOD\n...................................................................................................................................................\n...................................................................................................................................................\nNIGRAM\nmol–1 lattice enthalpy of MgO = ................................................. kJ\nexplanation ...............................................................................................................................\nSIHT\nNI ...................................................................................................................................................\nETIRW\n...................................................................................................................................................\nTON\n[4]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(c) Magnesium reacts with chlorine as shown.\nSIHT\nmol–1 K–1 NI (g) MgCl (s) ΔS = –198.3 J Mg(s) + Cl ⦵\n2 2\nETIRW\n(i) Define entropy.\nTON\n...........................................................................................................................................\nOD\n...........................................................", "pdf_path": "9701-topic-23-chemical-energetics/print/9701-2026-mj-44-q04-0f11f28c7a.pdf" }, { "id": "9701-2026-mj-44-q05", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 5, "topic_number": 27, "topic": "Group 2", "topic_slug": "9701-topic-27-group-2", "marks": 7, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 10, 11 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-27-group-2/assets/9701-2026-mj-44-q05-p01-7b4b913c8a.png", "9701-topic-27-group-2/assets/9701-2026-mj-44-q05-p02-b2b2c27143.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q05", "html": "9701-topic-27-group-2/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:1)(cid:44)\n5 (a) The Group 2 nitrates undergo thermal decomposition.\nSIHT\nNI (i) Write an equation for the thermal decomposition of anhydrous calcium nitrate.\nETIRW\n..................................................................................................................................... [1]\nTON\n(ii) Describe the trend in thermal stability of the nitrate compounds going down Group 2.\nOD\nExplain your answer.\ntrend ..................................................................................................................................\nNIGRAM\nexplanation ........................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n...........................................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) (i) A spatula measure of magnesium hydroxide, Mg(OH) (s), is stirred into a beaker of\nSIHT 2\nSO (aq). A solution is formed with no solid remaining. H\n2 4\nNI\nETIRW\n(s), is stirred into a different beaker of A spatula measure of barium hydroxide, Ba(OH)\n2\nSO (aq). A permanent precipitate is seen. H\n2 4\nTON\nExplain these observations.\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n..................................................................................................................................... [1]\nSIHT\n(s) is stirred into a beaker of water. Very little of the (ii) A spatula measure of Mg(OH)\n2 NI\nsolid dissolves.\nETIRW\n(s) is stirred into a different beaker of water. A solution is A spatula measure of Ba(OH)\n2 TON\nformed with no solid remaining.\nOD\nExplain these observations in terms of the energy changes involved.\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT\n...........................................................................................................................................\nNI\n", "pdf_path": "9701-topic-27-group-2/print/9701-2026-mj-44-q05-0b0dfb8f1a.pdf" }, { "id": "9701-2026-mj-44-q06", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 6, "topic_number": 28, "topic": "Chemistry of transition elements", "topic_slug": "9701-topic-28-chemistry-of-transition-elements", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 12, 13, 14 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-44-q06-p01-01f4bcbeb1.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-44-q06-p02-edd53db1af.png", "9701-topic-28-chemistry-of-transition-elements/assets/9701-2026-mj-44-q06-p03-ee0504a970.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q06", "html": "9701-topic-28-chemistry-of-transition-elements/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:3)(cid:44)\n6 Transition elements can form complex ions.\nSIHT\nNI (a) Define complex.\nETIRW\n...................................................................................................................................................\nTON\n............................................................................................................................................. [1]\nOD\nRh3+, form ten different octahedral complexes with chloride and ammonia (b) Rhodium ions,\nligands, including isomers.\nNIGRAM\n]n ) Cl where x and y can be any integer from These complexes have the formula [Rh(NH\n3 x y\nSIHT zero to six, and n represents a charge between 3 – and 3+.\nNI\nRh3+, chloride and ammonia ligands. (i) Complexes B and C both contain ETIRW\nB has a 2– charge. C has a 1+ charge.\nTON\nOD\nState the values of x and y in B and in C.\nx in B = .................. y in B = ..................\nNIGRAM\nx in C = .................. y in C = ..................\n[2]\nSIHT\n) Cl ], is uncharged. It exists as a pair of isomers. (ii) Complex D, [Rh(NH\n3 3 3\nNI\nETIRW Rh3+ in D. State the coordination number of\nTON ..................................................................................................................................... [1]\nOD\n(iii) Complete the three-dimensional diagrams in Figure 6.1 to show the two isomers of D,\n) Cl ]. [Rh(NH\n3 3 3\nNIGRAM\nSIHT\nNI\nETIRW\nRh Rh\nTON\nOD\nNIGRAM\nSIHT\nFigure 6.1\nNI\n[2]\nETIRW\nTON\nNIGRAM\n(iv) Complete Table 6.1 by placing one tick (✓) in each row to indicate whether the type of\nSIHT\nisomerism is shown in D.\nNI\nETIRW\nTable 6.1\nTON\nshown in D\ntype of isomerism OD\nyes no\nstereoisomerism\noptical isomerism NIGRAM\ngeometrical isomerism\nSIHT [1]\nNI\nETIRW\n]2+ Nickel(II) salts dissolve in water to form the [Ni(H O) complex. (c)\n2 6\nTON\n]2+. ) The expression for K of E is shown. Nickel can also form complex E, [Ni(NH\n3 6 stab\nOD\n]2+] [[Ni(NH )\n3 6 107 = 4.80 × (units not shown) = K\nstab ]2+][NH ]6 [[Ni(H O)\n2 6 3\nNIGRAM (i) Define stability constant, K .