Topic
6
Fossil Fuels and Carbon Compounds
Part A Unit-based exercise
10
Unit 24 Fossil fuels
is used as fuel for ships and power
Fuel oil
stations.
1
and
Petroleum and
from
,
coal
.
natural gas
animals and plants that lived
marine
millions of years ago.
3
which radiates back into space. The feature is
known as the
greenhouse
effect.
13 The four major air pollutants from car engines
Hydrocarbons found in petroleum can be divided
into three major classes:
4
reaction.
exothermic
12 Carbon dioxide can trap some of the energy
were formed
natural gas
an
are
a) carbon monoxide
;
a) alkanes
;
b) hydrocarbons
;
b) cycloalkanes
;
c) suspended particulates
;
c) aromatic hydrocarbons
.
d) oxides of nitrogen
.
Compounds in petroleum can be sorted
into groups by a process called
distillation
Unit 24
2
11 A reaction in which heat is released is
The three major fossil fuels are
petroleum
Part A
Fill in the blanks
fractional
14 Air pollutants
nitrogen dioxide
and
sulphur
are major causes of acid rain.
dioxide
.
15 Unburnt hydrocarbons and oxides of nitrogen are
5
In industry, fractional distillation of petroleum is
carried out in an
tall towers called
major causes of
fractionating towers
16 To reduce sulphur dioxide emission from power
.
7
Hong Kong town gas is manufactured from the
or
petroleum fraction
stations.
Besides town gas,
naphtha
.
. There are
oil refinery
stations, flue gas
6
photochemical smog
.
liquefied petroleum gas
is
another common domestic fuel in Hong Kong.
scrubbers
desulphurization
system
can be installed in power
17 To reduce particulates in dirty gases from power
stations,
electrostatic precipitators
can be
installed.
8
Bitumen
is used for surfacing roads.
9
Diesel oil
is used as fuel for heavy vehicles
and factories.
1
18 In a catalytic converter,
Multiple choice questions
a) nitrogen monoxide is changed to
nitrogen
29 Which of the following statements concerning
fossil fuels is correct?
;
b) carbon monoxide is changed to
carbon dioxide
;
c) unburnt hydrocarbons are changed to
carbon dioxide
and
water
.
A They are all liquids.
B They are all formed from marine animals that
lived millions of years ago.
C Their resources are limited.
D They are usually found with town gas. C
Part A
30 Which of the following substances is NOT a source
of organic chemicals?
Unit 24
True or false
Decide whether each of the following statements is
true or false.
19 Petroleum is a mixture of many different
compounds.
T
20 Fractional distillation of petroleum involves
breaking and forming of covalent bonds.
F
21 Petroleum fraction with a lower boiling
point range evaporates more easily.
T
22 Compared with the petrol fraction, the
heavy oil fraction is more viscous.
T
A
B
C
D
Natural gas
Petroleum
Rock
Wood
31 Which of the following is an alkane?
A
H
H
B
23 The exhaust gas of a diesel engine
contains a higher concentration of
particulates than that of a petrol engine.
T
24 One major air pollutant that causes the
formation of acid rain is carbon dioxide.
F
H
C
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
H
C
C
C
H
H
H
C
H
H
25 Using liquefied petroleum gas as fuel for
motor vehicles can help reduce the level
of carbon monoxide at the road side.
T
26 In Hong Kong, taxis have switched from
using diesel to using natural gas as fuel.
F
27 In the catalytic converter installed in a
motor car, unburnt hydrocarbons are
changed to carbon particles.
F
28 Installing scrubbers can reduce the
emission of carbon monoxide from a
factory.
2
C
H
C
C
C
C
H
H
D
F
C
C
H
H
H
H
H
N
C
C
H
H
H
A
32 Which of the following statements about coal is
INCORRECT?
A Coal is a source of organic chemicals.
B Coal is a renewable energy source.
C Coal is the most abundant fossil fuels in the
Earth.
D Coal can be burnt directly to provide
energy.
B
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Part A
Directions: Questions 33 and 34 refer to the following
experiment.
Directions: Questions 35 – 37 refer to properties
of main petroleum fractions from the
fractionating tower shown below.
mŞ
EFMJWFSZUVCF
Unit 24
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NJOFSBMXPPMTPBLFE
XJUIDSVEFPJM
mŞ
'SBDUJPO
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BCPWF
IFBU
33 Which of the following set-ups should be
connected to the delivery tube to collect the
products obtained?
A
'SBDUJPO
GVSOBDF
'SBDUJPO
B
35 Which fraction has the lowest boiling point
range?
JDF
A
B
C
D
DPMEXBUFS
C
'SBDUJPO
QFUSPMFVN
D
Fraction
Fraction
Fraction
Fraction
1
2
3
4
A
36 Which of the following combinations is
correct?
XBUFS
B
34 Which of the following statements concerning
the experiment is correct?
A A chemical change occurs.
B Large hydrocarbon molecules are converted
to smaller hydrocarbon molecules.
C Aromatic hydrocarbon molecules are converted
to aliphatic hydrocarbon molecules.
D The products obtained are mixtures of
hydrocarbons.
D
A
B
C
D
Fraction
Name of fraction
2
3
4
5
kerosene
fuel oil
diesel oil
petrol
C
37 Which of the following statements is correct?
A Fraction
3.
B Fraction
C Fraction
3.
D Fraction
1 is darker in colour than fraction
2 is less viscous than fraction 4.
5 burns more easily than fraction
6 burns with a clear flame.
B
3
38 Which of the following petroleum fractions has
the highest carbon content?
A
B
C
D
Diesel oil
Fuel oil
Kerosene
Petrol
B
39 Which of the following combinations is
correct?
Part A
Petroleum fraction
Unit 24
A Diesel oil
B Fuel oil
C Naphtha
Alcohol
Household bleach
Plastic
Detergent
B
yCO2 + zH2O
What are the values of w, x, y and z
respectively?
A
B
C
D
w
x
y
z
1
1
2
2
13
6
6
13
4
4
8
8
10
5
5
10
Carbon monoxide
Dark smoke
Hydrogen
Oxides of nitrogen
VOJWFSTBM
JOEJDBUPS
The colour of universal indicator would turn
A
B
C
D
blue.
purple.
red.
yellow.
C
45 Which of the following pairs is correctly
matched?
Pollutant
A
B
C
D
D
A
A
B
C
D
Carbon dioxide
Oxides of nitrogen
Sulphur dioxide
Unburnt hydrocarbons
Effect
photochemical smog
liver diseases
acid rain formation
heart diseases
C
It
It
It
It
can cause acid rain.
contains mainly carbon particles.
can cause serious lung diseases.
can reduce visibility.
A
47 Rainwater samples collected in industrial areas
have pH lower than those collected in the
countryside. Which of the following air pollutants
is responsible for this phenomenon?
A
B
C
D
4
EFMJWFSZUVCF
46 Which of the following statements concerning
dark smoke in car exhaust gas is INCORRECT?
42 Which of the following substances causes dizziness
even in small amounts?
A
B
C
D
A
44 Car exhaust gas is passed into universal indicator
as shown in the following diagram.
B
41 The following equation represents the complete
combustion of butane.
wC4H10 + xO2
Cars
Factories
Volcanoes
Coal-fired power stations
DBS
FYIBVTU
HBT
40 Which of the following substances is NOT derived
from petroleum?
A
B
C
D
A
B
C
D
Main use
as a domestic fuel
as a fuel for ships
for manufacturing
natural gas
as lubricating oil
for machines
D Kerosene
43 Which of the following is NOT a major source
of sulphur dioxide?
