C13 - Earth's Atmosphere

Question 1

What is the percentage of nitrogen in the atmosphere?

Answer 1

80%

Question 2

What is the percentage of oxygen in the atmosphere?

Answer 2

20%

Question 3

What other gases are in the atmosphere in small proportions?

Answer 3

Carbon dioxide, water vapour and noble gases

Question 4

Why is evidence for the early atmosphere limited?

Answer 4

Because it was formed too long ago

Question 5

How long ago did the early atmosphere form?

Answer 5

4.6 billion years

Question 6

How do we think the Earth’s early atmosphere formed?

Answer 6

Volcanic activity that released gases

Question 7

How do we think the oceans formed?

Answer 7

As the earth cooled water vapour condensed

Question 8

What other planets’ atmospheres may Earth’s may have been like in the past?

Answer 8

Mars and Venus today

Question 9

How do we think nitrogen got into the atmosphere?

Answer 9

Volcanic activity

Question 10

What other gases could have been in the early atmosphere in small proportions?

Answer 10

Methane and ammonia

Question 11

Why did the formation of the oceans cause carbon dioxide levels to decrease?

Answer 11

Carbon dioxide dissolved in water and carbonates precipitated producing sediments

Question 12

How is oxygen released into the atmosphere?

Answer 12

Photosynthesis

Question 13

What is the word equation for photosynthesis?

Answer 13

Carbon dioxide + water → Glucose + Oxygen

Question 14

What is the formula equation for photosynthesis?

Answer 14

6CO2 + 6H2O → C6H12O6 +6O6

Question 15

When did algae first produce oxygen?

Answer 15

2.7 billion years ago

Question 16

How long did it take for oxygen levels to build up so that animals could evolve?

Answer 16

A billion years

Question 17

Why did the percentage of carbon dioxide decrease further when plants evolved?

Answer 17

• Algae and plants doing photosynthesis and removing it from the atmosphere.
• It became locked in sedimentary locks and in fossil fuels

Question 18

Why are some greenhouse gases in the atmosphere important?

Answer 18

They maintain temperatures on Earth high enough to support life

Question 19

What are 3 examples of greenhouse gases?

Answer 19

Water vapour, carbon dioxide and methane

Question 20

What is the greenhouse effect in terms of interaction of short and long wavelength radiation with matter?

Answer 20

• Short-wavelength radiation from the Sun passes through the atmosphere and is absorbed by the Earth’s surface and causes it to heat up.
• The heated Earth emits long-wavelength radiation(infrared) back into space

Question 21

What human activities increase the amount of carbon dioxide in the atmosphere?

Answer 21

• Burning fossil fuels
• deforestation

Question 22

What human activities increase the amount of methane in the atmosphere?

Answer 22

Farming cattle and farming rice in paddy fields

Question 23

What are the 4 potential effects of global climate change?

Answer 23

• Ice caps melting
• sea levels rising
• patterns of rainfall changing
• habitats changing

Question 24

What is the scale, risk and environmental implications of global climate change?

Answer 24

More frequent and intense weather events, disruption of ecosystems and threats to human well being - heatwaves

Question 25

Why is it difficult to model complex systems as global climate change?

Answer 25

- There are simplified models - speculation and opinions presented can be based on only parts of evidence and which may be biased

Question 26

What is the carbon footprint?

Answer 26

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

Question 27

How can carbon footprint be reduced?

Answer 27

Reducing emissions of carbon dioxide and methane

Question 28

What can be done to reduce emissions of carbon dioxide?

Answer 28

- Increasing carbon sinks - rainforests(photosynthesis) - decreasing emissions from vehicles - increase taxes to discourage car use - make public transport more affordable - decreasing emissions from fossil fuel power stations - reduce electricity use

Question 29

What can be done to reduce emissions of methane?

Answer 29

- Decreasing emissions from landfill from decomposition of biodegradable materials - decreasing emissions from farming

Question 30

Why could these actions to reduce emissions of carbon dioxide and methane be limited?

Answer 30

Cost

Question 31

What is a major source of atmospheric pollutants?

Answer 31

Combustion of fuels

Question 32

What do most fuels like coal contain?

Answer 32

Contain carbon and/or hydrogen and may contain some sulfur

Question 33

What 5 gases can be released when a fuel is burned?

Answer 33

- Carbon dioxide - water vapour - carbon monoxide - sulfur dioxide - oxides of nitrogen

Question 34

What else can be released from the atmosphere?

Answer 34

- Solid particles - unburned hydrocarbons may also be released that form particulates in the atmosphere

Question 35

How is carbon monoxide produced when burning fossil fuels?

Answer 35

During incomplete combustion which happens when there is not enough oxygen for the fuel to burn completely

Question 36

How is soot(carbon particles) produced when burning fossil fuels?

Answer 36

During incomplete combustion, often seen as smoke or ash

Question 37

How are oxides of nitrogen produced when burning fossil fuels?

Answer 37

High temperatures can cause nitrogen and oxygen from the air to react - contributes to air pollution

Question 38

Why is sulfur dioxide produced when a fossil fuel is burned?

Answer 38

The fuels contain some sulfur atoms, at high combustion temperatures, sulfur reacts with oxygen to form sulfur dioxide

Question 39

What is carbon monoxide?

Answer 39

A toxic gas - colourless and odourless and not easily detected

Question 40

What problems does sulfur dioxide cause?

Answer 40

- Respiratory problems - acid rain

Question 41

What problems do nitrogen oxides cause?

Answer 41

- Respiratory problems - acid rain

Question 42

What problems do particulates cause?

Answer 42

- Global dimming - Health problems for humans