Six-mark level of response questions

74 level of response questions, the ones marked with an asterisk (*), grouped by topic. Each A-level paper has two of them; each AS paper has one or two. Pick one to answer under timed conditions (about eight minutes), then open the mark scheme with its three levels and indicative points and decide your level.

How they are marked

Level	Marks	What it takes
Level 3	5–6	All the strands of the question are answered with correct chemistry, in a clear and logical line of reasoning, with the evidence or working to support it.
Level 2	3–4	Most of the chemistry is right but one strand is missing or wrong, or the reasoning has some structure but gaps.
Level 1	1–2	Some correct points, but one strand only or an answer without a clear structure.

The examiner first decides the level from the chemistry, then picks the higher or lower mark in that level from how well the answer is communicated. Most questions have two or three strands (for example: do the calculation, identify the compound, explain the evidence): attempt every strand. Summary written by the site from OCR's marking instructions; being checked by our tutor.

Timed practice

(random from the selected topics, or from all)

All the questions by topic

Practical skills: planning, analysis and evaluation (4)

Series	Paper	What it asks
June 2024	AS Paper 2 Q3(b)	A student carries out an experiment to determine the enthalpy change for the reaction between zinc and copper(II) nitrate solution. Zn(s) + Cu(NO3)2(aq) Zn(NO3)2(aq) + Cu(s) ΔrH Equation 3.1
June 2023	AS Paper 2 Q4(b)(ii)	i)* Use the student’s results to determine ∆cH of butan-1-ol in kJ mol–1. Explain why this value of ΔcH is different from the data book value and suggest how the experimental design could be modified to improve the accuracy of the
June 2019	AS Paper 2 Q2(a)	A student plans to prepare 250.0 cm3 of a 0.4000 mol dm–3 solution of magnesium nitrate, starting from magnesium nitrate crystals, Mg(NO3)2•6H2O. Describe how the student would prepare the solution, giving full details of quantiti
June 2017	AS Paper 2 Q2	A student was asked to carry out an experiment to determine the initial rate of reaction of zinc and hydrochloric acid. The student plans to collect a total of about 72 cm3 of hydrogen at RTP and to use an excess of

Practical techniques and apparatus (PAGs) (7)

Series	Paper	What it asks
June 2025	AS Paper 2 Q5(c)	2-Chlorobutane, CH3CH2CHCl CH3, is an organic liquid with a boiling point of 70 °C. A student prepares 2-chlorobutane from butan-2-ol, CH3CH2CHOHCH3, as shown in the equation below.
June 2022	Paper 3 Q3(a)	Draw a diagram to show how the student would have carried out the reflux and calculate the percentage yield of 1-bromobutane that the student obtains. Describe how the student could have obtained pure 1-bromobutane from the reacti
November 2021	AS Paper 2 Q7(b)	The student’s method for the preparation is outlined below. • Add 10.0 cm3 (7.70 g) of (CH3)3COH and 30 cm3 concentrated hydrochloric acid (an excess) to a round-bottom flask. Stopper the flask.
November 2020	Paper 2 Q20(a)	Calculate the mass of cyclopentanol that the student should use and explain how pure cyclopentene could be obtained from the distillate.
June 2019	AS Paper 2 Q2(a)	A student plans to prepare 250.0 cm3 of a 0.4000 mol dm–3 solution of magnesium nitrate, starting from magnesium nitrate crystals, Mg(NO3)2•6H2O. Describe how the student would prepare the solution, giving full details of quantiti
June 2019	AS Paper 2 Q5(b)(i)	A student plans to prepare 4.20 g of hex-1-ene by this method. Calculate the mass of hexan-1-ol that the student should use and explain how you could obtain pure hex-1-ene from the mixture obtained after reflux.
June 2018	AS Paper 2 Q5(a)(i)	Draw a labelled diagram to show how you would safely set up apparatus for the preparation. Outline a method to obtain a pure sample of 1-bromobutane from the reaction mixture.

Formulae and equations (4)

Series	Paper	What it asks
November 2021	Paper 3 Q5(c)	This question is about two reactions of ammonia. Reaction 1 Excess ammonia is reacted with 4.77 g of copper(II) oxide. The reaction produces 3.81 g of
November 2020	AS Paper 2 Q1(c)	A student is provided with samples of three nickel compounds. One sample is nickel(II) bromide, another is nickel(II) sulfate and the third is nickel(II) carbonate. The student doesn’t know which sample is which.
November 2020	Paper 1 Q22(a)	B and C are compounds of two different transition elements. A student carries out test tube reactions on aqueous solutions of B and C. The observations of the student’s tests are shown below.
June 2019	Paper 3 Q6(b)	Compound C is a hydrated ionic compound with the empirical formula: FeH18N3O18. A student investigates the thermal decomposition of compound C as outlined below. Stage 1

