P2- Chemistry of the atmosphere

Question 1

How long ago was the earth said to be formed?

Answer 1

4.6 billion years ago

Question 2

What is phase 1 of the evolution of the atmosphere?

Answer 2

1) Intense volcanic activity releasing gases that formed the earth’s early atmosphere
2) At the start, the atmosphere may be like Mars and Venus’ today, mainly CO2 with little to no O2
3) Volcanoes also produced nitrogen which built up in the atmosphere over time as well as water vapour and small amounts of methane and ammonia

Question 3

What is phase 2 of the evolution of the atmosphere?

Answer 3

1) Water vapour condensed to form the oceans
2) CO2 dissolved in the water and carbonates were precipitated to produce sediments
3) This reduced the amount of CO2 in the atmosphere

Question 4

What is phase 3 of the evolution of the atmosphere? (oxygen increase)

Answer 4

1) Algae and green plants produced O2 that is now in the atmosphere by photosynthesis
2) Algae first produced oxygen about 2.7 billion years ago and soon after this oxygen appeared in the atmosphere
3) Over the next billion years plants evolved and the % oxygen gradually increased to a level that enabled animals to evolve

Question 5

3 ways carbon dioxide decreased in the evolution of the atmosphere

Answer 5

1) Algae and plants decreased the % CO2 in the atmosphere by photosynthesis
2) The formation of sedimentary rocks that contain
carbon (e.g. limestone and coal)
3) the production of fossil fuels from the remains of dead plants and animals when they decayed

Question 6

% of nitrogen in the atmosphere today

Answer 6

80

Question 7

% of oxygen in the atmosphere today

Answer 7

20

Question 8

What are the 3 main gases that make up about 1% of the atmosphere today

Answer 8

Carbon dioxide
Methane
Water vapour

Question 9

What are carbon dioxide, methane and water vapour all examples of?

Answer 9

Greenhouse gases

Question 10

What do greenhouse gases do?

Answer 10

Act like an insulating layer in the Earth’s atmosphere to allow the earth to be warm enough to support life

Question 11

What don’t greenhouse gases absorb?

Answer 11

The incoming short wavelength radiation from the sun

Question 12

What do greenhouse gases absorb?

Answer 12

The long wavelength radiation that gets reflected back off the earth.

Question 13

What happens after greenhouse gases absorb the long wavelength radiation that gets reflected back off the earth?

Answer 13

They re-radiate it in all directions, including back to the earth

Question 14

Why are greenhouse gases causing global warming?

Answer 14

The long wavelength radiation that the greenhouse gases absorb and re radiate back on to the earth is thermal radiation, so it results in the warming of the surface of the earth, otherwise known as the greenhouse effect

Question 15

4 examples of human activity that affect the amount of greenhouses gases in the earth’s atmosphere

Answer 15

1) Deforestation (less CO2 removed via photosynthesis)
2) Burning fossil fuels (carbon gets released)
3) Agriculture (farm animals produce methane)
4) Waste from landfill sites and agriculture means more CO2 and methane released by decomposition of waste

Question 16

What do scientists agree will cause global warming and therefore climate change?

Answer 16

Human activity

Question 17

Why is scientists agreeing that human activity is causing extra CO2 and climate change reliable?

Answer 17

It has been peer-reviewed

Question 18

Why is it hard to fully understand the earth’s climate? What does this lead to?

Answer 18

It is so complex and there are so many variables so it is hard to model. This leads to oversimplified models, speculation and opinion which could be biased or only use some info

Question 19

4 examples of the dangerous consequences of climate change?

Answer 19

1) Polar ice caps melting causing a rise in sea levels, increased flooding in coastal areas and coastal erosion
2) Changes in rainfall patterns (too much or little water which is bad for farming and crops)
3) Frequency and severity of storms might increase
4) Changes in temp and amount of water in a habitat may affect wild species, leading to differences in their distribution

Question 20

What are carbon footprints?

Answer 20

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

Question 21

How can carbon footprint be reduced?

Answer 21

Reducing emissions of carbon dioxide and methane

Question 22

4 ways to reduce carbon footprint

Answer 22

1) Renewable energy sources/nuclear energy instead of fossil fuels
2) More efficient processes to conserve energy and cut waste
3) Govt tax companies/people based on amount of GG they emit
4) Govt capping GG emissions that companies make

Question 23

4 reasons why reducing emissions is difficult

Answer 23

1) Still a lot of work to be done on alternative technologies
2) Govt are worried these changes will impact economic growth of communities (bad for people’s wellbeing especially in developing countries)
3) Hard to make international agreements as not everyone is on board
4) Individuals in developed countries might not want to or aren’t educated enough as to why change is necessary

Question 24

What do fossil fuels contain?

Answer 24

Hydrocarbons

Question 25

What is complete combustion?

Answer 25

When there’s plenty of oxygen so all the fuel burns

Question 26

What is incomplete combustion?

Answer 26

When there’s not enough oxygen so some of the fuel doesn’t burn

Question 27

What happens under the conditions of incomplete combustion?

Answer 27

Solid particles (particulates) of soot (carbon) and unburnt fuel are released and carbon monoxide and dioxide are produced

Question 28

2 problems particulates in the air cause

Answer 28

1) Can get stuck in the lungs when inhaled and cause damage. This can then cause respiratory problems
2) Global dimming- Reflect sunlight back into space which means less light reaches the earth

Question 29

The main problem carbon monoxide in the air causes

Answer 29

1) Stoops blood carrying oxygen around the body by binding to haemoglobin which would normally carry oxygen. This can lead to fainting, a coma or death.

Question 30

What does sulfur dioxide contain?

Answer 30

Sulfur impurities (the sulfur in the fuel becomes oxidised)

Question 31

How are nitrogen oxides created?

Answer 31

A reaction between the nitrogen and oxygen in the air, caused by the heat of the burning.

Question 32

Where does nitrogen oxide being created tend to occur?

Answer 32

In the internal combustion engine of a car

Question 33

What happens when sulfur dioxide or nitrogen oxides mix with clouds?

Answer 33

They form dilute sulfuric acid or dilute nitric acid which then falls as acid rain.

Question 34

3 problems caused by acid rain

Answer 34

1) Kills plants
2) Damages buildings and statues
3) Makes metal corrode

Question 35

2 consequences of sulfur dioxide and/or nitrogen oxides

Answer 35

1) Acid rain
2) Respiratory problems