C13

Question 1

Proportion of gases

Answer 1

For 200 million years the proportion of gases in the atmosphere have been:
78% Nitrogen
21% Oxygen
0.9% Argon
0.04% Carbon dioxide
water vapour

Question 2

Volcano theory

Answer 2

Volcanoes released carbon dioxide, water vapour and nitrogen which formed the early atmosphere. Water vapour condensed as the Earth cooled down and fell as rain.

Question 3

Oxygen in the atmosphere

Answer 3

Algae evolved and soon after this oxygen began to exist in the atmosphere. Photosynthesis by plants and algae released oxygen, which gradually built up in the atmosphere.

Question 4

oxygen in atmosphere equation

Answer 4

carbon dioxide + water –> glucose + oxygen

Question 5

Early atmosphere

Answer 5

Earths atmosphere may have been like the atmosphere of Mars and Venus consisting of CO2 with little O2.

Question 6

How did CO2 reduce in the atmosphere

Answer 6

Carbon dioxide is taken in by plants and algae and converted to glucose and oxygen during photosynthesis. When animals eat the plants some of the carbon is transferred to the animal tissues, skeletons and shells, There they became covered with fine sediment under pressure it formed carbonated rock.

Question 7

coal

Answer 7

sedimentary rock formed from thick deposits of animal material. Plants died and buried in absence of oxygen and compressed over million of years.

Question 8

crude oil

Answer 8

Natural gas formed from the remains of plankton on the seabed. Remains were covered by sediment that become rocks after being compressed over millions of years.

Question 9

Ammonia and methane

Answer 9

Any methane or ammonia found in Earths early atmosphere reacted with oxygen formed by plants. This removed methane and ammonia from the atmosphere.

Question 10

CO2 helps maintain earths temp.

Answer 10

CO2 allows short wavelength radiation to pass through greenhouse gases. These gases absorb infra red radiation and are trapped in the atmosphere.

Question 11

Greenhouse effect

Answer 11

The trapping of the suns warmth in planets lower atmosphere, due to greater transparency of the atmosphere to visible radiation from the sun that infra red radiation emitted from planets surface.

Question 12

Why is the greenhouse effect essential?

Answer 12

Greenhouse gases keep Earth at a suitable temperature for life. Without this effect the heat emitted by the earth would pass into space and Earth would have a temperature of -20.

Question 13

greenhouse gases

Answer 13

Gases in the earths atmosphere that trap heat. Sun shines through the earths atmosphere warming its surface.

Question 14

consequences of greenhouse gases

Answer 14

• farming cattle releases methane
• burning fossil fuels release CO2
• deforestation releases CO2 and reduces Co2 absorption through photosynthesis ……

Question 15

Carbon footprint

Answer 15

The carbon footprint of a product, service or event is the total amount of carbon dioxide and other greenhouse gases emitted over its full life cycle

Question 16

reducing carbon footprint

Answer 16

• carbon capture and storage
• less demand for beef
• electric cars

Question 17

pollution issues

Answer 17

• sulfur dioxide can cause acid rain from burning fuels
• breathing problems from oxides of nitrogen
• unburnt hydrocarbon particles travel into the atmosphere reflecting sunlight back into space causing global dimming