Separation and purification: past paper questions
Real questions on separation and purification
The newest 20 of 20 written questions. Open one to see it on the real paper.
- 5070/41 · May/June 2025 · Q4[6]
Q is a mixture of solid magnesium oxide and solid barium sulfate. Magnesium oxide is insoluble in water. It reacts with dilute hydrochloric acid to make a solution of magnesium chloride. Barium sulfate is insoluble in water and does not react with dilute hydrochloric acid. Plan an investigation to obtain pure magnesium...
See it on the paper → - 5070/21 · May/June 2021 · Q3a(i)[1]
Name the process used to separate petroleum (crude oil) into fractions.
See it on the paper → - 5070/21 · May/June 2021 · Q3a(ii)[1]
Name one other fraction separated from petroleum (crude oil). Give a large-scale use for this fraction. fraction use
See it on the paper → - 5070/22 · May/June 2021 · Q5a[2]
Describe how petroleum (crude oil) is separated to make fractions such as naphtha and petrol (gasoline).
See it on the paper → - 5070/42 · May/June 2021 · Q4c(ii)[1]
Name the process used to separate the three liquids in apparatus Q.
See it on the paper → - 5070/42 · May/June 2021 · Q4c(iii)[1]
State why this process is suitable. You should refer to a physical property of the liquids.
See it on the paper → - 5070/42 · May/June 2021 · Q5a(i)[1]
Name an alternative piece of apparatus that could be used, instead of the measuring cylinder, to collect the gas and measure its volume.
See it on the paper → - 5070/42 · May/June 2021 · Q5a(ii)[2]
The gas collected in the measuring cylinder is hydrogen. Give a test and its result to show that this gas is hydrogen. test result
See it on the paper → - 5070/42 · May/June 2021 · Q5b[2]
Another student thinks it would be easier to remove the bung from the flask, add the metal directly to the acid and then replace the bung. State two disadvantages of this method compared with the one described.
See it on the paper → - 5070/42 · May/June 2020 · Q4c[2]
There is a process missing between steps 2 and 3. Identify the missing process and explain why it is important.
See it on the paper → - 5070/42 · May/June 2020 · Q4d[3]
Step 3 will not make crystals of hydrated copper(II) sulfate. State and explain how the student should change step 3 to make pure, dry crystals of hydrated copper(II) sulfate.
See it on the paper → - 5070/42 · May/June 2020 · Q4e[2]
Describe two observations the student makes during the preparation of pure, dry crystals of hydrated copper(II) sulfate. For each observation make clear at which step it is seen. observation observation
See it on the paper → - 5070/21 · October/November 2019 · Q3a[3]
Describe how and explain why water can be separated from aqueous copper(II) sulfate by distillation. In your answer include a description of distillation. You may draw a labelled diagram.
See it on the paper → - 5070/21 · October/November 2019 · Q3b[1]
Copper(II) sulfate can be prepared by heating excess copper(II) oxide with dilute sulfuric acid. CuO(s) + H 2 SO 4 (aq) CuSO 4 (aq) + H 2 O(l) What method is used to separate excess copper(II) oxide from the reaction mixture?
See it on the paper → - 5070/21 · October/November 2019 · Q9a[1]
Polyesters and polyamides are both polymers formed by condensation reactions. What is meant by the term condensation reaction?
See it on the paper → - 5070/22 · May/June 2019 · Q4a[3]
Outline the separation of petroleum (crude oil) into fractions such as petrol, diesel and bitumen.
See it on the paper → - 5070/22 · May/June 2019 · Q4b[1]
State one large scale use of bitumen.
See it on the paper → - 5070/22 · May/June 2019 · Q6c(i)[1]
Describe how insoluble solids are removed from river water.
See it on the paper → - 5070/22 · May/June 2019 · Q6c(ii)[1]
Name the substance used to remove bad tastes and odours from river water.
See it on the paper → - 5070/22 · May/June 2019 · Q6c(iii)[1]
Name the substance used to disinfect river water so it is safe to drink. Section B Answer three questions from this section in the spaces provided. The total mark for this section is 30.
See it on the paper →
What examiners said
Many candidates recognised that the process was fractional distillation.
— Examiner report, May/June 2021, 5070/21 Q3(a)(i) (Cambridge)
Candidates were often able to list another fraction separated from petroleum. The most popular fraction was bitumen with a use related to road surfaces or water proofing. Kerosene or paraffin was another popular choice of fraction. Centres should advise candidates that a use stated as ‘fuel’ should be qualified by the name of the vehicle that uses the fuel e.g. kerosene as aviation fuel.
— Examiner report, May/June 2021, 5070/21 Q3(a)(ii) (Cambridge)
Most candidates were able to give a brief description of fractional distillation. There were only a few examples where candidates confused fractional distillation with cracking.
— Examiner report, May/June 2021, 5070/22 Q5(a) (Cambridge)
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