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Chemistry C1

OCR 21st Century Science: Chemistry: C1

What two gases are the main constituents of air? Nitrogen, oxygen
After nitrogen and oxygen, what are three next most common gases in air? Argon, water vapour, carbon dioxide
What proportion of the air is nitrogen? 78%
What proportion of the air is oxygen? 21%
What proportion of the air is argon? 1%
Billions of years ago, what were the most common gases in the earth's atmosphere? Carbon dioxide and water vapour
As the planet evolved, photosynthesising organisms added what gas to the atmosphere? Oxygen
As the planet evolved, photosynthesising organisms removed what gas from the atmosphere? Carbon dioxide
How does carbon monoxide poison humans? Reduces the amount of oxygen the blood can carry
Which gas is the main cause of acid rain? Sulphur dioxide
How are fossil fuels formed? Sedimentary rocks created from carboniferous organisms
What are the main changes that human activity has caused in the atmosphere? Carbon dioxide and carbon particles. Small amounts of carbon monoxide, nitrogen oxides, sulphur dioxide
What is coal made of? Carbon, mostly
What is a hydrocarbon? A compound of hydrogen and carbon
What type of compound are petrol, diesel and fuel oil? Hydrocarbons
When fuels burn, what chemical reactions occur? Hydrogen and carbon atoms in the fuel combine with oxygen in the air to form water (hydrogen oxide) and carbon dioxide
What element needs to be present for hydrocarbons to burn? Oxygen
Why do hydrocarbon fuels burn better in pure oxygen than air? More oxygen
What is oxidation? A compound combining with oxygen
What is reduction? A compound losing oxygen in a chemical reaction
Do combustion reactions involve oxidation or reduction? Oxidation
What happens in a chemical reaction? Atoms get rearranged
What is conserved in a chemical reaction? Mass (same number of atoms of each element)
If a fuel is burned that contains sulphur, what sulphurous compound will be created? Sulphur dioxide
How are nitrogen oxides (pollutants) produced in combustion engines? Combination of atmospheric oxygen and nitrogen at high engine temperatures
What's the chemical formula for carbon dioxide CO2
What's the chemical formula for carbon monoxide CO
What's the chemical formula for sulphur dioxide SO2
What's the chemical formula for nitrogen dioxide NO2
What's the chemical formula for nitrogen monoxide NO
What's the chemical formula for water H20
What does NOx mean? Collective name for nitrogen oxides: NO and NO2
What three methods can be used to reduce pollution caused by fossil fuel burning power stations Use less electricity. Remove sulphur from fossil fuels. Remove sulphur dioxide and particulates from flue gases.
What technique is used for removing sulphur dioxide from flue gases? Wet scrubbing
How can pollution from car emissions be reduced Less fuel (better engines, drive less) Low sulphur fuels Catalytic converters More public transport Limits on exhaust emissions
Which two reactions take place in a car's catalytic converter Nitrogen monoxide reduced to nitrogen Carbon monoxide oxidised to carbon dioxide
What are the two most important alternatives to fossil fuels for motor vehicles Biofuels Electricity
Created by: HaydonPeter



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