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Chemistry 1- Hydrocarbons as fuels (Waste products released when fuels…
Chemistry 1- Hydrocarbons as fuels
Waste products released when fuels burn- harm environment through global warming/dimming, and acid rain
Fuels burn when they react with oxygen in the air- plenty of air- complete combustion
Coal mostly carbon
During complete combustion carbon oxidised to carbon dioxide
Carbon+Oxygen>Carbon dioxide
Carbon dioxide- greenhouse gas contributes to global warming
Hydrocarbon fuels contain carbon and hydrogen
During combustion hydrogen oxidised to water (H20)- water oxide of hydrogen
Hydrocarbon+Oxygen> Carbon dioxide+Water
Combustion of fuel may release several gases into atmosphere
Not enough air- incomplete combustion happens- hydrogen still oxidised to water but carbon forms carbon monoxide instead
Carbon monoxide harmful- ventilation important when burning fuels
Solid particulates also released- contain carbon seen as soot or smoke- cause global dimming- reduce sunlight reaching earth surface
Carbon dioxide dissolves in water in atmosphere to form weak acidic solution- rainwater slightly acidic- products from burning fuels makes rainwater more acidic- acid rain
Acid rain reacts with metals such as limestone causing damage to buildings and statues
Acid rain damages waxy layer of leaves- more difficult for leaves to absorb minerals needed for healthy growth- may die
Acid rains makes some lakes and rivers too acidic for some aquatic life to survive
Coal and most hydrocarbon fuels naturally contain some suphur compounds
When burnt suphur oxidises to sulphur dioxide
Sulphur+Oxygen>Sulphur dioxide
Gas dissolves in water to form acidic solution- cause of acid rain
Sulphur can be removed from fuels before they are burnt
Low suphur petrol and diesel available
In factories carbon dioxide can be removed from waste gases before they are released into the atmosphere from chimneys
Waste gases treated with powdered limestone- sulphur reacts to from calcium sulphate- makes plasterboard's for lining interior walls
At high temperatures in ovens or furnaces-nitrogen and oxygen from the air can react together- forms various oxides of nitrogen- cause acid rain
Coal and crude oil- non renewable energy resources
Take so long to reform that they cannot be replaced once they have all been used up
Likely to become more expensive as they begin to run out
Petrol diesel etc from burning crude oils make a lot of harmful substance when burnt such as carbon dioxide carbon monoxide, water vapour, particulates, sulphur dioxide, and oxides of nitrogen
Biofuels- fuels produced from plant materials
Bio diesel- made from rapeseed oil and other plant oils, can be used in diesel engines without modification
Ethanol (C2H5OH)- not hydrocarbon as it contains oxygen as well as hydrogen and carbon
Ethanol- liquid that burns well
Bio ethanol made from fermenting sugars from sugar cane wheat and other substances
Cannot be used on own unless engine is modified- some cars can use petrol with ethanol
Ethical concerns- could be used for food
Economic issues- human resources- more people needed for production of biofuels, increased income for farmers, lower fuel prices as they limit demand for fossil fuels
Little environmental issues with biofuel- little bit of sulphur
Carbon neutral- amount of CO2 released as they burn same as plants absorb as they grow- reduce greenhouse gas
Bio fuels not carbon neutral as they use fuels to be made