\nstab\n...........................................................................................................................................\nSIHT\n..................................................................................................................................... [1] NI\nETIRW\nfor E. (ii) State the units of K\nstab\nTON\n..................................................................................................................................... [1]\nOD\n]2+. , E and [Ni(H O) (iii) F is an aqueous solution containing ammonia, NH\n3 2 6\ndm–3 dm–3. ] = 0.455 mol and [E] = 0.0762 mol In solution F, [NH\n3 NIGRAM\ndm–3, ]2+ of [Ni(H O) in F. Calculate the concentration, in mol\n2 6\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\n]2+ dm–3 O) in F = .......................................... mol [2] concentration of [Ni(H\n2 6\nNI\nETIRW\nNIGRAM\n]2+ (iv) Complete the equation for th", "pdf_path": "9701-topic-28-chemistry-of-transition-elements/print/9701-2026-mj-44-q06-297a6b252e.pdf" }, { "id": "9701-2026-mj-44-q07", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 7, "topic_number": 36, "topic": "Organic synthesis", "topic_slug": "9701-topic-36-organic-synthesis", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 16, 17, 18 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-36-organic-synthesis/assets/9701-2026-mj-44-q07-p01-b2e0a2dc0c.png", "9701-topic-36-organic-synthesis/assets/9701-2026-mj-44-q07-p02-fa9382e24a.png", "9701-topic-36-organic-synthesis/assets/9701-2026-mj-44-q07-p03-3a97e179ee.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q07", "html": "9701-topic-36-organic-synthesis/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:2)(cid:7)(cid:44)\n7 (a) The molecular formula of benzene is C H . The six carbon atoms in benzene form a\nSIHT 6 6\nsix-membered ring.\nNI\nETIRW\n(i) State the C–C–H bond angle in benzene and the hybridisation of each carbon atom.\nTON bond angle ........................................................................................................................\nOD\nhybridisation ......................................................................................................................\n[1]\n(ii) The bonds between neighbouring carbon atoms in benzene involve two types of orbital\nNIGRAM\noverlap, giving σ and π bonds.\nName the orbitals involved, and describe the orbital overlap, in σ and π bonds. SIHT\nNI\norbitals involved in σ bonds ...............................................................................................\nETIRW\norbital overlap in σ bonds ..................................................................................................\nTON\nOD orbitals involved in π bonds ...............................................................................................\norbital overlap in π bonds ..................................................................................................\n[2]\nNIGRAM\n(b) Figure 7.1 describes a four-step synthesis of phenol, starting with benzene.\nSIHT\nNI J\nETIRW\nG\nbenzene\nTON\nOD\nNO\n2\nreaction reaction\nNIGRAM 2 1\nSIHT\nNI\nETIRW\nreaction 3\nTON\nK phenol OD\n– Cl\n+\nOH N N\nNIGRAM reaction\n4\nSIHT\nFigure 7.1\nNI\nETIRW\nTON\nNIGRAM\n(i) State the reagents and conditions for reaction 1 in Figure 7.1.\nSIHT\n..................................................................................................................................... [1] NI\nETIRW\n(ii) The reagents and conditions for reaction 2 are concentrated HCl and Sn, heated\nTON under reflux.\nOD\nDraw the structure of compound J in Figure 7.1. [1]\n(iii) State the reagents and conditions for reactions 3 and 4 in Figure 7.1.\nNIGRAM\nreaction 3 ..........................................................................................................................\nreaction 4 ..........................................................................................................................\nSIHT\n[2]\nNI\nETIRW\nCOCl, in the presence of an Al Cl catalyst. (c) Benzene reacts with ethanoyl chloride, CH\n3 3\nTON\nC+O ion. In this reaction, the electrophile is the CH\nOD 3\n(i) Complete the mechanism in Figure 7.2 for this reaction.\nInclude all relevant curly arrows and charges.\nNIGRAM\norganic intermediate\nSIHT\nNI\nETIRW\nTON\nOD\nC\nC+ CH O\n3\nO CH\n3\nNIGRAM\n+ .....................\nSIHT\nFigure 7.2\nNI\n[3]\nETIRW\nH COCH , can be oxidised by (ii) The product of the reaction shown in Figure 7.2, C\n6 5 3 TON\n. heating with alkaline KMnO\n4\nOD\nThe reaction mixture is then acidified. Benzoic acid, C H COOH, is produced.\n6 5\nComplete the equation for the overall reaction, where ", "pdf_path": "9701-topic-36-organic-synthesis/print/9701-2026-mj-44-q07-0e14791ed1.pdf" }, { "id": "9701-2026-mj-44-q08", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 8, "topic_number": 37, "topic": "Analytical techniques", "topic_slug": "9701-topic-37-analytical-techniques", "marks": 10, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 20, 21, 22 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-37-analytical-techniques/assets/9701-2026-mj-44-q08-p01-c38077e96f.png", "9701-topic-37-analytical-techniques/assets/9701-2026-mj-44-q08-p02-12df530bc4.png", "9701-topic-37-analytical-techniques/assets/9701-2026-mj-44-q08-p03-252cfe04ff.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q08", "html": "9701-topic-37-analytical-techniques/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:1)(cid:44)\n(1H) 8 The proton NMR spectra of three compounds, P, Q and R, are shown in Figure 8.1. The\nSIHT\nin each case. solvent used is CDCl\n3\nNI\nETIRW\ncompound P\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\n10 11 9 8 7 6 5 4 3 2 1 0\nchemical shift, δ / ppm TON\nOD\ncompound Q\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\n9 8 7 6 5 4 3 2 1 0\nchemical shift, δ / ppm\nNIGRAM\ncompound R\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\n12 10 8 0 6 4 2\nSIHT\nchemical shift, δ / ppm\nNI\nETIRW\nFigure 8.1\nTON\nNIGRAM\nTable 8.1\nSIHT\nNI chemical shift\nETIRW\nenvironment of proton example range\nδδ / ppm\nTON\n, –CH –, >CH– 0.9–1.7 alkane –CH\n3 2 OD\n–C=O, –CH –C=O, >CH–C=O 2.2–3.0 alkyl next to C=O CH\n3 2\n–Ar, –CH –Ar, >CH–Ar 2.3–3.0 alkyl next to aromatic ring CH\n3 2\nNIGRAM –O, –CH –O, –CH –Cl 3.2–4.0 alkyl next to electronegative atom CH\n3 2 2\nattached to alkene =CHR 4.5–6.0\nSIHT\nattached to aromatic ring H–Ar 6.0–9.0\nNI\naldehyde HCOR 9.3–10.5 ETIRW\nalcohol ROH 0.5–6.0\nTON\nphenol Ar–OH 4.5–7.0\nOD\ncarboxylic acid RCOOH 9.0–13.0\nalkyl amine R–NH– 1.0–5.0\nNIGRAM\n3.0–6.0 aryl amine Ar–NH\n2\namide RCONHR 5.0–12.0\nSIHT\nNI (a) Identify the substance responsible for the peak at δ = 0 ppm on each spectrum.