GCSE Chemistry (AQA)

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The Atmosphere Today

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Chemistry of the atmosphere The composition and evolution of the Earth's atmosphere

The Atmosphere Today

2:22 Changes in Earth's Atmosphere Over Time
Spec 4.9.1.1
Previous Reaction Profile for Catalysed Reaction Next The Early Atmosphere
  • The Earth's atmosphere is a thin layer of gases held by gravity.
  • The atmosphere becomes less dense further from Earth.
  • The atmosphere's boundary is hard to define.
  • The atmosphere has changed significantly since Earth's formation.
  • 4.6 billion years ago, Earth had no oceans, and the surface was hot.
  • The atmosphere 200 million years ago was similar to today's.
  • The balance of gases has been stable for 200 million years.
  • Current atmosphere composition:
  • Approximately 80% nitrogen.
  • Approximately 20% oxygen.
  • Small proportions of other gases: carbon dioxide, water vapor, noble gases.
  • Carbon dioxide is less than 1% of the atmosphere but significantly impacts the environment.

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