Formulae: past paper questions
Real questions on formulae
The newest 20 of 151 written questions. Open one to see it on the real paper.
- 5070/21 · October/November 2025 · Q3b[1]
test observation if carbon dioxide present (b) Describe a chemical test for carbon dioxide.
See it on the paper → - 5070/21 · October/November 2025 · Q5c[3]
Compound X contains nickel, carbon and oxygen only. X contains 28.1% by mass carbon and 37.4% by mass oxygen. Calculate the empirical formula of compound X. empirical formula =
See it on the paper → - 5070/21 · October/November 2025 · Q6b(i)[2]
Calculate the number of molecules of ethyne in this sample. One mole of ethyne contains 6.02 × 10 23 molecules. number of molecules =
See it on the paper → - 5070/21 · October/November 2025 · Q6b(ii)[1]
Calculate the total number of atoms in this sample of ethyne. number of atoms =
See it on the paper → - 5070/21 · May/June 2025 · Q4c(i)[3]
Calculate the volume of hydrogen formed measured at room temperature and pressure. Give your answer to two significant figures. volume = dm 3
See it on the paper → - 5070/21 · May/June 2025 · Q6e[3]
A chloride of iron contains 34.5% iron by mass. Calculate the empirical formula of this chloride. Show your working. empirical formula
See it on the paper → - 5070/21 · May/June 2025 · Q8c(ii)[2]
A sample of 80 g of methylbut‑2‑enoate is reacted to make the addition polymer. There is a 100% yield. State the mass of addition polymer made. Explain your answer. mass of addition polymer = g explanation
See it on the paper → - 5070/22 · May/June 2025 · Q5a(i)[1]
One compound in diesel oil has the formula C 12 H 26 . Construct the symbol equation to show the complete combustion of C 12 H 26 .
See it on the paper → - 5070/22 · May/June 2025 · Q6e[3]
A bromide of phosphorus contains 7.2% phosphorus by mass. Calculate the empirical formula of this bromide. Show your working. empirical formula
See it on the paper → - 5070/21 · October/November 2024 · Q4c(ii)[2]
When undecane is cracked, shorter hydrocarbon molecules are formed. Construct the symbol equation for a reaction in which undecane is cracked and the only products are butane, propene and ethene.
See it on the paper → - 5070/21 · October/November 2024 · Q5c[3]
Excess copper( II ) carbonate is added to 22.0 cm 3 of 0.500 mol / dm 3 hydrochloric acid. Calculate the volume of carbon dioxide released measured at room temperature and pressure. Give your answer to two significant figures. volume of carbon dioxide gas = dm 3
See it on the paper → - 5070/21 · October/November 2024 · Q6d[3]
Disulfur dichloride reacts with water as shown. S 2 Cl 2 + 3H 2 O 2HCl + H 2 S + H 2 SO 3 13.5 g of disulfur dichloride is reacted with 8.00 g of water. Show by calculation that water is in excess.
See it on the paper → - 5070/22 · October/November 2024 · Q5a[1]
Complete the equation by adding state symbols for the products. Zn(s) + 2HCl (aq) ZnCl 2 (….) + H 2 (….)
See it on the paper → - 5070/22 · October/November 2024 · Q5c[3]
Excess zinc is added to 16.0 cm 3 of 0.400 mol / dm 3 hydrochloric acid. Calculate the volume of hydrogen gas released measured at room temperature and pressure. Give your answer to two significant figures. volume of hydrogen gas = dm 3
See it on the paper → - 5070/21 · May/June 2024 · Q2a[2]
Construct the symbol equation for this reaction.
See it on the paper → - 5070/21 · May/June 2024 · Q5c[3]
Calculate the maximum mass of zinc oxide that can be made from 25.5 g of zinc sulfite. mass of zinc oxide = g
See it on the paper → - 5070/21 · May/June 2024 · Q5e[2]
Solid zinc sulfite reacts with dilute nitric acid to give sulfur dioxide gas, an aqueous zinc salt and a colourless liquid. Construct the symbol equation for this reaction. Include state symbols.
See it on the paper → - 5070/22 · May/June 2024 · Q2a[2]
Construct the symbol equation for this reaction.
See it on the paper → - 5070/22 · May/June 2024 · Q5c[3]
Calculate the maximum mass of zinc oxide that can be made from 4.23 g of zinc carbonate. mass of zinc oxide = g
See it on the paper → - 5070/22 · May/June 2024 · Q6a[1]
Describe one adverse effect of higher levels of methane in air.
See it on the paper →
What examiners said
Candidates found this quite challenging. Many gave either C5H7COOH or a full structural formula.
— Examiner report, October/November 2023, 5070/21 Q5(a)(ii) (Cambridge)
Better performing candidates correctly completed the equation. SO4, 2SO4, SO2 + O2 and 2S + O2 were popular responses. A small number omitted the question.
— Examiner report, October/November 2023, 5070/21 Q7(e)(iii) (Cambridge)
Candidates found constructing this equation very challenging. Typical errors were writing chlorine as Cl and carbon as C2. Other candidates gave carbon dioxide as the product rather than carbon monoxide.
— Examiner report, October/November 2023, 5070/22 Q2(c) (Cambridge)
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