C9 - Chemistry of the Atmosphere

Question 1

What is phase 1 of the Earth’s early atmosphere?

Answer 1

Volcanoes gave out gases - Mostly carbon dioxide.
Volcanic activity also released nitrogen, which built up in the atmosphere over time, as well as water vapour and small amounts of methane and ammonia

Question 2

What planets do we think the Earth’s atmosphere from phase 1 was most like?

Answer 2

Mars and Venus (or Titan, a moon)

Question 3

How did nitrogen levels increase in Earth’s early atmosphere to now?

Answer 3

As volcanic activity also released nitrogen, which built up in the atmosphere over time. As well as water vapour and small amounts of ammonia and methane

Question 4

What was phase 2 of Earth’s early atmosphere?

Answer 4

Oceans (from condensed water vapour), algae and green plants absorbed carbon dioxide

Question 5

What was phase 3 of Earth’s early atmosphere?

Answer 5

The green plants and algae produced oxygen

Question 6

How did levels of carbon dioxide reduce?

Answer 6

1) Green plants and algae took in CO2 for photosynthesis

2) Oceans absorbed CO2 as well, being trapped in sedimentary rocks

Question 7

What happens when plants, plankton and marine animals die?

Answer 7

They fall into the seabed and get buried by layers of sediment. Over millions of years, they become compressed and form sedimentary rocks, oil and gas - trapping the carbon within them

Question 8

What is limestone?

Answer 8

A sedimentary rock - mostly made of calcium carbonate deposits from the shells and skeletons of marine organisms

Question 9

Why is it difficult to tell what the Earth’s early atmosphere was like?

Answer 9

Because the average temperature was around 400C, and with no oxygen there was no life that we can date

Question 10

How were crude oil and natural gases formed?

Answer 10

From deposits of plankton. These fossil fuels form reservoirs under the seabed when they get trapped in rocks

Question 11

How is coal made?

Answer 11

It is a sedimentary rock made from thick plant deposits

Question 12

What do the shells and skeletos of marine animals contain?

Answer 12

Carbonates from the oceans that absorbed CO2

Question 13

Which plant evolved first?

a) Trees
b) Grass
c) Algae
d) Daisies

Answer 13

c) Algea - around 2.7 billion years ago

Question 14

Complete the sentence:

As oxygen levels built up over time in the atmosphere.

Answer 14

More complex life (like animals) could evolve

Question 15

Give some rough percentages of Earth’s atmosphere today

Answer 15

Nitrogen - 78-80%
Oxygen - 20%
CO2 - 0.03% around
Water vapour - <1%

Question 16

What are greenhouse gases?

Answer 16

Gases that act as an insulating layer in the Earth’s atmosphere - which allows it to be warm enough to support life

Question 17

How do these forms of human activity affect the amount of greenhouse gases in the atmosphere?

a) Deforestation
b) Burning fossil fuels
c) Agriculture
d) Creating waste

Answer 17

a) Fewer trees = less CO2 removed from atmosphere by photosynthesis
b) Carbon trapped in these fuels is released
c) More farm animals produce more methane through their digestive processes
d) More landfill sites and more waste from agriculture means more CO2 and methane released by decomposition of waste

Question 18

All particles absorb certain frequencies of radiation. Greenhouse gasses don’t absorb the incoming short wavelength from the sun - but they do absorb long wavelength that gets reflected back towards the Earth. This wavelength is thermal radiation, so it results in warming the surface of the Earth. What s this?

Answer 18

The greenhouse effect

Question 19

Increasing carbon dioxide is linked to what?

Answer 19

Climate change

Question 20

What are the dangerous consequences of climate change?

Answer 20

1) An increase in global temperature could lead to polar ice caps melting - rising the sea levels, increasing flooding in coastal areas and coastal erosion
2) Changes in rainfall patterns (amount, timing and distribution) may cause some regions to get too much/ little water. This along with changes in temperature, may affect the ability of certain regions to produce food
3) The frequency and severity of storms may also increase - extreme weather
4) Changes in temperature and the amount of water available in a habitat may affect wild species, leading to differences in their distribution

Question 21

What is a carbon footprint?

Answer 21

A measure of the environmental impact a product has over its full life cycle
A measure of the amount of CO2 and other greenhouse gases released over the full cycle of something. That can be a service (school bus), an event (Olympics), a product (toastie maker) - almost anything

Question 22

How can you reduce carbon footprints?

Answer 22

1) Renewable energy sources or nuclear energy used instead of fossil fuels
2) More efficient processes may conserve energy and cut waste. Lots of waste decomposes to release methane, so this will reduce methane emissions
3) Gov could tax companies or individuals based on amount of greenhouse gases they emit
4) Gov could put a cap on emissions of all greenhouse gases that companies make, then sell licenses for emissions up to that cap
5) Also tech that captures CO2 produced by burning fossil fuels before it’s released into the atmosphere, then it can be stored deep underground in cracks in the rock such as old oil wells

Question 23

Why is reducing carbon footprints difficult?

Answer 23

Gov worries about economic growth of communities - could be bad for people’s well being
Not everyone is on board, so some people won’t sacrifice their economic developments
Still a lot of work to be done on alternative technologies that result in lower CO2 emissions
It is difficult to change your lifestyle, and there isn’t enough education on how to do so

Question 24

Combustion of fossil fuels releases what?

Answer 24

Gases and particles - they contain hydrocarbons. So, during combustion the carbon and hydrogen articles are oxidises forming carbon dioxide and water vapour to be released

Question 25

What does the incomplete combustion of fossil fuels cause? How is this dangerous?

Answer 25

(Incomplete means not enough oxygen). Solid particles of soot (carbon) called particulates and unburnt fuel are released, and carbon monoxide can be produced too
Dangerous because if particulates are inhaled, they can get stuck in the lungs and cause damage, leading to respiratory problems
Also they’re bad for the environment. They (or the clouds they help produce) reflect sunlight back into space, meaning less light reaches Earth, causing global dimming
Carbon monoxide is odourless and colourless and poisonous (as binds to haemoglobin in red blood cells which is irreversible)

Question 26

How is carbon monoxide dangerous?

Answer 26

It can stop blood from carrying oxygen around the body, as it binds to haemoglobin in the red blood cells, which is irreversible, so oxygen can’t travel to the muscles. It is odorlus, colourless and tasteless, so it can easily kill due to oxygen debt

Question 27

Sulfur dioxide is released when?

Answer 27

During the combustion of fossil fuels, such as coal, that contain sulfur impurities - the sulfur in the fuel becomes oxidised

Question 28

How are oxides of nitrogen made?

Answer 28

In engines - created from a reaction between nitrogen and oxygen in the air, caused by the heat of the burning

Question 29

How are oxides of nirogen and sulfur dioxide harmful to the environment?

Answer 29

When they mix with clouds, they fall as acid rain, which kills plants and damages buildings and statues. It also makes metal corrode
Also bad for human health, as they cause respiratory problems when breathed in