Chemistry of the Atmosphere

Question 1

What percentage of the modern atmosphere is oxygen?

Answer 1

About 20%

Question 2

What percentage of the modern atmosphere is nitrogen?

Answer 2

About 80%

Question 3

How long has the atmosphere been like like today’s?

Answer 3

200 million years

Question 4

How was the early atmosphere first formed?

Answer 4

Volcanoes released carbon dioxide, water vapour, and nitrogen (and small amounts of methane and ammonia)

Question 5

How did the oceans form?

Answer 5

Water vapour in the atmosphere condensed to fall as rain into hollows in the earth, forming oceans

Question 6

What is the balanced chemical equation for photosynthesis?

Answer 6

6CO2 + 6H2O –> C6H12O6 + 6O2

Question 7

How did oxygen appear in the atmosphere?

Answer 7

Algae and plants absorbed carbon dioxide through photosynthesis and released oxygen as a waste product. Over years oxygen levels increased until eventually animals could evolve

Question 8

Why did the amount of carbon dioxide in the early atmosphere decrease?

Answer 8

Algae and plants took in carbon dioxide through photosynthesis

Formation of fossil fuels

Carbon dioxide dissolved into the oceans and reacted with metal oxides to form sediments (carbonates)

Question 9

Which chemicals did volcanoes in the early atmosphere release?

Answer 9

Carbon dioxide
Water vapour
Nitrogen

Question 10

Name three greenhouse gases

Answer 10

Carbon dioxide
Water vapour
Methane

Question 11

What is the greenhouse effect?

Answer 11

The Sun heats up the Earth, and about 30% of the energy is reflected back into space. The greenhouse gases in the atmosphere let short wave electromagnetic radiation pass through but not long wave. The surface of the Earth cools down by emitting long wave radiation.

Question 12

How is crude oil formed?

Answer 12

Dead marine organisms being crushed underground over millions of years under high temperatures and pressure

Question 13

Why have carbon dioxide levels in the modern atmosphere remained fairly constant?

Answer 13

The carbon cycle

Question 14

How is coal formed?

Answer 14

Plant material from land being crushed over millions of years

Question 15

Which human activities increase greenhouse gas levels?

Answer 15

• Burning fossil fuels
• Cattle - growing amount of waste products decomposing

Question 16

What are four effects of climate change?

Answer 16

• Rising sea levels
• Extreme weather events
• Temperature/rainfall levels changing
• Wildlife distribution

Question 17

Why is rising sea levels a problem?

Answer 17

Causes flooding and increased coastal erosion

Question 18

Why is temperature / rainfall changes a problem?

Answer 18

Some places may become less suited to growing crops

Question 19

Why is wildlife distribution changes a problem?

Answer 19

Some species may become extinct
Ecosystems put under stress

Question 20

What is carbon footprint?

Answer 20

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

Question 21

What problems does carbon monoxide cause?

Answer 21

Toxic gas (starves the body of oxygen, causes drowsiness and eventually death)
Not easily detected as it’s colourless and odourless

Question 22

What problems does sulphur dioxide cause?

Answer 22

Forms acid rain and causes respiratory problems

Question 23

How is carbon monoxide produced from burning fuels?

Answer 23

When there is not enough oxygen in car engines, incomplete combustion occurs

Question 24

How do particulates cause problems?

Answer 24

Global dimming - they reflect sunlight back into space
May damage lung cells or even cause cancer

Question 25

How are nitrogen oxides produced by burning fuels?

Answer 25

High temperatures inside engines allow usually unreactive nitrogen in air to react with oxygen, forming nitrogen oxides

Question 26

How are particulates produced?

Answer 26

Diesel engines burn hydrocarbons with bigger molecules than in petrol engines, meaning the molecules do not always burn completely. Tiny particles containing carbon and unburnt hydrocarbons are produced.