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\n(b) P, Q and R are phenol, ethanol and ethanoic acid, but not necessarily in this order.\n(i) Identify which compound is phenol.\nNIGRAM\nExplain your answer, identifying the protons responsible for the peaks in the\nrelevant spectrum.\nSIHT\nphenol is compound .......................\nNI\nETIRW\nexplanation ........................................................................................................................\nTON\n...........................................................................................................................................\nOD\n...........................................................................................................................................\n[2]\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(ii) The spectrum of P has peaks at δ = 1.2 ppm and δ = 3.7 ppm.\nSIHT\nNI Name the splitting pattern of each of these peaks and give a reason why the peaks are\nETIRW\nsplit in this way.\nTON splitting pattern of the peak at δ = 1.2 ppm ........................................................................\nOD\nreason for this splitting pattern ..........................................................................................\n...........................................................................................................................................\nNIGRAM\nsplitting pattern of the peak at δ = 3.7 ppm ........................................................................\nreason for this splitting pattern .......................................................................................... SIHT\nNI\n......................", "pdf_path": "9701-topic-37-analytical-techniques/print/9701-2026-mj-44-q08-59005ac6bb.pdf" }, { "id": "9701-2026-mj-44-q09", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 9, "topic_number": 34, "topic": "Nitrogen compounds", "topic_slug": "9701-topic-34-nitrogen-compounds", "marks": 9, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 23, 24 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-44-q09-p01-c27b7f7536.png", "9701-topic-34-nitrogen-compounds/assets/9701-2026-mj-44-q09-p02-a6a67dd97d.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q09", "html": "9701-topic-34-nitrogen-compounds/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:4)(cid:44)\n9 (a) Using a gel buffered at pH 7.6, electrophoresis is performed on a mixture of three\nSIHT\namino acids: asparagine, histidine and lysine.\nNI\nETIRW\n– + x TON\nOD\nmixture applied here\nNIGRAM\nFigure 9.1\nSIHT The isoelectric points of these amino acids are given in Table 9.1.\nNI\nTable 9.1 ETIRW\nTON amino acid isoelectric point\nOD asparagine 5.4\nhistidine 7.6\nlysine 9.7\nNIGRAM\nDescribe the direction of movement of each amino acid during the electrophoresis.\nSIHT\nExplain your answers.\nNI\nETIRW\nasparagine ................................................................................................................................\nTON\n...................................................................................................................................................\nOD\nhistidine ....................................................................................................................................\n...................................................................................................................................................\nNIGRAM\nlysine ........................................................................................................................................\nSIHT\n...................................................................................................................................................\n[3] NI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(b) Serine, H NCH(CH OH)COOH, is an amino acid. It exists as a pair of optical isomers.\nSIHT 2 2\nNI (i) Draw diagrams in Figure 9.2 to show the three-dimensional structures of the two optical\nETIRW\nisomers of serine.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nFigure 9.2\n[1]\nNIGRAM\n(ii) Give the name for a mixture containing equal amounts of the two optical isomers.\nSIHT\n..................................................................................................................................... [1]\nNI\nETIRW\n(iii) Describe two properties that are different for the two optical isomers.\nTON ...........................................................................................................................................\nOD\n...........................................................................................................................................\n..................................................................................................................................... [2]\nNIGRAM\n. (iv) Serine is treated with an excess of phosphorus pentachloride, PCl\n5\nSIHT . The phosphorus-containing product of this reaction is POCl\n3\nNI\nComplete the equation for this reaction. Use the structural formula of the\nETIRW\norganic product.\nTON\n................................................... NCH(CH OH)COOH + ............... PCl H\n2 2 5\nOD\n................................................... [2]\n[Total: 9]\nNIGRAM\nSIHT\nNI\n", "pdf_path": "9701-topic-34-nitrogen-compounds/print/9701-2026-mj-44-q09-fbf96ba3bc.pdf" }, { "id": "9701-2026-mj-44-q10", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 4, "variant": "44", "question_number": 10, "topic_number": 35, "topic": "Polymerisation", "topic_slug": "9701-topic-35-polymerisation", "marks": 6, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-44.pdf?download=true", "source_pages": [ 25, 27, 28 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_44.pdf", "image_paths": [ "9701-topic-35-polymerisation/assets/9701-2026-mj-44-q10-p01-26c1cdbecb.png", "9701-topic-35-polymerisation/assets/9701-2026-mj-44-q10-p02-46135cc184.png", "9701-topic-35-polymerisation/assets/9701-2026-mj-44-q10-p03-af2324c806.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-44-q10", "html": "9701-topic-35-polymerisation/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:6)(cid:44)\n10 Cl OCCOCl can be used to make many polymers.