Separation and purification: past paper questions
Real questions on separation and purification
The newest 20 of 62 written questions. Open one to see it on the real paper.
- 0971/42 · May/June 2026 · Q3e(ii)[1]
Name this technique of insoluble salt preparation.
See it on the paper → - 0971/42 · May/June 2026 · Q3e(iii)[3]
Describe how pure lead(II) sulfate can be obtained from the reaction mixture.
See it on the paper → - 0971/32 · October/November 2025 · Q3b[1]
The water sample is not suitable for use in practical chemistry. Name a process that makes the water suitable for use in practical chemistry.
See it on the paper → - 0971/42 · October/November 2025 · Q3a[2]
Complete the symbol equation for the reaction. Include state symbols.
See it on the paper → - 0971/42 · October/November 2025 · Q3d[1]
State the colour of the solid formed in step 2.
See it on the paper → - 0971/42 · October/November 2025 · Q3e[1]
The mixture is filtered in step 3. State the general term given to a solid left in the filter paper after filtration.
See it on the paper → - 0971/42 · October/November 2025 · Q3f[2]
The actual mass of dry BaSO 4 collected in step 4 is greater than the expected mass. This is because the student should do an additional step between step 3 and step 4. Suggest what the student should do in this additional step, and explain why the actual mass collected is greater than the expected mass.
See it on the paper → - 0971/42 · October/November 2025 · Q3g[1]
State the name of this method of salt preparation.
See it on the paper → - 0971/62 · October/November 2025 · Q1b(i)[2]
Draw a labelled diagram of the apparatus the student should use to filter the mixture.
See it on the paper → - 0971/31 · May/June 2025 · Q4a(i)[1]
Name the process that separates petroleum into its useful components.
See it on the paper → - 0971/31 · May/June 2025 · Q6b[1]
Crystals of copper( II ) chloride are prepared by adding excess copper( II ) oxide powder to dilute hydrochloric acid. Describe how to prepare a sample of pure, dry copper( II ) chloride crystals after the reaction is complete. In your answer, describe how to: • • • remove the excess copper( II ) oxide from the reactio...
See it on the paper → - 0971/32 · May/June 2025 · Q4a(ii)[1]
Petroleum is a mixture of hydrocarbons. Outline how petroleum is separated into its useful components. Include in your answer: • • • the name of the separation technique the property of the hydrocarbons which allows them to be separated a description of how this technique separates the petroleum into its useful compone...
See it on the paper → - 0971/32 · May/June 2025 · Q5a(ii)[1]
Name the method used to remove excess solid zinc oxide from the reaction mixture.
See it on the paper → - 0971/32 · May/June 2025 · Q5a(iii)[2]
Describe how crystals of the pure salt are made from an aqueous solution of the salt formed.
See it on the paper → - 0971/61 · May/June 2025 · Q1f[1]
Describe what the student should now do to obtain crystals of pure potassium sulfate.
See it on the paper → - 0971/32 · October/November 2024 · Q7a(ii)[1]
State the method used to separate the excess solid zinc oxide from the reaction mixture.
See it on the paper → - 0971/42 · October/November 2024 · Q4g(i)[1]
Suggest the missing step.
See it on the paper → - 0971/41 · May/June 2024 · Q1b[1]
obtain water from aqueous sodium chloride
See it on the paper → - 0971/41 · May/June 2024 · Q1d[1]
separate petroleum into useful substances
See it on the paper → - 0971/41 · May/June 2024 · Q5a(ii)[2]
Describe how to produce a pure sample of lead( II ) bromide from the mixture of aqueous solutions in (a)(i).
See it on the paper →
What examiners said
The distinction between fractional distillation and cracking confused many candidates. Some candidates were close with ‘distillation’, but fractional distillation is required.
— Examiner report, May/June 2025, 0971/31 Q4(a)(i) (Cambridge)
Few candidates gained full credit with many simply repeating the bullet points. The first step should be to filter the mixture. Candidates who filtered after heating the mixture (to saturation) were not awarded credit because this would remove more than the excess copper(II) oxide. Most candidates could recall a method for drying the crystals, but few fully described the idea of heating crystalli...
— Examiner report, May/June 2025, 0971/31 Q6(b) (Cambridge)
Candidates are expected to be familiar with methods of salt preparation, including the preparation of a soluble salt by a titration-based method. They should also be familiar with the process of crystallisation. As a pure sample of potassium sulfate was required, the first stage should have been to mix together the volumes of aqueous potassium carbonate and dilute sulfuric acid that have been fou...
— Examiner report, May/June 2025, 0971/61 Q1(f) (Cambridge)
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