C9 - Chemistry of the Atmosphere

Question 1

Describe the makeup of Earth’s atmosphere

Answer 1

• about 80% nitrogen
• about 20% oxygen
• about 1% carbon dioxide and argon

Question 2

Describe how the Earth’s atmosphere has changed

Answer 2

• carbon dioxide has decreased
• nitrogen has increased
• oxygen is now present (increased)

Question 3

Describe phase 1 of the evolution of the atmosphere

Answer 3

• volcanoes erupted and released lots of gases
• water vapour cooled and condensed to form oceans

Question 4

Describe phase 2 of the evolution of the atmosphere

Answer 4

• lots of carbon dioxide was removed from the atmosphere because it dissolved in the oceans
• plants/algae also absorbed some carbon dioxide to photosynthesise

Question 5

Describe phase 3 of the evolution of the atmosphere

Answer 5

• plants/algae also produced oxygen by photosynthesis
• oxygen levels built up over time and more complex life could evolve

Question 6

Name the 3 greenhouse gases and one way that they’re produced

Answer 6

• water vapour - present due to the water cycle
• carbon dioxide - present due to combustion of fuels, deforestation etc.
• methane - present due to farming of animals, decomposition of waste

Question 7

Describe how carbon dioxide warms the Earth’s surface
(reference to wavelength radiation)

Answer 7

• short wavelength infrared radiation is emitted from the sun and Earth absorbs it
• Earth emits long wavelength IR radiation - some is absorbed by CO₂ and reflected back to Earth’s surface
• infrared radiation trapped on Earth causes it to get warmer

Question 8

Why has the amount of carbon dioxide in Earth’s atmosphere increased recently?

Answer 8

• more factories
• more people using transport
• more farming because of the higher population

Question 9

Describe carbon dioxide (how is it produced, effects and ways to reduce)

Answer 9

• CO₂
• produced by complete combustion
• effect = enhanced greenhouse effect
• reduce by using electric cars

Question 10

Describe carbon monoxide (how is it produced, effects and ways to reduce)

Answer 10

• CO
• produced by incomplete combustion
• effect = it’s toxic
• reduce by using catalytic converters

Question 11

Describe nitrogen dioxide (how is it produced, effects and ways to reduce)

Answer 11

• NO₂
• produced because nitrogen reacts with the oxygen in the air when heated
• effect = causes acid rain
• reduce by using catalytic converters

Question 12

Describe sulphur dioxide (how is it produced, effects and ways to reduce)

Answer 12

• SO₂
• produced as an impurity in fossil fuels
• effects = causes acid rain
• reduce by removing sulphur dioxide when making fuel

Question 13

Describe carbon particulates (how is it produced, effects and ways to reduce)

Answer 13

• C
• produced by unreacted carbon in fuel (due to low oxygen supply)
• effects = global dimming
• reduce by using catalytic converters

Question 14

What is the difference between global warming and climate change?

Answer 14

Global warming refers to the overall increase in the Earth’s temperature. Climate change is a consequence of global warming and refers to the effects on the climate, such as large-scale shifts in weather patterns

Question 15

Describe how carbon monoxide is harmful to humans

Answer 15

• when we breathe in carbon monoxide it diffuses into our bloodstream, and binds to our haemoglobin
• this reduces the amount of oxygen that haemoglobin can carry
• so less oxygen is transported to the tissues, which can cause symptoms such as fainting, coma and death