\nSIHT\nNI (a) Suggest the name of Cl OCCOCl.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\nN(CH ) NH to form a polymer. (b) (i) Cl OCCOCl reacts with H\n2 2 4 2\nDraw a section of the polymer showing only one repeat unit.\nNIGRAM\nAny functional groups should be fully displayed.\nSIHT\nNI\nETIRW\nTON\nOD\n[2]\nNIGRAM\n(ii) State the type of polymerisation involved and the linkage between the monomers.\nSIHT\ntype of polymerisation .......................................................................................................\nNI\nETIRW linkage ...............................................................................................................................\n[1]\nTON\nOD\nNCO(CH ) CONH reacts with a suitable reagent, H N(CH ) NH forms. (c) When H\n2 2 2 2 2 2 4 2\nIdentify this reagent.\nNIGRAM\n............................................................................................................................................. [1]\nSIHT\nN(CH ) NH . (d) 1,4-dibromobutane can be used to form H\n2 2 4 2\nNI\nETIRW\nDescribe the reagents and conditions used.\nTON ...................................................................................................................................................\nOD\n............................................................................................................................................. [1]\n[Total: 6]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nImportant values, constants and standards\nSIHT\nNI K–1 mol–1 molar gas constant R = 8.31 J\nETIRW\n104 mol–1 Faraday constant F = 9.65 × C\nTON\n1023 mol–1 Avogadro constant L = 6.022 ×\nOD\n10–19 electronic charge e = –1.60 × C\ndm3 mol–1 = 22.4 at s.t.p. (101 kPa and 273 K) molar volume of gas V\nm\ndm3 mol–1 = 24.0 at room conditions V\nm\nNIGRAM\n10–14 mol2 dm–6 = 1.00 × (at 298 K (25 °C)) ionic product of water K\nw\nkg–1 K–1 g–1 K–1) (4.18 J specific heat capacity of water c = 4.18 kJ\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nPermission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every\nNIGRAM\nreasonable effort has been made by the publisher (Cambridge University Press & Assessment) to trace copyright holders, but if any items requiring clearance\nhave unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity.\nTo avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in our Copyright SIHT\nAcknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live\nexamination ser", "pdf_path": "9701-topic-35-polymerisation/print/9701-2026-mj-44-q10-bb4753537f.pdf" }, { "id": "9701-2026-mj-51-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-51.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-51-q01-p01-d850b48329.png", "9701-experimental-skills/assets/9701-2026-mj-51-q01-p02-17b00a6c75.png", "9701-experimental-skills/assets/9701-2026-mj-51-q01-p03-c4e847a3b4.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-51-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Solid mixture X contains only anhydrous calcium chloride, CaCl , and anhydrous calcium nitrate,\nSIHT 2\n) . An experiment is done to find the percentage by mass of Ca(NO ) in the mixture. Ca(NO\n3 2 3 2\nNI\nETIRW\nstep 1 Weigh an empty crucible. Add approximately 5 g of mixture X to the crucible.\nTON step 2 Reweigh the crucible with mixture X.\nOD\nstep 3 Heat the crucible gently for one minute and then strongly for four minutes. The calcium\nnitrate decomposes.\n) (s) 2CaO(s) + 4NO (g) + O (g) 2Ca(NO\nNIGRAM 3 2 2 2\nstep 4 Allow the crucible to cool. Reweigh the crucible and contents.\nSIHT\n(a) Identify the piece of apparatus that should be used to support the crucible during heating in\nNI\nstep 3.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\n(b) Suggest why heating is gentle at first in step 3.\n............................................................................................................................................. [1]\nNIGRAM\n(c) Give one reason why the heating should be done in a fume hood.\nSIHT\n............................................................................................................................................. [1] NI\nETIRW\n(d) The student carries out the experiment and obtains the results shown in Table 1.1. TON\nOD\nTable 1.1\nmass / g\nNIGRAM\nmass of crucible 12.74\nmass of crucible + contents before heating 17.81\nSIHT\nmass of crucible + contents after heating 16.53\nNI\nETIRW\ngas lost (i) Use the data from Table 1.1 to calculate the amount, in mol, of NO\n2\nduring heating.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nlost = .................................................. mol [2] amount of NO\n2\nTON\nNIGRAM\n(ii) Calculate the percentage error in the measurement of the mass of the\nSIHT\ncrucible + contents before heating.\nNI\nETIRW\nShow your working.\nTON\nOD\nNIGRAM percentage error = ..................................................... % [1]\n(iii) Other than changing the apparatus, suggest how the percentage error in 1(d)(ii) can\nSIHT\nbe reduced.\nNI\nETIRW ..................................................................................................................................... [1]\nTON\n(e) The experiment is repeated using 4.98 g of mixture X. In this experiment, 0.0223 mol of NO\n2 OD\ngas is lost during heating.\n) in this sample of mixture X. Calculate the percentage by mass of Ca(NO\n3 2\nNIGRAM\n: Ca(NO ) , 164.1] [M\nr 3 2\nSIHT\nNI\nETIRW\nTON\npercentage by mass of Ca(NO ) = ..................................................... % [2]\n3 2\nOD\n(f) (i) Suggest one additional step that should be done to ensure that the Ca(NO ) has\n3 2\ncompletely thermally decomposed.\nNIGRAM\n..................................................................................................................................... [1]\n", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-51-q01-70bfbff493.pdf" }, { "id": "9701-2026-mj-51-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "51", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-51.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_51.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-51-q02-p01-cc84470ebf.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p02-3f6c16fe9d.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p03-1d794b2b8e.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p04-4964fbf410.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p05-f50349d9b4.