Age 14-16
The Energy Institute
Fossils into fuels
Notes for teachers
Contents
This electronic resource covers topics in GCSE Science courses that are linked to the chemistry and
geology of fossil fuels, including the formation of crude oil, its processing into fuels and other useful
products, as well as some of the environmental impacts of fossil fuel combustion.
There are five sections in the electronic resource:
1
Introduction to the nature of fossils fuels and their economic importance in the modern world.
2
Sources of crude oil and natural gas describes not only the biological and geological origins of
crude oil and gas, but also the importance of earth science in the formation of oil traps, the discovery
of oil reserves and their exploitation.
3
Processing and delivering fuels helps students to understand how useful substances are derived
from crude oil by fractional distillation. It also describes the cracking of some crude oil fractions and
the usefulness of the products in the petrochemical industry.
4
The future of fossil fuels considers the environmental impact of fossil fuel combustion and gives an
overview of future developments that will reduce the effect of carbon emissions on the environment.
5
Careers in the petroleum industry provides a brief outline of entry qualifications and of job
opportunities that exist in the oil and gas industry.
1
www.schoolscience.co.uk/content/4/chemistry/fossils/index.html
The Energy Institute
Age 14-16
Fossils into fuels
Notes for teachers
Curriculum links (using the COL keyword scheme)
Scientific enquiry
Contexts for science
Benefits & drawbacks of scientific developments
Science: historical & contemporary examples
Obtaining & using materials
Fossil resources - generally
Fossil fuels
Hydrocarbons
Atoms & molecules
Covalent bonds
Earth science
Rock formation - generally
Igneous rocks
Sedimentary rocks
Lithosphere & tectonic processes
Elements, compounds & mixtures
Distillation
Separation - other
Waves
Seismic waves
Energy
Energy resources
Web links
Distillation animation
www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/distillation.htm
Cracker animation
www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/cracking.htm
Virtual visit to Fawley oil refinery
www.schoolscience.co.uk/content/4/chemistry/petroleum/fawley/index.html
InfoBank – distillation
www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/2index.htm?fractions.html
Discover petroleum games
http://www.schoolscience.co.uk/petroleum/trail2/index.htm
2
www.schoolscience.co.uk/content/4/chemistry/fossils/index.html
The Energy Institute
Age 14-16
Fossils into fuels
Notes for teachers
Using the resource
The electronic resource can be used to support the teaching and revision of most of the topics normally
linked to the oil industry in KS4 examination specifications. The most important of these topics are:
•
•
•
•
Crude oil formation
Fractional distillation
Cracking
Fossil fuel combustion and the environment.
1 - Crude oil formation
Pages 3 to 5 of the electronic resource take students
through the basics of how crude oil was formed and begin
to touch on the ways that it is discovered and extracted.
You can also use game 5 of the Discover petroleum site
(Web link 5 above). Although this is aimed at primary school
children, your students may still enjoy it and get something
out of it.
2 - Fractional distillation
Use Student worksheet 1, Fractional distillation, to reinforce
the principles of distillation. They are linked to diagrams
in the electronic resource and are supplemented by
animations of the process that occurs in the fractionating
column (see Web links 1 and 4 above).
Question 5 in the worksheet assumes some knowledge
of the relationship between hydrocarbon chain length and
properties of crude oil fractions, such as flammability,
viscosity and volatility. These links are not given explicit
coverage in the resource and may need clarification (see,
for example, Section H of Chemistry [Nelson Science] by
Holman and Stone.)
3 - Cracking
Use worksheet 2, Cracking, with links to illustrations in the electronic resource to reinforce the principles of
the cracking process.
Web link 2, Crack
Cracker animation , takes students on an interactive tour of a catalytic cracker, including a surf
board ride on a zeolite crystal.
Investigations of the cracking reaction in Student worksheet 2, Cracking, can be carried out in the school
laboratory. See Section H2 (Practical work and investigations) of the Teacher Resource Pack for Chemistry
[Nelson Science].
3
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The Energy Institute
Fossils into fuels
Student worksheet 1
Age 14-16
Fractional distillation
One of the aims of this activity is to help you understand how crude oil is separated into more
useful substances by fractional distillation.
1. Distillation is a method of separating a mixture of liquids with different boiling points. In the
oil industry, distillation involves the use of a fractionating column. Look at a diagram of this
column, such as the one in the electronic resource at:
www.schoolscience.co.uk/content/4/chemistry/fossils/p8.html
With the help of the diagram, answer the following questions:
a
In which part of the fractionating column is the temperature highest?
b
Why is the column hotter in some places than in others?
2. The crude oil vaporises in the furnace (on the left of the diagram) and the vapour passes into
the fractionating column. As the vapour rises through the column, it condenses.
a
Why does condensation occur as the vapour passes through the column?
b
Use the diagram to describe how condensation leads to separation of the substances in
the crude oil.
3. Fractional distillation separates crude oil into liquids or fractions with different boiling points.
Many of these fractions are extremely valuable fuels.
Use the diagram to describe the link between the boiling points of the fractions and their carbon
chain lengths.
4. To see an animation of crude oil distillation in an oil refinery, go to:
www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/distillation.htm
Use the ‘unzip’ button in the animation to look inside the distillation column. What can you see
inside the column that helps to separate the fractions in crude oil?
5 The carbon chain length is linked to other properties of the crude oil fractions.
a What can you say about the link between the flammability of a crude oil fraction and its
carbon chain length? (Hint: notice the uses of the fractions in the diagram of the distillation
column.)
b Describe one other property of the crude oil fractions that is linked to their carbon chain
lengths.
S1
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The Energy Institute
Fossils into fuels
Age 14-16
Student worksheet 2
Cracking
Cracking reactions change hydrocarbon molecules with long chains into those with shorter chains.
The next activity will help you to understand:
• The importance of cracking reactions in the oil industry;
• The molecular changes that take place during cracking.
1. Look at the graph in Figure 20 – Relative supply and demand for some oil fractions. You can
find it at the following page in the electronic resource:
www.schoolscience.co.uk/content/4/chemistry/fossils/p9.html
a
For which crude oil fraction is the supply greater than the demand?
b
For which crude oil fraction is the demand greater than the supply?
2. Oil companies try to balance the demand for their products with the supply. They use cracking
reactions to change surplus products into those that are in greater demand.
Look at the example of a cracking reaction on the following page:
www.schoolscience.co.uk/content/4/chemistry/fossils/p9.html
a
What is happening to the molecule of decane during this reaction?
b
Each of the two products of this reaction is more valuable than decane. Explain why (there
are two different reasons).
3. Cracking reactions require energy to break chemical bonds. Just heating certain crude oil
fractions can bring about this type of chemical change but sometimes a catalyst is used to
speed up the reaction.
a
Watch the simulation of a cracking reaction involving a zeolite catalyst at:
www.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/cracking.htm
b
When you have seen the simulation, write a short description of the cycle of changes that
a single crystal of the zeolite catalyst would undergo as it passes from the reactor vessel
to the re-generator and back again. Remember to describe the chemical changes that take
place during this cycle.
S2
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