C1 Topic 5 - Fuels Flashcards
Describe what crude oil is and how it is formed.
Crude oil is a mixture of different sized hydrocarbon molecules.
Organisms died in ancient oceans forming a layer of dead matter on the sea bed. Sand and mud buried the dead matter over millions of years which stopped it from decaying as oxygen was kept away. The sediment pushed down on the matter below as it built up this caused the temperature and pressure on the dead matter to rise. The high temperatures and pressures caused the sediment to become sedimentary rock and the dead matter, crude oil and natural gas.
Describe and explain fractional distillation.
Fractional distillation is the separating of hydrocarbons from crude oil. The substances with the least amount of hydrocarbons are extracted first and are commonly the gases.
Recall the names of different fractions and their uses.
- (Gases) - Used for cooking and heating.
- (Petrol) - Fuel for cars.
- (Naphtha) - Used as lighter fluid and in the chemical industry.
- (Kerosene/Jet fuel) - Used as an aircraft fuel.
- (Diesel) - Used as a fuel for lorries, trains and some cars.
- (Fuel oil) - Used as a fuel for ships and in some power stations.
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– (Bitumen) - Used to surface roads and roofs.
Describe how different fractions vary from each other.
The shorter the molecules, the more flammable (easier to ignite) the hydrocarbon is and the shorter the molecules, the more runny the hydrocarbon is (less viscous).
Describe complete and incomplete combustion.
Complete combustion happens when there’s plenty of oxygen. Incomplete combustion occurs when there’s not enough oxygen.
Discuss the problems of the products of incomplete combustion.
Incomplete combustion will produce a few of the following: carbon (soot), carbon monoxide, carbon dioxide and water. Carbon monoxide is a colourless, odourless and very toxic gas.
Describe how acid rain is formed and its problems.
Power stations burn fossil fuels which releases carbon dioxide, water vapour and sulphur impurities such as sulphur dioxide. Sulphur dioxide mixes with clouds so it forms dilute sulphuric acid. This falls falls to the ground as acid rain. Acid rain causes lakes to become acidic so organisms die, acid rain kills trees and damages limestone buildings.