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p06-89e4c4cd7f.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p07-f6eb6f2427.png", "9701-experimental-skills/assets/9701-2026-mj-51-q02-p08-c074a97ea1.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-51-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:6)(cid:44)\n2 Ozone, O (g), is a pollutant at ground level. Some experiments are done to determine the\nSIHT 3\n(g) in the air outside a school at different times of day. concentration of O\n3\nNI\nETIRW I–(aq). The method involves bubbling a sample of air through a solution of acidified iodide ions,\n–(aq). (g) in the sample of air reacts to form triiodide ions, I Any O\n3 3\nTON\n3I–(aq) 2H+(aq) –(aq) (g) + + I + O (g) + H O(l) O\nOD 3 3 2 2\n–(aq) ions. When starch solution is added to the mixture, it forms a coloured complex with I\n3\n–(aq) is found by colorimetry and the percentage of O (g) in the air The concentration of I\n3 3\nis determined.\nNIGRAM\nA diagram of the colorimeter used is shown in Figure 2.1.\nSIHT\nNI\nETIRW LED (light-emitting diode)\nTON\ncm3 10 OD\ncm3 10 measuring\nsolution cylinder\nNIGRAM\nblack\nbox\nSIHT\nNI\nETIRW\nphotocell\nTON\nFigure 2.1\nOD\nIn the colorimeter, light from the LED passes through the solution in the measuring cylinder.\n– ions. The photocell is Some of the light is absorbed by the complex containing starch and I\n3\nused to determine the absorbance of the solution in the measuring cylinder.\nNIGRAM\n(a) Suggest one reason why the colorimeter must be enclosed in a black box.\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(b) To calibrate the colorimeter shown in Figure 2.1, five solutions of different known\nSIHT\n–(aq) are prepared. For each solution, the following procedure is concentrations of I\n3\nNI carried out.\nETIRW\ncm3 –(aq) of I solution in a boiling tube. step 1 Place 15.0\n3\nTON\n–(aq) ions form a step 2 Add a few drops of starch solution to the boiling tube so that I\nOD 3\ncoloured complex.\nstep 3 Wait for ten minutes.\nNIGRAM\ncm3 cm3 of solution from the boiling tube to a 10 measuring cylinder. step 4 Transfer 10.0\nstep 5 Place the measuring cylinder into the colorimeter. SIHT\nNI\nstep 6 Switch on the LED and record the resistance of the photocell.\nETIRW\n–(aq) used and the resistance readings of the photocell, R , The known concentrations of I\n3 s TON\nare shown in Table 2.1.\nOD\nThe absorbance, A, of each solution is calculated using equation 1.\n/ R ) equation 1 A = log (R\ns 0\nNIGRAM\nis the resistance measured in a control experiment. The value of R in this experiment R\n0 0\nis 4.85 kΩ.\nSIHT\nTable 2.1 NI\nETIRW\n–(aq) resistance of photocell, R concentration of I\nabsorbance, A s 3 TON dm–3 / kΩ / mol\nOD\n10– 6 33.46 3.60 ×\n10– 6 23.42 2.94 ×\n10– 6 16.01 2.20 ×\nNIGRAM\n10– 6 9.68 1.52 ×\n10–7 7.50 7.90 ×\nSIHT\nNI\n(i) Complete Table 2.1.\nETIRW\nRecord your values to three significant figures. [1]\nTON\n(ii) Suggest what was placed in the measuring cy", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-51-q02-61ec3f817b.pdf" }, { "id": "9701-2026-mj-52-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-52.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-52-q01-p01-fc8796eaa4.png", "9701-experimental-skills/assets/9701-2026-mj-52-q01-p02-005b37ae7f.png", "9701-experimental-skills/assets/9701-2026-mj-52-q01-p03-fbdce73733.png", "9701-experimental-skills/assets/9701-2026-mj-52-q01-p04-c377db535a.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-52-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n–, 1 Under certain conditions, iodine forms a series of polyiodide anions with the formula I\nSIHT 2n+1\nwhere n is an integer.\nNI\nETIRW\n) NI . After preparing the This question is about the preparation of a polyiodide salt, (CH\n3 4 2n+1\n) NI is found by titration. polyiodide salt, the value of n in (CH\n3 4 2n+1 TON\n) NI is formed when tetramethylammonium iodide, (CH ) NI, reacts with methanolic (CH OD\n3 4 2n+1 3 4\n(meth). iodine solution, I\n2\n) NI + nI (CH ) NI (CH\n3 4 2 3 4 2n+1\nNIGRAM\n(a) Methanolic iodine solution, I (meth), is prepared by dissolving solid I in methanol.\n2 2 SIHT\ncm3 (s) needed to prepare 100.0 of (i) Calculate the mass, in g, of I\nNI\n2\ndm–3 I (meth). 0.300 mol ETIRW\n2\nTON\nOD\nmass = ...................................................... g [1]\nNIGRAM\ncm3 dm–3 of 0.300 mol I (meth), starting from (ii) Describe the steps taken to prepare 100.0\n2\ncm3 (s) calculated in 1(a)(i) in a 50 beaker. the mass of I\n2\nSIHT\nGive the name and capacity of any apparatus used.\nNI\nETIRW\nWrite your answer using a series of numbered steps.\nTON ...........................................................................................................................................\nOD\n...........................................................................................................................................\n...........................................................................................................................................\nNIGRAM\n...........................................................................................................................................\nSIHT ...........................................................................................................................................\nNI\n...........................................................................................................................................\nETIRW\n...........................................................................................................................................\nTON\nOD ...........................................................................................................................................\n..................................................................................................................................... [3]\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(b) The following steps are carried out.\nSIHT\ncm3 NI ) NI(s) to a dry conical flask. Add 10 of the I (meth) step 1 Add 0.250 g of (CH\n3 4 2\nETIRW\nsolution prepared in 1(a).\nTON\nstep 2 Carefully warm the conical flask in a water bath until no solid remains.\nOD\nstep 3 Allow to cool for about 30 minutes, swirling occasionally. Crystals of the product,\n) NI , form. (CH\n3 4 2n+1\nstep 4 Filter the mixture. NIGRAM\nstep 5 Wash the crystals with cold methanol.