For about how long have the overall proportions of gases in the Earth's atmosphere remained broadly similar to today?
For around the last 200 million years.
AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher · 5.9.1.1
Revise AQA GCSE Combined Science: Trilogy (8464) — Chemistry — Higher specification point 5.9.1.1, The proportions of different gases in the atmosphere, with free active-recall flashcards. Flip through the set or review every question and answer below.
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For about how long have the overall proportions of gases in the Earth's atmosphere remained broadly similar to today?
For around the last 200 million years.
Which two gases make up most of the modern Earth's atmosphere, and in roughly what proportions?
Which gases are present in the small remaining fraction of the Earth's atmosphere?
Carbon dioxide, water vapour, and noble gases.
What kind of substance is the Earth's atmosphere: a single gas or a mixture?
A mixture of gases.