Earth's Atmosphere Flashcards

1
Q

Composition of the Earth’s Atmosphere today?

A
  1. nitrogen (78%)
  2. oxygen (21%)
  3. Argon (0.93%)
  4. carbon dioxide (0.035%)
  5. water vapor + traces of other gases (noble gases)
    Our current atmosphere has been roughly the same for nearly 200 million years
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Composition of the Earth’s Atmosphere billions of years ago?

A
  1. Carbon dioxide (95%)
  2. Water vapour (4%)
  3. Traces of other gases - nitrogen, ammonia and methane
    The atmosphere about 3,500 million years ago would’ve been similar to mars atmosphere today
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happened to the nitrogen and why?

A

The level of Nitrogen increased because it was

  1. Released by volcanoes
  2. Ammonia reacted with the oxygen to form nitrogen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happened to the oxygen and why?

A

The level of oxygen increased because it was

  1. Produced due to photosynthesis of early organisms (cyanobacteria)
  2. Later plants alro released oxygen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What happened to the carbon dioxide and why?

A

The levels of carbon dioxide decreased because it was

  1. Dissolved in the oceans
  2. Photosynthesis of early organisms + plants absorbed the carbon dioxide
  3. marine organisms used it to make shells
  4. shells formed sedimentary rocks like limestone that locked up carbon dioxide
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happened to the water vapour and why?

A

The levels of water vapour decreased because water vapour condensed into clouds when the earth cooled and then formed our oceans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

List the greenhouse gases

A
  1. Water
  2. Carbon dioxide
  3. methane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does the greenhouse gas effect work?

A

Short wavelengths of radiation from the sun (UV or Visible Light) enter the earth’s atmosphere
Radiation is absorbed by the Earth’s surface and then re-emitted when the earth cools at a higher wavelength
Some radiation is transmitted into space and some is absorbed by greenhouse gases
This means the heat cannot escape and lead to global warming

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the difference between climate and weather?

A

weather is the change in atmospheric conditions and climate is the weather pattern

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is combustion?

A

burning - usually in air/oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What kind of reaction is combustion?

A

exothermic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What happens when you burn a fuel? Name an example

A

natural gas/ methane - fuel stores potential energy which is released as heat when burnt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the difference between complete and incomplete combustion?

A

Complete combustion takes place in the presence of a sufficient amount of oxygen while an incomplete combustion reaction takes place when there is an insufficient amount of oxygen supply.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is complete combustion?

A

fuel + excess oxygen → carbon dioxide + water vapor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Complete combustion gas flame colour?

A

blue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is incomplete combustion?

A

fuel + not enough oxygen → carbon monoxide + water

+ soot can be produced (&/or)

17
Q

Incomplete combustion gas flame colour?

A

yellow

18
Q

methane complete combustion?

A

CH4 + 2O2 → CO2 + 2H2O

19
Q

methane incomplete combustion?

A

2CH4 + 3O2 → 2CO + 4H2O

CH4 + O2 → C + 2H2O - less oxygen

20
Q

What are the products of combustion and their effects?

A
  1. water vapour - harmless
  2. CO2 - greenhouse gas = global warming
  3. CO - toxic
  4. unburnt carbon - particulate (pollutant)
  5. SO/SO2 - acid rain
  6. NO/NO2 - acid rain
21
Q

Complete combustion for propane?

A

C3H8 + 5O2 → 3CO2 + 4H2O

22
Q

Incomplete combustion for propane?

A

2C3H8 + 7O2 → 6CO + 8H2O

C3H8 + 2O2 → 3C + 4H2O

23
Q

Possible products of burning fossil fuels?

A
  1. Sulphur dioxide
  2. Water
  3. Carbon dioxide
  4. Carbon monoxide
  5. Soot/particulates
  6. Unburned fuels
  7. Nitrogen oxides
24
Q

Sulphur dioxide

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

SO2

  1. Combustion of fuels containing S (sulphur)
  2. Causes acid rain
  3. Remove S before burning; react fumes with CaO/CaO3 - flue gas desulphurisation
25
Q

Water

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

H20

  1. Combustion of fuels containing H (hydrogen)
  2. None - H2O is a greenhouse gas but not a problem as it is naturally maintained
26
Q

Carbon Dioxide

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

CO2

  1. Complete combustion of fuels containing C (carbon)
  2. Greenhouse gas - causes global warming
  3. Burn less fossil fuels
27
Q

Carbon Monoxide

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

CO

  1. Incomplete combustion of fuels containing C (carbon)
  2. Toxic
  3. Ensure good oxygen supply (air) when fuel is burning
28
Q

Soot / particulates

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

C

  1. Incomplete combustion of fuels containing c (carbon)
  2. Global dimming + blackens buildings
  3. Ensure good oxygen supply (air) when fuel is burning
29
Q

Unburned Fuels

  1. How is it formed?
  2. Problems?
  3. Solutions?
A
  1. Some fuel may not burn
  2. Wastes fuel and some fuels might be greenhouse gases (CH4)
  3. Make sure engine is well tuned
30
Q

Nitrogen oxides

  1. How is it formed?
  2. Problems?
  3. Solutions?
A

NO / NO2

  1. Reaction between N2 and O2 in the air at high temps
  2. Causes acid rain
  3. Use a catalytic converter in cars
31
Q

What is carbon footprint?

A

The total amount of carbon dioxide and other greenhouse gases emitted over a full life cycle

32
Q

What are the 5 methods for reducing CO2 levels

A
  1. Carbon capture and storage
  2. Decrease demand for meat
  3. Biofuels which are carbon neutral
  4. Insulate homes
  5. Replacing cut down trees - offsetting
33
Q

What does carbon neutral mean

A

Carbon-neutral fuel is fuel which produces no net-greenhouse gas emissions or carbon footprint.