Amount of substance (moles) (33)

Series	Paper	What it asks
June 2025	AS Paper 2 Q5(c)	2-Chlorobutane, CH3CH2CHCl CH3, is an organic liquid with a boiling point of 70 °C. A student prepares 2-chlorobutane from butan-2-ol, CH3CH2CHOHCH3, as shown in the equation below.
June 2025	Paper 1 Q19(c)	A student plans to prepare a buffer solution with a pH of 4.85 using propanoic acid, CH3CH2COOH, and sodium propanoate, CH3CH2COONa. Ka for CH3CH2COOH = 1.32 × 10–5 mol dm–3.
June 2025	Paper 2 Q17	This question is about an organic synthesis. A student plans a two-stage synthesis of compound F from compound D, as shown below. Cl OH OH O
June 2025	Paper 3 Q6	The enthalpy change of Reaction 6.1, ∆H1, shown below, is difficult to measure directly by experiment. 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g) ∆H1 Reaction 6.1
June 2024	AS Paper 2 Q3(b)	A student carries out an experiment to determine the enthalpy change for the reaction between zinc and copper(II) nitrate solution. Zn(s) + Cu(NO3)2(aq) Zn(NO3)2(aq) + Cu(s) ΔrH Equation 3.1
June 2024	Paper 3 Q3(b)(iv)	v)* In the titration, 5 mol of iron(II) ethanedioate reacts with 3 mol of manganate(VII) ions. Analyse the student’s results to find the number of waters of crystallisation, x, in the hydrated iron(II) ethanedioate, FeC2O4•xH2O.
June 2023	AS Paper 2 Q3(a)	Seawater contains very small quantities of dissolved iodide ions. The concentration of potassium iodide, KI, in seawater is 0.150 g dm–3. Iodine can be extracted by bubbling chlorine gas through seawater.
June 2023	Paper 2 Q23	An unknown organic compound is analysed. The results are shown below. Addition of 2,4-DNP
June 2023	Paper 3 Q6(e)	Three reactions involving sulfuric acid are shown below. Reaction 1 Dilute sulfuric acid is reacted with nickel(II) hydroxide to form a green solution.
June 2022	Paper 1 Q22(c)	This question is about copper and copper compounds. Experiment 1 Hydrochloric acid, HCl (aq), is added to an aqueous solution containing [Cu(H2O)6]2+
June 2022	Paper 2 Q19(e)	A student intends to synthesise compound I. O O
June 2022	Paper 3 Q3(a)	Draw a diagram to show how the student would have carried out the reflux and calculate the percentage yield of 1-bromobutane that the student obtains. Describe how the student could have obtained pure 1-bromobutane from the reacti
November 2021	AS Paper 2 Q4(a)	Use the student’s results to calculate ∆H2 for Reaction 2 and determine the enthalpy change ∆H1, in kJ mol–1, for the decomposition of magnesium carbonate (Reaction 1), using the energy cycle in Fig. 4.1.
November 2021	AS Paper 2 Q7(b)	The student’s method for the preparation is outlined below. • Add 10.0 cm3 (7.70 g) of (CH3)3COH and 30 cm3 concentrated hydrochloric acid (an excess) to a round-bottom flask. Stopper the flask.
November 2021	Paper 1 Q17(b)(ii)	i)* Determine the formulae of A and B. Write the ionic equation for the ligand substitution and show 3D structures for the three stereoisomers of B.
November 2021	Paper 1 Q22(c)	Nitrous acid, HNO2, is a weak Brønsted–Lowry acid with a pKa value of 3.34 at room temperature. HNO2 can be prepared by reacting N2O3 with water.
November 2021	Paper 2 Q19(b)	A student intends to synthesise compound A using the two-stage route below. O Stage 1 Stage 2
November 2021	Paper 3 Q5(c)	This question is about two reactions of ammonia. Reaction 1 Excess ammonia is reacted with 4.77 g of copper(II) oxide. The reaction produces 3.81 g of
November 2020	Paper 2 Q20(a)	Calculate the mass of cyclopentanol that the student should use and explain how pure cyclopentene could be obtained from the distillate.
November 2020	Paper 2 Q22(b)	Determine the structure of compound I, showing all your reasoning.
June 2019	AS Paper 2 Q2(a)	A student plans to prepare 250.0 cm3 of a 0.4000 mol dm–3 solution of magnesium nitrate, starting from magnesium nitrate crystals, Mg(NO3)2•6H2O. Describe how the student would prepare the solution, giving full details of quantiti
June 2019	AS Paper 2 Q5(b)(i)	A student plans to prepare 4.20 g of hex-1-ene by this method. Calculate the mass of hexan-1-ol that the student should use and explain how you could obtain pure hex-1-ene from the mixture obtained after reflux.
June 2019	Paper 2 Q18(e)(i)	A student intends to synthesise ester C. H O
June 2019	Paper 2 Q21	Analysis of an unknown organic compound produced the following results. Elemental analysis by mass C: 73.17%; H: 7.32%; O: 19.51%
June 2019	Paper 3 Q5(a)(i)	Calculate ∆solH(CuSO4(s)) for reaction 5.2 and determine the enthalpy change of reaction 5.1, ∆rH. Assume that the specific heat capacity, c, of the solution is the same as for water.
June 2019	Paper 3 Q6(b)	Compound C is a hydrated ionic compound with the empirical formula: FeH18N3O18. A student investigates the thermal decomposition of compound C as outlined below. Stage 1
June 2018	Paper 1 Q21(d)	Three different reactions of copper compounds are described below. Reaction 1: Aqueous copper(II) sulfate reacts with excess aqueous ammonia in a ligand substitution reaction. A deep-blue solution is formed, containing an octahedr
June 2018	Paper 2 Q22(d)	A scientist is researching compounds that might be suitable as fuel additives. One of the compounds gives the analytical results below. Elemental analysis by mass:
June 2018	Paper 3 Q4(b)(ii)	i)* A chemist prepares a pure solid sample of paracetamol from 4-nitrophenol in two stages: H Stage 1 Stage 2
June 2017	AS Paper 2 Q2	A student was asked to carry out an experiment to determine the initial rate of reaction of zinc and hydrochloric acid. The student plans to collect a total of about 72 cm3 of hydrogen at RTP and to use an excess of
June 2017	Paper 1 Q23(b)	A hydrated nickel(II) complex, A, is heated in a crucible to remove the water of crystallisation. The anhydrous complex B is formed. The results are shown below. Mass of crucible + hydrated complex A = 59.554 g
June 2017	Paper 2 Q17(a)(ii)	i)* A chemist carries out the reaction in Equation 17.1 using 4.97 g of benzoic acid. The chemist obtains 3-nitrobenzoic acid as an impure solid. The chemist purifies the solid to obtain 4.85 g of 3-nitrobenzoic acid.
June 2017	Paper 3 Q2(a)	Calculate the enthalpy change of reaction 3.2 and the enthalpy change of reaction 3.1. Show all your working.