Carbon dioxide
Nitrogen dioxide
Particulates
Unburnt hydrocarbons
B
48 Which of the following can help reduce the level
of carbon monoxide at the road side?
52 Which of the following is / are cycloalkane(s)?
(1)
A Installing electrostatic precipitators in motor
vehicles
B Installing scrubbers in motor vehicles
C Using smaller exhaust pipes for motor
vehicles
D Using liquefied petroleum gas as fuel for motor
vehicles
D
H
C
H
H
H
H
H
H
H
H
C
C
C
C
(3)
(1) It burns with a clear flame.
(2) It is a mixture of different hydrocarbons.
(3) Its constituents can be separated into
different groups by cracking.
B
Unit 24
C
Part A
H
H
51 Which of the following statements concerning
petroleum is / are correct?
H
C
H
50 Which of the following changes occurs in a
catalytic converter installed in a motor car?
only
only
and (3) only
and (3) only
C
H
Installing scrubbers
Installing electrostatic precipitators
Increasing the height of the chimney
Using fuels with a lower sulphur content
(1)
(2)
(1)
(2)
C
H
C
A
B
C
D
C
H
(2)
A Nitrogen monoxide changes to nitrogen.
B Carbon dioxide changes to carbon
monoxide.
C Unburnt hydrocarbons change to carbon
particles.
D Sulphur changes to sulphur dioxide.
A
H
C
49 Which of the following measures CANNOT reduce
the emission of air pollutants from a coal-fired
power station?
A
B
C
D
H
H
H
H
H
C
C
H
H
C
C
C
C
H
H
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
53 Which of the following changes in properties
occur(s) when the number of carbon atoms in
molecules of a petroleum fraction increases?
(1) The boiling point range increases.
(2) The fraction burns with a clearer flame.
(3) The fraction becomes more viscous.
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
5
54 The following table shows the combustion results
of three petroleum fractions.
Fraction
Combustion result
X
unsooty flame
Y
sooty flame
Z
very sooty flame
A
B
C
D
Part A
Which of the following statements concerning
the fractions are probably correct?
Unit 24
(1) Their boiling point ranges are in the order
of X < Y < Z.
(2) The viscosity of fraction Z is the lowest.
(3) Hydrocarbons in fraction Z contain the
greatest number of carbon atoms in their
molecules.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(2) Installing low nitrogen oxide burners
in power stations can reduce their
emission.
(3) They are converted to nitrogen in scrubbers
installed in car exhaust systems.
B
55 Which of the following would contribute to the
greenhouse effect?
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) It can be caused by burning low-grade
petroleum.
(2) It can corrode iron window frames.
(3) Carbon dioxide is a major air pollutant
that causes acid rain.
A
B
C
D
D
59 Which of the following measures can reduce the
formation of acid rain?
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
(1) Using a catalytic converter to reduce
nitrogen monoxide
(2) Using a scrubber to reduce sulphur
dioxide
(3) Using an electrostatic precipitator to reduce
carbon monoxide
D
57 Which of the following statements about oxides
of nitrogen are correct?
(1) High temperatures inside car engines cause
their formation.
6
A
60 Which of the following methods can reduce the
air pollutant mentioned?
(1) Absorption by sea water
(2) Burning of fossil fuels
(3) Deforestation
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) Installing catalytic converters in cars
(2) Installing electrostatic precipitators in power
stations
(3) Using fuels of low sulphur content in
factories
56 Which of the following processes would affect the
amount of carbon dioxide in the atmosphere?
A
B
C
D
A
58 Which of the following statements concerning
acid rain are correct?
(1) Carbon dioxide
(2) Chlorofluorocarbons
(3) Methane
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
Directions :
A
B
C
D
Each question (Questions 61 – 67) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
Part A
1st statement
2nd statement
Both petroleum and natural gas are formed
A
from the remains of marine animals and plants.
62 Fractional distillation can convert large alkane
molecules to small alkane molecules.
The boiling points of alkanes with large
molecules are different from those of alkanes
with small molecules.
C
63 Town gas is produced from coal.
Coal is a renewable energy source.
D
64 Low-boiling petroleum fractions are more viscous
than high-boiling petroleum fractions.
Low-boiling petroleum fractions contain
hydrocarbons with a smaller number of carbon
atoms in their molecules than high-boiling
petroleum fractions.
C
65 Carbon dioxide can cause acid rain.
Carbon dioxide gives carbonic acid when
dissolved in water.
C
66 Installing catalytic converters in car exhaust
systems can help reduce the formation of acid
rain.
Catalytic converters can help reduce the level
of carbon monoxide at the road side.
B
67 Installing electrostatic precipitators in factories
can help reduce the emission of sulphur dioxide.
The catalyst in an electrostatic precipitator can
convert sulphur dioxide to sulphur.
D
Unit 24
61 Petroleum and natural gas are often found
together in nature.
7
Unit 25 Homologous series,
structural formulae
and naming of carbon
compounds
True or false
Decide whether each of the following statements is
true or false.
Fill in the blanks
1
The
formula of a compound
structural
shows how the atoms are joined together.
2
An atom, or a group of atoms, which determines
most of the properties of a compound is called
Part A
a
Unit 25
All alkanols contain a
4
Members in a
group.
hydroxyl
homologous
series have the
same general formula.
5
The general formula of alkanes is
CnH2n+2
.
6
The general formula of alkenes is
CnH2n
.
7
The relative molecular mass of each successive
member of a homologous series differs
8
The first member of the alkane series
is
9
.
14
methane
ethene
methanol
.
11 B u t a n e a n d m e t h y l p r o p a n e h a v e t h e
same
molecular
formula.
12 Propane and butane have the same
formula.
F
15 The general formula of cycloalkanes is
CnH2n+2.
F
16 2-methylbutane and pentane have the
same skeletal formula.
F
17 Alkenes are aliphatic hydrocarbons.
T
18 Ethene is the second member of the
alkene series.
F
19 All alkanoic acids contain a hydroxyl
functional group.
F
20 But-1-ene and but-2-ene have different
molecular formula.
F
21 Both propan-1-ol and butan-2-ol can be
represented by the same general formula.
T
22 Ethanoic acid is the first member of the
alkanoic acid series.
F
.
10 The first member of the alkanol series
is
14 Members in the same homologous series
have the same structural formula.
.
The first member of the alkene series
is
T
group.
functional
3
by
13 Carbon can form a large number of
compounds with long carbon chains.
general
Multiple choice questions
23 Which of the following statements concerning
members in the same homologous series is
correct?
A They have the same molecular formula.
B Each member differs from the next by a
–CH3– unit.
C They show a gradual change in physical
properties.
D They show the same chemical properties.
C
8
24 Which of the following is correctly matched?
Homologous series
The compounds have the same
Functional group
A
Alkane
C
C
B
Alkene
C
C
C
Alkanol
O
H
A
B
C
D
C
Alkanoic acid
H
C
key:
carbon atom
hydrogen atom
25 Three members of the cycloalkene homologous
series are shown below.
C
C
C
C
H
H
C
Which of the following statements concerning
the compound is correct?
H
H
H
H
C
H
H
H
H
C
H
H
C
H
H
C
C
C
H
C
C
H
C
C
H
H
H
H
H
The general formula for this homologous series
is
A
B
C
D
CnH2n+2.
CnH2n.
CnH2n–2.
CnH2n–4.
