- The earth is surrounded by a thin layer of gases called the atmosphere which contain:
- 78% - Nitrogen (N2)
- 21% - oxygen (O2)
- 1% - Argon (Ar) and other noble gases
- 0.04% - Carbon Dioxide (CO2)
- 0-4% - Water vapour (varies according to weather conditions)
- The earth's atmosphere id just 1km thick while the diameter is over 12 000km.
- the earth is heated by the sun but at the same time the earth also radiates heat back out as infrared energy. the earth's greenhouse gases (methane [CH4], Carbon dioxide [CO2], Water Vapour [H2O]) absorb the heat to stop it from escaping into space. So the earth is warmer then it would be.
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- Sulphur Dioxide (SO2) - causes acidic rain which kills plants and water creatures.
- Carbon Monoxide (CO) - A poisonous gas which reacts with blood.
- Nitrogen Dioxide (NO2) - causes acidic rain, causes breathing problems, makes asthma conditions worse.
- Particulates - make things dirty, make lung infections worse, makes asthma worse.
- Units used for measurement are PPB(parts per billiion) or PPM (parts per million).
- Measurements can vary because:
- Varibles - factors that change
- Measuring equipment has a limited digree of accuracy
- the user's skill of accuracy
- Chemicals - atom -> element -> Molecules.
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- For a complete combustion all the reactants must be present with the right amount needed to make the products.
- Incomplete combustion happens when there is a shortage of an element that is needed to make the product.
Water(H2O) + Carbon Dioxide(CO2) -----> Oxygen(O2) + Glucose(C6H12O6)
- Carbon dioxide enters the atmosphere by:
- Burning fossil fuels
- Humans breathing out
- Land use
- Carbon dioxide is removed from the atmosphere by:
- Dissolves in ain water and sea water
- Some is stored in Limestone
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Improving Air Quality
- Emissions from power stations can be reduced by:
- Using less energy so less fuel is burned
- Using a filter system to remove Sulphur dioxide and particulates from flue gases before they leave a coal burning power station.
- Removing toxic chemicals before they are burned.
- Using alternative renewable energy sources like solar, wind, hydroelectric energy instead of fuels.
- Emissions from motor vehicles can be reduced by:
- Buying a car with a modern engine that burns less fuel.
- Buying a hybrid car which uses electric power in the city centre and can change to petrol for longer journeys,
- Using a low sulphur fuel to reduce the amount of sulphur dioxide released.
- Converting the engine to run on biodiesel, a renewable fuel.
- Using public transport so there are less vehicles on the road.
- A catalytic converter chances a harmful chemical and changes it into a less harmful chemical without itself being effected.
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