Acids, bases and titrations (3)

Series	Paper	What it asks
November 2020	AS Paper 2 Q1(c)	A student is provided with samples of three nickel compounds. One sample is nickel(II) bromide, another is nickel(II) sulfate and the third is nickel(II) carbonate. The student doesn’t know which sample is which.
June 2019	AS Paper 2 Q2(a)	A student plans to prepare 250.0 cm3 of a 0.4000 mol dm–3 solution of magnesium nitrate, starting from magnesium nitrate crystals, Mg(NO3)2•6H2O. Describe how the student would prepare the solution, giving full details of quantiti
June 2018	Paper 1 Q21(d)	Three different reactions of copper compounds are described below. Reaction 1: Aqueous copper(II) sulfate reacts with excess aqueous ammonia in a ligand substitution reaction. A deep-blue solution is formed, containing an octahedr

Redox and oxidation numbers (3)

Series	Paper	What it asks
June 2025	AS Paper 2 Q2(a)(ii)	i)* Magnesium and calcium differ in their reactivity. Give a balanced equation for the reaction of calcium with water and describe what would be observed. Explain why this is a redox reaction.
June 2023	Paper 3 Q6(e)	Three reactions involving sulfuric acid are shown below. Reaction 1 Dilute sulfuric acid is reacted with nickel(II) hydroxide to form a green solution.
June 2022	Paper 1 Q22(c)	This question is about copper and copper compounds. Experiment 1 Hydrochloric acid, HCl (aq), is added to an aqueous solution containing [Cu(H2O)6]2+

Electron structure and orbitals (1)

Series	Paper	What it asks
June 2023	Paper 1 Q22(a)	Explain, with examples from Period 4, what is meant by the terms d-block element and transition element. Explain why some d-block elements are not transition elements.

