Chemical energetics: past paper questions
Real questions on chemical energetics
The newest 20 of 110 written questions, plus 147 multiple-choice. Open one to see it on the real paper.
- 0620/42 · May/June 2026 · Q5c(i)[2]
State how the equation shows this reaction is: exothermic
See it on the paper → - 0620/42 · May/June 2026 · Q6d[2]
Write the symbol equation for the complete combustion of ethanol. (d) Ethanol is a fuel.
See it on the paper → - 0620/43 · May/June 2026 · Q3b(ii)[1]
Oxygen has a low melting point. State the general term for the weak forces of attraction that cause oxygen to have a low melting point.
See it on the paper → - 0620/61 · May/June 2026 · Q2c[1]
State if the energy change in the reaction is exothermic or endothermic. Use the results in Table 2.1 to explain your answer. energy change explanation
See it on the paper → - 0620/63 · May/June 2026 · Q2a[1]
Use the information in the description of the experiments and the thermometer diagrams to complete Table 2.1. Calculate the temperature change using the equation shown. temperature change = initial temperature – final temperature Table 2.1 experiment mass of sodium thiosulfate / g initial thermometer diagram 1 2 3 4 5...
See it on the paper → - 0620/63 · May/June 2026 · Q2f[1]
State if the energy change when sodium thiosulfate powder is dissolved in distilled water is exothermic or endothermic. Use the results in Table 2.1 to explain your answer. energy change explanation
See it on the paper → - 0620/32 · February/March 2026 · Q2a(ii)[2]
Name two substances that are produced when ethane undergoes complete combustion. and
See it on the paper → - 0620/42 · February/March 2026 · Q4d[4]
The equation for the reaction of hydrogen with carbon dioxide can be represented as shown in Figure 4.2. H H H H H + O H H C O C H H + H O O H ΔH = – 40 kJ / mol H Table 4.2 bond H–H C=O O–H C–O bond energy in kJ / mol 440 805 460 360 Use the bond energies in Table 4.2 and the value of ΔH for the forward reaction to ca...
See it on the paper → - 0620/31 · October/November 2025 · Q4g(i)[1]
Name this type of endothermic reaction.
See it on the paper → - 0620/32 · October/November 2025 · Q4d[1]
Petroleum is a fossil fuel. Name one other fossil fuel.
See it on the paper → - 0620/32 · October/November 2025 · Q4e(i)[1]
have the longest chain length (i)
See it on the paper → - 0620/32 · October/November 2025 · Q4e(ii)[1]
have the highest volatility (ii)
See it on the paper → - 0620/32 · October/November 2025 · Q4e(iii)[1]
are used for home heating systems.
See it on the paper → - 0620/32 · 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 → - 0620/41 · October/November 2025 · Q5b(i)[6]
Complete Table 5.1. method 1 glucose as starting material method 2 ethene as starting material typical temperature used / °C two other essential conditions 1 1 2 2 Table 5.1
See it on the paper → - 0620/43 · October/November 2025 · Q3c(i)[1]
State the meaning of the symbol ΔH.
See it on the paper → - 0620/43 · October/November 2025 · Q3c(ii)[1]
State what can be deduced about the reaction from the negative sign in ΔH = – 850 kJ / mol.
See it on the paper → - 0620/31 · May/June 2025 · Q7a(i)[1]
State which experiment shows the greatest temperature change.
See it on the paper → - 0620/32 · May/June 2025 · Q7c(i)[1]
State which experiment shows the greatest temperature change.
See it on the paper → - 0620/32 · May/June 2025 · Q7c(ii)[1]
State which experiment is the most endothermic.
See it on the paper →
What examiners said
Comprehensive responses • Many candidates knew that carbon dioxide and water are the two substances produced during complete combustion. Limited responses • A few candidates confused complete combustion with incomplete combustion and gave incorrect products. For example, carbon monoxide or carbon.
— Examiner report, February/March 2026, 0620/32 Q2(a)(ii) (Cambridge)
Comprehensive responses • Most candidates were able to calculate the energy needed to break the bonds in the reactants. • Many candidates were able to calculate the energy released when the bonds in water form. • Some candidates were able to use these two calculated figures to determine the bond energy of the C–H bond. • Some candidates who arrived at the correct answer did not work through the ca...
— Examiner report, February/March 2026, 0620/42 Q4(d) (Cambridge)
Most candidates answered this question correctly. Few gave Experiment 1 or 3.
— Examiner report, May/June 2025, 0620/31 Q7(a)(i) (Cambridge)
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