H
A
28 A straight-chain carbon compound X has the
molecular formula C3H6Br2. How many possible
structures does X have?
A
B
C
D
2
3
4
5
C
29 Consider the following compounds, X and Y:
C
26 Consider the following compounds, X and Y:
H
A It is a straight-chain alkane.
B Its condensed structural formula is
CH3CH(CH3)CH3.
C Its skeletal formula is C4H10.
D It is a liquid at room temperature and
pressure.
Unit 25
H
Part A
H
H
B
27 The diagram below shows the molecular model
of a compound.
O
D
condensed structural formula.
molecular formula.
skeletal formula.
structural formula.
H
H
H
H
H
C
C
C
C
C
H
H
H
X
H
H
H
CH3 H
H
C
C
C
C
H
H
H
Y
H
CH3CH=CHCH3
X
CH3CH2CH=CH2
Y
Which of the following statements concerning
the compounds is correct?
H
A They have different molecular formulae.
B They can be represented by the general formula
CnH2n.
C They belong to different homologous series.
D They have the same skeletal formula.
B
H
9
30 The diagram below shows the molecular model
of a compound.
34
H
key:
carbon atom
oxygen atom
hydrogen atom
Part A
Its structural formula is C2H6O.
It is an alkanol.
Its general formula is CnH2n+2OH.
It contains a carboxyl group.
A
B
C
D
Unit 25
CH2O
CH4O
C2H5O
C2H6O2
C
C
C
C
C
H
H
H
H
H
H
CH3 H
A
B
C
D
36
CH3
CH3 H
CH3
C
C
C
H
H
H
A
B
C
D
Cl
1-chloro-1,3-dimethylpropane
3-chloro-1,3-dimethylpropane
1-chloro-1-methylbutane
2-chloropentane
H
H
H
C
C
C
H
H
C
H
H
10
A
What is the IUPAC name of the above
compound?
H
A
C
2-bromo-2-methylbutane
2-bromo-2-ethylpropane
1-bromo-1,1-dimethylpropane
3-bromo-3,3-dimethylpropane
37
C
A
What is the IUPAC name of the above
compound?
H
B CH3CH2CH(CH3)CH2CH2CH3
D
H
H
CH3
33 Which of the following is a straight-chain
alkane?
A H
C
Br
B
H
C
2-methylbutane.
3-methylbutane.
methylbut-2-ane.
methylbut-3-ane.
H
H
C
CH2
C
H
C
B
C25H25
C25H50
C25H52
C25H100
CH3 H
H
H3C
32 Which of the following molecular formulae
represents an alkanol?
A
B
C
D
H
35
31 Candle wax contains an alkane with 25 carbon
atoms per molecule. What is the molecular
formula of this alkane?
A
B
C
D
H
The IUPAC name of the above compound is
Which of the following statements concerning
the compounds is correct?
A
B
C
D
H
D
What is the IUPAC name of the above
compound?
A
B
C
D
H
but-1-ene
but-3-ene
1-methylpropene
3-methylpropene
38
C
A
D
H
CH3
H
H
H
CH3 CH3
C
C
C
C
C
H
CH3 OH
H
H
H
H
H
H
H
H
C
C
C
C
C
C
H
CH3 OH
H
H
H
H
CH3
A
What is the IUPAC name of the above
compound?
39
H
H
A
H
H
CH3
C
C
C
H
H
CH3
OH
H
What is the IUPAC name of the above
compound?
A
B
C
D
2,2-dimethylpropan-1-ol
3,3-dimethylpropan-3-ol
pentan-2-ol
2-methylbutan-2-ol
D
40 The condensed structural formula of a carbon
compound is CH3CH(CH3)CH(OH)C(CH3)3.
H
B
H
H
H
OH
CH3
C
C
C
C
H
CH3 H
CH3
H
H
H
OH
CH3
C
C
C
C
C
A
B
C
D
H
H
H
H
CH3
H
C
C
C
H
OH
H
H
H
H
C
C
C
H
H
H
H
OH
boiling point.
density.
relative molecular mass.
viscosity.
C
42 Which of the following statements concerning
members of a homologous series is / are
correct?
(1) The members have the same structural
formula.
(2) The relative molecular mass of each
successive member differs by 14.
(3) The volatility of the members increases
with relative molecular mass.
CH3
CH3
H
The two compounds have the same
Which of the following is another way of
representing this structure?
A
H
Unit 25
1-methylcyclohexene
2-methylcyclohexene
1-methylcyclopentene
2-methylcyclopentene
Part A
A
B
C
D
41 Consider the following two compounds:
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
B
11
43 Which of the following are different ways of
drawing the same molecule?
(1)
CH2
CH3
CH
45 The diagram below shows the molecular model
of a compound.
CH3
key:
carbon atom
oxygen atom
hydrogen atom
CH2
CH3
(2)
(3)
Part A
Unit 25
A
B
C
D
CH3
CH3
CH2
CH
CH3
CH3
CH
CH3
CH
CH
CH2
CH3
CH3
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Which of the following statements concerning
the compound is / are correct?
CH3
(1) It is an alkanoic acid.
(2) It is a non-electrolyte.
(3) It contains a hydroxyl group.
C
44 Which of the following statements concerning
but-2-ene are correct?
(1) It has the same molecular formula as but1-ene.
(2) It is in the same homologous series as
propane.
(3) Its condensed structural formula is
CH3CH=CHCH3.
A
B
C
D
12
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
46 Consider the structure of the compound shown
below.
CH2=CHCH2OH
Which of the following functional groups does
the compound contain?
(1) Carbon-carbon double bond
(2) Carboxyl group
(3) Hydroxyl group
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
Directions :
A
B
C
D
Each question (Questions 47 – 54) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
1st statement
2nd statement
B
48 Members in the same homologous series have
the same chemical properties.
Members in the same homologous series have
the same molecular formula.
D
49 Cyclohexane is an aromatic hydrocarbon.
Cyclohexane can be represented by the
general formula CnH2n.
C
50 Propane and butane belong to the same
homologous series.
Propane and butane are hydrocarbons.
B
51 Ethene is the first member of the alkene series.
Ethene contains a carbon-carbon double bond.
B
52 The straight-chain compounds C2H6 and C3H6
belong to the same homolgous series.
The straight-chain compounds C2H6 and C3H6
are hydrocarbons.
C
53 Pent-1-ene and pent-2-ene belong to the same
homologous series.
Pent-1-ene and pent-2-ene have the same
molecular formula.
B
54 Propanoic acid contains three carboxyl groups.
Propanoic acid is the third member of the
alkanoic acid series.
C
Unit 25
Carbon atoms can form double covalent
bonds with atoms of other elements.
Part A
47 Carbon can form a large number of compounds
with long carbon chains.
13
Unit 26 Alkanes and alkenes
10 When ethene is shaken with bromine dissolved
in an organic solvent,
Fill in the blanks
1
a) the
A h y d ro c a r b o n w i t h d o u b l e o r t r i p l e
bond(s) between carbon atoms is called a /
an
.
2
Saturated hydrocarbons are called
3
In a good supply of oxygen, alkanes undergo
combustion
alkanes
b) the product is called
.
1,2-dibromoethane
True or false
Decide whether each of the following statements is
true or false.
11 The volatility of members in a homologous F
series increases with relative molecular mass.
A reaction in which an atom in a molecule is
T
reaction.
12 The boiling point of butane is higher than
that of ethane.
The three major steps involved in the reaction
13 Pentane is more viscous than hexane.
F
14 Compared with pentane, octane burns
with a more sooty flame.
