1. C1C2C3 04 properties of hydrocarbons

2. C123 June 2012 10 4 Crude oil is a mixture of hydrocarbons.
(a) Which elements are found in a hydrocarbon?
Put rings around the names of the two correct elements.
carbon
hydrogen
nitrogen
oxygen
potassium
sulfur
[2]
(b) The hydrocarbon molecules in crude oil are of many different sizes and boil at different temperatures.
In a refinery the hydrocarbons in crude oil are separated into fractions.
Approximate number
Approximate boiling
of carbon atoms per
temperature in °C
molecule in the fraction
fractions
fuel gas
1 - 4
below room temperature
petrol 7 50
paraffin 10
150
diesel 15
250
heavy oil
more than 20
400
heated crude oil
bitumen
over 70
over 600
C123 June 2012

3. 11
Use the information opposite to describe the link between the size of the molecules in each fraction and the temperature at which the fraction boils.
Explain this pattern using ideas about forces, molecular size and the way in which molecules are arranged in liquids and gases.
The quality of written communication will be assessed in your answer.
[6]
(c) The sentences describe how some of the hydrocarbon molecules from crude oil are used. Put a ring around the correct word from each pair to complete the sentences.
Polymerisation reactions use many small /
big molecules
called monomers /
polymers.
They join together to make monomers /
polymers
which have very short /
long molecules.
[2]
[Total: 10]
C123 June 2012
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4. C123 Jan 2013 6 3 Crude oil is a mixture of hydrocarbons.
(a) Crude oil is refined to make chemicals that are used in different ways.
One way they are used is as raw materials, for example to make polymers. Write down two other ways that chemicals from refined crude oil are used. 1 2
[2]
(b) Some hydrocarbons boil at higher temperatures than others. Explain why.
Use ideas about the length of molecules and the forces between them.
[2]
(c) Some of the chemicals from crude oil are polymerised to make polymers. Which of these statements describe polymerisation?
Put ticks (✓) in the boxes next to the two correct statements. Large molecules are broken down to make smaller ones. Hydrocarbons are burned to release energy. Many small monomer molecules join together. Monomer molecules are separated.
Large molecules with long chains of atoms are made.
[2]
C123 Jan 2013

5. 7
(d) Modern synthetic materials have replaced some materials that were used in the past. Give one example of an object that is now made from a better synthetic material. object
old material
new material
[2]
[Total: 8]
C123 Jan 2013
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6. 16
© OCR 2013