Physical and chemical changes: past paper questions
Real questions on physical and chemical changes
The newest 20 of 30 written questions. Open one to see it on the real paper.
- 0653/41 · October/November 2025 · Q4c(i)[2]
Identify the type of chemical reaction shown in Fig. 4.2. Explain your answer. type of chemical reaction explanation
See it on the paper → - 0653/41 · October/November 2025 · Q4c(ii)[1]
Draw an arrow on Fig. 4.2 to show the activation energy for this reaction.
See it on the paper → - 0653/41 · October/November 2025 · Q4c(iii)[2]
Define activation energy.
See it on the paper → - 0653/41 · October/November 2025 · Q4c(iv)[2]
Describe what is meant by a catalyst.
See it on the paper → - 0653/33 · May/June 2025 · Q6c(i)[1]
Identify the compound that exists as simple molecules.
See it on the paper → - 0653/42 · February/March 2025 · Q5c[3]
The reaction between aluminium and iron( III ) oxide is exothermic. A flame is used to provide the activation energy to start the reaction. Fig. 5.1 shows the incomplete reaction pathway diagram for this reaction. Complete Fig. 5.1. • • • the energy level of the products a labelled arrow to show the activation energy,...
See it on the paper → - 0653/21 · October/November 2024 · Q15[1]
Which process is not a chemical change?
See it on the paper → - 0653/21 · May/June 2024 · Q15[1]
What is an example of a physical change?
See it on the paper → - 0653/43 · May/June 2023 · Q8d[2]
State two reasons why cracking is described as a chemical change and not a physical change.
See it on the paper → - 0653/43 · May/June 2023 · Q8e(i)[1]
Explain why the boiling point of butane is lower than the boiling point of decane. Use ideas about forces in your answer.
See it on the paper → - 0653/43 · May/June 2023 · Q8e(ii)[1]
Suggest one reason why propane and butane are in the same fraction obtained by fractional distillation of petroleum.
See it on the paper → - 0653/32 · February/March 2023 · Q2a(i)[1]
State whether the change shown in the equation is a chemical change or a physical change. Explain your answer. change explanation
See it on the paper → - 0653/12 · October/November 2022 · Q13[1]
Which letter represents combustion?
See it on the paper → - 0653/63 · October/November 2022 · Q2b(i)[3]
On the grid, plot a graph of mass of solid remaining in the test-tube (vertical axis) against mass of sodium hydrogencarbonate heated.
See it on the paper → - 0653/63 · October/November 2022 · Q2b(ii)[1]
Circle the anomalous point on the graph.
See it on the paper → - 0653/63 · October/November 2022 · Q2b(iii)[1]
Draw the best-fit straight line.
See it on the paper → - 0653/63 · October/November 2022 · Q2b(iv)[1]
Describe the relationship between the mass of solid remaining in the test-tube and the mass of sodium hydrogencarbonate heated.
See it on the paper → - 0653/63 · October/November 2022 · Q2b(v)[1]
Use your graph to estimate the mass of solid remaining in the test-tube when 4.7 g of solid sodium hydrogencarbonate is heated. mass of solid remaining in the test-tube = g
See it on the paper → - 0653/63 · October/November 2022 · Q2c(i)[1]
Explain how the results in Table 2.1 support this conclusion.
See it on the paper → - 0653/63 · October/November 2022 · Q2c(ii)[1]
The student thinks that the gas given off is carbon dioxide. Describe the test for carbon dioxide and state the observation for the positive result. test observation
See it on the paper →
What examiners said
In this question, the compound that exists as simple molecules had to contain two different elements. Water, H2O, was the only correct answer. The other simple molecules, O 2 and H2, are molecules of elements. Candidates found this question very demanding.
— Examiner report, May/June 2025, 0653/33 Q6(c)(i) (Cambridge)
Most candidates were able to draw the correct general shape of the reaction pathway diagram. Candidates should be advised to draw their labelled arrows showing the activation energy and the overall energy change very carefully. The best answers showed the reactant and product energy levels extended so that there was no uncertainty where arrows started and finished. Candidates who drew diagrams sho...
— Examiner report, February/March 2025, 0653/42 Q5(c) (Cambridge)
Some of the popular answers that were awarded credit included the idea that cracking was not reversible and the general ideas that molecules or chemical bonds are broken down or that new bonds are formed. The suggestion that cracking involves a chemical reaction is a repetition of information in the question and so cannot be awarded credit. Different ways of expressing the same idea, such as new p...
— Examiner report, May/June 2023, 0653/43 Q8(d) (Cambridge)
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