www.schoolscience.co.uk/content/4/chemistry/fossils/index.html

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The Energy InstituteFossils into fuels

Notes for teachers

Age 14-16Age 14-16Age 14-16Age 14-16Age 14-16

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:

Introduction to the nature of fossils fuels and their economic importance in the modern world.

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.

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.

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.

Careers in the petroleum industry provides a brief outline of entry qualifications and of job opportunities that exist in the oil and gas industry.

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The Energy InstituteFossils into fuels

Notes for teachers

Age 14-16Age 14-16Age 14-16Age 14-16Age 14-16

Curriculum links (using the COL keyword scheme)

Scientific enquiry

Contexts for scienceBenefits & drawbacks of scientific developmentsScience: historical & contemporary examples

Atoms & molecules

Covalent bonds

Elements, compounds & mixtures

DistillationSeparation - other

Energy

Energy resources

Obtaining & using materials

Fossil resources - generallyFossil fuelsHydrocarbons

Earth science

Rock formation - generallyIgneous rocksSedimentary rocksLithosphere & tectonic processes

Waves

Seismic waves

Web links

Distillation animationwww.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/distillation.htm

Cracker animationwww.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/flash/cracking.htm

Virtual visit to Fawley oil refinerywww.schoolscience.co.uk/content/4/chemistry/petroleum/fawley/index.html

InfoBank – distillationwww.schoolscience.co.uk/content/4/chemistry/petroleum/knowl/4/2index.htm?fractions.html

Discover petroleum gameshttp://www.schoolscience.co.uk/petroleum/trail2/index.htm

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The Energy InstituteFossils into fuels

Notes for teachers

Age 14-16Age 14-16Age 14-16Age 14-16Age 14-16

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 Chemistry [Nelson Science] by ChemistryHolman 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, Cracker animation Cracker animation Crack , 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].

Age 14-16

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The Energy InstituteFossils into fuelsStudent worksheet 1

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.

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Age 14-16

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The Energy InstituteFossils into fuelsStudent 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.

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