1d,e Making Crude Oil Useful + Making Polymers
Surfacing Heating Oil
This page is
just a front
The Alkane and Alkene Hydrocarbon Families
• Hydrocarbons are compounds made from ____________ and __________ only.
• The 2 families of hydrocarbons that you need to learn about are called the
_______________ and the _______________ (be very careful with your
handwriting and spelling – examiners will not be kind to you!)
• Carbon must always form 4 covalent chemical bonds
(you will find out why in another module what covalent bonds are but for now you must just learn
this fact and the name of the bonds because it will help you).
• When we draw and name chemicals we use rules to help us:
1. The name of a molecule with 1 carbon atom has the prefix
2. The end of the molecule name tells us which family of chemicals the
molecule belongs to
e.g. alkane names end in ane
To show how these rules work, consider the first 4 alkanes:
The Alkenes C=C
• Alkenes are also hydrocarbons because they are made from hydrogen and carbon
• The difference between alkenes and alkanes is that alkenes have a carbon-carbon
double covalent bond, C=C
• This makes alkenes more chemically reactive than alkanes e.g. for making polymers
• Using the same 2 rules as before but adding a C=C we can draw and name the
What would be the name and molecular formula of the next alkene in the series?
You do not need to learn about the alkynes but they have a carbon-carbon triple bond.
See if you can use the rules that you have learned to draw and name three alkynes.
If you want a really hard challenge, try writing a general formula for the alkynes.
Testing for Alkanes and Alkenes
• Alkanes are said to be saturated because their carbon atoms are surrounded by as
many single covalent bonds as possible.
• Alkenes have at least one carbon-carbon double covalent bond, C=C, so they are said
to be unsaturated.
• For each of the displayed formulae below state whether they are saturated or
unsaturated (name the first 2 compounds):
• The C=C in alkenes means that alkenes are more reactive and there is a chemical
test you must learn that tells us whether we have a saturated hydrocarbon (alkane)
or an unsaturated hydrocarbon (alkene).
Testing for unsaturation with bromine water
Bromine water is a
(alkanes) (alkenes, C=C)
Why does the bromine water decolourise?
1. The __________ breaks in the alkene
2. The Br-Br bond breaks
3. Each bromine atom in the molecule attaches itself to a ______________ carbon atom
4. As the bromine molecules are used up their brown colour ________________
because the product is colourless.
• ____________ Fuels are fuels that were made over _________________ of
years from dead plants and animals.
• There are 3 fossil fuels:
1. ________ – made from dead trees
2. ____________ – made from dead sea creatures
3. _____________ - usually found with crude oil
• Fossil fuels are ________________ resources. That means that there is a
______________ amount and they will run out.
• Fossil fuels are also said to be ___________________. That means that they are
being used up faster than they can be made.
• Crude oil is made from many different ________________ mixed together
• These fractions are made from chemical compounds called ___________________
• Hydrocarbons are compounds made from the elements _________ and ______ only
• Hydrocarbons can be different sizes which gives them different boiling points. This
allows us to separate fractions by their different boiling points using fractional
distillation. Large fractions have high boiling points
Separating Crude Oil into fractions by Fractional Distillation
1. The crude oil is heated and _____________
and then fed into the fractionating tower
2. The hot vapours ________ and _________
3. As the fractions cool below their boiling point
they ___________ and are collected as liquids.
(Note that fractionating towers work 24 hours a day. In industry
they call this a continuous process)
See the separate table and learn the properties and uses of
The Laboratory Fractional Distillation of Crude Oil
In the lab we distil a small amount of crude oil. This is called a ____________ process
1. The hydrocarbon mixture is ______________________
2. When the liquid reaches the boiling point (bpt) of the _____________ fraction
that fraction _______________ then cools and _____________ in the test tube.
3. When all the smallest fraction has been collected the temperature of the liquid
starts to ____________ again. It increases to the bpt of the next largest fraction
which then evaporates. This process continues until all of the fractions have been
covalent bond, C-H
How does fractional distillation work?
1. Covalent bonds between carbon and hydrogen atoms within a hydrocarbon molecule
are stronger than the ________________ forces between hydrocarbon molecules
2. During boiling intermolecular forces are ______________
3. Intermolecular forces between large hydrocarbon molecules are ______________
than those between smaller hydrocarbon molecules
4. Hydrocarbons with large molecules have a ________________ boiling temperature
than those with smaller molecules
• The fractions produced in fractional distillation have different uses
• There is a greater demand for the ______________ fractions e.g. petrol than we
can meet but there is an _____________ of the larger fractions (more than we
• If we ___________ the large hydrocarbons with a ___________ (aluminium oxide,
Al2O3) we can ___________ them into shorter more ____________ hydrocarbons.
Test with bromine water
To find out if we have made both an alkane and an alkene we can test each fraction
with ____________ water. Alkenes turn bromine water from ________ to
1. Cracking converts large alkane molecules into smaller __________ and
2. Cracking makes useful alkene molecules that can be used to make ____________
3. Cracking helps oil refineries match their ______________ of useful products such
as petrol with the __________________ for them (it turns long useless fractions
poly = many more useful ones)
mer = part
mono = one
• The molecules in plastics are called _____________ molecules
• Polymers are very ____________ molecules
• They are made by adding lots of small molecules together called _____________
• The reaction that makes polymers from monomers is called __________________
• Polymerisation is a process that needs the following conditions:
Higher What monomers are used to make polymers?
Unsaturated hydrocarbons make good monomers because of their carbon-carbon double
bonds, C=C, so we often use alkene molecules as monomers
e.g. ______________ makes _______________ also known as polythene
Polymers are formed in two steps
1. One bond in the carbon-carbon double bond _____________
2. The molecules join end to end to make a long _______________
The ends of the chain are
left open to show that
more monomers could join
(This is the only time in
chemistry you are allowed to
leave a bond unfinished).
First write “poly” and then the name of the monomer in brackets afterwards e.g.
_______________ poly(vinyl chloride) PVC
Polymers can be made from hundreds of monomers joined together. It is not necessary
to draw every monomer in a polymer chain and instead we draw the _______________
or vinyl chloride
styrene (replace H on ethene with benzene ring, C6H5)
tetrafluoroethene makes PTFE (substitute all 4 H on ethene with F)