C9 atmosphere

Question 1

what percentage of the atmosphere are oxygen and nitrogen and ‘others’

Answer 1

21%
78%
small proportion of carbon, water vapour, noble gases

Question 2

what is believed to be the cause of the earths early atmosphere

Answer 2

volcanic activity released gases that formed the atmosphere.
the gases then cooled and condensed to form oceans
also released carbon, nitrogen,
methane and ammonia

Question 3

what are the 2 mains differences in the early atmosphere and today

Answer 3

early- contained large amounts of carbon
- contained little oxygen

Question 4

how did changes in the amount of carbon occur

Answer 4

• water vapour condensed
• carbon dissolved in water to form a weak acid
• this reacted with minerals forming precipitates
• this formed sediments of carbonate rock

Question 5

how did changes in the amount of oxygen occur

Answer 5

-photosynthetic algae evolved
- photosynthesis then produced oxygen
-plants evolved increasing oxygen
- this lead to animals evolving
- dead animals caused carbon to be trapped in fossil fuels

Question 6

what are the 3 main fossil fuels

Answer 6

coal
gas
oil

Question 7

what are the 3 main greenhouse gases

Answer 7

carbon
water vapour
methane

Question 8

what are the effects of the greenhouse effect

Answer 8

ice caps melting
sea levels rising
flooding and storms
distribution of insects
drought