C1:5 Clean air

Question 1

What happened to the levels of oxygen, nitrogen, Carbon dioxide, ammonia and methane as the atmosphere formed?

Answer 1

The oxygen and nitrogen levels increased.
The Carbon dioxide, ammonia and methane levels decreased.

Question 2

what stops the atmosphere from disappearing into space?

Answer 2

gravity

Question 3

What 2 gases make up 99% of the worlds atmosphere?

Answer 3

Oxygen and nitrogen

Question 4

How did the atmosphere form?

Answer 4

1. Lots of volcanic activity spewed large amounts of water vapour and Carbon dioxide into the atmosphere along with smaller amounts of ammonia and methane.
2. The water vapour condensed to form oceans, leaving an atmosphere of mostly carbon dioxide. Little or no oxygen.
3. Photosynthesis caused the concentrations of Carbon dioxide to go down in the atmosphere. Carbon dioxide is soluble in water and so a lot dissolved into the oceans.
4. This was then used by marine organisms to make their shells which was then fossilised into Limestone.
5. Ammonia was broken down by sunlight and by its reaction with oxygen, forming nitrogen which is chemically stable and so the concentration grew until they reached today’s levels.

Question 5

What impact did Photosynthesis have on the creation of the atmosphere?

Answer 5

It decreased the concentration of Carbon dioxide in the atmosphere.

Question 6

Describe three processes responsible for reducing the level of carbon dioxide in the early atmosphere.

Answer 6

Photosynthesis. Carbon dioxide dissolving into the oceans. Marine organisms using the Carbon dioxide dissolved in the water to make their shells.

Question 7

Explain why the level of nitrogen in the atmosphere increased.

Answer 7

The level of nitrogen increased until they reached it reached it level today because Ammonia breaks down in its reaction with sunlight and oxygen into nitrogen. Nitrogen is chemically very stable and so its concentration just grew.