Chem of the atmosphere (Topic 9)

• What percentage of the atmosphere is oxygen?

  20% (1/5)
• What percentage of the atmosphere is nitrogen?

  80% (4/5)
• What other gases are in the atmosphere?

  • CO2
  • Water vapour
  • Nobel Gases
• What happened during the earths early atmosphere?

  intense volcanic activity produced early gases, water vapour which condensed into oceans (atmosphere like Mars/Venus today)
• What gases were produced by volcanic activity aswell as CO2 and water vapour?

  Methane, Ammonia, nitrogen
• What happened when the oceans were formed in the early atmosphere?

  carbon dioxide dissolved in the water and carbonates were precipitated producing sediments,
• How did oxygen increase in the early atmosphere?

  Algae and plants began to photosynthesise which produced O2,
• What is the equation for photosynthesis?

  Carbon Dioxide + water -> glucose + oxygen

  6CO2 + 6H2O -> C6H12O6 + 6O2.
• How did carbon dioxide decrease in the early atmosphere?

  Photosynthesis & formation of sedimentary rock & fossil fuels containing carbon
• What are 3 examples of greenhouse gases?

  Carbon dioxide, methane, water vapour
• Greenhouse gases maintain temperatures on earth high enough to support life
• Greenhouse gases don't absorb the short wavelengths from the sun but they absorb the long wavelengths reflected from earth. These gases trap these wavelengths and radiate them back to earth. These long wavelengths is thermal radiation so causes GLOBAL WARMING.
• How does human activity increase levels of carbon dioxide?

  Deforestation - fewer trees means less CO2 removed from atmosphere

  Burning fossil fuels - CO2 is released from combustion

  Creating waste (landfill) - as things decay, CO2 and CH4 is released
• How does human activity increase the levels of methane (CH4)?

  Agriculture - more farming causes more CH4 being released

  Waste (landfill) - CH4 relased as things decay/decompose
• What is the main cause of climate change?

  increase in global temperature from greenhouse affect
• What are the consequences from climate change?

  • ice caps melting, rising sea levels, flooding & destroying habitats
  • Extreme weather conditions (tsunamis & tornados)
  • Affect rainfall, affect growth of crops
• What is carbon footprint?

  Total amount of carbon dioxide and other greenhouse gases emmition during the lifespan of a product
• How can a carbon footprint be reduced?

  By reducing carbon dioxide and methane emmisions
• How can you reduce carbon footprint?

  • Using renewable energy sources (not fossil fuels)
  • Recycle & reuse things more
  • Use efficient processes which conserve energy
• What is the main source of atmospheric pollutants?

  The combustion of fuels (fossil fuels)
• During combustion of fossil fuels, what products are released into the atmosphere?

  Carbon dioxide & water vapour
• Solid particles and unburned hydrocarbons are released into the atmosphere as particulates
• What are the properties of carbon monoxide? (CO)

  • toxic gas
  • Colourless & Odourless
  • Not easily detected
  • Dangerous as binds to red blood cells,
• What are the issues of Sulfur dioxide and oxides of nitrogen?

  Causes acid rain & respiratory problems in humans