Air and Oxygen:
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The atmosphere is a layer of odourless, colourless gas surrounding our planet
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The atmosphere protects us from many things such as the harmful rays of the sun
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Combustion is the chemical reaction that occurs when fuel reacts with oxygen
Definitions to know
Our Atmosphere:
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The gases that make up our atmosphere are oxygen, nitrogen and inert gases/carbon dioxide
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There is 78% nitrogen, 21% oxygen and 1% inert gases
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Air is a mixture of gases and in an exam we must be able to prove this
Why is Air a Mixture:
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Air consists of different gases which all have different boiling points. If cooled the air turns to a liquid. The gases could then be warmed up again and each gas would distill at differnt points due to the differnce in boiling points. For example nitrogen boils off at -196 degrees. Basically as all the gases would boil at different times it would show that there are differnt gases with different biling points in air
2.If the right gases are mixed together the correct proportions at a fixed temperature something is formed with similiar properties to that of air is formed . Therefore, since a mixture of air can be formed air is a mixture
3. If air was a compound its compisition would be constant. However the composition of air is not constant. Air's composition in a crowded room would be different to the air in a countryside.
Creation of Oxygen:
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Hydrogen Peroxide is a compound of water and oxygen
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Its chemical formula is 2h2o2
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A substance called Mangenede Dioxide is a catylst. A catylst is a substance which speeds up a chemical reaction without being used up in the reaction itself
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Manganese is used with Hydrogen Peroxide to form oxyge
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The chemical formula for Manganese Dioxide is MnO2
Properties of Oxygen:
Chemical Properties: Physical Properties:
-Reacts with elements to form oxides -Slightly heavier than air
-Supports combustion -Slightly soluble in water
-No effect on litmus -Colourless and Odourless gas
Uses of Oxygen
Experiment for the creation of Oxygen
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Space Rockets: Oxygen is combined with fuel to create energy to take off
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Can be compressed into canisters used for hospital patients with breathing difficulties, people pulled out of smoking buildings, for deep sea diving and mountain climbing
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Used in the manafacture of steel to burn off impurities in iton
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Cutting and welding. Acetlyene is a gas that burns in air but when combined with oxygen it burns more fiercly and can be used to cut through steel
