Chemistry of the Atmosphere

Question 1

What are the gases that make up today’s atmosphere? What are their proportions?

Answer 1

78 percent of the atmosphere is nitrogen.
21 percent is oxygen
The rest is a small proportion of gases.

Question 2

What was the the earth like for the first billion years? What were the gases being formed in the atmosphere?

Answer 2

There was an intense volcanic activity, these released gases that formed the atmosphere, one being water vapour. They also released a large amounts of carbon dioxide.

Question 3

How were oceans formed?

Answer 3

Water vapour from volcanos condense to form oceans.

Question 4

What gases were produced by volcanos?

Answer 4

Nitrogen, Carbon Dioxide, and small amounts of ammonia and methane.

Question 5

How did the percentage of carbon dioxide levels decrease in the atmosphere? (3)

Answer 5

• When oceans formed carbon dioxide dissolved to form weak acids.
• This reacted with minerals to form precipitates, forming sediments of carbonate rock.
• Coral and shells were made by Carbon Dioxide, when they died they formed limestone - removing Co2 from the atmosphere.

Question 6

How did the levels of oxygen rise in the atmosphere? (3)

Answer 6

• Photosynthetic algae started to evolve, producing oxygen.
• These began to evolve, increasing the amount of O2 in the atmosphere.
• Animals then evolved, increase o2 levels.

Question 7

What is coal formed by? How is it formed?

Answer 7

It is formed by the remains of ferns and trees. They do not decompose so prevent bacteria from carrying out decomposition, the plant remains covered with sediment and compressed and high temperatures and high pressure produce coal.

Question 8

What is crude oil + natural gas formed by? How is it formed?

Answer 8

Formed from mostly plankton, they die and settle in the sea bad and do not decompose, and get covered in sediment.

Heat and pressure convert them into crude oil + natural gas.

Question 9

What are the 3 greenhouse gases?

Answer 9

Carbon Dioxide, Methane and Water.

Question 10

‘Describe the greenhouse effect’ (4)

Answer 10

1) Energy travels from sun to the earth in short wavelength radiation.
2) Some of it is reflected back into space, but most just passes through.
3) The energy of radiation is now absorbed when it reaches the surface of the earth.
4) As the energy interacts with our greenhouse gases, it causes the atmosphere temperature to increase.

Question 11

Why is the greenhouse effect important? What will happen without it?

Answer 11

• It keeps the temperatures warm to support life.
• It would be too cold without it.

Question 12

What are two human activities that increase the amount of c02?

Answer 12

• Burning rainforests
• Destruction of tropical rainforests.

Question 13

What are two human activities that increase methane levels?

Answer 13

• Paddy Fields to graze cattle.
• Cows passing wind.

Question 14

What are the four potential effects of global climate change?

Answer 14

1) Rising temperatures would increase melting ice caps, so sea levels rise.
2) More Flooding
3) Lead to more severe weather, like storms.
4) Could change distribution of animals such as insects, and increase diseases in them e.g malaria.

Question 15

Why do many scientists believe that human activities will result in global climate change?

Answer 15

• As the evidence is shared between different scientists.

Question 16

What is ‘peer review’? What does it allow for?

Answer 16

It is scientists checking over other peoples work so they can criticise evidence and report on its validity. It allows scientists to detect false claims, e.g lack of evidence or bias.

Question 17

Why is their uncertainty in the evidence in climate change? (3)

Answer 17

• It is complex and difficult to model, stories can be simplified or too bias.
• We also see speculation because of this, they should be working harder to communicate ideas to public.
• We cannot predict certainty how much the temperature of the atmosphere will increase, leading to speculation in the media.

Question 18

What is carbon footprint?

Answer 18

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

Question 19

How can we reduce carbon dioxide emissions? (4) What are the two problems?(2)

Answer 19

1) Insulating homes or turning down heating.
2) Use public transport
3) Renewable sources of electricity.
4 ) Reduce how much energy we use at home.

Problems
1) Expensive
2) Inconvenient.

Question 20

How can we reduce methane emissions? (2) What are the two problems (2)?

Answer 20

1) People eat less beef and dairy products
2) Trapping methane and burning it to produce electricity.

Problems
1) People enjoy eating these things, wont change diet.
2) Costly process to produce electricity.

Question 21

What is coal used for? What are hydrocarbons used for?

Answer 21

Coal used to produce electricity, and hydrocarbons are used to power vehicles.

Question 22

What does incomplete combustion produce What are the properties of what is produced?

Answer 22

Carbon Monoxide
Properties - Toxic gas, no colour.

Question 23

How is sulphur dioxide produced? Why are oxides of nitrogen produced?

Answer 23

Sulphur dioxide is produced when burning coal.
Oxides of nitrogen are produced to provide a range of different molecules at high temp.

Question 24

What are the effects of sulfur dioxide and oxides of nitrogen?

Answer 24

They can cause breathing problems in humans, and form acid rain which can damage trees and corrode limestone on buildings.

Question 25

What is soot? What type of pollution is it? What are the negative effects of it?

Answer 25

Soot is a particle of carbon, and they are known as particulates. They can damage human health, and reduce amount of energy from the sun that reaches the earth's surface, known as global dimming. Which can affect rain patterns.