topic c9- chemistry of the atmosphere

• the evolution of the atmosphere- phase 1

  • volcanoes gave out gases
  • the atmosphere was mostly CO2
  • there was no O2
  • volcanic activity released nitrogen, water vapour, methane, ammonia
• the evolution of the atmosphere- phase 2

  • increases O2 level
  • water vapour condensed to form oceans
  • CO2 dissolved to form carbon precipitates that formed sediments on the seabed
  • green plants + algae evolved to photosynthesise
  • carbon became locked up in rocks as fossil fuels
• the evolution of the atmosphere- phase 2

  • crude oil + natural gas formed from plankton deposits
  • coal formed from thick plant deposits
  • limestone formed from calcium carbonate deposits from shells + marine skeletons
• the evolution of the atmosphere- phase 2

  • oceans, algae + green plants absorbed CO2
• the evolution of the atmosphere- phase 3

  • green plants + algae produce O2
  • algae evolved 2.7 billion years ago
  • plants evolved over the next billion years
  • the increase of O2 led to the evolution of animals
• today

  • 80% nitrogen
  • 20% oxygen
  • <1% CO2, water e.t.c.
• greenhouse effect

  • when greenhouse gases (CO2, methane, water vapour) in the atmosphere absorb long wavelength radiation + re-radiate it in all directions, including towards the Earth, heating it up
• human activities

  • deforestation- less CO2 is removed from the atmosphere via photosynthesis
  • burning fossil fuels- carbon is increased as CO2
  • agriculture- farm animals produce methane through digestion
  • creating waste- more landfill sites means more CO2
  • scientists believe this is causing climate change
• consequences of climate change (increase in Earths temp)

  1. flooding, coastal erosion + polar ice caps melting
  2. changes in rainfall patterns so difficult to produce food
  3. more frequent + severe storms
  4. change in temp leads to changes in the distribution of species if habitats change
• carbon footprints

  • how much CO2 and other greenhouse gases are released over something's full life cycle e.g. a product
  • reducing CO2 + methane emissions reduces the carbon footprint
  • actions to reduce carbon footprints may be limited if individuals + governments are unwilling or unable to make changes
  • renewable energy sources or nuclear energy could be used instead of fossil fuels
• types of air pollution

  • carbon monoxide
  • carbon particulates
  • sulfur dioxide
  • oxides of nitrogen
• carbon monoxide

  • Formation:
  • there is a mix of carbon monoxide, carbon particulates (soot), water vapour, CO2
  • there is an incomplete combustion of fossil fuels
  • effects:
  • stops blood from transporting enough O2 around the body, can cause coma or death
• carbon particulates

  • formation:
  • there is a mix of carbon monoxide, carbon particulates (soot), water vapour, CO2
  • there is an incomplete combustion of fossil fuels
  • effects:
  • respiratory problems
  • global dimming
• sulfur dioxide

  • formation:
  • oxidation of sulfur impurities in fossil fuels during combustion
  • effects:
  • sulfur dioxide and nitric oxides go into cloud
  • acid rain causes damage to plants, buildings
  • acid rain
  • respiratory problems
• oxides of nitrogen

  • formation:
  • reaction between nitrogen + O2 in the air caused by the heat of burning fuels, e.g. in car engines
  • effects:
  • sulfur dioxide and nitric oxides go into cloud
  • acid rain causes damage to plants, buildings
  • acid rain
  • respiratory problems