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9.1 The composition and evolution of the Earth's atmosphere

9.1 The composition and evolution of the Earth's atmosphere

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This question is about the historical and modern composition of the Earth's atmosphere.

a.

Which gas was the most abundant in the Earth's early atmosphere, similar to the atmosphere of Venus today?

  • Nitrogen
  • Oxygen
  • Carbon dioxide
  • Argon
[1]
b.

What is the approximate percentage of nitrogen (N2\text{N}_2N2​) in the Earth's atmosphere today?

  • 1%1\%1%
  • 21%21\%21%
  • 78%78\%78%
  • 95%95\%95%
[1]
c.

Which two of the following processes significantly reduced the percentage of carbon dioxide in the Earth's early atmosphere over geological time?

  • Respiration by early animals
  • Photosynthesis by algae and plants
  • Carbon dioxide dissolving in the oceans and forming sedimentary carbonate rocks
  • Volcanic activity releasing sulfur dioxide
  • Combustion of hydrocarbons by early life forms
[2]
Markscheme

9.1 The composition and evolution of the Earth's atmosphere Questions

  1. GCSE
  2. /Chemistry
  3. /9.1 The composition and evolution of the Earth's atmosphere

7 exam-style questions on AQA GCSE Chemistry 9.1 The composition and evolution of the Earth's atmosphere, covering 9.1.1 The proportions of different gases in the atmosphere, 9.1.2 The Earth's early atmosphere, 9.1.3 How oxygen increased, and 9.1.4 How carbon dioxide decreased. Each one has a worked solution and a mark scheme showing where the marks go.

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