72-73 - The Atmosphere Flashcards
What are the major components of today’s atmosphere?
Nitrogen - 78%
Oxygen - 21%
Argon, CO2, noble gases etc.
What are the three phases of atmospheric evolution?
- Volcanic eruptions
- Evolution of plants
- Development of ozone layer
Explain phase 1 of atmospheric evolution
Volcanoes continuously erupted
Gases given off became oceans and atmosphere
Water vapour condensed into seas
Explain phase 2 of atmospheric evolution
Green plants and algae photosynthesised
O2 was put into the atmosphere
Carbon in these plants was locked up - they became fossil fuels
Explain phase 3 of atmospheric evolution
Build up of O2 led to complex organisms
Ozone layer blocked harmful sun rays
Now very little CO2 in atmosphere
What is the Primordial Soup Theory?
Lightning causes chemical reactions and the formation of amino acids
What was the proposed atmosphere in the Primordial Soup theory?
Nitrogen, hydrogen, ammonia, methane
What is referred to as “primordial soup”?
The body of water and amino acids which life emerged from
What did the Miller-Urey experiment show?
Amino acids were formed, but less than expected
Showed the theory could be correct, but something may be missing
What is the first step of fractional distillation of air?
Dust is removed by filtration
What are the steps of the fractional distillation of air after dust has been removed?
- Cooled to -200^c to form a liquid
- Water vapour condenses and js removed
- CO2 freezes and is removed
- Liquid air is heated in a fractionating column
- Fractional distillation separates the gases
What are two issues associated with the increase of CO2?
Global warming/climate change
Acidity of oceans - unsuitable for some organisms
How were early oceans formed?
Water vapour from volcanoes condensed into seas
What is ammonia?
Nitrogen and hydrogen