T
15 The reaction between ethane and bromine
occurs readily in the dark.
F
16 When propane reacts with bromine, the
colour of the reaction mixture fades.
T
17 The reaction between butane and chlorine
is an effective way for the preparation of
dichlorobutane.
F
18 During the cracking process, alkanes are
heated in the presence of air to a high
temperature.
F
19 The cracking of petroleum fractions is
an endothermic reaction.
T
20 Propene can be manufactured by
fractional distillation of petroleum.
F
21 Both ethane and ethene are insoluble
in water.
T
Part A
replaced by another atom is a
Unit 26
5
solution disappears quickly;
to produce carbon
dioxide and water.
4
colour of the bromine
hydrocarbon.
unsaturated
complete
orange
substitution
between methane and chlorine are
a)
initiation
(how the reaction gets
started);
b)
(how the reaction keeps
propagation
going);
c)
6
A
(how the reaction stops).
termination
haloalkane
is an alkane in which one or
more hydrogen atom(s) has / have been replaced
by halogen atom(s).
7
A chlorine atom having an unpaired electron is
a free
8
radical
.
The breaking down of larger hydrocarbon
molecules with heat or catalyst to
produce smaller hydrocarbon molecules is
called
9
cracking
.
A reaction in which two or more molecules react
to give a single product is a / an
reaction.
14
addition
22 Both but-1-ene and but-2-ene can
decolorize bromine dissolved in an organic
solvent.
T
23 Substitution reaction occurs when hydrogen F
bromide reacts with ethene to form
bromoethane.
24 2,2-dichloropropane is formed when
propene reacts with chlorine.
F
25 When ethene reacts with acidified
potassium permanganate solution, the
oxidation number of manganese changes
from +7 to +2.
T
29 Which of the following statements concerning
the straight-chain hydrocarbons C2H6 and C3H8
is INCORRECT?
A
B
C
D
Their relative molecular masses differ by 14.
They have the same structural formula.
They have the same general formula.
The volatility of C2H6 is higher than that of
C3H8.
B
30 The model shown below represents a compound
containing 2 carbon atoms (black spheres) and 6
hydrogen atoms (white spheres).
A Successive members differ by a –CH– unit.
B Members show similar chemical properties.
C Melting points of alkanes decrease as the
number of carbon atoms in the alkane
molecules increases.
D Members undergo addition reaction with
halogens.
B
27 Which of the following is an unsaturated straightchain hydrocarbon?
A
B
C
D
C2H6
C3H8
C4H8
C5H12
28 Which of the following alkanes is probably a
non-volatile liquid?
A
B
C
D
C2H6
C5H12
C13H28
C20H42
Which of the following statements concerning
the compound is INCORRECT?
A It is the first member of the alkane series.
B Its molecular formula is C2H6.
C It is a gas at room temperature and
pressure.
D It undergoes incomplete combustion to give
carbon monoxide when oxygen supply is
limited.
A
31 The structures of two carbon compounds are
shown below.
CH3CH2CH2CH3
C
C
Unit 26
26 Which of the following statements concerning
the alkane series is correct?
Part A
Multiple choice questions
CH3CH(CH3)CH3
Which of the following statements concerning
the compounds is correct?
A They are saturated hydrocarbons.
B They can undergo addition reactions.
C They burn in excess oxygen to form carbon
and water.
D They can decolorize bromine dissolved in an
organic solvent in the dark.
A
15
32 Consider the following information:
Compound
Relative molecular mass
C2H4
28
C3H8
44
CH3CH2OH
46
CH3CH2OCH3
60
36 The flow diagram shows the manufacture of
ethene from hydrocarbons in petroleum.
QFUSPMFVN
C2H4
C3H8
CH3CH2OH
CH3CH2OCH3
IZESPDBSCPOT
1SPDFTT
:
FUIFOF
Which of the following combinations is
correct?
When 1 g of each of these compounds undergoes
complete combustion, which one will produce the
greatest number of moles of carbon dioxide?
A
B
C
D
1SPDFTT
9
A
A
B
C
D
Process X
Process Y
Cracking
Cracking
Fractional distillation
Fractional distillation
fractional distillation
substitution
cracking
substitution
C
37 Cracking of heavy petroleum fractions should be
done in the absence of air because
Part A
it contains impurities.
it is made from alkane.
there are carbon particles in the flame.
carbon monoxide is produced in the burning
process.
C
A the impurities in air will poison the catalyst
used in cracking.
B air will support the combustion of the fractions
at high temperatures.
C air will decrease the reaction rate.
D air will increase the amount of toxic gases
given off.
B
34 Benzene burns with a very smoky flame, producing
lots of soot. This is because
38 Which of the following equations represents a
cracking reaction?
33 A candle burns with a yellow flame because
Unit 26
A
B
C
D
A it is manufactured from petroleum.
B it has very large molecules.
C it has a high ratio of carbon to hydrogen
atoms.
D it is very toxic.
C
35 Which of the following statements concerning
the reaction of propane with bromine is
INCORRECT?
A The reaction occurs faster under sunlight than
in the dark.
B A displacement reaction is involved.
C The colour of the reaction mixture fades.
D The reaction is slower than that between
propane and chlorine.
B
A
B
C
D
C5H12
C3H8 + C2H4
C5H10 + H2
C5H12
C6H12O6
2C2H5OH + 2CO2
C4H8 + H2O
C4H9OH
A
39 Upon cracking, one molecule of undecane (C11H24)
gives two molecules of propene and one molecule
of an alkane, X. What is X?
A
B
C
D
C5H10
C5H12
C8H16
C8H18
B
40 W h i c h o f t h e f o l l o w i n g p r o c e s s e s i s
endothermic?
A Burning of a candle
B Cracking petroleum fractions
C Dilution of concentrated sulphuric acid with
water
D Reaction between sodium and water
B
16
41
key:
carbon atom
hydrogen atom
43 Which of the following compounds is formed
from the reaction of but-1-ene with chlorine?
A
Cl
Which of the following statements concerning
the compound shown above is correct?
A
B
C
D
It always undergoes substitution reaction.
It is a saturated hydrocarbon.
It is insoluble in water.
It is a liquid at room temperature and
pressure.
C
B
Cl
C
42 A student passed propene into acidified dilute
potassium permanganate solution.
H
D
Which of the following compounds would be
formed?
A
H
B
H
C
H
D
H
H
H
H
C
C
C
OH
H
OH
H
H
OH
C
C
C
H
H
OH
H
OH
H
C
C
C
H
OH
H
H
H
H
C
C
C
H
OH
OH
H
H
C
C
C
C
H
H
H
H
H
Cl
H
H
C
C
C
C
H
H
H
H
H
Cl
H
H
C
C
C
C
H
Cl
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
H
Unit 26
Cl
BDJEJGJFEEJMVUFQPUBTTJVN
QFSNBOHBOBUFTPMVUJPO
H
Part A
QSPQFOF
Cl
Cl
B
44 Consider the following reaction:
Br
HBr
H
What is the type of reaction involved?
A
B
C
D
H
Addition
Cracking
Distillation
Substitution
A
45 Which of the following statements concerning the
reaction between propene and bromine dissolved
in an organic solvent is INCORRECT?
H
A
B
C
D
H
An addition reaction occurs.
The reaction occurs in the dark.
The bromine is decolorized.
The structure of the organic product is
CH2BrCH2CH2Br.
D
D
17
46 Which of the following statements concerning
straight-chain hydrocarbons with molecular
formulae C3H6 and C4H10 is correct?
