C9 - chemistry of the atmosphere

• which gases make up the atmosphere?

  nitrogen - 79%

  oxygen - 21%

  argon

  carbon dioxide

  water vapour
• why cant scientists determine what earth's early atmosphere was like?

  the time scale of 4.6 billion years is too large
• what is phase 1 of scientists theories about the evolution of the atmosphere?

  the earth's early atmosphere - the first billion years the earth's surface was covered in volcanoes that erupted and released various gases most carbon dioxide

  they also released nitrogen, water vapour and small amounts of methane and ammonia
• what is phase 2 of scientists theories about the evolution of the atmosphere?

  • water vapour released into the atmosphere condensed and became oceans
  • lots of carbon dioxide released had dissolves into the ocean - these went through chemical reactions
  • green plants and algae formed and took in some carbon dioxide for photosynthesis
  • marine animals evolved from the carbonates in the ocean
• what is phase 3 of scientists theories about the evolution of the atmosphere?

  • plants release oxygen in photosynthesis
  • algae first produced 2.7 billion years ago so increased oxygen which enable animals to evolve
• how are fossil fuels formed?

  • plants, plankton and marine animals die and fall on the seabed
  • get buried in layers of sediment
  • over millions of years, they become compressed and form coal, oil and gas
• what are the key greenhouse gases?

  carbon dioxide, methane and water vapour
• what is the purpose of greenhouse gases?

  to maintain temperatures on earth high enough to support life
• what is the greenhouse effect?

  • the idea that the short wavelength radiation form the sun passes through the atmosphere and is re-ammited off the earths
  • these re-ammited rays become long wavelength radiation and are absorbed by the atmosphere - cannot be radiated into space
  • results in the warming of the atmosphere
• what human activities increase the amounts of greenhouse gases in the atmosphere?

  deforestation - increases carbon dioxide as less CO2 being taken in by photosynthesis

  burning of fossil fuels - carbon dioxide

  agriculture - methane

  waste decomposition - methane and water vapour
• what are the consequences of climate change?

  • could lead to polar ice caps melting - leads to increase sea levels so flooding
  • changes in rainfall patterns - some areas could get more or too less rain
  • storms increase
• what is the issue with scientists understanding of climate change?

  to complex model - hard to make a model that isn't oversimplifies or bias

  peer review
• what is a carbon footprint?

  the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product
• how can someone reduce their carbon footprint?

  • insulating homes - use less heating
  • using buses or walking - less cars burning fuel
  • use renewable source e.g. solar power
• how can companies or industries reduce their carbon footprint?

  • government could tax companies based on their gas emissions
  • capturing the methane produced and burning it
  • renewable energy sources
• what are the issues with these changes?

  • expensive
  • inconvenient
• how are coal and oil harmful?

  • produce carbon dioxide from complete combustion
  • produce carbon monoxide from incomplete combsution
  • produce particulates from incomplete combustion
  • sulfur dioxide from burning of fossil fuels
  • nitrogen oxide from reaction between nitrogen and oxygen
• what are the issues with the release of carbon monoxide?

  • no colour or smell - toxic gas
  • can bind to haemoglobin in body and reduce oxygen taken in
• what are the issues with the release of particulates?

  • if inhaled they could get stuck in lungs and cause damage
  • bad for environment
• what are the issues with the release of sulfur dioxide and nitrogen oxides?

  when these gases mix with cloud they form acid rain which kills plants, damages buildings and statues and causes respiratory problems if breathed in