The Earth’s Atmosphere Flashcards
What was the atmosphere like billions of years ago?
Mainly carbon dioxide, nitrogen, water vapour and hydrogen based compounds
What did volcanoes release in the early atmosphere?
Carbon dioxide, water vapour and nitrogen
What happened when the Earth cooled?
Water vapour condensed and formed oceabs
How else was water brought to Earth?
Comets
What appeared 3.4 billion years ago?
Bacteria like organisms that used chemosynthesis to make energy
When did bacteria like organisms evolve into photosynthesising bacteria and algae?
2.7 billion years ago
How did photosynthesising organisms change the atmosphere?
By adding oxygen
What happened when plants and animals began to evolve?
Oxygen levels increases and carbon dioxide levels decreased
How much nitrogen is in the atmosphere today?
78%
How much oxygen is in the atmosphere today?
21%
How much carbon dioxide is in the atmosphere today?
0.04%
How much argon is in the atmosphere today?
0.9%
How much of other gases is in the atmosphere today?
0.06%
Why did nitrogen levels build up?
Nitrogen is very unreactive
What is the equation for methane reacting with oxygen in the early atmosphere?
Methane + Oxygen —> Carbon Dioxide + Water
CH4 + 2O2 —> CO2 + 2H2O