\nSIHT\nstep 6 Transfer the crystals to an evaporating ", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-52-q01-68bd2da592.pdf" }, { "id": "9701-2026-mj-52-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "52", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-52.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_52.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-52-q02-p01-82f5aee206.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p02-16ae1e91b8.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p03-f64fe7045f.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p04-2f302fe51a.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p05-6f1736cdbe.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p06-85d1735e36.png", "9701-experimental-skills/assets/9701-2026-mj-52-q02-p07-399012571a.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-52-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 This question is about the rate of the reaction between aqueous sodium ethanedioate,\nSIHT\nC O (aq), and aqueous sodium peroxydisulfate, Na S O (aq). Na\n2 2 4 2 2 8\nNI\nETIRW\nC O (aq) + Na S O (aq) 2Na SO (aq) + 2CO (g) Na\n2 2 4 2 2 8 2 4 2\nTON C O (aq) is in excess, the rate equation for this reaction is: When Na\n2 2 4\nOD\n]m S O rate = k [Na\n2 2 8\nwhere k is the rate constant and m is the order of the reaction with respect to Na S O (aq).\n2 2 8\nNIGRAM\nC O (aq) is added to a sample of Na S O (aq) in a side‑arm In an experiment, excess Na\n2 2 4 2 2 8\n(g), produced is measured at regular conical flask. The volume of carbon dioxide gas, CO\n2\ntime intervals. SIHT\nNI\nFigure 2.1 shows the results from the experiment plotted on the grid. A curved line of best fit has\nETIRW\nbeen drawn.\nTON\n12\nOD\n10\nNIGRAM\nSIHT\n8\nNI\nETIRW\nvolume\n(g) of CO\nTON 2 6\nproduced\nOD cm3 /\n4\nNIGRAM\nSIHT\n2\nNI\nETIRW\n0 TON\n0 200 400 600 800 1000 1200 1400 1600\nOD\n/ s time\nFigure 2.1\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(a) Complete Figure 2.2 to show how the apparatus should be set up for measurement of the\nSIHT\n(g) produced. CO (g) is soluble in water. volume of CO\n2 2\nNI Label your diagram.\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nFigure 2.2\nSIHT [2]\nNI\nETIRW\n(b) Identify the independent variable.\nTON\n............................................................................................................................................. [1]\nOD\n(c) Suggest a timing error that could have led to the anomalous point in Figure 2.1.\nNIGRAM\n............................................................................................................................................. [1]\nSIHT\n(d) On Figure 2.1, draw a second curve to show the graph produced if the experiment is done at\nNI a higher temperature. All other conditions stay the same. [1]\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(e) A student carries out the same procedure using different concentrations of Na S O . The\nSIHT 2 2 8\nresults are used to produce the data shown in Table 2.1.\nNI\nETIRW\nTable 2.1\nTON\n[Na S O ] rate\n2 2 8 log [Na S O ] log (rate)\ndm–3 s–1 OD dm–3 / mol 2 2 8 / mol\n10–2 1.00 × 0.02760\nNIGRAM 10–3 0.01160 5.74 ×\n10–3 0.00549 3.67 × SIHT\nNI\n10–3 0.00398 2.88 ×\nETIRW\n10–3 0.00250 2.08 ×\nTON\nOD\n10–3 0.00169 1.57 ×\n(i) Complete Table 2.1.\nRecord your values to two decimal places. [2] NIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(ii) Use the results from Table 2.1 to plot a graph on the grid in Figure 2.3 to show\nSIHT\nS O ] and log (rate). Use a cross (×) to plot each the relationship between log [Na\n2 2 8\nNI data point.\nETIRW\nDraw a straight line of best fit.\nTON\n–1.4\nOD\n–1.6\nNIGRAM\nSIHT\n–1.8\nNI\nETIRW\n–2.0\nTON\nlog\nOD\n(rate)\n–2.2\nNIGRAM\n–2.4\nSIHT\nNI\nETIRW –2.6\nTON\nOD\n–2.8\n–2.8 –2.7 –2.6 –2.5 –2.4 –2.3 –2.2 –2.1 –2.0 –2.9\nlog [Na S O ]\n2 2 8\nNIGRAM\nFigure", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-52-q02-2ac6828328.pdf" }, { "id": "9701-2026-mj-53-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 13, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-53.pdf?download=true", "source_pages": [ 2, 3, 4 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-53-q01-p01-8f52ee7216.png", "9701-experimental-skills/assets/9701-2026-mj-53-q01-p02-8333faae51.png", "9701-experimental-skills/assets/9701-2026-mj-53-q01-p03-33a4cd51c5.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-53-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 Solid mixture X contains only anhydrous calcium chloride, CaCl , and anhydrous calcium nitrate,\nSIHT 2\n) . An experiment is done to find the percentage by mass of Ca(NO ) in the mixture. Ca(NO\n3 2 3 2\nNI\nETIRW\nstep 1 Weigh an empty crucible. Add approximately 5 g of mixture X to the crucible.\nTON step 2 Reweigh the crucible with mixture X.\nOD\nstep 3 Heat the crucible gently for one minute and then strongly for four minutes. The calcium\nnitrate decomposes.\n) (s) 2CaO(s) + 4NO (g) + O (g) 2Ca(NO\nNIGRAM 3 2 2 2\nstep 4 Allow the crucible to cool. Reweigh the crucible and contents.\nSIHT\n(a) Identify the piece of apparatus that should be used to support the crucible during heating in\nNI\nstep 3.\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\n(b) Suggest why heating is gentle at first in step 3.\n............................................................................................................................................. [1]\nNIGRAM\n(c) Give one reason why the heating should be done in a fume hood.\nSIHT\n............................................................................................................................................. [1] NI\nETIRW\n(d) The student carries out the experiment and obtains the results shown in Table 1.1. TON\nOD\nTable 1.1\nmass / g\nNIGRAM\nmass of crucible 12.74\nmass of crucible + contents before heating 17.81\nSIHT\nmass of crucible + contents after heating 16.53\nNI\nETIRW\ngas lost (i) Use the data from Table 1.1 to calculate the amount, in mol, of NO\n2\nduring heating.\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nlost = .................................................. mol [2] amount of NO\n2\nTON\nNIGRAM\n(ii) Calculate the percentage error in the measurement of the mass of the\nSIHT\ncrucible + contents before heating.\nNI\nETIRW\nShow your working.\nTON\nOD\nNIGRAM percentage error = ..................................................... % [1]\n(iii) Other than changing the apparatus, suggest how the percentage error in 1(d)(ii) can\nSIHT\nbe reduced.