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S5/6 Chemistry Review Sheet – Unit 2
Before beginning this topic you should be able to:
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describe the way fossil fuels have been formed;
describe the main constituents of crude oil;
define and use the terms: fractional distillation and cracking;
define the term "greenhouse effect";
describe what is meant by the terms hydrocarbon; homologous series;
saturated; unsaturated;
name and draw structural formulae for straight chain alkanes (C1 - C8), alkenes
(C2 - C6) and cycloalkanes (C3 - C6);
use, appropriately, molecular formulae and full and shortened structural
formulae;
identify and draw structural formulae for isomers;
use the bromine test to show the presence of an alkene;
identify the functional group in alkenes.
The following tasks are designed to test how confident you are with this learning.
Complete the tasks to the best of your ability.
Task 1-Sequencing
Sort the following fossil fuel formation statements into the correct order.
A:
They were covered by layers of mud and rocks. Over a long period of time more
of these layers began to build up.
B:
Our seas and oceans are inhabited by sea creatures, plants and microscopic
organisms.
C:
The continued pressure from the layers of mud and rock, lack of oxygen and
heat changed the plants and animals into gas and oil.
D:
Millions of years ago, when these sea creatures, plants and microscopic
organisms died, they sank to the bottom of the sea bed.
E:
We drill down underground to retrieve the oil and gas formed over millions of
years.
………………………………………………………………………………………..
Task 2-Definition match
Match the correct word to the correct definition
Fuel
A means of separating crude oil into groups of
hydrocarbons with similar boiling points.
Cracking
The breaking up of larger hydrocarbon molecules (usually
alkanes) to produce a mixture of smaller molecules.
Fractional distillation
A compound containing the elements carbon and hydrogen
only.
Hydrocarbon
The trapping of the sun’s warmth in the planet’s lower
atmosphere.
Greenhouse effect
A substance which burns and releases energy.
Task 3-Fantastic fractions
Look at the diagram below which shows how crude oil is separated into fractions and answer
the questions which follow.
Fractional distillation is a process used to separate the hydrocarbons in crude oil into their
useful consumer products.
(a)
Which fraction could be used to tarmac roads?
(b)
Which fraction could be used to fill camping gas stoves?
(c)
What is meant by the term viscosity?
(d)
What is meant by the term flammability?
(e)
Which fraction is the least flammable?
(f)
The temperature at the top of the tower is cooler than at the bottom of the tower.
What is the relationship between the number of carbons in the molecule and the
boiling point?
Task 4-Get cracking
Octane is a hydrocarbon. The diagram shows the apparatus used to crack octane.
Octane is cracked using an aluminium oxide catalyst. Bromine solution is used to show that
some of the products are unsaturated.
(a)
Label the diagram of the apparatus used to crack octane.
(b)
One of the reactions taking place is:
C8H18  C3H6 + X
Identify X.
Task 5-Odd one out
Look at the compounds shown below. In each set decide which is the odd one out and circle
it. Say why you think it is the odd one out.
Use the terms hydrocarbon, homologous series, saturated and unsaturated to describe
why the compound you have chosen is the odd one out.
Set 1:
propene
ethane
cyclobutane
cyclopentene
It is the odd one out because……………………………………………………………………………………………………….
Set 2:
CH3OH
C2H5OH
C3H7OH
C4H8O
It is the odd one out because……………………………………………………………………………………………………….
Set 3:
C2H4
C3H6O
C5H12
C50H102
It is the odd one out because……………………………………………………………………………………………………….
Set 4:
C4H8O
propene
C2H5OH
C5H12
It is the odd one out because……………………………………………………………………………………………………….
Task 6-Naming and drawing
From the name draw the full structural formulae and vice versa.
Butane
H
H
_C_
H
H
Pentene
H
H
Cyclopropane
_
C _C
H
H
H
H
_ C _H
_
H C
H
_
C _ C_H
H
H
Task 7-Fabulous formulae
Complete the following table.
Name
Molecular formula
Full structural
formula
Shortened
structural formula
propane
CH3CH2CH2CH3
ethene
CH2CHCH3
cyclohexane
H2C
H2C
CH2
CH2
Task 8-Past paper practice
2010 SG Credit
The structures of some hydrocarbons are shown in the grid.
(a)
Identify the hydrocarbon which is the first member of a homologous series.
(b)
Identify the two isomers of
CH2
CH2
2008 Intermediate 2
Which of the following molecules is an isomer of heptane?
Task 9-Isomers
Draw three isomers of C5H12.
Task 10-The bromine test
Use a coloured pencil to shade in the colour that would be seen in each of the following test
tubes.
Complete labels for each test tube using the wordbank below.
Statement bank
saturated hydrocarbon
rapidly decolourises
unsaturated hydrocarbon
does not rapidly decolourise
Test:
Test:
Alkane +
Alkene +
bromine solution
bromine solution
Result:
Result:
Task 11-Identifying alkenes
Circle the molecules that are alkenes.
C5H12
CH3CH2CH2CH2CH2CH3
CH2CHCH3
CH3COCH3
C6H6
Which functional group is found in alkenes?
Next Steps:
If you feel you need to review the work covered in this section log onto the website
www.evans2chemweb.co.uk using the username: dunbar and the password: atoms
Navigate your way to the revision materials section and focus on Standard Grade Topic
5&6.
There is also a good section on fuels and hydrocarbons on
http://www.bbc.co.uk/bitesize/standard/chemistry/materialsfromoil/