Hwa Chong Institution
CHEMISTRY
Worksheet – Organic Chemistry 2
Name: __________________(
)
Class: 4 ____
Date: _________
Section A:
1 Which of these molecular formulae represent the first three members of the alkene
family?
A C2H2 , C3H4, C4H6,
C C2H4 , C3H4, C4H8,
B C2H2 , C3H4, C4H6,
D CH2 , C2H4, C3H6,
(
)
2 In an experiment, 1 dm3 of a hydrocarbon required 3 dm3 of oxygen for complete
combustion to give 2 dm3 of carbon dioxide, all gas volumes being measured at r.t.p.
Which one of the following molecular formulae represents the hydrocarbon used in
the experiment?
A
C
C2H4
C4H6
B C2H6
D C4H8
(
)
3 Two compounds are thought to be isomers. Possible similarities and differences are
listed below. Which combination would confirm isomerism?
A
B
C
D
Identical
molecular mass
molecular structure
chemical properties
physical properties
Different
molecular structure
molecular mass
physical properties
chemical properties
(
)
(
)
4 Organic compound X  an alkane + and alkene
What type of compound is X?
A An alcohol
B an alkene
C
an alkane
D an acid
5 Ethene is manufactured by cracking large alkane molecules. What is the maximum
number of ethane molecules that can be obtained from cracking C20H42 ?
A 1
B 5
C 9
D
10
(
)
6 Which of the following statements about the members of an homologous series is
correct?
A
B
C
D
they are isomers of each other.
they undergo similar reactions.
they have the same empirical formula.
they have the same percentage composition by mass.
By Mrs. Liew SG/Science Department /HCI
(
)
Page 1
Hwa Chong Institution
CHEMISTRY
7 On complete combustion, 1 mole of an organic compound gave 4 moles of water.
The compound could be
A methanol
B propane
C ethane
D
butane
(
)
8 The second member of a homologous series has the formula C7H8. What is the
formula of the first member of this series?
A C6H6
B C6H8
C
C7H6
D C8H10
(
)
9 In a preparation of ethene, ethanol is added a drop at a time to be heated reagent Y.
the impure ethene is washed by bubbled through a solution Z and then collected.
What could reagent Y and solution Z be ?
A
B
C
D
Reagent Y
acidified potassium dichromate (VI)
concentrated sulfuric acid
concentrated sulfuric acid
concentrated sodium hydroxide
Solution Z
dilute sodium hydroxide
dilute sulfuric acid
dilute sodium hydroxide
concentrated sulfuric acid
(
)
10 The diagram shows how useful products can be obtained by cracking lone chain
hydrocarbons.
Substance X used
as a rocket fuel
Long chain
hydrocarbons
Heated
catalyst
Substance Y used to
make plastics
Other products
Which two substances could be X and Y?
A
B
C
D
Substance X
ethanol
hydrogen
methane
steam
substance Y
propene
ethene
ethane
ethene
(
)
(
)
11 They are so many compounds that contain carbon because carbon can
A
B
C
D
have variable oxidation states.
form covalent bonds readily.
react vigorously with many elements.
join together to form long chains and rings.
By Mrs. Liew SG/Science Department /HCI
Page 2
Hwa Chong Institution
CHEMISTRY
12 Polystyrene is an addition polymer. Which statement about the polymer is not ture?
A
B
C
D
It is non-biodegradable.
It is a synthetic polymer.
It is made form two types of monomers.
The monomers contain carbon carbon double bonds.
(
)
Section B Structured Questions
1 Olive oil contains oleic acid which is unsaturated.
(a) (i) By naming the reagent and giving the observation, describe a simple test to
confirm that olive oil contains an acid.
__________________________________________________________________
__________________________________________________________________
(ii)
Explain what is meant by the term ‘unsaturated’
__________________________________________________________________
(iii) By naming the reagent and giving the observation, describe a simple test to
confirm that oleic acid is unsaturated.
__________________________________________________________________
__________________________________________________________________
(b) The molecular formula of oleic acid is C17H31CO2H . How many double bonds
between carbon atoms are present in one molecule of oleic acid ? Explain your
answer.
__________________________________________________________________
__________________________________________________________________
2 Crude oil is a mixture of hydrocarbon molecules. The hydrocarbons below are some
of the fractions obtainable form crude oil.
Bitumen
diesel
lubricating oil
naptha
petrol
(a) Name the method used to extract the various fractions. ____________________
(b) Arrange the hydrocarbons according to their boiling points, starting with the one
with the lowest boiling point.
________________________________________________________________
By Mrs. Liew SG/Science Department /HCI
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Hwa Chong Institution
CHEMISTRY
(c) Give a use for kerosene.
___________________________________________________________________
(d) Give one reason why hydrocarbons having a large number of carbon atoms are
not useful as fuels.
___________________________________________________________________
3 Butane and butene can be formed by a process known as cracking, whereby a larger
hydrocarbon molecule is broken down at high temperature.
e.g. C8H18 (l)  C4H8 (g) + C4H10 (g)
(a) Is C8H18 an alkane or an alkene ? Describe one chemical test you can conduct
to confirm your answer.
__________________________________________________________________
__________________________________________________________________
(b) On cracking, the products obtained will depend on the actual conditions used.
However, an alkene is always obtained. Write balanced chemical equations to
show how cracking of C4H10 produces
(i) hydrogen
_______________________________________________________________
(ii) ethene
_______________________________________________________________
4 When 48 cm3 of an alkane burns completely in air, 288 cm3 of carbon dioxide gas is
liberated at room temperature and pressure.
Deduce the formula for this alkane.
By Mrs. Liew SG/Science Department /HCI
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Hwa Chong Institution
CHEMISTRY
5 The structural formula of two hydrocarbons, cyclobutane and methylpropene are
shown below.
(a) Compare the similarities and differences of cyclobutane and methylpropene in
terms of their
 Structure, and
 Reaction with aqueous bromine
Your answer should include the equations and conditions for any reactions you
discuss.
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
_____________________________________________________________
(b) Under high temperature and pressure, methylpropene molecules can be joined
together to form a long-chain polymer.
(i) Name the type of polymerization that takes place.
_______________________________________________________________
(ii) Give the full structural formula for the repeating unit in this polymer’s
structure.
_______________________________________________________________
(c) 3.10 kg of methylpropene was reacted with excess steam at 300 oC and 70 atm,
using phosphoric acid as catalyst. After the reaction, 3.60kg of methylpropanol
had been made.
Calculate the percentage yield of methylpropanol.
[Mr of methylpropene, 56; Mr of methylpropanol, 74]
 THE
By Mrs. Liew SG/Science Department /HCI
END 
Page 5