\nNI\nETIRW ..................................................................................................................................... [1]\nTON\n(e) The experiment is repeated using 4.98 g of mixture X. In this experiment, 0.0223 mol of NO\n2 OD\ngas is lost during heating.\n) in this sample of mixture X. Calculate the percentage by mass of Ca(NO\n3 2\nNIGRAM\n: Ca(NO ) , 164.1] [M\nr 3 2\nSIHT\nNI\nETIRW\nTON\npercentage by mass of Ca(NO ) = ..................................................... % [2]\n3 2\nOD\n(f) (i) Suggest one additional step that should be done to ensure that the Ca(NO ) has\n3 2\ncompletely thermally decomposed.\nNIGRAM\n..................................................................................................................................... [1]\n", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-53-q01-0ef8f50f6a.pdf" }, { "id": "9701-2026-mj-53-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "53", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 17, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-53.pdf?download=true", "source_pages": [ 5, 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_53.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-53-q02-p01-1a9f83389c.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p02-92f7b44cba.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p03-2a379dcc69.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p04-90751bae0f.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p05-5a0e0ecd3d.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p06-758933ae18.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p07-c673b0b4d6.png", "9701-experimental-skills/assets/9701-2026-mj-53-q02-p08-776790c2c5.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-53-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:6)(cid:44)\n2 Ozone, O (g), is a pollutant at ground level. Some experiments are done to determine the\nSIHT 3\n(g) in the air outside a school at different times of day. concentration of O\n3\nNI\nETIRW I–(aq). The method involves bubbling a sample of air through a solution of acidified iodide ions,\n–(aq). (g) in the sample of air reacts to form triiodide ions, I Any O\n3 3\nTON\n3I–(aq) 2H+(aq) –(aq) (g) + + I + O (g) + H O(l) O\nOD 3 3 2 2\n–(aq) ions. When starch solution is added to the mixture, it forms a coloured complex with I\n3\n–(aq) is found by colorimetry and the percentage of O (g) in the air The concentration of I\n3 3\nis determined.\nNIGRAM\nA diagram of the colorimeter used is shown in Figure 2.1.\nSIHT\nNI\nETIRW LED (light-emitting diode)\nTON\ncm3 10 OD\ncm3 10 measuring\nsolution cylinder\nNIGRAM\nblack\nbox\nSIHT\nNI\nETIRW\nphotocell\nTON\nFigure 2.1\nOD\nIn the colorimeter, light from the LED passes through the solution in the measuring cylinder.\n– ions. The photocell is Some of the light is absorbed by the complex containing starch and I\n3\nused to determine the absorbance of the solution in the measuring cylinder.\nNIGRAM\n(a) Suggest one reason why the colorimeter must be enclosed in a black box.\nSIHT\n...................................................................................................................................................\nNI\nETIRW\n............................................................................................................................................. [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(b) To calibrate the colorimeter shown in Figure 2.1, five solutions of different known\nSIHT\n–(aq) are prepared. For each solution, the following procedure is concentrations of I\n3\nNI carried out.\nETIRW\ncm3 –(aq) of I solution in a boiling tube. step 1 Place 15.0\n3\nTON\n–(aq) ions form a step 2 Add a few drops of starch solution to the boiling tube so that I\nOD 3\ncoloured complex.\nstep 3 Wait for ten minutes.\nNIGRAM\ncm3 cm3 of solution from the boiling tube to a 10 measuring cylinder. step 4 Transfer 10.0\nstep 5 Place the measuring cylinder into the colorimeter. SIHT\nNI\nstep 6 Switch on the LED and record the resistance of the photocell.\nETIRW\n–(aq) used and the resistance readings of the photocell, R , The known concentrations of I\n3 s TON\nare shown in Table 2.1.\nOD\nThe absorbance, A, of each solution is calculated using equation 1.\n/ R ) equation 1 A = log (R\ns 0\nNIGRAM\nis the resistance measured in a control experiment. The value of R in this experiment R\n0 0\nis 4.85 kΩ.\nSIHT\nTable 2.1 NI\nETIRW\n–(aq) resistance of photocell, R concentration of I\nabsorbance, A s 3 TON dm–3 / kΩ / mol\nOD\n10– 6 33.46 3.60 ×\n10– 6 23.42 2.94 ×\n10– 6 16.01 2.20 ×\nNIGRAM\n10– 6 9.68 1.52 ×\n10–7 7.50 7.90 ×\nSIHT\nNI\n(i) Complete Table 2.1.\nETIRW\nRecord your values to three significant figures. [1]\nTON\n(ii) Suggest what was placed in the measuring cy", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-53-q02-bd0f714f99.pdf" }, { "id": "9701-2026-mj-54-q01", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 1, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 16, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-54.pdf?download=true", "source_pages": [ 2, 3, 4, 5 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-54-q01-p01-ce1868e17b.png", "9701-experimental-skills/assets/9701-2026-mj-54-q01-p02-60155d6256.png", "9701-experimental-skills/assets/9701-2026-mj-54-q01-p03-123f8c0dc0.png", "9701-experimental-skills/assets/9701-2026-mj-54-q01-p04-ec3ad029b8.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-54-q01", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:3)(cid:44)\n1 A student uses two different methods to determine the value of integer x in hydrated\nSIHT\nCO •xH O(s). sodium carbonate crystals, Na\n2 3 2\nNI\nETIRW\nMethod 1\nTON The student uses the following procedure.\nOD\nstep 1 Weigh an empty crucible.\nCO •xH O(s) to the crucible. step 2 Add approximately 5 g of Na\n2 3 2\nNIGRAM\nstep 3 Weigh the crucible and contents.\nstep 4 Heat the crucible and contents for 5 minutes. SIHT\nNI\nstep 5 Allow the crucible to cool. Weigh the crucible and residue.\nETIRW\n(a) Suggest what the student should do to ensure all the water is removed from the\nTON\nhydrated salt.\nOD\n............................................................................................................................................. [1]\nNIGRAM (b) The student’s results are shown in Table 1.1.