A They belong to the same homologous
series.
B They are saturated compounds.
C They are gases at room temperature and
pressure.
D They have similar chemical properties.
C
Directions: Questions 49 – 52 refer to the following
set-up.
VOHMB[FEQPSDFMBJO
QJFDFT
HBTFPVT
QSPEVDU9
NJOFSBMXPPM
IFBU
TPBLFEXJUI
NFEJDJOBMQBSBGGJO
DMBNQ
XBUFS
47 Gas X is bubbled into solution Y as shown
below.
49 W h a t i s t h e re a c t i o n i n v o l v e d i n t h e
experiment?
HBT9
Part A
A
B
C
D
TPMVUJPO:
Unit 26
Which of the following combinations would give
NO visible change in the test tube?
X
A Carbon dioxide
B Chlorine
C Propene
D Sulphur dioxide
Y
calcium hydroxide solution
litmus solution
acidified potassium
dichromate solution
iron(III) sulphate solution
C
48 Which of the following is an advantage of using
wind energy?
A
B
C
D
It
It
It
It
is reliable.
causes low land impact.
causes low air pollution.
can be used in every part of the world.
C
Addition
Cracking
Dehydration
Distillation
B
50 What is the function of the unglazed porcelain
pieces in the experiment?
A
B
C
D
As
As
As
As
a catalyst
a dehydrating agent
an oxidizing agent
a reducing agent
A
51 Which of the following statements concerning
the gaseous product X is correct?
A It burns less easily than medicinal paraffin.
B It can decolorize bromine dissolved in an
organic solvent.
C It has no smell.
D It is pure ethene.
B
52 Which of the following actions are correct for
the experiment?
(1) Discard the first few cm 3 of gas
collected.
(2) Do not heat the medicinal paraffin
continuously.
(3) Remove the delivery tube from the water
after heating is stopped.
A
B
C
D
18
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
53 The molecular formulae of three straight-chain
hydrocarbons are listed below.
(1) CH4
(2) C3H6
(3) C5H12
57 Consider the following two compounds:
Compound X
H
W h i c h o f t h e s e h y d ro c a r b o n s i s / a re
unsaturated?
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
Compound Y
B
54 Ethane reacts with bromine under suitable
conditions. Which of the following statements
concerning this reaction is / are correct?
only
only
and (3) only
and (3) only
55 CH4(g) + Cl2(g)
D
CH3Cl(g) + HCl(g)
only
only
and (3) only
and (3) only
D
(1) It is an aromatic hydrocarbon.
(2) It can be represented by the general
formula CnH2n.
(3) It can decolorize acidified dilute potassium
permanganate solution.
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
H
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
H
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
58 Which of the following account for the importance
of cracking in the petrochemical industry?
(1) High-boiling fractions are cracked to
produce extra petrol.
(2) Cracking produces more lubricating oil and
bitumen.
(3) Cracking produces alkenes that are
used to make a great variety of organic
chemicals.
56 Which of the following statements concerning
cyclohexane is / are correct?
A
B
C
D
C
(1) The boiling point of Y is higher than that
of X.
(2) Both can decolorize acidified dilute
potassium permanganate solution.
(3) Both are saturated compounds.
(1) an addition reaction.
(2) a substitution reaction.
(3) a redox reaction.
(1)
(2)
(1)
(2)
C
Which of the following statements concerning
the compounds are correct?
The above reaction can be classified as
A
B
C
D
H
Unit 26
(1)
(2)
(1)
(2)
H
Part A
(1) The reaction occurs readily in the dark.
(2) The reaction gives a mixture of carbon
compounds.
(3) The colour of the reaction mixture
fades.
A
B
C
D
H
H
B
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
59 Which of the following substances can be
produced directly from ethene?
(1) Carbon dioxide
(2) Ethanol
(3) Polythene
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
19
60 A compound has the following structure:
H
62 A carbon compound X has the molecular formula
C 3H 5Cl. Which of the following statements
concerning X is / are correct?
H
C
CH3
C
(1) X must be an unsaturated compound.
(2) X has at least four possible structures.
(3) X can decolorize acidified dilute potassium
dichromate solution.
H
Which of the following statements concerning
the compound is / are correct?
(1) It can burn in air.
(2) It can decolorize acidified dilute potassium
dichromate solution.
(3) The following product is formed when it
reacts with bromine dissolved in an organic
solvent: CH2BrCH2CH2Br.
Part A
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
B
C
D
Unit 26
A
B
C
D
C
H
H
C
C
C
C
C
H
ethyne
Which of the following statements concerning
ethene and ethyne are correct?
(1) They contain the same functional group.
(2) Both are insoluble in water.
(3) Ethyne burns with a more sooty flame
than ethene.
A
A
B
C
D
20
only
only
and (3) only
and (3) only
H
H
ethene
Br
only
only
and (3) only
and (3) only
(1)
(2)
(1)
(2)
64 Both ethene and ethyne are gaseous hydrocarbons.
Their structures are shown below.
Br
(1)
(2)
(1)
(2)
B
(1) Ethane and ethene
(2) Sodium carbonate and sodium
hydrogencarbonate
(3) Sodium sulphite solution and sodium
sulphate solution
61 Which of the following statements concerning
cyclohexene is / are correct?
A
B
C
D
only
only
and (3) only
and (3) only
63 Which of the following pairs of compounds can be
distinguished by treating with acidified potassium
permanganate solution?
A
(1) It is a liquid at room temperature and
pressure.
(2) It gives an equal number of moles of
carbon dioxide and water upon complete
combustion.
(3) It reacts with bromine dissolved in an
organic solvent to give the compound
shown below:
(1)
(2)
(1)
(2)
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
C
Directions :
A
B
C
D
Each question (Questions 65 – 74) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
1st statement
2nd statement
C
66 Ethane is a gas at room temperature and
pressure.
There are only weak attractive forces between
ethane molecules.
A
67 The boiling point of propane is higher than that
of ethane.
The intermolecular forces between alkane
molecules increase as the number of carbon
atoms in the molecules increases.
A
68 A compound with the molecular formula C4H8
must be an unsaturated compound.
A compound with the molecular formula
C4H8 must contain a carbon-carbon double
bond.
D
69 Propene undergoes incomplete combustion to
give carbon monoxide.
Propene is an unsaturated compound.
B
70 Cyclohexene burns with a more sooty flame
than cyclohexane.
Compared with cyclohexane, cyclohexene has
a higher percentage of carbon by mass.
A
71 The reaction of methane with chlorine is an
effective way for preparing dichloromethane.
Methane and chlorine undergo substitution
reaction when mixed under sunlight.
C
72 Cracking is an exothermic reaction.
Cracking can convert large alkane molecules
C
to small alkane molecules and alkene molecules.
73 Both but-1-ene and but-2-ene can decolorize
acidified dilute potassium permanganate solution.
But-1-ene and but-2-ene have the same
molecular formula.
B
74 Wind power is a low-cost energy.
Wind power is a renewable energy source.
C
Unit 26
The relative molecular mass of each successive
member of a homologous series differs by 14.
Part A
65 The volatility of members of a homologous
series increases down the series.
21
Unit 27 Alkanols
Fill in the blanks
1
The alcohol in drinks is
2
Methylated spirit is a mixture of
and
3
ethanol
The functional group of alkanols is the
group.
The water solubility of alkanols
decreases
as the length of the carbon chain in their molecules
increases.
