Relative masses of atoms and molecules: past paper questions
Real questions on relative masses of atoms and molecules
The newest 20 of 24 written questions. Open one to see it on the real paper.
- 5070/21 · May/June 2025 · Q3b[1]
Explain why this reaction is an example of substitution.
See it on the paper → - 5070/22 · May/June 2025 · Q3a[1]
Describe the observation when ethene gas is bubbled through aqueous bromine.
See it on the paper → - 5070/41 · October/November 2024 · Q2f(ii)[1]
Use your answer from (f)(i) to deduce the value of n in C 2 H 2 O 4 •nH 2 O. Give your answer to the nearest whole number. [A r : H, 1; C, 12; O, 16] n
See it on the paper → - 5070/21 · May/June 2024 · Q6c(i)[1]
Write the word equation for photosynthesis.
See it on the paper → - 5070/21 · May/June 2024 · Q6c(ii)[1]
Describe the conditions needed for photosynthesis.
See it on the paper → - 5070/21 · October/November 2023 · Q9c[2]
A compound of phosphorus, oxygen and chlorine contains 20.2% phosphorus, 10.4% oxygen and 69.4% chlorine by mass. Deduce the empirical formula of this compound. empirical formula
See it on the paper → - 5070/22 · May/June 2023 · Q4e[2]
Calculate the percentage by mass of nitrogen in magnesium nitrate. Give your answer to two significant figures. percentage by mass
See it on the paper → - 5070/41 · May/June 2023 · Q2f[1]
Use your answers to (b) and (e) to calculate the mass of ethanoic acid in 500 cm 3 of A. mass g
See it on the paper → - 5070/21 · May/June 2022 · Q9b(ii)[2]
Calculate the percentage by mass of nitrogen in ammonium nitrate. percentage by mass =
See it on the paper → - 5070/21 · October/November 2021 · Q4d[2]
An organic compound contains 54.5% carbon, 9.10% hydrogen and 36.4% oxygen by mass. Calculate the empirical formula of this compound. empirical formula
See it on the paper → - 5070/41 · May/June 2021 · Q5c(ii)[1]
The M r of carbon dioxide is 44. Use your answer to (a)(ii) to calculate the number of moles of carbon dioxide made in the reaction. number of moles of carbon dioxide
See it on the paper → - 5070/41 · May/June 2021 · Q5c(iv)[1]
Use your answers to (a)(i) and (c)(iii) to calculate the mass of one mole of the metal carbonate. mass of one mole of metal carbonate g
See it on the paper → - 5070/21 · October/November 2020 · Q1e[1]
is a hydrocarbon that is formed from the bacterial decay of vegetable matter?
See it on the paper → - 5070/21 · October/November 2020 · Q2c[1]
Ethyne is an unsaturated hydrocarbon. State the meaning of the term hydrocarbon.
See it on the paper → - 5070/21 · October/November 2020 · Q2d[1]
Ethyne is a member of the alkyne homologous series. The molecular formulae of the first four members of the alkyne homologous series are shown. C 2 H 2 C 3 H 4 C 4 H 6 C 5 H 8 Predict the formula for the fifth member of the alkyne homologous series.
See it on the paper → - 5070/21 · October/November 2020 · Q3e[3]
A 2.25 g sample of an oxide of copper contains 0.250 g of oxygen. Deduce the empirical formula of this oxide of copper.
See it on the paper → - 5070/21 · May/June 2020 · Q7c(i)[1]
Give the equation for the fermentation of glucose.
See it on the paper → - 5070/21 · May/June 2020 · Q7c(ii)[2]
State two essential conditions needed for fermentation.
See it on the paper → - 5070/21 · October/November 2019 · Q5d[2]
Hydrated nickel(II) chloride has the formula NiCl 2 .xH 2 O. It has a relative formula mass of 238. Calculate the value of x in this formula. [The relative atomic mass of nickel, Ni, is 59] x = 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 → - 5070/22 · May/June 2019 · Q9c(i)[1]
Give one large scale use of nylon.
See it on the paper →
What examiners said
The majority of candidates deduced the empirical formula correctly. Some candidates used atomic numbers, mixed up the percentages, used K for phosphorus, C for chlorine or divided by 32 for oxygen or 71 for chlorine.
— Examiner report, October/November 2023, 5070/21 Q9(c) (Cambridge)
Most candidates were aware that they should use a ratio of the two means in the calculation of this question, but they often got the ratio the wrong way around. Candidates should double check what the question is asking for and think what value they would expect to get, before doing the calculation. In this case, the question was asking for the mass of ethanoic acid in A. As the mean volume of A u...
— Examiner report, May/June 2023, 5070/41 Q2(f) (Cambridge)
Many candidates calculated the percentage correctly. The most common error was dividing 14 by 80 rather than 28 for the two nitrogens in the compound.
— Examiner report, May/June 2022, 5070/21 Q9(b)(ii) (Cambridge)
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