Chemistry of the Atmosphere

Question 1

what is the percentage composition of the atmosphere?

Answer 1

• 78% nitrogen
• 21% oxygen
• 1% all other gases incl. water vapour and CO2 (0.03%)

Question 2

what was the atmosphere like 4.6 billion years ago?

Answer 2

• massive amounts of volcanic activity helped the earth cool down more quickly by releasing heat energy
• large amounts of CO2 released, as a consequence, along with water vapour - but the earth’s surface was still too hot for the water vapour to condense onto - at this time the atmosphere was ~90% CO2

Question 3

what was the atmosphere like 3.4 billion years ago?

Answer 3

• the earth’s surface became cool enough for water to condense onto it, allowing lakes, rivers and oceans to develop
• CO2 dissolved into the developing oceans, enabling the amount of CO2 in the atmosphere to decrease

Question 4

what was the atmosphere like 2.7 billion years ago?

Answer 4

• plants and algae photosynthesised, decreasing CO2 and increasing O2 levels
• O2 reacted in the atmosphere to produce ozone (O3) providing a protective layer of gas around the outer limits of the atmosphere, protecting life on earth from UV radiation

Question 5

what was the atmosphere like 200 million years ago?

Answer 5

• oxygen rich, CO2 poor
• Nitrogen levels in the atmosphere begin to increase as denitrifying bacteria in soil break down compounds containing nitrogen

Question 6

describe 5 ways in which today’s atmosphere is different from that of the Earth 4.6 billion years ago

Answer 6

• Higher oxygen levels
• higher nitrogen levels
• lower co2 levels
• less water vapour
• less hydrogen

Question 7

describe the 4 key events that scientists theorise have changed the composition of the Earth’s atmosphere, from what is was 4.6 billion years ago to what it is today

Answer 7

• earth’s surface cooled enough for water vapour to condense on it
• CO2 dissolved in newly formed oceans and rivers
• plants and algae that photosynthesise began to evolve, increasing O2 and decreasing CO2 levels
• denitrifying bacteria began to break down nitrogen-containing compounds

Question 8

what were the factors that reduced atmospheric carbon dioxide levels?

Answer 8

• formation of the oceans
• photosynthetic organisms evolved
• evolution of marine animals

Question 9

how is human activity causing CO2 levels to rise?

Answer 9

• by unlocking carbon dioxide that has been locked up in fossil fuels and sedimentary rocks
• deforestation
• cattle farming

Question 10

how is carbon dioxide unlocked from fossil fuels and sedimentary rocks?

Answer 10

• burning fossil fuels releases locked-up CO2 and energy - CH4 + O2 ⇒ CO2 +H2O
• thermal decomposition of limestone to produce cement and concrete released locked-up CO2 - CaCO3 ⇒ CaO + CO2

Question 11

how do greenhouse gases cause global warming?

Answer 11

• UV radiation with a short wavelength comes from the sun and hits the earth’s surface
• it reflects as longer wavelength infra-red radiation but can’t get through the greenhouse gases, so the heat gets trapped

Question 11

how do greenhouse gases help to support life on earth?

Answer 11

stop infra-red radiation passing out of the atmosphere and trapping heat which maintains a suitable temperature for life to thrive.

Question 12

give two potential consequences of rising sea levels

Answer 12

Increased flooding and loss of coastal habitats/coastal erosion

Question 13

give some potential consequences of climate change

Answer 13

Rising sea levels, extreme weather events, loss of biodiversity, crop failure and famine, drought

Question 14

name 5 atmospheric pollutants from burning fossil fuels

Answer 14

• Carbon monoxide
• sulfur dioxide
• nitrogen oxides (NOx gases)
• carbon particulates
• carbon dioxide

Question 15

what are NOx gases caused by?

Answer 15

oxygen and nitrogen in the atmosphere reacting in very hot engines

Question 16

why are NOx gases bad?

Answer 16

they cause acid rain

Question 17

what is a remedy for NOx gases in the atmosphere?

Answer 17

use a catalytic converter to convert NOx gases back into nitrogen and oxygen

Question 18

what is sulfur dioxide in the atmosphere caused by?