Bonding, structure and shapes of molecules (4)

Series	Paper	What it asks
June 2025	Paper 1 Q16(d)	The hydrides of silicon, phosphorus and sulfur have simple molecular structures, but their molecules have different shapes. Explain why molecules of SiH4, PH3 and H2S have different shapes.
June 2024	Paper 1 Q20(c)	The table shows the melting points of some of the elements in Period 3 of the periodic table. Element Al Si P4 S8 Melting point / °C 660 1410 44 119
November 2020	Paper 1 Q16(c)	Table 16.1 shows some physical properties of magnesium, bromine and magnesium bromide. Electrical conductivity Substance Melting point / °C
June 2018	Paper 2 Q20(d)	Methylcinnamaldehyde reacts with iodine monochloride, ICl, by electrophilic addition. The reaction produces a mixture containing two different organic products. CHO

Periodicity and ionisation energy (4)

Series	Paper	What it asks
June 2025	AS Paper 2 Q2(a)(ii)	i)* Magnesium and calcium differ in their reactivity. Give a balanced equation for the reaction of calcium with water and describe what would be observed. Explain why this is a redox reaction.
June 2024	Paper 1 Q20(c)	The table shows the melting points of some of the elements in Period 3 of the periodic table. Element Al Si P4 S8 Melting point / °C 660 1410 44 119
June 2023	Paper 1 Q22(a)	Explain, with examples from Period 4, what is meant by the terms d-block element and transition element. Explain why some d-block elements are not transition elements.
November 2020	Paper 1 Q16(c)	Table 16.1 shows some physical properties of magnesium, bromine and magnesium bromide. Electrical conductivity Substance Melting point / °C

Group 2 (1)

Series	Paper	What it asks
June 2025	AS Paper 2 Q2(a)(ii)	i)* Magnesium and calcium differ in their reactivity. Give a balanced equation for the reaction of calcium with water and describe what would be observed. Explain why this is a redox reaction.

The halogens (2)

Series	Paper	What it asks
June 2023	AS Paper 2 Q3(a)	Seawater contains very small quantities of dissolved iodide ions. The concentration of potassium iodide, KI, in seawater is 0.150 g dm–3. Iodine can be extracted by bubbling chlorine gas through seawater.
November 2020	AS Paper 2 Q1(c)	A student is provided with samples of three nickel compounds. One sample is nickel(II) bromide, another is nickel(II) sulfate and the third is nickel(II) carbonate. The student doesn’t know which sample is which.

Qualitative analysis: tests for ions (2)

Series	Paper	What it asks
November 2020	AS Paper 2 Q1(c)	A student is provided with samples of three nickel compounds. One sample is nickel(II) bromide, another is nickel(II) sulfate and the third is nickel(II) carbonate. The student doesn’t know which sample is which.
November 2020	Paper 1 Q22(a)	B and C are compounds of two different transition elements. A student carries out test tube reactions on aqueous solutions of B and C. The observations of the student’s tests are shown below.

Enthalpy changes and Hess’ law (8)

Series	Paper	What it asks
June 2025	Paper 3 Q6	The enthalpy change of Reaction 6.1, ∆H1, shown below, is difficult to measure directly by experiment. 2NaHCO3(s) Na2CO3(s) + H2O(l) + CO2(g) ∆H1 Reaction 6.1
June 2024	AS Paper 2 Q3(b)	A student carries out an experiment to determine the enthalpy change for the reaction between zinc and copper(II) nitrate solution. Zn(s) + Cu(NO3)2(aq) Zn(NO3)2(aq) + Cu(s) ΔrH Equation 3.1
June 2023	AS Paper 2 Q4(b)(ii)	i)* Use the student’s results to determine ∆cH of butan-1-ol in kJ mol–1. Explain why this value of ΔcH is different from the data book value and suggest how the experimental design could be modified to improve the accuracy of the
June 2022	Paper 3 Q5(a)	A student plans to determine the enthalpy change of hydration of calcium ions. The student finds the information below from data tables. Enthalpy change ∆H / kJ mol–1
November 2021	AS Paper 2 Q4(a)	Use the student’s results to calculate ∆H2 for Reaction 2 and determine the enthalpy change ∆H1, in kJ mol–1, for the decomposition of magnesium carbonate (Reaction 1), using the energy cycle in Fig. 4.1.
November 2020	Paper 3 Q3(b)	The student determines the standard enthalpy change of combustion of propane using the bond enthalpies in the table. An experiment is not needed. Bond enthalpy
June 2019	Paper 3 Q5(a)(i)	Calculate ∆solH(CuSO4(s)) for reaction 5.2 and determine the enthalpy change of reaction 5.1, ∆rH. Assume that the specific heat capacity, c, of the solution is the same as for water.
June 2017	Paper 3 Q2(a)	Calculate the enthalpy change of reaction 3.2 and the enthalpy change of reaction 3.1. Show all your working.

