Chemical energetics: past paper questions
Real questions on chemical energetics
The newest 20 of 59 written questions, plus 58 multiple-choice. Open one to see it on the real paper.
- 0971/42 · May/June 2026 · Q5c(i)[2]
(i) State how the equation shows this reaction is: CXOTNEPMIC ooo. .......... .......... .......... FEVEFSIDIC. .......... .......... ..........
See it on the paper → - 0971/42 · May/June 2026 · Q5c(iii)[4]
(iii) The equation for the forward reaction can be represented as shown. H—N—H + FF = F—N—F + H—F | F—F H—F H F—F F H—F Table 5.1 bond N-H F-F N-F bond energy in kJ/mol 390 150 270 Use the bond energies in Table 5.1 and the AH value of -870 kJ/mol for the forward reaction to calculate the H-F bond energy. Use the follo...
See it on the paper → - 0971/42 · May/June 2026 · Q6d[2]
Ethanol is a fuel. Write the symbol equation for the complete combustion of ethanol.
See it on the paper → - 0971/32 · October/November 2025 · Q4d[1]
Petroleum is a fossil fuel. Name one other fossil fuel.
See it on the paper → - 0971/32 · October/November 2025 · Q8c[2]
Fig. 8.2 shows the reaction pathway diagram for the reaction of dilute hydrochloric acid with aqueous sodium sulfide. 2HCl + Na 2 S energy 2NaCl + H 2 S progress of reaction Fig. 8.2 Deduce the type of energy change shown in the diagram in Fig. 8.2. Explain your answer.
See it on the paper → - 0971/31 · May/June 2025 · Q7a(i)[1]
State which experiment shows the greatest temperature change.
See it on the paper → - 0971/32 · May/June 2025 · Q7c(i)[1]
State which experiment shows the greatest temperature change.
See it on the paper → - 0971/32 · May/June 2025 · Q7c(ii)[1]
State which experiment is the most endothermic.
See it on the paper → - 0971/32 · May/June 2025 · Q7c(iv)[2]
Fig. 7.1 shows an incomplete reaction pathway diagram for an endothermic reaction. progress of reaction Fig. 7.1 Complete Fig. 7.1 by labelling: the vertical axis the reactants • •
See it on the paper → - 0971/41 · May/June 2025 · Q6d(ii)[3]
Iodine and bromine react at high temperatures to form iodine monobromide, IBr. The equation is shown. I 2 (g) + Br 2 (g) 2IBr(g) The structures of the molecules involved in the reaction are I–I, Br–Br and I–Br. Table 6.1 bond energy in kJ / mol I–I 150 Br–Br 193 I–Br 175 Calculate the enthalpy change, ΔH, for the react...
See it on the paper → - 0971/61 · May/June 2025 · Q4[6]
Solid sodium hydrogencarbonate, NaHCO 3 , reacts with dilute hydrochloric acid and with dilute ethanoic acid. NaHCO 3 (s) + HCl (aq) NaHCO 3 (s) + CH 3 COOH(aq) NaCl (aq) + CO 2 (g) + H 2 O(l) CH 3 COONa(aq) + CO 2 (g) + H 2 O(l) These two reactions are endothermic. Plan an investigation to find which of the two reacti...
See it on the paper → - 0971/62 · May/June 2025 · Q2d[1]
The energy, in J, given out when 2.0 g of anhydrous lithium chloride dissolves is calculated using the equation shown. energy given out = temperature change × 4.2 × volume of water Calculate the energy given out when 2.0 g of anhydrous lithium chloride dissolves in Experiment 5. energy given out = J
See it on the paper → - 0971/62 · May/June 2025 · Q2e[1]
Estimate the temperature change when Experiment 1 is repeated using 4.0 g of anhydrous lithium chloride instead of 2.0 g. Give a reason for your answer. temperature change reason
See it on the paper → - 0971/32 · October/November 2024 · Q7b(iii)[1]
Neutralisation reactions are exothermic. Define the term exothermic.
See it on the paper → - 0971/32 · October/November 2024 · Q7b(iv)[1]
Fig. 7.1 shows the reaction pathway diagram for an exothermic reaction. reactants energy products progress of reaction Explain how Fig. 7.1 shows that the reaction is exothermic. Fig. 7.1
See it on the paper → - 0971/42 · May/June 2024 · Q3b[1]
State the meaning of ∆H.
See it on the paper → - 0971/42 · October/November 2023 · Q5a[1]
State the term used for the transfer of thermal energy during a reaction.
See it on the paper → - 0971/42 · October/November 2023 · Q5b(iii)[3]
Fig. 5.1 shows an incomplete reaction pathway diagram for the forward reaction. CCl 4 (g) + 2H 2 O(g) CO 2 (g) + 4HCl (g) energy progress of reaction Fig. 5.1 On Fig. 5.1: ● ● ● i nsert the formulae of the reactants and products draw an arrow, labelled E a , to show the activation energy draw an arrow, labelled ∆H, to...
See it on the paper → - 0971/42 · October/November 2023 · Q5b(iv)[2]
Define the term activation energy.
See it on the paper → - 0971/42 · October/November 2023 · Q5b(v)[1]
State one way in which the activation energy of a reaction can be changed.
See it on the paper →
What examiners said
Most candidates answered this question correctly. Few gave Experiment 1 or 3.
— Examiner report, May/June 2025, 0971/31 Q7(a)(i) (Cambridge)
This was answered very well. Some final answers did not have a sign despite the instruction. Others showed signs on the first two values.
— Examiner report, May/June 2025, 0971/41 Q6(d)(ii) (Cambridge)
This planning task was a quantitative task and so candidates were expected to make measurements as part of the plan. Those measurements should have included the quantities of each reagent and the temperature before and after the reaction. There was some confusion with the meaning of the term endothermic. An endothermic reaction is one in which heat energy (from the surroundings) is converted to c...
— Examiner report, May/June 2025, 0971/61 Q4 (Cambridge)
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