Chemistry - Topic 9 the atmosphere

Question 1

What is the composition of the atmosphere today?

Answer 1

Nitrogen-78%
Oxygen-21%
Argon-0.8%
Carbon Dioxide-0.04%
Other gasses-0.16%

Question 2

State two ways the amount of CO2 decreased from the early atmosphere.

Answer 2

Taken in by plants through photosynthesis.
Absorbed by the oceans and then dissolved.
Locked away in cedimentary rock.

Question 3

Name 3 greenhouse gasses.

Answer 3

Methane
Carbon dioxide
Water Vapour

Question 4

State two human activities which have increased the number of greenhouse gasses in our atmosphere.

Answer 4

Increased cattle farming which causes the release of methane.
Increased burining of fossil fuels.

Question 5

Describe the greenhouse effect.

Answer 5

The sun emits short-wavelength radiation which passes through the atmosphere to Earth. The Earth absorbs short-wavelength radiation. The Earth re-emits long-wavelength radiation. Greenhouse gases absorb long-wavelength radiation. The greenhouse gases re-radiate the long-wavelength radiation in all directions.

Question 6

List three ways carbon footprint can be reduced.

Answer 6

Reducing meat intake.
Reducing the use of cars.
Switching to reneable elctricity.

Question 7

State two ways the large amount of CO2 decreased from the early atmosphere.

Answer 7

Dissolved in the oceans

And used for photosynthesis

Question 8

Describe the earth’s early atmosphere.

Answer 8

The early atmosphere was probably mostly carbon dioxide, with little or no oxygen. There were smaller proportions of water vapour, ammonia and methane. As the Earth cooled down, most of the water vapour condensed and formed the oceans.