Chemistry Of The Atmosphere

Question 1

What was the idea behind phase 1?-volcanoes

Answer 1

• surface was covered in volcanoes that erupted and released lots of gases
• we think this was how early atmosphere was formed
• was probably made up of CO2 with no oxygen
• volcanic activity released nitrogen which built up as well as water vapour, and small amounts of methane and ammonia

Question 2

What was the idea behind phase 2?-absorption of CO2

Answer 2

• when water vapour in atmosphere condensed, it formed oceans
• lots of CO2 was removed from early atmosphere as it dissolved in oceans
• this dissolved Co2 formed carbon ppts which formed sediments on the seabed
• marine animals evolved. Their skeletons contained some of these carbonates
• algae absorbed some of the CO2 for photosynthesis

Question 3

How does carbon become trapped in rock?

Answer 3

• when animals die, they fall to 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)
• coal, crude oil and natural gas are made by this process and are called ‘fossil fuels’

Question 4

What is the idea behind phase 3?-oxygen production

Answer 4

Green plants and algae produced oxygen by photosynthesis

• this made green plants evolve over time
• as oxygen levels built up in atmosphere, more complex life could evolve (animals)

Question 5

What is the photosynthesis equation? (Green plants and algae)

Answer 5

carbon dioxide + water —> glucose + oxygen

6CO2 + 6H2O —> C6H12O6 + 6O2

Question 6

What are greenhouse gases?

Answer 6

• carbon dioxide, methane, water vapour

- act like an insulating layer in the Earths atmosphere which allows earth to be warm enough to support life

Question 7

What is the greenhouse effect?

Answer 7

• greenhouse gases don’t absorb the incoming short wavelength radiation from the sun
• they absorb the long wave length radiation that gets reflected back off earth
• they re-radiate it in all directions-including back towards earth

Question 8

How does deforestation affect the amount of greenhouse gases in the atmosphere?

Answer 8

Fewer trees means less CO2 is removed from the atmosphere via photosynthesis

Question 9

How does burning fossil fuels affect the amount of greenhouse gases in the atmosphere?

Answer 9

Carbon that was ‘locked up’ in these fuels is released as CO2 through combustion

Question 10

How does agriculture affect the amount of greenhouse gases in the atmosphere?

Answer 10

More farm animals produce more methane through their digestive processes

Question 11

How does creating waste affect the amount of greenhouse gases in the atmosphere?

Answer 11

More landfill sites and more waste means more CO2 and methane released by decomposition of waste

Question 12

How could climate change be dangerous?

Answer 12

• increase in temp could lead to polar ice caps melting-rise in sea levels, flooding
• changes in rainfall patterns-decreases food production
• severity and frequency of storms may increase
• may affect a habit of a species

Question 13

What is a carbon footprint?

Answer 13

A measure of the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something

Question 14

How can the carbon footprint be reduced?

Answer 14

• using renewable energy or nuclear energy sources instead of fossil fuels
• using more efficient processes
• governments could tax companies based on amount of greenhouse gases they emit

Question 15

How can an individual reduce their personal carbon footprint?

Answer 15

• choosing to cycle or walk instead of using car
• reducing how much they use air travel
• do things that save energy at home

Question 16

Why is measuring a carbon footprint hard?

Answer 16

Have to consider many factors

-count emissions released in manufacturing and in use and disposal of it

Question 17

What happens in combustion of fossil fuels?

Answer 17

Carbon and hydrogen are oxidised, so that carbon dioxide and water vapour are released back into atmosphere

Question 18

What happens in complete combustion?

Answer 18

-when there’s plenty of oxygen, all of the fuel burns

Question 19

What happens in incomplete combustion?

Answer 19

• when there’s not enough oxygen so some of the fuel doesn’t burn
• carbon monoxide can be released too (unburned hydrocarbons and particulates are formed)

Question 20

What problems can particulates in the air cause?

Answer 20

• if particles inhaled, they get stuck in lungs and cause respiratory problems
• bad for environment, reflect sunlight back into space (global dimming)

Question 21

What problems can carbon monoxide (CO) cause?

Answer 21

• very dangerous as it can stop blood carrying oxygen round body which can lead to death
• has no colour or smell and is very hard to detect

Question 22

When is sultry dioxide (SO2) released?

Answer 22

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

Question 23

How are nitrogen oxides?

Answer 23

Created from a reaction between nitrogen and oxygen in the air, caused by the heat of burning
-can cause respiratory problems if breathed in

Question 24

What happens when sulfur dioxide and nitrogen oxides mix with water in clouds?

Answer 24

• they form dilute sulfuric acid or dilute nitric acid

- this falls as acid rain

Question 25

What are the affects of acid rain?

Answer 25

• kills plants
• damages buildings and statues
• makes metal corrode

Question 26

How can you test for sulfur impurities?

Answer 26

Bubbling gases from combustion through universal indicator solution
-if fuel contains sulfur, gases will contain SO2 which will form sulfuric acid and universal indicator will turn red