Chemistry of Atmosphere

• How was the early atmosphere formed?

  Surface of Earth covered in volcanoes that erupted and released lots of gases
• What did the early atmosphere contain?

  Mostly carbon dioxide but also contained nitrogen, water vapour and small amounts of methane and ammonia
• How was carbon dioxide removed from the early atmosphere?

  It dissolved in the oceans
• What happened to dissolved carbon dioxide?

  Went through a series of reactions to form carbon precipitates which formed sediments on the seabed
• How did green plants and algae evolve?

  They evolved and absorbed some of the carbon dioxide to carry out photosynthesis.
• What do skeletons of marine animals contain?

  Carbon precipitates
• How was carbon dioxide absorbed?

  -dissolved in oceans

  -absorbed by green plants and algae for photosynthesis

  -stored in rocks and fossil fuels
• How was carbon dioxide removed from the atmosphere in the sea?

  When plants,plankton and marine 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 within them which reduced carbon dioxide in the atmosphere
• How is crude oil and natural gas formed?

  Deposits of plankton
• Coal


  A sedimentary rock made from thick plant deposits
• Limestone

  a sedimentary rock made mostly of calcium carbonate deposits from the shells and skeletons of marine organisms
• What else did green plants and algae produce.

  Oxygen
• When did algae first evolve?

  2.7 billion years ago - over the next billion years, green plants also evolved
• What Happend when oxygen levels built up?

  More complex life evolved
• What happened 200 million years ago?

  The atmosphere reached a composition to what it is today - 80% nitrogen, 20% oxygen & small amounts of other gases (less than 1% of the atmosphere), mainly CO2, noble gases & water vapour
• 3 greenhouse gases


  carbon dioxide, water vapor, methane
• greenhouse effect


  Green house gases don't absorb incoming short wave radiation from the sun but they do absorb the long wavelength radiation that gets reflected back off the earth. Then they re radiate it in all directions including back towards earth. The long wave radiation is thermal radiation so it results in warming of the earths surface.
• Forms of human activity that affect the amount of greenhouse gases in the atmosphere

  Deforestation

  Burning fossil fuels

  Agriculture

  Creating waste
• What will lead to climate change?

  Extra carbon dioxide from human activity which increases the average temperature of the earths surface
• Why is it hard to understand the earths climate?

  1) It's very complex

  2) There are lots of variables

  3) It's very hard to make a model that isn't oversimplified
• consequences of climate change

  -ice caps melting which could cause a rise in sea levels, increased flooding in coastal areas and costal erosion

  -changes in rainfall patterns which can effect production of food in some regions

  -frequency and severity of storms may increase

  -changes in temp and amount of water in habitat may affect wild species
• Carbon footprint


  A measure of the amount of carbon dioxide and other greenhouse gases released over the full cycle of something. This can be a service,an event, a product
• Why is it hard to measure carbon footprint?

  Lots of different factors that need to be considered

  For example:

  You would have to count the emissions released as a result of all the parts of your toastie maker & in making it, as well as the emissions produced when you actually use it & finally dispose of it
• how is carbon footprint measured?


  A rough calculation
• reducing carbon footprint


  Renewable energy sources or nuclear energy could be used instead of fossil fuels

  
  

  Using more efficient processes could conserve energy and cut waste. Lots of waste decomposes to release methane, so this will reduce methane emissions.

  
  

  Governments could tax companies or individuals based on the amount of greenhouse gases they emit.

  
  

  Governments could also put a cap on emissions of all greenhouse gases that companies make- then sell licenses for emissions up to that cap

  
  

  Technology that captures co2 produced by burning fossil fuels before it's released into the atmosphere- it can then be stored deep underground in cracks in the rock such as old oil wells
• Why is it hard to reduce co2 emissions?

  -lot of work to be done on alternative technologies that result in lower CO2 emissions

  -governments are worried that making these changes will impact on the economic growth of communities- which could be bad for peoples well being especially in countries that are developing.

  -hard to make international agreements to reduce emissions as most countries don't want to sacrifice their economic development .

  -hard to get individuals to make changes if they don't want to and if there isn't enough education provided about why the changes are necessary and how to make them.
• What do fossil fuels contain?

  hydrocarbons
• What happens to carbon and hydrogen during combustion?

  They are oxidised
• What is released in combustion.

  Carbon dioxide and water vapour
• Complete combustion


  A combustion reaction in which the only products are carbon dioxide and water
• Incomplete combustion


  When there is not enough oxygen, some of the fuel doesn't burn and under these conditions , particulates of soot and unburnt fuel are released and carbon monoxide can be produced as well as carbon dioxide
• What problems do particulates cause?

  If they are inhaled, they can get stuck in the lungs and cause damage. This can lead to respiratory problems.

  
  

  They are also bad for the environment - they themselves or the clouds they help to produce reflect sunlight back into space. This means less light reaches the earth- causing global dimming
• What problems do carbon monoxide cause?

  It can stop your blood form doing it's proper job of carrying oxygen around the body.

  
  

  It does this by binding to haemoglobin in your blood that normally carries O2- so less oxygen is able to be transported round your body

  
  

  A lack of oxygen in the blood can lead to fainting,coma or even death.

  
  

  It also does not have any colour or smell so it's very hard to detect
• What releases sulphur dioxide?

  Combustion of fossil fuels
• What happens to sulfur during combust of fossil fuels?

  It becomes oxidised
• What is nitrogen oxides made from?

  Reaction between the nitrogen and oxygen in the air caused by the heat of the burning.
• What happens when nitrogen oxides and sulfur dioxide mix with clouds?

  they form dilute sulfuric acid or dilute nitric acid which then falls as acid rain
• What does acid rain do?

  Kills plants and damages buildings and statues and makes metal corrode
• What harm does sulfur dioxide and nitrogen oxide cause to the body?

  If breathed in they can cause respiratory problems