5
During oxidation, alkanols are first oxidized
to
alkanals
Part A
6
, and then to
To prepare ethanoic acid, ethanol is heated with
Unit 27
acidified
potassium dichromate solution / potassium
permanganate solution
7
alkanoic
.
acids
under reflux.
13 The boiling point of ethanol is higher than
that of butan-1-ol.
F
14 The boiling point of propan-1-ol is lower
than that of propane.
F
15 A visible colour change occurs when
T
ethanol is warmed with acidified potassium
dichromate solution.
16 A fractionating column is required in the
experimental set-up for heating a reaction
mixture under reflux.
F
17 To prepare propanal, a mixture of
propan-1-ol and acidified potassium
permanganate solution is heated under
reflux.
F
18 During the preparation of ethyl ethanoate
from ethanol and ethanoic acid,
concentrated sulphuric acid is used as an
oxidizing agent.
F
The reaction of an alkanoic acid with an
alkanol to form an ester and water is
called
8
T
.
methanol
hydroxyl
4
.
ethanol
12 Excessive drinking of alcoholic beverages
may lead to stomach ulcer.
esterification
.
A reaction in which two or more molecules
react together to form a larger molecule with
the elimination of a small molecule is called
a
condensation
Multiple choice questions
19 Which of the following hazard warning labels
should be displayed on a bottle of ethanol?
A
B
C
D
reaction.
True or false
Decide whether each of the following statements is
true or false.
9
22
The ethanol content of beer is lower than
that of red wine.
T
10 Ethanol is soluble in water but not in oils.
F
11 Ethanol is a cleaner fuel than petrol.
T
D
20 Which of the following statements concerning
ethanol is INCORRECT?
A
B
C
D
It
It
It
It
is a good solvent.
can conduct electricity.
is found in alcoholic beverages.
can be used as a fuel for cars.
B
21 Which of the following lists the compounds in
increasing order of water solubility?
A
B
C
C
pentane < ethanol < pentan-1-ol
pentane < pentan-1-ol < ethanol
pentan-1-ol < ethanol < pentane
pentan-1-ol < pentane < ethanol
24 What is the function of the piece of apparatus
labelled X?
A
B
C
D
B
To
To
To
To
separate the products of the reaction.
purify the products of the reaction.
condense the reaction mixture.
prevent any loss of the reaction mixture.
D
22 The following flow diagram shows the industrial
preparation of ethanol.
QFUSPMFVN
GSBDUJPO
Stage I
A
B
C
D
Stage II
FUIFOF
FUIBOPM
Which of the following combinations is
correct?
Stage I
Stage II
Cracking
Cracking
Fractional distillation
Fractional distillation
dehydration
hydration
dehydration
hydration
A
B
C
D
H
O
C
C
H
OH + H
H
9
A
B
C
D
BDJEJGJFEQPUBTTJVN
EJDISPNBUFTPMVUJPO
BOEQSPQBOPM
23 What is the function of acidified potassium
dichromate solution in the experiment?
As
As
As
As
a catalyst
a drying agent
an oxidizing agent
a solvent
OH
H
product X
+ H2O
esterification.
hydrolysis.
neutralization.
oxidation.
A
28 What is product X?
IFBU
A
B
C
D
C
27 The type of reaction involved is
XBUFSJO
BOUJCVNQJOH
HSBOVMFT
D
Directions: Questions 27 and 28 refer to the following
equation.
H
XBUFSPVU
Addition
Condensation
Hydration
Oxidation
Unit 27
A reaction mixture containing acidified potassium
dichromate solution and propan-1-ol is heated using
the set-up shown below.
D
26 A bottle of wine was left open. It tasted sour
after a few days. Which of the following types
of reactions leads to this change?
B
Directions: Questions 23 – 25 refer to the following
experiment.
Propane
Propanal
Propene
Propanoic acid
Part A
A
B
C
D
25 What is the organic product obtained?
A
B
C
D
CH3COOCH2CH3
CH3COOCH3
HCOOCH2CH3
HCOOCH3
B
C
23
29
32 What is the function of concentrated sulphuric
acid in the reaction of Y and methanol?
CBOBOB
NJMLTIBLF
DIFXJOHHVN
Which of the following types of compounds give
the above substances a sweetish smell?
A
B
C
D
Alkenes
Alkanoic acids
Alkanols
Esters
C
D
a catalyst
an oxidizing agent
a reducing agent
a solvent
A
O
H3C
B
C
Part A
Unit 27
O
C
CH3
D
O
B
Directions: Questions 31 and 32 refer to the following
flow diagram.
X, Y and Z are carbon compounds. The flow diagram
below shows the conversion of X to Z.
DPOD)40
IFBU
;
NFUIBOPM
31 Z has a pleasant smell and its molecular formula
is C4H8O2.
What is the systematic name of X?
A
B
C
D
24
Ethanol
Ethanoic acid
Propanal
Propanoic acid
CH3
D
34 Consider the ester shown below.
O
CH3
C
O
CH
CH3
CH3
Which of the following statements about the
ester is correct?
:
IFBU
O
CH3 .
CH3
9
CH3
C
C
C
formed is CH3
OH
O
C
It is neutral to litmus solution.
It systematic name is propanol.
It is soluble in water.
When it reacts with ethanoic acid, the ester
O
H
BDJEJGJFE
,$S0BR
A
33 What product, in addition to water, is produced
by the following reaction?
OH is INCORRECT?
CH3
A
B
C
D
As
As
As
As
CH3OH + C6H5COOH
30 Which of the following statements concerning
H
H3C
A
B
C
D
C
A It has the same molecular formula as pentanoic
acid.
B Its systematic name is ethyl propanoate.
C It is produced from propanoic acid.
D It is produced from propan-1-ol.
A
O
35
CH3
CH2
C
CH2
O
38 Which of the following compounds CANNOT be
produced directly from ethanol?
CH3
CH2
What is the IUPAC name of the above
compound?
A
B
C
D
butyl ethanoate
ethyl butanoate
ethyl pentanoate
propyl ethanoate
B
C
(CH3)2CH
O
CH3
UIFSNPNFUFS
TUJMMIFBE
O
C
C
C
H
H
PSHBOJD
QSPEVDU9
O
C
H
H
H
H
H
O
C
C
C
C
H
H
H
Q
O
39 What is the organic product X collected in the
conical flask?
A
B
C
D
H
They have the same odour.
P is more volatile than Q.
They have the same chemical properties.
P dissolves in water readily while Q does
not.
B
Butane
Butanone
Butanal
Butanoic acid
C
40 Which of the following statements concerning
the experiment are correct?
(1) Butan-1-ol undergoes oxidation.
(2) The colour of the reaction mixture changes
from orange to green.
(3) Organic product X will also be obtained if
acidified potassium permanganate solution
is used instead of acidified potassium
dichromate solution.
Which of the following statements concerning
these two compounds is correct?
A
B
C
D
JDFXBUFS
CBUI
H
P
H
XBUFSJO
SFDFJWFS
BEBQUPS
Unit 27
H
DPOEFOTFS
Part A
BOUJCVNQJOH
HSBOVMFT
HFOUMFIFBU
C
37 The structures of two carbon compounds P and
Q are shown below:
H
XBUFSPVU
FYDFTTCVUBOPM
BDJEJGJFEQPUBTTJVN
EJDISPNBUFTPMVUJPO
butyl methanoate
methyl butanoate
methyl methylpropanoate
methylpropyl methanoate
H
B
Directions: Questions 39 and 40 refer to the following
experiment.
