IGCSE Combined Science 0653 · Chemistry · 87

0653.C10.2.01 — State the composition of clean, dry air as approximately 78% nitrogen, N2, 21% oxygen, O2, and the remainder as a mixture of noble gases and: past paper questions

10 real questionsasked in 4 of the last 10 exam series2022–2025usually: State, Identify, Use, Complete, Suggest

Real questions on 0653.c10.2.01 — state the composition of clean, dry air as approximately 78% nitrogen, n2, 21% oxygen, o2, and the remainder as a mixture of noble gases and

The newest 10 of 10 written questions. Open one to see it on the real paper.

0653/32 · May/June 2025 · Q4e(i)[1]
State the percentage of nitrogen gas in clean, dry air. %
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0653/32 · February/March 2025 · Q5a(i)[1]
Use the data in Table 5.1 to calculate the percentage of other gases in the sample of natural gas. percentage of other gases =
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0653/32 · February/March 2025 · Q5a(ii)[1]
State the named gas in Table 5.1 that is in clean air.
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0653/21 · October/November 2024 · Q22[1]
What is the gas?
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0653/21 · October/November 2024 · Q25[1]
Which pie chart shows the composition of clean air?
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0653/32 · October/November 2024 · Q5a[3]
Complete the sentences about air. Use the words from the list. Each word may be used once, more than once or not at all. compound methane mixture nitrogen oxygen • Air is a . • The gas with the largest percentage in clean air is .
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0653/32 · February/March 2023 · Q5d(i)[1]
State the percentage of oxygen in clean air. %
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0653/32 · February/March 2023 · Q5d(ii)[1]
Suggest the percentage of argon in clean air. %
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0653/32 · February/March 2023 · Q5d(iii)[1]
State why argon does not react with copper.
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0653/33 · October/November 2022 · Q8c(i)[1]
State the percentage of oxygen in clean air. %
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What examiners said

A small number of candidates successfully stated that the percentage of nitrogen gas in clean, dry air is 78%. There was no pattern to the incorrect answers.
— Examiner report, May/June 2025, 0653/32 Q4(e)(i) (Cambridge)

Most candidates successfully calculated the missing percentage of gases in natural gas, which represented other gases.
— Examiner report, February/March 2025, 0653/32 Q5(a)(i) (Cambridge)

Nitrogen, the named gas present in clean air, was given by many candidates. The most common incorrect answer was methane. Candidates should be reminded that methane is a pollutant that is also a greenhouse gas.
— Examiner report, February/March 2025, 0653/32 Q5(a)(ii) (Cambridge)

Practise this topic

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Practise 0653.c10.2.01 — state the composition of clean, dry air as approximately 78% nitrogen, n2, 21% oxygen, o2, and the remainder as a mixture of noble gases and

In the syllabus

87 0653.C10.2.01 — State the composition of clean, dry air as approximately 78% nitrogen, N2, 21% oxygen, O2, and the remainder as a mixture of noble gases and

State the composition of clean, dry air as approximately 78% nitrogen, N2, 21% oxygen, O2, and the remainder as a mixture of noble gases and carbon dioxide, CO2
State the source of each of these air pollutants, limited to: (a) . carbon dioxide from the complete combustion of carbon-containing fuels (b) . carbon monoxide and particulates from the incomplete combustion of carbon- containing fuels (c) . methane from the decomposition of vegetation and waste gases from digestion in animals (d) . oxides of nitrogen from car engines (e) . sulfur dioxide from the combustion of fossil fuels which contain sulfur compounds
State the adverse effect of these air pollutants, limited to: (a). carbon dioxide: higher levels of carbon dioxide leading to increased global warming, which leads to climate change (b). carbon monoxide: toxic gas (c). particulates: increased risk of respiratory problems and cancer (d). methane: higher levels of methane leading to increased global warming, which leads to climate change (e). oxides of nitrogen: acid rain and respiratory problems (f). sulfur dioxide: acid rain
State and explain strategies to reduce the effects of climate change: (a) . planting trees (b) . reduction in livestock farming, (c) . decreasing use of fossil fuels (d) . increasing use of renewable energy, e.g. wind, solar
State strategies to reduce the effects of acid rain: reducing emissions of sulfur dioxide by using low-sulfur fuels
Describe how the greenhouse gases carbon dioxide and methane cause global warming, limited to: (a) . the absorption, reflection and emission of thermal energy (b) . reducing thermal energy loss to space

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