Chemistry Paper 2

Chemistry of the Atmosphere

Phase 1- Volcanoes gave out gases The early atmosphere was formed by volcanoes erupting and releasing gases Early atmosphere was mainly carbon dioxide and little to no oxygen Volcanic activity also released nitrogen , water vapour and small amounts of methane and ammonia Phase 2-Oceans, algae and green plants absorbed carbon dioxide When the water vapour condensed it formed oceans Lots of the carbon doxide from the early atmosphere was removed as it dissolved in the oceans This dissolved carbon went through a series of reactions to form carbon precipitates. Green plants and algae dissolved some of the carbon dioxide so that they could carry out photosynthesis Marine animals evolved, their shells and skeletons contained carbonates from the oceans Some of the carbon the organisms took in from the atmosphere and oceans got trapped in rocks and fossil fuels after the organism died Notes When plants, plankton and marine animals, they fall to the seabed and are buried by layers of sediment Over time it becomes compresses, trapping the carbon within them and reducing the carbon dioxide levels in the atmosphere Phase 3-Green plants and algae produced oxygen As well as absorbing the carbon dioxide, green plants nd algae produced oxygen by photosynthesis Algae evolved first As the oxygen levels in the atmosphere built up more complex organisms evolved.

Greenhouse Gases Greenhouse gases act as an insulating layer in the earth`s atmosphere- among other factors this allowed the earth to warm enough to support life

Climate Change An increase in temperature could lead to polar ice caps melting, causing a rise in sea levels, increased flooding in coastal areas and coastal erosion Changes in rainfall patterns may cause some regions to get too much or too little ater. This and other factors such as temperature affects the ability of some regions to produce food The frequency and severity of storms and other natural disasters would also increase Changes in temperature and the amount of water available may affect biodiversity Carbon Footprint A carbon footprint is the amount of carbon dioxide and other greenhouse gases released over the full life cycle of something There are many factors to consider when measuring a carbon footprint so it can be hard to give an exact figure Reduction of Carbon Footprint Renewable energy sources or nuclear energy could be used instead of fossil fuels Using more efficient processes would conserve energy and reduce waste The government could tax companies or individuals based on the amount of greenhouse gases they emit Governments can also put a cap n all greenhouse gases that companies make capture the carbon dioxide released then store it deep underground Air Pollution Increasing levels of carbon dioxide causing climate change Other gases such as oxides of nitrogen, sulfur dioxide and carbon monoxide 

Combustion of Fossil Fuels Fossil fuels such as crude oil and coal, contain hydrocarbons During combustion, the carbon and hydrogen in the compounds are oxidised meaning that carbon dioxide and water vapour is released into the atmosphere When there`s plenty of oxygen, all of the fuel burns- this is called complete combustion When there isn`t enough oxygen, some of the fuel doesn`t burn- this is called incomplete combustion Under these conditions particulates, unburnt fuel, carbon monoxide and carbon dioxide are released Particulates Particulates in the air can cause problems If particulates are inhaled, they can get stuck in the lungs which can lead to respiratory roblems It is also bad for the environment Carbon Monoxide Carbon monoxide is extremely dangerous because it can stop blood from carrying oxygen around the body It binds to the haemoglobin that normally carries oxygen, meaning that less oxygen can be transported around the body Carbon monoxide doesn`t have any colour or smell so it`s hard to detect which makes it even more dangerous