C9 - Chemistry of the atmosphere

Question 1

What is composition of the atmosphere?

Answer 1

Approximately 80% Nitrogen, 20% Oxygen and small amounts of CO2,water vapour and Nobel gases

Question 2

What was the composition of the earth’s early atmosphere?

Answer 2

Lots of carbon dioxide and water vapour from volcanic eruptions and small amounts of methane and ammonia

Question 3

How did the level of water vapour reduce?

Answer 3

The earth cooled so the water vapour condensed and formed oceans

Question 4

Give 3 ways the level of CO2 decreased

Answer 4

The CO2 dissolved in oceans and formed sedimentary rocks such as limestone.
Plants evolved and photosynthesised which uses CO2 and produces O2.
CO2 taken in by animals and becomes part of their skeleton when they die, forming sedimentary rock.

Question 5

Why are greenhouse gases important for life on earth?

Answer 5

They maintain the earth’s temperature so it is high enough to support life

Question 6

Name three greenhouse gases

Answer 6

Methane, water vapour and carbon dioxide

Question 7

How do greenhouse gases maintain the earth’s temperature?

Answer 7

Short wavelength radiation from the sun is transmitted through the atmosphere and absorbed by the earth. It is re-emitted from the earth at a longer wavelength, which is absorbed by the greenhouse gases.

Question 8

How have humans contributed to CO2 levels rising?

Answer 8

Deforestation of trees reducing photosynthesis, burning of fossil fuels.

Question 9

How have humans contributed to methane levels rising?

Answer 9

Intensive cattle farming, rice paddy fields and decomposition in land fill sites.

Question 10

What are 4 implications of global temperature increases from climate change?

Answer 10

Sea level rise - flooding and erosion
More frequent and severe storms.
Temperature and water stress for life on Earth.
Changes to distribution of wildlife.

Question 11

What does the term carbon footprint mean?

Answer 11

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

Question 12

How can people reduce their carbon footprint?

Answer 12

Use less energy
Use renewable energy
Offset their emissions by planting trees
Carbon capture and storage.
Carbon taxes.

Question 13

What elements do most fuels contain?

Answer 13

Carbon and or hydrogen and may contain sulphur impurities.

Question 14

What are the products of complete combustion?

Answer 14

Carbon dioxide and water

Question 15

What are the products of incomplete combustion?

Answer 15

Carbon monoxide, carbon particulates and water

Question 16

When does incomplete combustion occur?

Answer 16

If there is a limited amount of oxygen

Question 17

How does carbon dioxide form during combustion?

Answer 17

Carbon from the fuel reacts with oxygen from the air by complete combustion

Question 18

How does carbon monoxide form during combustion?

Answer 18

Carbon from the fuel reacts with oxygen from the air by incomplete combustion

Question 19

How does sulphur dioxide form during combustion?

Answer 19

Sulphur impurities in the fuel react with oxygen from the air

Question 20

How do nitrogen oxides form during combustion of fuels?

Answer 20

Nitrogen from the air reacts with oxygen from the air inside a hot car engine

Question 21

What problems are associated with carbon monoxide?

Answer 21

It is a toxic gas that can kill, it is hard to detect as it is colourless and odourless

Question 22

What problems are associated with sulphur dioxide and nitrogen oxides?

Answer 22

They cause acid rain as well as respiratory problems.

Question 23

What problems are associated with carbon particulates?

Answer 23

They cause global dimming and irritate the lungs.

Question 24

What was the early climate of the earth?

Answer 24

Very hot.

Question 25

What gases are released during a volcanic eruption?

Answer 25

Carbon dioxide, Nitrogen, Methane, Ammonia and water vapour.

Question 26

How did the oxygen levels increase?

Answer 26

Algae and plants produced O2 through photosynthesis.

Question 27

What does the CO2 in the oceans react with and forms what?

Answer 27

Reacts with metal ions and forms insoluble carbonates such as CaCO3.

Question 28

Why is the greenhouse effect important?

Answer 28

To maintain temperatures high enough to support life on Earth.

Question 29

What is carbon capture and storage?

Answer 29

CO2 is trapped in solvents and stored underground.

Question 30

What are 5 problems with reducing carbon footprint?

Answer 30

Scientific disagreement over causes and consequences of climate change.
Lack of public information and education.
Lifestyle changes.
Expensive.
Needs international cooperation.

Question 31

What are the advantages of complete combustion?

Answer 31

Less carbon particulates.
More energy is released.
Poisonous carbon monoxide not produced.

Question 32

What gases are released when a fuel burns?

Answer 32

Sulfur dioxide, carbon dioxide, carbon monoxide, nitrous oxides.
Unburned hydrocarbons and solid particles are also released.

Question 33

What does acid rain do?

Answer 33

Damages plants and buildings.

Question 34

What problems do particulates cause?

Answer 34

Global dimming. Damage to lungs - health problems.

Question 35

What is global dimming?

Answer 35

Reducing the amount of sunlight that reaches the Earth’s surface.

Question 36

Why are scientists not certain about the early atmosphere?

Answer 36

4.6 billion years ago - not evidence.