Topic 9 - Chemistry Of The Atmosphere Flashcards

1
Q

How long have the properties of different gases in the atmosphere in how they are today?

A

200 million years

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2
Q

What is the composition of gases in the atmosphere?

A

80% nitrogen
20% oxygen
Small amounts of other gases including CO2, water vapour and noble gases

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3
Q

Why is evidence for the early atmosphere limited?

A

Because of the timescale of 4.6 billion years

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4
Q

What does one theory suggest about first billion years of the Earth’s existence?

A

There was intense volcanic activity that released gases which formed the early atmosphere and water vapour that condensed to form oceans

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5
Q

During the first billion years of the earths existence what was the earths atmosphere like?

A

It may have been like the atmospheres of Mars and Venus today, consisting of mainly carbon dioxide with little or no oxygen gas

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6
Q

What did volcanoes produce?

A
  • Nitrogen which gradually built up in the atmosphere

- small portions of methane and ammonia

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7
Q

What happened when the oceans formed?

A

Carbon dioxide dissolved in the water and carbonates precipitated producing sediments, reducing the amount of carbon dioxide in the atmosphere

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8
Q

What is thought to have produced the oxygen that is now in the atmosphere?

A

Algae and plants produced the oxygen by photosynthesis

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9
Q

What is the word equation for photosynthesis?

A

Carbon dioxide + water — light—> glucose + oxygen

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10
Q

What is the symbol equation for photosynthesis?

A

6CO2 + 6H2O —> C6H12O6 + 6O2

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11
Q

When did algae first produce oxygen?

A

About 2.7 billion years ago and soon after this oxygen appeared in the atmosphere

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12
Q

What happened over the next billion years after algae first produced oxygen?

A

Plants evolved and the percentage of oxygen gradually increased to a level that enabled animals to evolve

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13
Q

How did carbon dioxide in the atmosphere decrease?

A
  • Algae and plants decreased the percentage of carbon dioxide in the atmosphere by photosynthesis
  • sedimentary rocks and fossil feels that contain carbon were formed, decreasing carbon dioxide
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14
Q

How are crude oil and natural gases formed?

A

From deposits of plankton. They form reservoirs under the seabed when they get trapped in rocks

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15
Q

How is coal formed?

A

Thick plant deposits make a sedimentary rock

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16
Q

How is limestone formed?

A

Calcium carbonate deposits from the shells and skeletons of marine organisms forming a sedimentary rock

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17
Q

How are sedimentary rocks, oil and gas formed?

A

When plants, plankton and marine animals die, they fall to the seabed and get buried in layers of sediment which become compressed over millions of years, trapping carbon within them to help reduce CO2 levels in the atmosphere

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18
Q

What do you greenhouse gases in the atmosphere maintain?

A

They maintain temperatures on Earth high enough to support life

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19
Q

Give examples of greenhouse gases?

A

Water vapour, carbon dioxide and methane

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20
Q

What is the greenhouse effect?

A

Greenhouse gases resorb the long wavelength radiation (thermal radiation) that gets reflected back off the Earth, they then re-radiate it in all directions which results in warning of the surface of the Earth

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21
Q

Do greenhouse gases absorb the incoming short wavelength radiation from the Sun?

A

No

22
Q

Which forms of human activity affect the amount of greenhouse gases in the atmosphere?

A
  • deforestation
  • Burning fossil fuels
  • agriculture
  • creating waste
23
Q

How does deforestation affect the amount of greenhouse gases in the atmosphere?

A

Fewer trees means less carbon dioxide is removed from the atmosphere by photosynthesis

24
Q

How does burning fossil fuels affect the amount of greenhouse gases in the atmosphere?

A

Carbon that was ‘locked up’ in these fuels is released as CO2

25
Q

How does agriculture affect the amount of greenhouse gases in the atmosphere?

A

More farm animals produce more methane through their digestive processes

26
Q

How does creating waste affect the amount of greenhouse gases in the atmosphere?

A

More landfill sites and more waste from agriculture means more carbon dioxide and methane released by decomposition of waste

27
Q

Why is it hard to fully understand the earths climate?

A

Because it’s so complex and there are so many variables that it’s very hard to make a model that isn’t complex

28
Q

What has the complexity of the earths climate lead to?

A

Simplified models, speculation and opinions presented in the media that may be based on only some parts of the evidence making it biased

29
Q

What do many scientists believe that human activities will cause?

A

The temperature of the earths atmosphere to increase at the surface which will result in global climate change

30
Q

Why is the evidence about human activities causing global climate change reliable?

A

Evidence for this has been peer-reviewed

31
Q

Give a major cause of climate change

A

An increase in the average global temperature

32
Q

What are the potential effects of global climate change?

A
  • polar ice caps melting
  • changes in rainfall patterns
  • changes to the habitats of many wild species
33
Q

How does the melting of polar ice caps affect the Earth?

A

It causes a rise in the sea levels, increased flooding and coastal erosion

34
Q

How do you changes in rainfall patterns affect the Earth?

A

Some regions may get too little or too much water, which can affect the growth of food crops and the frequency and severity of storms may also increase

35
Q

What is the carbon footprint?

A

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

36
Q

How can we reduce the carbon footprint?

A

By reducing emissions of carbon dioxide and methane

37
Q

Give examples of how we can reduce emissions of carbon dioxide and methane?

A
  • renewable energy sources or nuclear energy used instead of fossil fuels
  • using efficient processes to conserve energy and cut waste
  • tax companies on the amount of greenhouse gases they emit
  • cap emissions of all greenhouse gases the companies make
  • use technology that captures the carbon dioxide produced and stored underground
38
Q

Why are actions to reduce carbon footprints limited?

A
  • changes will impact economic growth of communities (bad for wellbeing)
  • hard to make international agreements to reduce emissions
  • individuals in developed countries need to change their lifestyles but many don’t want to or don’t know that they should or how to do so
39
Q

Give an example of a major source of atmospheric pollutants?

A

Combustion of fuels

40
Q

What do most fuels, including coal, contain?

A

Carbon and/or hydrogen and some also contain sulphur

41
Q

What may the gases released into the atmosphere when a fuel is burned increase?

A

Carbon dioxide, water vapour, carbon monoxide, sulphur dioxide and oxides of nitrogen

42
Q

What are the substances may also be released when a fuel is burned that form particulates in the atmosphere?

A

Solid particles and unburned hydrocarbons form particulates in the atmosphere

43
Q

How is carbon monoxide and soot produced?

A
  • If there is not enough oxygen, some of the fuel doesn’t burn (incomplete combustion)
  • under these conditions carbon monoxide and soot can be produced
44
Q

How is sulphur dioxide produced by burning fuels?

A

Sulphur dioxide is released during the combustion of fossil feels that contain sulphur impurities (the sofa in the fuel becomes oxidised)

45
Q

How are nitrogen oxides produced by burning fuels?

A

Nitrogen oxides are created from a reaction between the nitrogen and oxygen in the air, caused by the heat of burning

46
Q

What happens when sulphur dioxide and nitrogen oxides mix with the clouds?

A

They form dilute sulphuric acid or dilute nitric acid which falls as acid rain

47
Q

How is acid rain harmful?

A

Acid rain kills plants and damages buildings and statues and makes metal corrode

48
Q

How are sulphur dioxide and nitrogen oxides bad for humans?

A

They can cause respiratory problems if they are breathed in

49
Q

What is the negative effects of particulates?

A

Particulates cause global dimming and health problems for humans

50
Q

What is carbon monoxide?

A

A toxic gas that is colourless and odourless so difficult to detect