Elements, compounds and mixtures: past paper questions
Real questions on elements, compounds and mixtures
The newest 20 of 51 written questions. Open one to see it on the real paper.
- 5070/21 · October/November 2025 · Q6c[1]
Explain why ethyne is a hydrocarbon.
See it on the paper → - 5070/22 · October/November 2025 · Q5d[3]
Compound X contains nickel, hydrogen and oxygen only. X contains 2.2% by mass of hydrogen and 34.5% by mass of oxygen. Calculate the empirical formula of compound X. empirical formula =
See it on the paper → - 5070/22 · October/November 2025 · Q6d[1]
Barium peroxide reacts with cold dilute sulfuric acid to produce hydrogen peroxide. Barium peroxide contains the ions Ba 2+ and O 22− only. Deduce the formula of barium peroxide.
See it on the paper → - 5070/22 · October/November 2025 · Q7b(i)[1]
Name the small molecule.
See it on the paper → - 5070/22 · October/November 2025 · Q9a[1]
State the meaning of the term hydrated.
See it on the paper → - 5070/22 · May/June 2025 · Q1a[1]
is prepared using a precipitation reaction
See it on the paper → - 5070/22 · May/June 2025 · Q1d[1]
has an aqueous solution that reacts with dilute sulfuric acid to give a white precipitate
See it on the paper → - 5070/22 · May/June 2025 · Q1e[1]
has an aqueous solution that reacts with aqueous bromine.
See it on the paper → - 5070/22 · May/June 2025 · Q3b[3]
Table 3.1 shows some bond energies. Table 3.1 bond bond energy in kJ / mol C H 410 C C 350 C C 610 Br Br 193 C Br 280 Show by calculation that the enthalpy change of the reaction between ethene and bromine, ΔH, is –107 kJ / mol.
See it on the paper → - 5070/22 · May/June 2025 · Q5b(ii)[1]
One mole of sulfur dioxide reacts with one mole of calcium carbonate to make one mole of carbon dioxide and only one other product. Suggest the formula of this product. formula
See it on the paper → - 5070/22 · May/June 2025 · Q6c(i)[2]
State the oxidation number of bromine in Br 2 and in Br – . Br – (i)
See it on the paper → - 5070/21 · October/November 2024 · Q1a(iii)[1]
an atom of a monatomic gas
See it on the paper → - 5070/22 · October/November 2024 · Q1a(i)[1]
an atom of a noble gas
See it on the paper → - 5070/21 · May/June 2024 · Q7d[3]
The symbol of an iodide ion is shown. 126 – 53 I Complete Table 7.1 about this iodide ion. Table 7.1 particle number of particles electrons neutrons protons
See it on the paper → - 5070/42 · May/June 2024 · Q3c[2]
Solution R is made from a mixture of two different ionic compounds. Suggest the names of these two compounds.
See it on the paper → - 5070/21 · October/November 2023 · Q6a(i)[1]
The nitrogen for this process comes from the air. State the percentage by volume of nitrogen in clean, dry air.
See it on the paper → - 5070/21 · October/November 2023 · Q6a(ii)[1]
State a source of hydrogen for the Haber process.
See it on the paper → - 5070/21 · May/June 2023 · Q4a[3]
3– (a) The formula for a phosphide ion can be written as 31 15 P . Complete Table 4.1 to show the number of particles in this phosphide ion. Table 4.1 particle number of particles electron neutron proton
See it on the paper → - 5070/21 · May/June 2023 · Q4b[1]
State why the formula for a phosphide ion is P 3– rather than P 2– or P 4– .
See it on the paper → - 5070/22 · May/June 2023 · Q9d[1]
Carbon dioxide is removed from the atmosphere by photosynthesis. State the word equation for photosynthesis.
See it on the paper →
What examiners said
The percentage of nitrogen in the air was well known. 79%, 21% and 80% were popular responses.
— Examiner report, October/November 2023, 5070/21 Q6(a)(i) (Cambridge)
The source of hydrogen was quite well known. Air and ammonia were popular responses. A small number omitted the question.
— Examiner report, October/November 2023, 5070/21 Q6(a)(ii) (Cambridge)
Most candidates gave the correct numbers of particles in the ion. The most common error was to describe the phosphorus atom rather than the ion.
— Examiner report, May/June 2023, 5070/21 Q4(a) (Cambridge)
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