c9 - chemistry of the atmosphere

• the first organisms eventually died because they could not tolerate the high levels of oxygen
• the earths atmosphere is 80% nitrogen , 20% oxygen and less than 1% of other gases such as the noble gases and water vapour
• levels of nitrogen build up in the atmosphere because it is unreactive
• carbon dioxide, water vapour and methane are the greenhouse gases
• carbon dioxide is converted into glucose by plants, and transferred into animal tissue when they eat the plants.
• skeletons contain calcium carbonate and form sedimentary rock
• carbon dioxide is dissolved in the oceans
• some of the carbon dioxide went into crude oil and natural gases
• Oxygen was released into the atmosphere by simple organisms that could make their own food. this is photosynthesis
• mars and Venus have similar atmospheres to our early earths atmosphere
• algae and bacteria are simple organisms that could complete photosynthesis during the formation of the early atmosphere.
• millions of years ago, highly reactive volcanoes were scattered around the earth, they released carbon dioxide into the atmosphere
• carbon dioxide dominated the earths early atmosphere
• the oceans were formed by water condensing, the oceans significantly reduced carbon dioxide levels by absorbing it
• the evolution of marine animals removed carbonates from the oceans as the animals used these to build their shells and skeletons
• long wavelength radiation is absorbed by greenhouse gases and re-transmitted back into earths atmosphere, as heat energy, heating up the earths surface
• short wavelength radiation is absorbed by the atmosphere and reflected back into space
• farm animals release methane in respiration
• decomposition of landfill waste released methane
• burning fossil fuels releases carbon dioxide
• deforestation reduces the amount of carbon dioxide removed from the atmosphere
• climate change causes :

  • melting of polar ice caps, sea levels rise, coastal erosion
  • extreme meteorological events, storms, droughts, floods
  • changes in precipitation, more/less frequent
• carbon footprint is a measure of the total amount of greenhouse gases emitted by a particular product, service or event
• we can reduce our carbon footprint by:

  • using renewable resources
  • planting more trees
  • minimising waste
  • reducing meat consumption
• sulfur is an impurity in all fossil fuels, when fossil fuels are burnt, they produce sulphur dioxide
• incomplete combustion occurs when there isn't enough oxygen present in a reaction. this produces carbo monoxide and particulates
• carbon monoxide binds with haemoglobin in the blood, restricting oxygen flow and eventually suffocating
• particulates are responsible for global dimming
• sulfur dioxide and nitrous oxides bond with water to form acids which contribute to acid rain - corrodes limestone and kills aquatic life
• fossil fuels are formed from organic material that has been buried and compressed. coal is formed from plant deposits, while crude oil is formed from plankton deposited on the sea floor