What is the IUPAC name of the above
compound?
A
B
C
D
Carbon dioxide
Ethane
Ethanoic acid
Ethyl ethanoate
In an experiment, a mixture of excess butan-1-ol and
acidified potassium dichromate solution is heated as
shown below.
O
36
A
B
C
D
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
25
Directions: Questions 41 and 42 refer to the following
experiment.
44 Which of the following statements about using
ethanol as a car fuel are correct?
Some concentrated sulphuric acid and anti-bumping
granules are added to an alkanol and an alkanoic acid.
The mixture is heated under reflux for some time and
the following compound is obtained:
(1) Ethanol is a cleaner fuel than petrol.
(2) Using ethanol as a car fuel is economical
in agricultural countries with sugar cane
as the main crop.
(3) Incomplete combustion of ethanol produces
ethanal.
H
H
H
H
C
C
C
H
H
H
O
O
H
C
C
A
B
C
D
H
H
41 Which of the following combinations is
correct?
Part A
A
B
C
D
Alkanol
Alkanoic acid
Ethanol
Ethanol
Propan-1-ol
Propan-1-ol
ethanoic acid
propanoic acid
ethanoic acid
propanoic acid
C
Unit 27
(1) Concentrated sulphuric acid acts as a
catalyst in the reaction.
(2) The purpose of adding anti-bumping
granules is to speed up the reaction.
(3) Heating under reflux can prevent the loss
of reactants and products.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
45 Which of the following can react with propan1-ol?
A
B
C
D
26
A
CH3 H
H
C
C
CH3
CH3 OH
Which of the following statements concerning X
is / are correct?
B
(1) Cirrhosis of the liver
(2) Sore throat
(3) Stomach ulcer
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
46 The structure of compound X is shown below:
(1) It has the same molecular formula as
pentan-1-ol.
(2) Its systematic name is 2-methylbutan-3-ol.
(3) It contains a carboxyl group.
43 Which of the following health problems are
associated with excessive drinking of alcohol?
A
B
C
D
D
(1) Acidified potassium dichromate solution
(2) Ethanoic acid
(3) Ethene
42 Which of the following statements concerning
the experiment are correct?
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
B
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
47 Consider the following two compounds:
Compound X
Compound Y
H
H
H
H
C
C
H
H
H
H
H
C
C
C
H
H
H
Which of the following statements concerning
the compound is / are correct?
(1) It is a liquid at room temperature and
pressure.
(2) It is a good conductor of electricity.
(3) It is produced from ethanol and propanoic
acid.
OH
A
B
C
D
OH
Which of the following statements concerning
the compounds is / are correct?
(1) Y is more volatile than X.
(2) They both contain a hydroxyl group.
(3) They both can dissolve iodine.
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
B
C
D
(1)
(2)
(1)
(2)
(3)
only
only
and (3) only
and (3) only
B
51 When methylpropan-2-ol is heated under reflux
with ethanoic acid in the presence of a catalyst,
compound X of molecular formula C6H12O2 is
formed.
Which of the following statements concerning
the experiment are correct?
(1) The reaction cannot go to completion.
(2) Concentrated sulphuric acid can be used
as a catalyst.
(3) The structure of compound X is
O
D
49 The following diagram shows the molecular model
of a compound.
key:
carbon atom
oxygen atom
hydrogen atom
(2)
Unit 27
(1) The reactants undergo esterification.
(2) The oxidation number of manganese
changes from +7 to +2.
(3) The purple colour of the reaction mixture
fades.
A
50 Which of the following hazard warning labels
should be displayed on a bottle of ethyl
ethanoate?
(1)
48 If ethanol is refluxed with acidified potassium
permanganate solution for an hour, which of the
following descriptions is / are correct?
A
B
C
D
only
only
and (3) only
and (3) only
Part A
A
B
C
D
(1)
(2)
(1)
(2)
CH3
A
B
C
D
C
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
O
C(CH3)3 .
D
27
52 A student adds a compound X to acidified
potassium dichromate solution and heats the
mixture under reflux. The reaction mixture turns
green in colour. X could be
Which of the following processes can this set-up
be used for?
(1) Preparing ethyl ethanoate from ethanol
and ethanoic acid
(2) Preparing propanal from propan-1-ol and
acidified potassium dichromate solution
(3) Separating ethanol and water
(1) CH3CH2COOH.
(2) CH2=CHCH2OH.
(3) CH3CH2CH2OH.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
53
C
CHCH2CH2C
OH
Part A
(1) Acidified dilute potassium permanganate
solution
(2) Sodium hydrogencarbonate solution
(3) Ethanol
Unit 27
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
54 An experimental set-up is shown below.
XBUFSPVU
DPOEFOTFS
XBUFSJO
BOUJCVNQJOH
HSBOVMFT
IFBU
28
only
only
and (3) only
and (3) only
A
(1) Detecting their odour
(2) Mixing with sodium hydrogencarbonate
solution
(3) Adding water to them
Which of the following chemicals can react with
the above compound?
A
B
C
D
(1)
(2)
(1)
(2)
55 Which of the following methods can be used to
distinguish between ethanol and ethanoic acid?
O
H2C
A
B
C
D
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
Directions :
A
B
C
D
Each question (Questions 56 – 61) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
1st statement
2nd statement
B
57 The boiling point of ethane is higher than that
of methanol.
An ethane molecule has two carbon atoms
while a methanol molecule has one.
C
58 Ethanol is a cleaner fuel than petrol.
Ethanol tends to undergo complete combustion
more readily than petrol.
A
59 Ethanal and ethanol can be distinguished by
warming with acidified potassium dichromate
solution.
The dichromate solution turns green when
D
warmed with ethanol but there is no observable
change with ethanal.
60 Esterification does not require a catalyst.
Esterification is a fast reaction.
D
61 The reaction between ethanoic acid and ethanol
is a neutralization reaction.
When ethanoic acid reacts with ethanol, water
is formed.
C
Unit 27
Both ethanol and water are covalent
compounds.
Part A
56 Ethanol is very soluble in water.
29
Unit 28 Plastics
Fill in the blanks
1
A large molecule that is made up of many smaller
molecules joined together repeatedly is called
a
2
polymerization and
condensation
The smallest part of a polymer molecule is called
a
.
repeating unit
Adding
plasticizer
to plastic makes it more
flexible.
5
Most plastics cannot be decomposed by bacteria.
They are said to be
6
non-biodegradable
.
Part A
Unit 28
a) landfilling
;
b) incineration
;
c) recycling
;
d) pyrolysis
.
True or false
Decide whether each of the following statements is
true or false.
The repeating unit of polypropene is
F
CH3 CH3
8
9
30
F
12 Polystyrene is commonly used to make
floor tiles.
F
13 Nylon is a thermoplastic.
T
14 Urea-methanal is an addition polymer.
F
15 Perspex is a condensation polymer.
F
16 Poly(ethylene terephthalate) is a
thermosetting plastic.
F
17 Thermosetting plastics are less flammable
than thermoplastics.
T
18 The flue gas produced by the incineration
of polyvinyl chloride can cause the
formation of acid rain.
T
Common methods for treating plastic waste
are
7
11 High density polythene is commonly used
to make handles of frying pans.
The two main types of polymerization are
polymerization.
4
T
.
polymer
addition
3
10 Polypropene is stronger than polythene.
C
C
H
H
Multiple choice questions
Directions: Questions 19 – 21 refer to the following
polymers.
