C9 Atmosphere

Question 1

name the current proportion of gases in the atmosphere (4)

Answer 1

• nitrogen 78%
• oxygen 21%
• other 1%
  -> carbon dioxide 0.035%
  argon/ water vapour/ noble gases

Question 2

describe the earth’s early atmosphere (+reason why)

Answer 2

• intense volcanic activity
• produced water vapour and gases (largely carbon dioxide, as well as methane/ ammonia/ nitrogen)
• similar to the current atmospheres of Mars+Venus

Question 3

describe how the oceans formed

Answer 3

• the earth’s early atmosphere contained water vapour
• which condensed as the earth began to cool
• formed rain clouds which precipitated to form oceans in basins