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9.1 The composition and evolution of the Earth's atmosphere

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Question 8

A model estimates the percentage of oxygen in the atmosphere before and after a long period of photosynthesis.

StageOxygen in the atmosphere (%)
Before the period0.050
After the period20

How many times greater was the percentage of oxygen after the period than before it?

[1]
A

4000

B

19.95

C

40

D

400

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

79 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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