Reaction rates and the Boltzmann distribution (2)

Series	Paper	What it asks
June 2022	AS Paper 2 Q4(a)(i)	Explain why these conditions are used industrially.
June 2017	AS Paper 2 Q2	A student was asked to carry out an experiment to determine the initial rate of reaction of zinc and hydrochloric acid. The student plans to collect a total of about 72 cm3 of hydrogen at RTP and to use an excess of

Chemical equilibrium and Kc (2)

Series	Paper	What it asks
June 2022	AS Paper 2 Q4(a)(i)	Explain why these conditions are used industrially.
June 2022	Paper 1 Q20(a)	Hydrogen is used industrially to manufacture ammonia. The equilibrium is shown below. N2(g) + 3H2(g) 2NH3(g) ∆H = –92 kJ mol–1 Equilibrium 20.1

Organic basics: naming, formulae and isomerism (4)

Series	Paper	What it asks
June 2024	Paper 2 Q19	Alkenes and carbonyl compounds take part in addition reactions. Describe one addition reaction of an alkene and one addition reaction of a carbonyl compound. Include reagents and reaction mechanisms.
June 2024	Paper 3 Q5(b)(ii)	i)* The student is provided with further information about compounds F–I. • They all have the molecular formula C5H10O. • One of the compounds is alicyclic.
June 2018	Paper 2 Q20(d)	Methylcinnamaldehyde reacts with iodine monochloride, ICl, by electrophilic addition. The reaction produces a mixture containing two different organic products. CHO
June 2016	AS Paper 2 Q3(c)	Compound A reacts with hydrogen bromide to form a mixture of two different organic products. H3C CH3 C C

Alkenes (7)

Series	Paper	What it asks
June 2024	Paper 2 Q19	Alkenes and carbonyl compounds take part in addition reactions. Describe one addition reaction of an alkene and one addition reaction of a carbonyl compound. Include reagents and reaction mechanisms.
June 2023	Paper 2 Q19	A student intends to synthesise compound Z, as shown in the flowchart below. H H C Br
June 2022	AS Paper 2 Q6	The organic compound A is unsaturated and is a trans stereoisomer. Compound A has the following composition by mass: C, 55.8%; H, 7.0%; O, 37.2%. The mass spectrum and the infrared spectrum of compound A are shown below.
June 2018	AS Paper 2 Q7	Compound F is a trans stereoisomer which is a useful intermediate in organic synthesis. The results of elemental and spectral analysis of compound F are shown below. Percentage composition by mass: C, 68.6 %; H, 8.6 %; O, 22.8 %.
June 2018	Paper 2 Q20(d)	Methylcinnamaldehyde reacts with iodine monochloride, ICl, by electrophilic addition. The reaction produces a mixture containing two different organic products. CHO
June 2018	Paper 3 Q6(b)	Many organic reactions use electrophiles as reagents. Explain the role of electrophiles in organic chemistry. Your answer should include one reaction of an aliphatic compound and one reaction of an
June 2016	AS Paper 2 Q3(c)	Compound A reacts with hydrogen bromide to form a mixture of two different organic products. H3C CH3 C C

Alcohols (4)

Series	Paper	What it asks
June 2025	Paper 2 Q17	This question is about an organic synthesis. A student plans a two-stage synthesis of compound F from compound D, as shown below. Cl OH OH O
June 2023	Paper 3 Q3	A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH
November 2020	AS Paper 2 Q5(f)	The structures of A–F are repeated below. OH OH OH
June 2017	AS Paper 2 Q4(c)	Describe the oxidation reactions of butan-1-ol forming an aldehyde and a carboxylic acid. Explain, using a diagram, how the aldehyde can be produced in the laboratory by controlling the reaction conditions.

Haloalkanes (1)

Series	Paper	What it asks
June 2025	Paper 2 Q17	This question is about an organic synthesis. A student plans a two-stage synthesis of compound F from compound D, as shown below. Cl OH OH O

Organic synthesis and practical techniques (Module 4) (8)

Series	Paper	What it asks
June 2025	AS Paper 2 Q5(c)	2-Chlorobutane, CH3CH2CHCl CH3, is an organic liquid with a boiling point of 70 °C. A student prepares 2-chlorobutane from butan-2-ol, CH3CH2CHOHCH3, as shown in the equation below.
June 2025	Paper 2 Q17	This question is about an organic synthesis. A student plans a two-stage synthesis of compound F from compound D, as shown below. Cl OH OH O
June 2022	Paper 3 Q3(a)	Draw a diagram to show how the student would have carried out the reflux and calculate the percentage yield of 1-bromobutane that the student obtains. Describe how the student could have obtained pure 1-bromobutane from the reacti
November 2021	AS Paper 2 Q7(b)	The student’s method for the preparation is outlined below. • Add 10.0 cm3 (7.70 g) of (CH3)3COH and 30 cm3 concentrated hydrochloric acid (an excess) to a round-bottom flask. Stopper the flask.
November 2020	Paper 2 Q20(a)	Calculate the mass of cyclopentanol that the student should use and explain how pure cyclopentene could be obtained from the distillate.
June 2019	AS Paper 2 Q5(b)(i)	A student plans to prepare 4.20 g of hex-1-ene by this method. Calculate the mass of hexan-1-ol that the student should use and explain how you could obtain pure hex-1-ene from the mixture obtained after reflux.
June 2018	AS Paper 2 Q5(a)(i)	Draw a labelled diagram to show how you would safely set up apparatus for the preparation. Outline a method to obtain a pure sample of 1-bromobutane from the reaction mixture.
June 2017	AS Paper 2 Q4(c)	Describe the oxidation reactions of butan-1-ol forming an aldehyde and a carboxylic acid. Explain, using a diagram, how the aldehyde can be produced in the laboratory by controlling the reaction conditions.

