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9.1 The composition and evolution of the Earth's atmosphere

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Question 24
H

A student states that the Earth's early atmosphere contained no oxygen at all. Why can a scientist not be certain that this statement is correct?

[1]
A

Volcanoes released small amounts of oxygen with the carbon dioxide

B

The oceans had already formed, so the oxygen dissolved in the water

C

Algae had already evolved and were producing oxygen by photosynthesis

D

The evidence is limited, so the theory may be revised in the future

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

40 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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