1 Crude oil is a dark smelly liquid which is a mixture of lots of different
chemicals compounds, mainly hydrocarbons(hydrogen and carbon compounds.
2 Hydrocarbon molecules with long molecule chains tend to have high
boiling points and viscosity, and short chains catch fire easily
3 Crude oil that comes straight from the ground isn't very useful because
there are too many other substances in it, all with different boiling points,.
4 Fractional distillation differs from distillation only in that it
separates a mixture into a number of different parts, called
5 Because they have different boiling points, the substances in crude oil can be separated using fractional
distillation. The crude oil is evaporated and its vapours allowed to condense at different temperatures in the
fractionating column. Each fraction contains hydrocarbon molecules with a similar number of carbon atoms
6 The main fractioinclude refinery gases, gasoline
(petrol), naphtha, kerosene, diesel oil, fuel oil, and a
residue that contains bitumen. These fractions are
mainly used as fuels, although they do have other uses
7 The main fractions include refinery gases,
gasoline (petrol), naphtha, kerosene, diesel oil,
fuel oil, and a residue that contains bitumen.
These fractions are mainly used as fuels,
although they do have other uses too
8 If there is plenty of air, we get complete
combustion and the carbon in hydrocarbons
is oxidised to carbon dioxide: hydrocarbon +
oxygen → water + carbon dioxide
9 If there is insufficient air for complete
combustion, we get incomplete combustion
instead. The hydrogen is still oxidised to
water, but instead of carbon dioxide we get
carbon monoxide. Particles of carbon, seen
as soot or smoke, are also released
10 Most hydrocarbon fuels naturally contain some sulfur
compounds. When the fuel burns, the sulfur it contains is
oxidised to sulfur dioxide.