Answer 18

Burning of fossil fuels containing sulfur, which reacts with oxygen

Question 19

why is sulfur dioxide in the atmosphere bad?

Answer 19

it causes acid rain

Question 20

what is a remedy for sulfur dioxide in the atmosphere?

Answer 20

remove sulfur from fuel and use FGD (flue-gas desulfurization)

Question 21

what are carbon particulates in the atmosphere caused by?

Answer 21

Incomplete combustion of fuels, creating smoke

Question 22

why are carbon particulates in the atmosphere bad?

Answer 22

create smog and poor air quality in turn, causing respiratory problems

Question 23

what is a remedy for carbon particulates in the atmosphere?

Answer 23

Using filters in industrial processes to capture carbon particulates or do complete combustion by providing more oxygen

Question 24

what is carbon monoxide in the atmosphere caused by?

Answer 24

Incomplete combustion of fossil fuels

Question 25

why is carbon monoxide in the atmosphere bad?

Answer 25

it is toxic

Question 26

what is a remedy for carbon monoxide in the atmosphere?

Answer 26

use more oxygen to complete combustion

Question 27

what is carbon dioxide in the atmosphere caused by?

Answer 27

burning fossil fuels

Question 28

why is carbon dioxide in the atmosphere bad?

Answer 28

is a greenhouse gas so contributes to global warming

Question 29

what is a remedy for carbon dioxide in the atmosphere?

Answer 29

• Carbon capture and storage (CCS) technology
• stop burning so many fossil fuels (burn alternative fuels
• use things requiring less energy
• use green energy

Question 30

name 4 greenhouse gases

Answer 30

• carbon dioxide
• carbon monoxide
• sulfur dioxide
• methane

Question 31

identify a natural and man-made source for the following GHG: methane, CO2, water vapour

Answer 31

• methane: cows and landfill sites
• CO2: combustion of fossil fuels and volcanoes
• water vapour: combustion of fossil fuels and volcanoes

Question 32

what is a caron footprint?

Answer 32

the total amount of emitted CO2 and other greenhouse gases over the lifecycle of a product, service, or event

Question 33

what are some ways companies/industry can reduce their carbon footprint?

Answer 33

• tax companies based on the size of their carbon footprint
• enforce companies to display their carbon footprint for their product/service
• produce carbon footprint limits for companies and fine them if they exceed their cap
• businesses should be forced to include carbon capture into their business plant
• allow tax reductions for companies that utilise carbon capture in their business

Question 34

what are some ways individuals can reduce their carbon footprint?

Answer 34

• use locally sourced goods
• use public transport or walk
• turn lights and electrical appliances off when not in use - leaving equipment in standby still uses electrical energy
• eat less red meat, as the carbon footprint for beef and lamb far exceeds that for other meats
• fly less
• use more energy efficient devices

Question 35

what are the 6 R’s in reducing carbon footprint?

Answer 35

• Recycle: reusing materials to make something out of them
• Re-use: reusing the same product again
• Reduce: buy less
• Repair: fix things instead of buying new ones
• Refuse: if it isn’t necessary, don’t buy it
• Re-think: how we buy things

Question 36

what are some ways governments can reduce their carbon footprint?

Answer 36

• governments should have national quotas for greenhouse gas emissions
• ban international markets that allow governments to trade quotas for greenhouse gas emissions

Question 37

what are some problems when trying to reduce carbon footprint?

Answer 37

• general public may not be aware of what they can do to reduce their carbon footprint or that they have one ⇒ the public needs educating about the environment consequences of their carbon footprint
• economic consideration: it may be expensive to change a lifestyle to one with a lower carbon footprint (ie heat pumps replacing traditional central heating boilers)
• general public can become confused by scientists disagreeing about the causes and consequences of climate change

Question 38

What reasons might people have to play down the contribution of greenhouse gas emissions to climate change?

Answer 38

• A common bias is that an individual is involved in an industry which relies on, for example, burning fossil fuels.
• Burning fossil fuels is central to this individual’s profession but it is also known to release lots of carbon dioxide, which is a greenhouse gas.
• Therefore, it is in the individual’s interest to play down the negative effects of greenhouse gases in order to avoid more regulation of the relevant industry.