chemistry of the atmosphere (paper 2)

Question 1

what is the earths atmosphere made up of today

Answer 1

nitrogen (80%)

oxygen (20%)

and a small amount of other gases

Question 2

what five gases were present in the earths early atmosphere

Answer 2

carbon dioxide

ammonia

nitrogen

methane

water vapour

Question 3

what happened to the water vapour as the earth cooled down

Answer 3

the steam condensed and fell as rain which filled up hollows in the earths crust and oceans were formed

Question 4

where do some scientists think that life first evolved

Answer 4

the first bacteria evolved near underwater volcanoes

Question 5

how did oxygen appear in the earths atmosphere

Answer 5

the first organisms such as algae used up carbon dioxide in water during photosynthesis and made the first molecules of oxygen gas

Question 6

what layer did oxygen form in the upper atmosphere

Answer 6

the ozone layer

Question 7

why is the ozone layer important for life on land

Answer 7

shielded the earth from harmful UV light

Question 8

what is the word equation for photosynthesis

Answer 8

carbon dioxide + water –> oxygen + glucose

Question 9

what is the word equation for respiration

Answer 9

oxygen + glucose –> carbon dioxide + water

Question 10

what happened to methane in the early atmosphere

Answer 10

methane was removed from the early atmosphere once oxygen was made

methane + oxygen –> carbon dioxide + water

CH4 +2O2 –> CO2 + 2H2O

Question 11

what happened to the ammonia in the early atmosphere

Answer 11

ammonia was removed from the atmosphere once oxygen was made

ammonia +oxygen —> nitrogen + water

4NH3 + 3O2 –> 2N2 + 6H20

Question 12

what is a carbon footprint

Answer 12

a measure of the amount of carbon dioxide and other greenhouse gases that are released over the life cycle of something

Question 13

how do greenhouse gases cause global warming

Answer 13

the sun emits short wavelength radiation which passes through the earths atmosphere as it isn’t absorbed by greenhouse gases

the short wavelength radiation reaches the earths surface as it is absorbed and then re - emitted as long wavelength radiation

the radiation is absorbed by by green house gases in the atmosphere, the greenhouse gases then re - radiate it in all directions including back towards earth

the long wave radiation is thermal radiation so it results in the warming in the surface of the earth

this is the greenhouse effect

Question 14

what is capture and storage

Answer 14

captures the carbon dioxide produced by fossil fuels and buried underground