C13: Chemistry of the Earth's Atmosphere

• What is the composition of the earth's atmosphere today?

  Nitrogen, oxygen, and other gases (Argon, Carbon dioxide, water vapour)
• What percentage of nitrogen is in the earths atmosphere today?


  78%
• What percentage of oxygen is in the earth's atmosphere today?

  21%
• What percentage of argon, carbon dioxide, water vapour are in the atmosphere?


  1%
• What were conditions like in the first billion years on earth?

  Lots of volcanic activity, No oxygen
• What gases were present in the Early earth?

  Lots of CO2 (carbon dioxide), quite a bit of N2 (Nitrogen), H2O Gas (water), NH3 (Ammonia), CH4 (Methane)
• How did water eventually form on the early Earth?

  Water vapour condensed as volcanic activity decreased
• How was the carbon dioxide on the early earth eventually used up over time?

  CO2 Dissolved in oceans

  CO2 formed precipitates (carbonates) that then formed sediments
• How does global warming work?

  1. Sun emits UV radiation - has higher energy as it has a shorter wavelength
  2. Some of this radiation is absorbed by theearth's surface. The rest is reflected back at a longer wavelength - Infrared
  3. The greenhouse gases are able to absorb only infrared . This is then re-emitted to neighbouring gas molecules
  4. This process repeats, spreading heat around the earths surface
• Initially the greenhouse effect was positive as it ensured that earths surface was warm enough for life
• Today the greenhouse effect is now causing global warming as the surface temperature is too hot
• What gases are known as greenhouse gases?

  CO2 - Carbon Dioxide, H2O - Water vapour, CH4 - Methane
• How is global warming different to climate change?

  Global warming: Earth's surface temperature is increasing

  Climate change: Changes in the weather patterns on earth
• Is it certain that global warming is causing all climate change?

  No - Some climate change occur naturally
• What are some examples and consequences of climate change?


  Drought - Affects food and drink sources for all living things, Damage to habitats which could lead to extinction

  Polar ice caps melting - Increasing sea levels leads to flooding which could lead to damage to habitats
• How is carbon footprint measured?

  How much CO2 is emitted/ consumed by an individual, organisation, or country
• How could you reduce an individual's carbon footprint?

  Plant trees, walk instead of drive, plant based diet
• What is the major barrier to tackling a large reduction in a country's carbon footprint?


  Most decisions on large emissions are decided by a few individuals whose priority may not be the environment
• What type of combustion is most likely to happen in a car engine?

  Incomplete combustion due to lack of oxygen
• What problems come from the soot of carbon?

  Respiratory problems when inhaled, Global dimming from smog
• What problems come from Carbon monoxide?

  Poisonous - colourless and odourless so its harder to detect
• What problems come from nitrogen oxides?

  Respiratory issues when inhaled, can form nitric acid and therefore acid rain
• What problems come from sulfur impurities?

  Acid rain forms - causes respiratory issues, damage plants, kill other wildlife, corrode buildings + metals
• Catalytic converters in car engines manage carbon monoxide and nitrogen oxide pollutants