chemisty C1 4.0 / 5 based on 6 ratings ? ScienceChemistryGCSEOCR Created by: megan sugarmanCreated on: 01-12-12 13:54 what's crude oil a mixture of? hydrocarbons 1 of 27 what's fractional distillation? using the fact that different hydrocarbons have different boiling points to seperate fractions of it and make more useful hydrocarbons. 2 of 27 describe a fractional distilation columns process? low boiling points leave at the top, high boiling points leave at the bottom. 3 of 27 what is made from naptha in cracking? petrol 4 of 27 what does cracking require? catalyst, high pressure and high temperature 5 of 27 what does cracking do? break down large alkane molecules into smaller, more useful alkane and alkene molecules 6 of 27 describe the forces between molecules in a hydrocarbon? strong covelant bonds between the atoms and weak intermolecular forces between molecules 7 of 27 the intermolecular forces betewen longer hydrocarbons are what than between shorted hydrocarbons stronger 8 of 27 whats the equation for complete combustion? hydrocan + oxygen = carbon dioxide + water 9 of 27 whats the equation for incomplete combustion? hydrogarbon + oxygen =carbon (monoxide) + water 10 of 27 what colour does limewater go when carbon dioxide is present? milky 11 of 27 what are the advantages of complete combustion? less soot, more heat energy and no carbon monoxide. 12 of 27 what is the composition of clean, dry air? 78% nitrogen, 21% oxygen, 1% other gases incl. 0.035% carbon dioxide 13 of 27 how does respiration and combustion help to maintain the atmospheres composition? it decreases oxygen and increases carbon dioxide 14 of 27 how does photosynthesis help to maintain the atmospheres composition? takes in carbon dioxide and releases oxygen 15 of 27 what did the earliest atmosphere contain? ammonia and carbon dioxide 16 of 27 whens sulfur dioxide made? when fossil fuels containing sulfur impurities burn. 17 of 27 what does acid rain do? kills plants and aquatic life. erodes stonework and corrodes iron work. 18 of 27 carbon monoxide poisunos gas formed from incomplete combustion in car engines 19 of 27 oxides of nitrogen formed in car engines, causing photochemical smog and acid rain. 20 of 27 what does burning of fossil fuels do? increase the amount of carbon dioxide in the atmosphere 21 of 27 what does deforestation do? means less photosynthesis and less removing of carbon dioxide from the atmosphere. 22 of 27 what does increase in world popluation do? directly contributes to deforestation and using more fossil fuels 23 of 27 what do catalytic converters do? contain catalysts to help poluting chemicals in car engines to react with oxygen. less harmful gases like carbon dioxide are released instead. 24 of 27 what is an alkane? contains only single covelant bonds and are saturated. 25 of 27 what is an alkene? have at least one double bond and is therefore unsaturated 26 of 27 how can you test for saturation? to test weather it's alkane or alkene you must use an addition reaction and add bromine water to the substance. 27 of 27
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