GCSE Chemistry

gold rings often aren't made from 100% gold state two reasons why
- because pure gold has a regular layer of atoms that can slide over each other making pure gold soft
- gold is a rare metal in the earths crust . So it is expensive
this table shows the percentages of some gases in the exhaust from a petrol engine
nitrogen 68
carbon dioxide 15
carbon monoxide 1
oxygen 0.75
nitrogen oxides 0.24
hydrocarbons 0.005
sulphur dioxide 0.005
other gases
what is the name of the other compound that makes up most of the other gases in the table

water vapour
state how nitrogen oxides are produced in a petrol engine

the nitrogen and oxygen in the air combine , this is because there are high temperatures in the engine
most scientists are concerned about the carbon dioxide realeased from burning fossil fuels such as petrol suggest why
- because carbon dioxide is a greenhouse gas and leads to global warming
- the amount of carbon dioxide in the atmosphere is increasing
what did Wenger mean by continental drift

he thought the continents were once joined , however now the continets are moving apart
give one environmental impact of recycling aluminium cans and one ethical or social impact of recycling aluminium cans
- environmental = less energy is needed to extract aluminium so less pollution
- ethical or social = creates employment
to make margerine from olive oil the percentage of unsaturated fats needs to be decreased why

so that it has a higher melting point and is harder

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GCSE Chemistry

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Updated

2012-05-29T15:37:52Z

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