Infrared spectroscopy and mass spectrometry (13)

Series	Paper	What it asks
June 2025	Paper 2 Q23(b)	An unknown organic compound N is analysed and produces the following results. Elemental analysis by mass C, 62.07%; H, 10.34%; O, 27.59%
June 2024	AS Paper 2 Q6	Compound X is an organic compound with two functional groups. Compound X has the percentage composition by mass: C, 40.91%; H, 4.54%; O, 54.55%.
June 2024	Paper 2 Q24	Analysis of an unknown organic compound J produces the following results. Elemental analysis by mass of compound J C, 80.60%; H, 7.46%; O, 11.94%
June 2023	Paper 2 Q23	An unknown organic compound is analysed. The results are shown below. Addition of 2,4-DNP
June 2022	AS Paper 2 Q6	The organic compound A is unsaturated and is a trans stereoisomer. Compound A has the following composition by mass: C, 55.8%; H, 7.0%; O, 37.2%. The mass spectrum and the infrared spectrum of compound A are shown below.
November 2021	Paper 3 Q5(c)	This question is about two reactions of ammonia. Reaction 1 Excess ammonia is reacted with 4.77 g of copper(II) oxide. The reaction produces 3.81 g of
November 2020	AS Paper 2 Q5(f)	The structures of A–F are repeated below. OH OH OH
November 2020	Paper 2 Q22(b)	Determine the structure of compound I, showing all your reasoning.
June 2019	Paper 2 Q21	Analysis of an unknown organic compound produced the following results. Elemental analysis by mass C: 73.17%; H: 7.32%; O: 19.51%
June 2018	AS Paper 2 Q7	Compound F is a trans stereoisomer which is a useful intermediate in organic synthesis. The results of elemental and spectral analysis of compound F are shown below. Percentage composition by mass: C, 68.6 %; H, 8.6 %; O, 22.8 %.
June 2018	Paper 2 Q22(d)	A scientist is researching compounds that might be suitable as fuel additives. One of the compounds gives the analytical results below. Elemental analysis by mass:
June 2017	Paper 2 Q21	Compound L is an organic compound containing carbon, hydrogen and oxygen only. The 1H NMR spectrum of compound L is shown below. The numbers by the peaks are the relative peak areas.
June 2016	AS Paper 2 Q7	Organic compound C has the following percentage composition by mass: C, 54.5%; H, 9.1%; O, 36.4%. The infrared spectrum and mass spectrum of compound C are shown below.

Rates: orders, rate equations and the Arrhenius equation (7)

Series	Paper	What it asks
June 2025	Paper 3 Q3(b)	A reaction takes place when aqueous solutions of propanone, CH3COCH3(aq), and bromine, Br2(aq), are mixed in the presence of dilute acid, H+(aq). The overall equation for this reaction is shown below.
June 2024	Paper 1 Q17(b)	Use the graph to determine the order of reaction with respect to CV, the rate of the reaction at three minutes and the rate constant, k. Your answer must show full working on the graph and on the lines below.
June 2023	Paper 1 Q17	Bromine, Br2, can be produced by the reaction: 5Br –(aq) + BrO3 –(aq) + 6H+(aq) 3Br2(aq) + 3H2O(l) A student investigates the rate of this reaction by carrying out four experiments at the same
November 2021	Paper 3 Q4(b)	The student’s experimental procedure shows that the reaction is first order with respect to iodine. Show that this statement is true and determine the initial rate of reaction and rate constant.
June 2019	Paper 1 Q21	Three students carry out a rates investigation on the reaction between bromine and propanone in the presence of hydrochloric acid. CH3COCH3(aq) + Br2(aq) CH3COCH2Br(aq) + HBr(aq)
June 2018	Paper 1 Q17(a)	Determine the rate constant and a possible two-step mechanism for this reaction that are consistent with these results.
June 2017	Paper 1 Q19(c)	Determine the initial rate of reaction, the order with respect to H2O2, and the rate constant. Your answer must show full working on the graph and on the lines below.

