C9 - Chemistry of the Atmosphere

• the first billion years on earths history were pretty explosive. the surface was covered in volcanoes. that erupted and released a lot of gases
• the early atmosphere was probably carbon dioxide with virtually no oxygen like mars and Venus today
• volcanic activity released nitrogen over time which built up in the atmosphere over time as well as water vapour and small amounts of methane and ammonia
• when the water vapour in the atmosphere condensed it formed the oceans
• lots of carbon dioxide was removed from the early atmosphere as it was dissolved in the oceans. this dissolved carbon dioxide then went through a series of reactions to form carbon precipitates that form sediments on the seabed
• green plants and algae evolved and absorbed some carbon dioxide so that they could carry out photosynthesis. later marine animals evolved. their shell and skeletons contained carbonates from the ocean
• some of the carbon these organisms took in from the atmosphere and oceans became locked up in rocks and fossil fuels after organism died
• as well as absorbing the carbon dioxide in the atmosphere green plants and algae produced oxygen by photosynthesis. this is when plant use light to convert carbon dioxide into water and sugars
• algae first evolved first about 2.7 billion years ago. then over the next billion years or so green plants also evolved
• as oxygen levels built up in the atmosphere over time more complex life could evolve
• eventually about 200 million years ago the atmosphere reached a composition similar to present day : approximately 80 % nitrogen 20% oxygen and small amounts of other gases mainly carbon dioxide, noble gases and water vapour
• 1. greenhouse gases like carbon dioxide, methane and water vapour act as an insulating layer in the earth atmosphere this keeps the earth warm
  2. all particles absorb certain frequencies of radiation. green house gases do not absorb short wavelength radiation from the sun but do absorb the long wave lengths that get reflected back to earth. then they r radiate it all directions back to earth. the long wave length is thermal radiation which creates greenhouse effect
• ways to reduce carbon footprint : renewable energy source, governments and less food miles