1.1 Examples of fossil fuels: crude oil,
coal and natural gas.
1.2 Formed over millions
1.3 Finite and non-renewable because they are used
up much faster than new supplies can be formed.
1.4 Can be used as a source of fuel or chemicals.
1.5 Scientists are now looking for alternatives for
crude oil due to it running out quickly.
1.5.1 Crude OIl
184.108.40.206 Transported to refineries through pipelines and oil
220.127.116.11.1 Oil often spills from the tanker and floats on the sea's
surface - this is known as slick and it can harm wildlife and
18.104.22.168.1.1 Detergents are used in order
to break up oil slicks.
22.214.171.124 The oil affects alot of wildlife. The chemicals
are toxic and can harm and kill wildlife.
126.96.36.199 Found in the Earth's
crust - pumped to the surface.
188.8.131.52 Is a mixture of hydrocarbons and
is formed from dead marine
2 Fractional distillation
2.1 The process of separating crude oil into useful fractions
(parts) that contain mixtures of hydrocarbons with
similar boiling points, is called fractional distillation.
2.1.1 Crude oil is a mixture of hydrocarbons -
a molecule that contains only hydrogen
and carbon atoms.
2.2 Crude oil is heated in a fractionating column.
2.2.1 This column has a temperature gradient.
184.108.40.206 This means that, fractions with low boiling points leave at the top of the fractionating
column and fractions with high boiling points leave at the bottom of the
2.3 The order of the
fractions (from the
column) from the
top to bottom are:
oil, fuel oil,
3.1 Hydrogen molecules can be described as alkanes and alkenes.
Large alkane molecules can be broken down into smaller, more
useful, alkane and alkene molecules - this is the industrial
process called cracking.
3.2 Needs ta catalyst, a high temperature and high pressure.
3.3 Used to make more
petrol from naptha. It can
also be used to make
alkene molecules that
may be used to make
4 Forces between molecules
4.1 A hydrocarbon molecule has: strong covalent bonds between
the atoms in the molecue and weak intermolecular forces
(this is forces of attraction between molecules).
4.1.1 Longer hydrocarbons have stronger intermolecular
forces than the forces between shorter hydrocarbons.
4.3 When a liquid hydrocarbon is boiled, its molecules move
faster and faster until all the intermolecular forces are
broken and it becomes a gas.
4.4 Small molecules
have very weak
forces of attraction
between them and
are easily overcome
4.4.1 It is their boiling points which allow us to seperate a mixture of
hydrocarbons (eg. crude oil) by the process of distillation.
5.1 Incomplete combustion
5.2 Complete Combustion
5.2.1 Of a hydrocarbon (fuel)
5.3 When fuels react with
oxygen (in air), they burn
snd release useful heat