Equilibrium constants Kc and Kp (1)

Series	Paper	What it asks
June 2022	Paper 1 Q20(a)	Hydrogen is used industrially to manufacture ammonia. The equilibrium is shown below. N2(g) + 3H2(g) 2NH3(g) ∆H = –92 kJ mol–1 Equilibrium 20.1

Acids, bases, pH and buffers (3)

Series	Paper	What it asks
June 2025	Paper 1 Q19(c)	A student plans to prepare a buffer solution with a pH of 4.85 using propanoic acid, CH3CH2COOH, and sodium propanoate, CH3CH2COONa. Ka for CH3CH2COOH = 1.32 × 10–5 mol dm–3.
November 2021	Paper 1 Q22(c)	Nitrous acid, HNO2, is a weak Brønsted–Lowry acid with a pKa value of 3.34 at room temperature. HNO2 can be prepared by reacting N2O3 with water.
June 2019	Paper 1 Q17(a)	Carbonic acid, H2CO3, is a weak acid which, together with hydrogencarbonate ions, HCO3 −, acts as a buffer to maintain the pH of blood. The pKa value for the dissociation of carbonic acid is 6.38.

Lattice enthalpy and Born–Haber cycles (2)

Series	Paper	What it asks
June 2022	Paper 3 Q5(a)	A student plans to determine the enthalpy change of hydration of calcium ions. The student finds the information below from data tables. Enthalpy change ∆H / kJ mol–1
June 2019	Paper 3 Q5(a)(i)	Calculate ∆solH(CuSO4(s)) for reaction 5.2 and determine the enthalpy change of reaction 5.1, ∆rH. Assume that the specific heat capacity, c, of the solution is the same as for water.

Redox titrations and electrode potentials (1)

Series	Paper	What it asks
June 2024	Paper 3 Q3(b)(iv)	v)* In the titration, 5 mol of iron(II) ethanedioate reacts with 3 mol of manganate(VII) ions. Analyse the student’s results to find the number of waters of crystallisation, x, in the hydrated iron(II) ethanedioate, FeC2O4•xH2O.

Transition elements (7)

Series	Paper	What it asks
June 2023	Paper 1 Q22(a)	Explain, with examples from Period 4, what is meant by the terms d-block element and transition element. Explain why some d-block elements are not transition elements.
June 2022	Paper 1 Q22(c)	This question is about copper and copper compounds. Experiment 1 Hydrochloric acid, HCl (aq), is added to an aqueous solution containing [Cu(H2O)6]2+
November 2021	Paper 1 Q17(b)(ii)	i)* Determine the formulae of A and B. Write the ionic equation for the ligand substitution and show 3D structures for the three stereoisomers of B.
November 2020	Paper 1 Q22(a)	B and C are compounds of two different transition elements. A student carries out test tube reactions on aqueous solutions of B and C. The observations of the student’s tests are shown below.
November 2020	Paper 3 Q2	Transition metal ions can bond to ligands to form complex ions with different shapes. Explain what is meant by the terms ligand, coordination number and ligand substitution, using suitable examples of complex ions with different s
June 2018	Paper 1 Q21(d)	Three different reactions of copper compounds are described below. Reaction 1: Aqueous copper(II) sulfate reacts with excess aqueous ammonia in a ligand substitution reaction. A deep-blue solution is formed, containing an octahedr
June 2017	Paper 1 Q23(b)	A hydrated nickel(II) complex, A, is heated in a crucible to remove the water of crystallisation. The anhydrous complex B is formed. The results are shown below. Mass of crucible + hydrated complex A = 59.554 g

Aromatic compounds: benzene and phenol (1)

Series	Paper	What it asks
June 2018	Paper 3 Q6(b)	Many organic reactions use electrophiles as reagents. Explain the role of electrophiles in organic chemistry. Your answer should include one reaction of an aliphatic compound and one reaction of an

Carbonyl compounds: aldehydes and ketones (4)

Series	Paper	What it asks
June 2024	Paper 2 Q19	Alkenes and carbonyl compounds take part in addition reactions. Describe one addition reaction of an alkene and one addition reaction of a carbonyl compound. Include reagents and reaction mechanisms.
June 2023	Paper 3 Q3	A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH
June 2022	Paper 2 Q21	Carbon-carbon bond formation is used in synthesis to increase the length of a carbon chain. Describe the formation of carbon–carbon bonds in aliphatic compounds by two different mechanisms.
June 2019	Paper 2 Q18(e)(i)	A student intends to synthesise ester C. H O

Carboxylic acids, esters and acyl chlorides (5)

Series	Paper	What it asks
June 2023	Paper 3 Q6(e)	Three reactions involving sulfuric acid are shown below. Reaction 1 Dilute sulfuric acid is reacted with nickel(II) hydroxide to form a green solution.
November 2021	Paper 3 Q5(c)	This question is about two reactions of ammonia. Reaction 1 Excess ammonia is reacted with 4.77 g of copper(II) oxide. The reaction produces 3.81 g of
June 2019	Paper 2 Q18(e)(i)	A student intends to synthesise ester C. H O
June 2018	Paper 3 Q4(b)(ii)	i)* A chemist prepares a pure solid sample of paracetamol from 4-nitrophenol in two stages: H Stage 1 Stage 2
June 2017	Paper 2 Q21	Compound L is an organic compound containing carbon, hydrogen and oxygen only. The 1H NMR spectrum of compound L is shown below. The numbers by the peaks are the relative peak areas.

