GCSE Science | Chemistry of the Atmosphere
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Atmospheric gases now
- 80% Nitrogen
- 20% Oxygen
- 0-1% other gases e.g. water vapour, carbon dioxide etc.
Early atmosphere
- a lot of carbon dioxide and water vapour
- very little oxygen
Why did oxygen increase and carbon dioxide decrease?
- plants produced oxygen
- carbon dioxide was absorbed by plants and algae (photosynthesis) and sedimentary rocks and the remains of dead plants and animals
Where did the nitrogen come from?
Where did the water vapour go?
Pollutants
- carbon monoxide: poisonous (blocks blood from carrying oxygen)
- particulates: global dimming
- sulfur dioxide and nitrogen oxides: cause acid rain and breathing problems
- nitrogen and oxygen react together near car engines as the temperature being high enough to start a reaction
- sulfur is released when burning fuels, and it reacts with oxygen in the air
Incomplete combustion
- burning something without enough oxygen
Greenhouse effect
- greenhouse gases in the atmosphere
- the Earth absorbs radiation from the Sun and reflects some
- the greenhouse gases are absorbing it and keeping the Earth warm
- higher temperatures
- ice caps melting
- changing habitats
Life cycle assessment
- assesses te environmental impact of all stages of a product
- extracting and processing raw materials, manufacturing and packaging, use of product, disposal (including transport and distribution at each stage)