\nTable 1.1\nSIHT\nNI\nmass / g ETIRW\nTON mass of empty crucible 17.68\nOD\nmass of crucible + contents 22.57\nCO •xH O(s) added mass of Na\n2 3 2 NIGRAM\nmass of crucible + residue 19.74\nSIHT\nmass of residue NI\nETIRW\n(i) Complete Table 1.1. Hence, calculate the mass, in g, of water lost.\nTON\nOD\nmass of water lost = ............................................................ g\n[1]\nNIGRAM\n(ii) Using the same apparatus, suggest a modification that the student could make to the\nmethod to reduce the percentage error in the measurement of the mass of water lost.\nSIHT\n...........................................................................................................................................\nNI\nETIRW\n..................................................................................................................................... [1]\nTON\nNIGRAM\n(c) Use the student’s results for Method 1 to calculate the value of x in Na CO •xH O(s).\nSIHT 2 3 2\nNI Show your working. Give your answer to the nearest whole number.\nETIRW\nTON\nOD\nx = ......................................................... [2]\nNIGRAM\n(d) Method 2\nSIHT The student uses the following procedure.\nNI\ncm3 of solution A containing 0.365 g of Na CO •xH O(s). step 1 Prepare 250.0 ETIRW\n2 3 2\ndm–3 hydrochloric acid, HCl (aq). step 2 Fill a burette with 0.0100 mol\nTON\nOD cm3 of solution A to a conical flask. step 3 Use a pipette to transfer 25.0\ndm–3 HCl (aq) using step 4 Titrate the contents of the conical flask against 0.0100 mol\nmethyl orange indicator.\nNIGRAM\nRepeat steps 3 and 4 as many times as necessary.\nSIHT\nThe equation for the reaction is shown.\nNI\nETIRW CO (aq) + 2HCl (aq) 2NaCl (aq) + H O(l) + CO (g) Na\n2 3 2 2\ncm3 TON of solution A, starting from 0.365 g of (i) Describe how the student should make 250.0\ncm3 CO •xH O(s) in a 50 beaker. Na\nOD 2 3 2\nGive the name and capacity of any apparatus used.\nWrite your answer using a series of numbered steps.\nNIGRAM\n.......................................................................................................................................", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-54-q01-294b0fcffc.pdf" }, { "id": "9701-2026-mj-54-q02", "subject": "9701", "year": 2026, "session": "May/June", "session_code": "mj", "paper": 5, "variant": "54", "question_number": 2, "topic_number": null, "topic": "Planning, analysis and evaluation", "topic_slug": "9701-experimental-skills", "marks": 14, "source_pdf": "https://pastpapers.co/api/file/caie/a-level/chemistry-9701/2026-may-june/9701-chemistry-june-2026-question-paper-54.pdf?download=true", "source_pages": [ 6, 7, 8, 9, 10, 11, 12 ], "local_pdf": "_source-pdfs/2026-May-June/qp/9701_s26_qp_54.pdf", "image_paths": [ "9701-experimental-skills/assets/9701-2026-mj-54-q02-p01-5c66a1849d.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p02-b69734951d.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p03-07a97c043e.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p04-5af8f1ffdc.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p05-53d17c5846.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p06-c139f7d219.png", "9701-experimental-skills/assets/9701-2026-mj-54-q02-p07-dea507d7da.png" ], "answer": { "status": "pending", "id": "9701-2026-mj-54-q02", "html": "9701-experimental-skills/answers.html" }, "text_excerpt": "NIGRAM\n(cid:44)(cid:1)(cid:1)(cid:1)(cid:1)(cid:9)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:1)(cid:7)(cid:44)\n2 A student makes ammonia gas, NH (g), in the laboratory by heating a mixture of solid\nSIHT 3\nCl (s), and solid calcium hydroxide, Ca(OH) (s). ammonium chloride, NH\n4 2\nNI\nETIRW\nCl (s) + Ca(OH) (s) CaCl (s) + 2NH (g) + 2H O(l) 2NH\n4 2 2 3 2\nTON (g). The student uses the apparatus shown in Figure 2.1 to collect a sample of NH\n3\nOD\ngas jar\nround-bottomed flask\ncontaining\nNIGRAM\n(s) + Ca(OH) (s) Cl NH\n2 4\nSIHT\nNI\nETIRW\nTON\nOD\ntube B containing\nheat calcium oxide granules\nNIGRAM\nFigure 2.1\nSIHT\nCl (s). Calculate the minimum mass, in g, of Ca(OH) (s) (a) (i) The student uses 5.00 g of NH\n4 2 NI\nCl (s). that should be added to the round-bottomed flask to react fully with 5.00 g of NH\nETIRW 4\nGive your answer to three significant figures.\nTON\nOD\nNIGRAM\n(s) = ....................................................... g [1] mass of Ca(OH)\nSIHT 2\nNI (ii) Suggest why the student carries out this experiment in a fume hood.\nETIRW\n..................................................................................................................................... [1]\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\n(iii) Tube B contains calcium oxide granules.\nSIHT\nNI (g) is passed through tube B before collection. Suggest why NH\n3\nETIRW\n..................................................................................................................................... [1]\nTON\n(g) is collected in an inverted gas jar as shown in Figure 2.1. (iv) NH\nOD 3\n(g) in this way. Suggest why it is possible to collect NH\n3\n..................................................................................................................................... [1]\nNIGRAM\n(b) Figure 2.2 shows an alternative method of collecting a gas. SIHT\nNI\nETIRW\ngas\nTON water\nOD\nNIGRAM\nSIHT\nFigure 2.2\nNI\nETIRW Suggest why the apparatus shown in Figure 2.2 is not suitable to collect the\n(g) produced. NH\n3\nTON\n............................................................................................................................................. [1]\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nNIGRAM\n(c) The student investigates the decomposition of NH (g) in the presence of a catalyst.\nSIHT 3\nNI (g) N (g) + 3H (g) 2NH\n3 2 2 ETIRW\n(g) as the reaction proceeds. The student measures the concentration of NH\n3\nTON\nTwo catalysts, tungsten and nickel-loaded silica, are compared.\nOD\nThe student’s results using tungsten are plotted on the grid in Figure 2.3. The line of best fit\nis labelled ‘tungsten’.\nNIGRAM\n0.0030\nSIHT\nNI\n0.0025 ETIRW\nTON\nOD\n0.0020\ntungsten\ndm–3 [NH ] / mol\n3\nNIGRAM\n0.0015\nSIHT\nNI\nETIRW\n0.0010\nTON\nOD\n0.0005\n200 400 600 800 1000 0\ntime / s\nNIGRAM\nFigure 2.3\nSIHT\nNI\nETIRW\nTON\nOD\nNIGRAM\nSIHT\nNI\nETIRW\nTON\nNIGRAM\nThe student repeats the experiment using nickel-loaded silica as the catalyst in place\nSIHT\nof tungsten.\nNI\nETIRW\nThe student’s results using nickel-loaded silica are s", "pdf_path": "9701-experimental-skills/print/9701-2026-mj-54-q02-ae899a6b49.pdf" } ] }