Chemical energetics: past paper questions
Real questions on chemical energetics
The newest 20 of 22 written questions, plus 11 multiple-choice. Open one to see it on the real paper.
- 5129/21 · October/November 2025 · Q8e[1]
complete combustion
See it on the paper → - 5129/21 · May/June 2025 · Q12a[1]
State the energy store in natural gas.
See it on the paper → - 5129/21 · May/June 2025 · Q14b[1]
The reaction is exothermic. State the meaning of ‘exothermic’.
See it on the paper → - 5129/21 · May/June 2025 · Q14c[1]
Explain why the reaction is not a physical change.
See it on the paper → - 5129/22 · May/June 2025 · Q14a(ii)[1]
Describe the change in temperature when ammonium nitrate dissolves in water.
See it on the paper → - 5129/22 · October/November 2024 · Q5a[1]
State the name of the energy store in biofuel gas.
See it on the paper → - 5129/22 · October/November 2024 · Q5b[3]
Complete the sentences: The biofuel gas is to release thermal energy. This heats water in a boiler. The steam produced turns a .
See it on the paper → - 5129/22 · October/November 2024 · Q5c[1]
State one advantage of using biofuel as an energy source.
See it on the paper → - 5129/22 · October/November 2023 · Q3a(iii)[1]
Describe the effect of a catalyst on the rate of formation of methanol.
See it on the paper → - 5129/22 · October/November 2023 · Q3a(iv)[1]
Compare the mass of a catalyst at the beginning of the reaction with the mass of the catalyst at the end of the reaction.
See it on the paper → - 5129/32 · May/June 2023 · Q2b(i)[1]
Fig. 2.2 shows the temperature of the acid before any magnesium is added. °C 25 20 15 Fig. 2.2 Use the information shown in Fig. 2.2 to complete the row of results for 0.00 g magnesium in Table 2.1.
See it on the paper → - 5129/32 · May/June 2023 · Q2b(ii)[1]
Complete Table 2.1 by calculating the temperature change for 0.60 g of magnesium.
See it on the paper → - 5129/32 · May/June 2023 · Q2b(iii)[1]
On the grid provided, plot a graph of temperature change on the y-axis against mass of magnesium on the x-axis. Draw a first straight line of best fit on the grid using only the first 5 rows in the table. Draw a second straight line of best fit on the grid using only the last 3 rows in the table. Extend both lines of b...
See it on the paper → - 5129/32 · May/June 2023 · Q2b(iv)[1]
Explain why the temperature change becomes constant.
See it on the paper → - 5129/32 · May/June 2023 · Q2b(v)[1]
Using your graph, determine the minimum mass of magnesium that reacts with all of the dilute hydrochloric acid. minimum mass of magnesium = g
See it on the paper → - 5129/32 · May/June 2023 · Q2c(i)[1]
Explain why the temperature changes calculated in this experiment are less than the true values.
See it on the paper → - 5129/32 · May/June 2023 · Q2c(ii)[1]
Suggest an improvement to the experiment that would make the calculated temperature changes more accurate. Question 3 begins over the page.
See it on the paper → - 5129/21 · October/November 2022 · Q5a(ii)[1]
Reaction 1 is an exothermic reaction. State the meaning of ‘exothermic’.
See it on the paper → - 5129/21 · October/November 2021 · Q13c[1]
Energy is produced when ethane reacts with oxygen. State the name given to reactions that produce energy.
See it on the paper → - 5129/21 · May/June 2021 · Q11c[1]
Explain why magnesium oxide does not react with hydrogen.
See it on the paper →
What examiners said
More able candidates knew the effect of catalysts on reaction rate.
— Examiner report, October/November 2023, 5129/22 Q3(a)(iii) (Cambridge)
There was a common misconception that the mass of a catalyst decreases during a reaction.
— Examiner report, October/November 2023, 5129/22 Q3(a)(iv) (Cambridge)
Whilst most candidates were able to read the initial temperature of the thermometer, only the strongest candidates appreciated that there would be no change in temperature when no magnesium was added to the hydrochloric acid and a number of candidates recorded a temperature change of 18 °C, rather than 0 °C.
— Examiner report, May/June 2023, 5129/32 Q2(b)(i) (Cambridge)
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