Chemistry in the Atmosphere

Question 1

What is the current composition of the atmosphere?

Answer 1

Approximately 80% nitrogen, 20% oxygen, and small proportions of other gases including carbon dioxide, water vapour, and trace noble gases.

Question 2

True or False: The proportion of gases in the atmosphere has changed significantly in the last 200 million years.

Answer 2

False

Question 3

What role does carbon dioxide play despite its small proportion in the atmosphere?

Answer 3

It plays a substantial role in global warming as a greenhouse gas.

Question 4

What was the early Earth’s surface like before the atmosphere formed?

Answer 4

The surface was molten for millions of years with no atmosphere.

Question 5

How did volcanoes contribute to the formation of the early atmosphere?

Answer 5

Volcanoes released gases from the Earth’s interior through violent eruptions, including large amounts of carbon dioxide and water vapour.

Question 6

What happened to water vapour when the Earth’s surface cooled?

Answer 6

The water vapour condensed and fell to the surface, forming the oceans.

Question 7

Fill in the blank: Carbon dioxide is a ________ gas and dissolves readily.

Answer 7

water soluble

Question 8

What processes occurred when large amounts of CO2 dissolved in the oceans?

Answer 8

Carbonate substances were precipitated, forming sediments.

Question 9

What caused the increase in oxygen levels in the atmosphere?

Answer 9

Photosynthesis by primitive plants and algae, which used up carbon dioxide and released oxygen.

Question 10

When did algae first evolve?

Answer 10

Around 2.7 billion years ago.

Question 11

What is the balanced symbol equation for photosynthesis?

Answer 11

Not provided in the text.

Question 12

How did the levels of oxygen and carbon dioxide change over billions of years?

Answer 12

Oxygen levels increased while carbon dioxide levels decreased.

Question 13

What happened to carbon dioxide levels in the early atmosphere?

Answer 13

They were high but decreased due to several factors including dissolution in oceans and absorption by plants.

Question 14

How did sedimentary rocks form in relation to carbon dioxide?

Answer 14

Animals fed on plants, transferring carbon to their tissues, and when these organisms died, their remains formed sedimentary rocks.

Question 15

What are fossil fuels and how do they relate to carbon?

Answer 15

Fossil fuels, such as crude oil, natural gas, and coal, are formed from dead organisms that ‘locked up’ carbon.

Question 16

Examiner Tip: What should you be able to describe for this topic?

Answer 16

The theory of how the atmosphere and oceans came about.

Question 17

What is a common exam question regarding carbon dioxide levels?

Answer 17

Giving reasons for why carbon dioxide levels decreased.

Question 18

What is the greenhouse effect?

Answer 18

The greenhouse effect is the process by which greenhouse gases maintain the temperatures on Earth high enough to support life.

Question 19

List three greenhouse gases.

Answer 19

• Carbon dioxide
• Methane
• Water vapour

Question 20

What type of radiation is emitted from the sun?

Answer 20

Short wavelength radiation (ultraviolet radiation)

Question 21

What happens to the radiation when it strikes the Earth’s surface?

Answer 21

Some of it is absorbed and some is re-emitted as long wavelength radiation (infrared radiation).

Question 22

True or False: Greenhouse gases can absorb and store energy.

Answer 22

True

Question 23

What are the main human activities contributing to the increase of greenhouse gases?

Answer 23

• Increasing waste sent to landfill
• Increased levels of farming
• Burning fossil fuels
• Deforestation

Question 24

What is the chemical equation for the reaction of methane with oxygen?

Answer 24

methane + oxygen → carbon dioxide + water

Question 25

Why is there a convincing correlation between CO2 levels and global temperature?

Answer 25

Analysis of CO2 percentage in the atmosphere and temperature changes over hundreds of years.

Question 26

What is the percentage of climate scientists who believe human activity is causing climate change?

Answer 26

About 97%

Question 27

What are the effects of climate change?

Answer 27

* Rising sea levels * Frequent and intense droughts * Increased storm intensity * Extreme heat waves and rainfall

Question 28

What is a carbon footprint?

