The three fossil fuels
are crude oil, coal and
Non-renewable means a fuel
that cannot be replaced,
renewed, or it takes millions of
years to make more
Fractional distillation is the name
of the process that is used to
separate crude oil.
The forces between molecules
are intermolecular forces
The seven fractions collected in the
fractionating column are LPG, petrol,
naphtha, paraffin, heating oil, fuel oils,
The bigger the molecule, the higher the boiling
A hydrocarbon is a compound
consisting of hydrogen and carbon
Cracking is the process that converts large,
useless alkanes into more useful ones.
The conditions for cracking are a
catalyst and a high temperature
When a hydrocarbon is
burned, the 2 products are
water and carbon dioxide
If a fuel releases 100KJ of energy
when 5g is burned, the amount of
energy released is 20KJ
When any hydrocarbon is burned in
limited oxygen, the two products formed
are water and carbon monoxide.
The oxide responsible for causing these things are
as follows: a) smog = nitrogen dioxide. b) acid rain =
sulfer dioxide. c) global warming = carbon dioxide.
The hydrocarbon that has single bonds are
alkanes and the hydrocarbon that has double
bonds is alkenes.
The chemical used to test for
unsaturation is Bromine water; it goes
from orange to colourless.
Crude oil is a mixture of hydrocarbons. These are
separated into useful products, such as fuels,
using a process called fractional distillation.
Alkanes are saturated - they have
only single bonds. Alkenes have a
double bond - they are unsaturated.
Alkanes are saturated hydrocarbons. This means
their carbon atoms are joined to each other by
single covalent bonds
Bromine water is a dilute solution of bromine that is
normally orange-brown in colour, but becomes
colourless when shaken with an alkene. Alkenes can
decolourise bromine water, while alkanes cannot
Fuels made from oil mixtures containing large
hydrocarbon molecules are not efficient. They
do not flow easily and are difficult to ignite.
Smaller hydrocarbons are more useful as fuels,
such as petrol.
alkenes are useful because they are used to
Fractions containing large hydrocarbon
molecules are vaporised and passed over by a
hot catalyst. This breaks chemical bonds in the
molecules and forms smaller hydrocarbon
Fuels react with oxygen to release
energy. Complete combustion happens
in a plentiful supply of air and
incomplete combustion occurs when
the supply of air is limited.
Complete combustion releases more energy than
incomplete combustion. Incomplete combustion also creates
carbon monoxide, and more soot. Several factors must be
considered when choosing the best fuel for a particular
The fossil fuels include coal, oil and natural gas. Various factors
need to be considered when deciding how to use a fossil fuel.
These include: the energy value of the fuel in kJ/g of fuel, the
availability of the fuel, how the fuel can be stored, the cost of the
fuel, the toxicity of the fuel - whether it is poisonous any
pollution caused when the fuel is used, such as acid rain, how
easy it is to use the fuel.
In general, solids such as coal are easier to store than
liquids and gases but they are often more difficult to light.
Liquids and gases ignite more easily. They also flow, which
means they can be transported through pipelines.
Fuels are substances that react with oxygen to release useful
energy. Most of the energy is released as heat, but light energy
is also released. About 21 per cent of the air is oxygen. When a
fuel burns in plenty of air, it receives enough oxygen for
The Earth is surrounded by an atmosphere
that is a mixture of gases. Some of these
gases are molecular elements, and some are
The air contains a number of gases. The amount of
water vapour in the air varies from place to place, and
day to day. For this reason, the proportions of the
gases in the air are usually given for dry air.
plants is thought to
be a key process in
the evolution of the
the atmosphere consists of mainly
nitrogen and oxygen, with smaller
proportions of other gases such as
the amount of carbon dioxide in the
atmosphere is maintained through a
balance between processes such as
photosynthesis, respiration and