Amines (2)

Series	Paper	What it asks
June 2022	Paper 2 Q19(e)	A student intends to synthesise compound I. O O
June 2018	Paper 3 Q4(b)(ii)	i)* A chemist prepares a pure solid sample of paracetamol from 4-nitrophenol in two stages: H Stage 1 Stage 2

Amino acids, amides and chirality (2)

Series	Paper	What it asks
June 2023	Paper 3 Q3	A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH
June 2022	Paper 2 Q19(e)	A student intends to synthesise compound I. O O

Carbon–carbon bond formation (4)

Series	Paper	What it asks
June 2023	Paper 2 Q19	A student intends to synthesise compound Z, as shown in the flowchart below. H H C Br
June 2023	Paper 3 Q3	A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH
June 2022	Paper 2 Q21	Carbon-carbon bond formation is used in synthesis to increase the length of a carbon chain. Describe the formation of carbon–carbon bonds in aliphatic compounds by two different mechanisms.
November 2021	Paper 2 Q19(b)	A student intends to synthesise compound A using the two-stage route below. O Stage 1 Stage 2

Organic synthesis (Module 6) (8)

Series	Paper	What it asks
June 2023	Paper 2 Q19	A student intends to synthesise compound Z, as shown in the flowchart below. H H C Br
June 2023	Paper 3 Q3	A chemist is investigating compound A, shown below, as a potential organic intermediate. O OH
June 2022	Paper 2 Q19(e)	A student intends to synthesise compound I. O O
November 2021	Paper 2 Q19(b)	A student intends to synthesise compound A using the two-stage route below. O Stage 1 Stage 2
June 2019	Paper 2 Q18(e)(i)	A student intends to synthesise ester C. H O
June 2018	Paper 3 Q4(b)(ii)	i)* A chemist prepares a pure solid sample of paracetamol from 4-nitrophenol in two stages: H Stage 1 Stage 2
June 2017	Paper 2 Q17(a)(ii)	i)* A chemist carries out the reaction in Equation 17.1 using 4.97 g of benzoic acid. The chemist obtains 3-nitrobenzoic acid as an impure solid. The chemist purifies the solid to obtain 4.85 g of 3-nitrobenzoic acid.
June 2017	Paper 3 Q5(b)	The structures for six naturally occurring organic compounds with pleasant smells, B–G, are shown below. The common names in brackets relate to their source and smell. OH

Chromatography and tests for functional groups (3)

Series	Paper	What it asks
June 2024	Paper 3 Q5(b)(ii)	i)* The student is provided with further information about compounds F–I. • They all have the molecular formula C5H10O. • One of the compounds is alicyclic.
November 2021	Paper 2 Q21	Compounds D, E and F are isomers with the molecular formula C5H10O. One of the compounds is alicyclic. A student carries out test-tube tests on the compounds.
June 2017	Paper 3 Q5(b)	The structures for six naturally occurring organic compounds with pleasant smells, B–G, are shown below. The common names in brackets relate to their source and smell. OH

NMR spectroscopy and combined techniques (8)

Series	Paper	What it asks
June 2025	Paper 2 Q23(b)	An unknown organic compound N is analysed and produces the following results. Elemental analysis by mass C, 62.07%; H, 10.34%; O, 27.59%
June 2024	Paper 2 Q24	Analysis of an unknown organic compound J produces the following results. Elemental analysis by mass of compound J C, 80.60%; H, 7.46%; O, 11.94%
June 2023	Paper 2 Q23	An unknown organic compound is analysed. The results are shown below. Addition of 2,4-DNP
November 2021	Paper 2 Q21	Compounds D, E and F are isomers with the molecular formula C5H10O. One of the compounds is alicyclic. A student carries out test-tube tests on the compounds.
November 2020	Paper 2 Q22(b)	Determine the structure of compound I, showing all your reasoning.
June 2019	Paper 2 Q21	Analysis of an unknown organic compound produced the following results. Elemental analysis by mass C: 73.17%; H: 7.32%; O: 19.51%
June 2018	Paper 2 Q22(d)	A scientist is researching compounds that might be suitable as fuel additives. One of the compounds gives the analytical results below. Elemental analysis by mass:
June 2017	Paper 2 Q21	Compound L is an organic compound containing carbon, hydrogen and oxygen only. The 1H NMR spectrum of compound L is shown below. The numbers by the peaks are the relative peak areas.

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