Gr 12 Common Test – August 2011
Organic Chemistry
Examiner: KK
45 Minutes , 50 marks
Question 1. – Multiple Choice. Write down the letter that corresponds to your choice of answer.
1.1
What is the formula of cyclohexane?
A. C6H12
B. C6H14
C. C7H14
D.
C7H16
1.2
Which homologous series has members which have fruity flavours?
A. Alkene
B. Alcohol
C. Aldehyde D. Ester
1.3
When margarine is manufactured from unsaturated vegetable oil which is a very liquid
substance, it needs to harden up so that it is sold as a solid slab or a tub of margarine. An
example of such a reaction is as follows;
H
R
C
C
R
+ H2
H
R
H
H
C
C
H
H
R
This reaction which occurs when the oils are changed into fats that are more solid can be
described as ……..
I
addition
II
hydrogenation
III
substitution
A. I only
B. II only
C. I & II only
D. III only
1.4
The diagrams below show the structures of three compounds.
Which compounds belong to the same homologous series?
A.
P and Q only
B.
P and R only
C.
Q and R only
D.
P, Q and R
1.5
Bromine water loses its colour when propene gas is bubbled through it. Which one of the
following compounds is the product of this reaction?
A.
1,2 - dibromopropene
B.
1,1 - dibromopropane
C.
1,1,2,2 - tetrabromopropane
D.
1,2 - dibromopropane
5 x (2) = [10]
Question 2. – One word/term answers.
2.1
2.2
2.3
A compound which has one or more double or triple carbon to carbon bonds.
An alcohol where the hydroxyl group (OH) is bonded to a carbon which is bonded directly to
only one other carbon. (Do not give an example.)
The property of carbon to bond together in long chains.
3 x (1) = [3]
Question 3.
3.1
Name the following molecules.
3.1.1
CH2CHCH2CH2CH3
[2]
3.1.2
CH3
CH3  CH2  C  CH2  CH  CH2  CH3
CH3
CH2  CH2
CH3
[2]
3.1.3
[2]
3.2
3.3
3.4
Draw the expanded structural formulae of
3.2.1 2-iodo-1,3-pentadiene.
3.2.2 CH3COCH3.
3.2.3 ethanal.
[2]
[2]
[2]
3.2.4
[1]
Name the structure in Question 3.2.2 above.
Copy and complete the following chemical equations:
3.3.1 C3H6 + O2 →
3.3.2 CH4 + Cl2 →
3.3.3 CH3CH2OH + HBr →
[2]
[2]
[2]
3.4.1
[2]
Define an isomer.
3.4.2. Name and draw the structural formula of an isomer of butane.
3.5
[2]
CH3CH2CH2COOCH3 is an ester responsible for the aroma in apples.
3.5.1
Write down the name of the acid that could be used to combine with an alcohol in the
synthesis of this compound.
3.5.2
[1]
Apart from the acid and the alcohol what other chemical is needed for this synthesis?
[1]
3.6
Alkenes can be produced by, amongst other means, the elimination of water from certain
alcohol molecules.
3.6.1
Write down the structural formula (expanded or condensed) of the alkene that can be
produced from the dehydration or elimination reaction of CH3CH2OH.
[2]
3.6.2
Why can CH3OH not be dehydrated to produce an alkene?
[2]
3.7
Data about ethene, C2H4, and methanol, CH3OH, are given in the table below.
C2H4
CH3OH
-98
Boiling Point/ C
-169
-104
Solubility in water
insoluble
high
Melting Point/oC
o
+65
3.7.1
The melting and boiling points of methanol are much higher than those of ethene, even
though its molecular mass is not that much greater than ethene. Suggest reasons for
these differences in terms of the intermolecular forces involved for each substance.
[4]
3.7.2
Of ethene and methanol, which (at the same temperature) would have the higher …
i)
vapour pressure,
[1]
ii)
viscoscity.
[1]
3.8
Draw an expanded diagram of the functional group of carboxylic acids.
[1]
3.9
Name a use of ketones.
[1]
TOTAL 50