Answer 28

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

Question 29

Fill in the blank: A life cycle assessment (LCA) is used to assess the _______ associated with all the stages in the life cycle of a product.

Answer 29

[environmental impact]

Question 30

List ways to reduce the carbon footprint.

Answer 30

* Using renewable energy supplies * Cutting out unnecessary journeys * Using public transport * Reducing consumption of meat * Buying locally sourced foods * Carbon off-setting * Switching to electric vehicles * Recycling and re-using materials

Question 31

What is carbon capture?

Answer 31

A range of technologies used to trap atmospheric carbon dioxide from power generation and other industries.

Question 32

What are some obstacles to reducing greenhouse gas levels?

Answer 32

* Alternative technologies are still in infancy * Governments are slow to act * Individual resistance to change * Lack of investment schemes for modernization

Question 33

What should be adopted alongside carbon footprint reduction to tackle climate change?

Answer 33

Climate mitigation strategies.

Question 34

What are some actions that can be taken to adapt to climate change?

Answer 34

* Changing types of crops grown * Investing in flood defense systems * Building houses on stilts * Changing building infrastructure * Repurposing land vulnerable to flooding * Using heat sinks in buildings

Question 35

What is the major source of atmospheric pollution?

Answer 35

The combustion of fossil fuels

Question 36

Name three types of fossil fuels.

Answer 36

* Coal * Oil * Natural gas

Question 37

What process is used to obtain non-renewable fossil fuels from crude oil?

Answer 37

Fractional distillation

Question 38

Which fuel is commonly used in cars?

Answer 38

Petrol

Question 39

What gas consists mainly of methane?

Answer 39

Natural gas

Question 40

What are the combustion products of fossil fuels?

Answer 40

* Carbon dioxide * Carbon monoxide * Oxides of nitrogen * Oxides of sulfur

Question 41

What occurs during complete combustion?

Answer 41

There is excess oxygen

Question 42

What are the products formed from the complete combustion of hydrocarbons?

Answer 42

* Water * Carbon dioxide

Question 43

What happens during incomplete combustion?

Answer 43

Some of the fuel does not undergo combustion, releasing unburned hydrocarbons

Question 44

Fill in the blank: Incomplete combustion may produce _______.

Answer 44

Carbon particles (soot) and carbon monoxide

Question 45

How are oxides of nitrogen produced in a car engine?

Answer 45

Nitrogen reacts with oxygen at high temperatures

Question 46

What is the chemical reaction for the formation of nitrogen monoxide?

Answer 46

N2 (g) + O2 (g) → 2NO (g)

Question 47

What is sulfur dioxide's role in atmospheric pollution?

Answer 47

It is a major atmospheric pollutant responsible for acid rain

Question 48

What is the chemical reaction for sulfur dioxide formation?

Answer 48

S (s) + O2 (g) → SO2 (g)

Question 49

What are the effects of carbon monoxide poisoning?

Answer 49

Prevents blood from carrying oxygen, leading to fainting, coma, or death

Question 50

Why are particulates a problem?

Answer 50

* Damage lungs * Cover buildings and statues * Cause global dimming

Question 51

What is sulfur dioxide's physical properties?

Answer 51

Colourless and pungent smelling

Question 52

What does sulfur dioxide form when it dissolves in rainwater?

Answer 52

Acid rain (H2SO4)

Question 53

What does acid rain cause?

Answer 53

* Corrosion to structures * Damage to aquatic organisms * Irritation to lungs, throats, and eyes

Question 54

What contributes to the formation of acid rain?

Answer 54

* Oxides of sulfur * Oxides of nitrogen

Question 55

What do oxides of nitrogen contribute to aside from acid rain?

Answer 55

Photochemical smog and breathing difficulties

Question 56

True or False: Greenhouse gases and atmospheric pollutants are the same.

Answer 56

False

Question 57

Fill in the blank: A pollutant is something which is not found in clean air and causes _______.

Answer 57

Problems close to the ground such as smog and breathing difficulties