Chemical reactions: past paper questions
Real questions on chemical reactions
The newest 20 of 100 written questions, plus 33 multiple-choice. Open one to see it on the real paper.
- 5129/21 · October/November 2025 · Q2b[1]
State the type of bonding in a molecule of nitrogen gas.
See it on the paper → - 5129/21 · October/November 2025 · Q2c(ii)[1]
Calcium nitride melts at 1195 °C. Deduce the type of bonding in calcium nitride.
See it on the paper → - 5129/21 · October/November 2025 · Q2c(iii)[2]
Describe the separation and motion of the particles in melted calcium nitride. separation motion
See it on the paper → - 5129/21 · October/November 2025 · Q8a[1]
precipitation
See it on the paper → - 5129/21 · October/November 2025 · Q8c[1]
redox
See it on the paper → - 5129/21 · October/November 2025 · Q14c[2]
The rate of this chemical reaction is increased by using a catalyst and by increasing the temperature of the reactants. State two other ways to increase the rate of this chemical reaction.
See it on the paper → - 5129/22 · October/November 2025 · Q6a[3]
Reading P is 54 cm 3 . Reading R is 49 g. Calculate the density of the liquid. Give your answer to 2 significant figures and state the unit. density = unit
See it on the paper → - 5129/22 · October/November 2025 · Q6b[2]
A small stone falls through the liquid in the measuring cylinder before coming to rest on the bottom. Explain why work is done by the stone as it falls through the liquid.
See it on the paper → - 5129/22 · October/November 2025 · Q8a[1]
a physical change
See it on the paper → - 5129/22 · October/November 2025 · Q8b[1]
a displacement reaction
See it on the paper → - 5129/22 · October/November 2025 · Q15a(i)[2]
Complete the word equation for the reaction. magnesium carbonate + acid magnesium sulfate + + water
See it on the paper → - 5129/22 · October/November 2025 · Q15a(ii)[2]
The student uses an excess of magnesium carbonate to ensure that all the acid reacts. Describe how the student makes a pure, dry sample of the magnesium sulfate from the reaction mixture.
See it on the paper → - 5129/22 · October/November 2025 · Q15b[1]
State one way in which the rate of the reaction between magnesium carbonate and the acid can be decreased.
See it on the paper → - 5129/31 · October/November 2025 · Q2e(ii)[2]
Aqueous sodium hydroxide is now added to the mixture of dilute sulfuric acid and the residue until the aqueous sodium hydroxide is in excess. Describe what the student observes.
See it on the paper → - 5129/31 · October/November 2025 · Q2f[2]
State the name of the gas produced in (e)(i) and describe the test and observation used to identify this gas. name of gas test and observation
See it on the paper → - 5129/21 · May/June 2025 · Q5a[1]
Explain how the equation shows that this is a precipitation reaction.
See it on the paper → - 5129/21 · May/June 2025 · Q5b(i)[1]
State the name of the method used to separate solid silver bromide, AgBr, from the reaction mixture.
See it on the paper → - 5129/21 · May/June 2025 · Q5b(ii)[1]
Describe how the sample of silver bromide is purified.
See it on the paper → - 5129/21 · May/June 2025 · Q14a[2]
Complete the word equation for the reaction. + lithium + water
See it on the paper → - 5129/22 · May/June 2025 · Q2b[2]
Bromine reacts with sodium iodide. Complete the word equation for the reaction. bromine sodium iodide + +
See it on the paper →
What examiners said
Most candidates recognised that two Na atoms are needed to react with a Br2 molecule to balance the symbol equation.
— Examiner report, October/November 2023, 5129/21 Q6(a)(i) (Cambridge)
Most candidates correctly selected words from the list to complete sentences about the preparation of magnesium sulfate.
— Examiner report, October/November 2023, 5129/21 Q10(a) (Cambridge)
Most candidates understood that reactant powders react faster than pieces.
— Examiner report, October/November 2023, 5129/21 Q10(b) (Cambridge)
Past papers, syllabus and examiner reports © UCLES (Cambridge University Press & Assessment). Questions are matched to topics from the official syllabus. AssessPro is independent and not endorsed by Cambridge.