Chemistry

Question 1

What gases were in the Earth’s early atmosphere?

Answer 1

• Mainly carbon dioxide
• Smaller amounts of water vapour and other gases
• Little or no oxygen

Question 2

How do volcanoes affect the atmospheres of planets?

Answer 2

Release large amounts of gases such as carbon dioxide and water vapour, and small amounts of other gases (including nitrogen).

Question 3

Why does the discovery of Titan’s icy interior not support the idea that the Earth’s early atmosphere was mainly nitrogen?

Answer 3

There is 98.4% of nitrogen which is likely to be released from volcanoes however it is covered in ice.

Question 4

Why do scientists think that the early Earth had an atmosphere similar to Venus?

Answer 4

The atmosphere is mainly carbon dioxide, thought to have been released by volcanoes.

Question 5

Describe how the Earth’s oceans may have formed?

Answer 5

Water vapour from the atmosphere condensed to liquid water

Question 6

What evidence supports the idea that oxygen was not present in the early Earth’s atmosphere?

Answer 6

Oxygen is not produced by volcanoes.

Question 7

Why are scientists more certain about the oxygen content of the early atmosphere compared to other gases?

Answer 7

They think oxygen from microorganisms reacted with iron in the early oceans, to produce insoluble iron oxides that formed layers on the seabed.

Question 8

The percentage of carbon dioxide in the Earth’s atmosphere today is ….?

Answer 8

0.04%

Question 9

The percentage of oxygen in the Earth’s atmosphere today is …?

Answer 9

21%

Question 10

The percentage of nitrogen in the Earth’s atmosphere today is…?

Answer 10

78%

Question 11

The percentage of argon in the Earth’s atmosphere today is …?

Answer 11

1%

Question 12

What are the 3 phases of the evolution of the atmosphere?

Answer 12

1) volcanoes gave out carbon dioxide and water vapour into the atmosphere
2) photosynthesising organisms took in CO2 and released O2
3) more complex organisms can evolve with presence of O2

Question 13

What has caused CO2 levels to decrease?

Answer 13

• photosynthesising organisms used CO2 (and released O2)
• CO2 dissolved in oceans
• organisms in oceans used CO2 to form
• CACO3 (calcium carbonate) to form shells

Question 14

What has caused CO2 levels to increase?

Answer 14

Human activity - burning fossil fuels e.g fuel in cars, or in factories

Question 15

Test for carbon dioxide

Answer 15

• bubble through limewater

- if solution goes cloudy, CO2 present

Question 16

Test for oxygen

Answer 16

• glowing splint in gas

- relights if O2 present

Question 17

State the greenhouse gases

Answer 17

• carbon dioxide
• methane
• water vapour

Question 18

What is the influence of the greenhouse effect?

Answer 18

Makes the temperature hotter

Question 19

Why might have industrialisation have led to an increase in greenhouse gases?

Answer 19

There was a steady increase in burning fuels such as factories. Meaning that carbon dioxide would’ve been released during combustion.

Question 20

What is global warming?

Answer 20

Increase in the overall temperature of the Earth’s atmosphere

Question 21

Compare global warming to climate change

Answer 21

Global warming is a cause of climate change which is changes to average weather conditions around the world.

Question 22

What is a ‘casual link’?

Answer 22

A link that ‘one thing causes another’`

Question 23

Why do many scientists believe that there is a casual link between CO2 level increase and a rise in temperature?

Answer 23

Satellite data confirms that as CO2 levels have increased, there has been a reduction in infrared waves from the Earth leaving the atmosphere

Question 24

How do scientists measure CO2 levels from the past?

Answer 24

Measuring concentrations of the gas trapped in ice cores

Question 25

CO2 and other gases in the atmosphere help to keep the Earth warm. State how these gases keep the Earth warm.

Answer 25

Gases in the air absorb energy from infrared waves. When the gases re-emit the energy, some of it goes back to the Earth’s surface and warms it.

Question 26

State 3 human activities that cause climate change

Answer 26

• Burning of fossil fuels
• Live stock farming
• Extracting oil from the ground

Question 27

How does livestock increase levels of greenhouse gases in the atmosphere?

Answer 27

Cattle produces a lot of methane due to bacteria in their stomachs to digest tough grass

Question 28

Describe why an increasing world population might lead to more greenhouse gases being released into the atmosphere?

Answer 28

There will be more farming to feed more people, more waste collecting and increase of burning fossil fuels due to more drivers.

Question 29

List 4 negative effects of climate change

Answer 29

• raised sea levels due to melting glaciers
• some animals and plants may become extinct
• areas will become drier, others wetter
• harm living organisms in sea and oceans

Question 30

Explain why an increased use of renewable energy might help to limit the impact of climate change?

Answer 30

It can reduce greenhouse gas emissions

Question 31

Explain why international cooperation is important in dealing with climate change

Answer 31

Countries will need to work together to reduce emissions and help pay for large-scale engineering as there is a risk that some countries will not help and delicate eco-systems may be disrupted

Question 32

Identify a way of limiting the impact of climate change and one risk

Answer 32

Helping local people adapt to new conditions e.g flood defences, dams and irrigation systems. However not everyone will cooperate