Properties of the polymer
A
lightweight and can be stretched into thin,
tough film
B
flexible, can be coloured and is a good
electrical insulator
C
tough, slippery and can be heated strongly
D
rigid, transparent and can easily be cut into
any shape
19 Which of the polymers is suitable for making the
electrical wire of a pot?
.
Polyvinyl chloride softens upon gentle
heating.
T
Both ethene and polythene belong to
the same homologous series.
F
QPMZNFS
B
20 Which of the polymers is suitable for making the
roof of a greenhouse?
Which of the following combinations is
correct?
Stage I
QPMZNFS
A Cracking
B Cracking
D
21 Which of the polymers is suitable for making a
shopping bag?
C Fractional
distillation
D Fractional
distillation
Stage II
Stage III
fractional
distillation
fractional
distillation
cracking
polymerization
cracking
distillation
distillation
polymerization
C
24 Which of the following statements concerning
but-2-ene is INCORRECT?
A
22 Which of the following items should be made of
a thermosetting plastic?
A
B
A It has the same molecular formula as but-1ene.
B It can burn in air.
C It can undergo addition polymerization.
D It can decolorize acidified dilute potassium
dichromate solution.
D
25 Which of the following polymers is made by the
polymerization of methyl methacrylate?
Part A
CH3
C
FMFDUSJDTXJUDI
H2C
A
CH3
B
IFBWZPJM
NPOPNFS
C
CH2
C
C
CH3
C
CH2
CH
H
C
CH2
C
CH3 H
CH2
COOCH3
C
C
OCH3
CH3
CH
COOCH3
D
CH3
OCH3
COOCH3
4UBHF
***
QPMZQSPQFOF
CPUUMF
C
CH2
CH3
C
QFUSPMFVN
CH3
OCH3
23 The flow diagram below shows the key stages
involved in the production of polypropene bottles
from petroleum.
4UBHF
**
C
CH2
DPWFSJOHBSPVOE
FMFDUSJDBMXJSFT
B
4UBHF
*
COOCH3
methyl methacrylate
D
QMBTUJDXBTI
CPUUMF
C
Unit 28
QMBTUJDVNCSFMMB
C
COOCH3
CH
CH3 H
COOCH3
C
CH3
COOCH3
COOCH3 COOCH3 COOCH3
C
C
C
CH3
CH3
CH3
B
31
26 Part of a polymer chain is shown below.
CH3 H
CH3 H
C
C
C
H
CH3 H
Which of the following combinations is
correct?
CH3 H
C
C
C
CH3 H
A
B
C
D
CH3
What is the monomer of the polymer?
A
B
C
D
1,2-dimethylethene
2,2-dimethylethene
methylpropene
but-2-ene
D
CN
CN
C
CH2
C
CH2
C
CH2
C
O
C
O
C
O
OCH3
OCH3
Part A
CN
OCH3
Unit 28
H
B
C
C
O
H
OCH3
H
CN
C
C
H
C
H
CN
C
H
D
CN
H
C
C
C
OCH3
H
C
O
O
B
28 The diagram below shows the structure of some
plastics.
32
H
H
H
C
C
C
C
X
H
X
H
A
H
H
CH3 H
H
H
C
C
C
C
C
C
H
H
H
H
H
H
A
B
C
D
Ethene and propene
Ethene and butene
Ethene and pentene
Propene and butene
A
A
B
C
D
Perspex
Polypropene
Polythene
Polyvinyl chloride
C
31 Which of the following combinations is correct?
OCH3
H
polystyrene
polyvinyl chloride
polypropene
Perspex
30 Which of the following plastics is commonly used
to make wash bottles in the laboratory?
OCH3
C
C6H5
HCl
CH4
COOCH3
Which pair of alkenes could be used as monomers
for this polymer?
What is the structure of the monomer of Super
Glue?
A
Name of plastic
29 Part of the structure of an addition polymer is
shown below. It is made using two different
monomers.
27 Part of the structure of Super Glue is shown
below.
CN
X
A
B
C
D
Polymer
Making
Perspex
Polypropene
Polystyrene
Polyvinyl chloride
shower screens
compact disc cases
bathroom floor tiles
yogurt pots
A
32 Which of the following combinations is
INCORRECT?
A
B
C
D
Polymer
Making
Polyvinyl chloride
Perspex
Polypropene
Polythene
raincoats
aircraft windows
car bumpers
advertising displays
D
33 Which of the following is NOT a common use
of nylon?
A
B
C
D
As a fibre for clothes
Making electric plugs
Making fishing nets
Making gears and bearings
37 Polymer X has the following structure:
B
34 ‘Newplast’ is a new plastic manufactured by a
company. It is biodegradable. It is used for stitches
after a surgical operation. The plastic stitches
do not need to be removed because bacteria in
the body will digest them. The company plans
to use ‘Newplast’ for other purposes. Which of
the following would NOT be a suitable use of
‘Newplast’?
A Making packets for sweets
B Making pots for putting plants into the ground
without disturbing the roots
C Making capsules containing medicine
D Making false teeth
D
H
CH3 H
CH3 H
CH3
C
C
C
C
C
C
H
H
H
H
H
H
Which of the following statements concerning X
is correct?
A X is commonly used to make shower screens.
B X cannot be remoulded.
C Van der Waals’ forces exist between the
polymer chains of X.
D The monomer of X is as shown below:
CH3 CH3
C
C
H
H
38 Plastic X has the following structure:
35 Which of the following statements concerning
polyvinyl chloride is correct?
C
C
Cl
Cl
.
C
36 Which of the following statements concerning
polystyrene is INCORRECT?
C
.
n
H
CH3
B It is an electrical insulator.
C It is hard.
D It is transparent.
C
CH2
COOCH3
C
COOCH3
Which of the following statements concerning X
is correct?
A
B
C
D
It is
It is
It is
The
highly transparent.
flexible.
commonly used to make raincoats.
monomer of X is as shown below:
CH3 H
A Its structure can be represented as
H
COOCH3
C
CH2
CH3
Unit 28
D Its repeating unit is
CH3
Part A
A It is used to make disposable lunch boxes.
B It is made from chloroethane.
C It gives off hydrogen chloride when burnt.
Cl
Cl
C
C
C
H
COOCH3
A
A
33
39 Compound X has the following structure:
43 The repeating unit of polymer X is shown
below:
C6H5CH=CH2
H
Which of the following statements concerning
the polymer formed from X is correct?
A The polymer is used to coat the inside of a
non-stick frying pan.
B The polymer is transparent.
C The polymer is very flexible.
D The repeating unit of the polymer is as shown
below:
C6H5 H
C
C
H
C6H5
B
40 Propene is an unsaturated hydrocarbon. Which
of the following is NOT a characteristic of its
unsaturated nature?
Part A
A It undergoes addition reaction with bromine
dissolved in an organic solvent.
B It undergoes incomplete combustion to give
carbon particles.
C It decolorizes acidified dilute potassium
permanganate solution.
D It undergoes polymerization to give
polypropene.
B
Unit 28
41 A type of polyvinyl chloride has a relative molecular
mass of 42 500. How many repeating units are
present in one molecule of the polymer?
(Relative atomic masses: H = 1.0, C = 12.0,
Cl = 35.5)
A
B
C
D
625
680
735
790
B
42 Which of the following substances is a thermoplastic
as well as a condensation polymer?
A
B
C
D
34
Perspex
Polyester
Polystyrene
Urea-methanal
B
N
O
(CH2)6
N
C
(CH2)4
H
C
O
Which of the following statements concerning
polymer X is correct?
A It is an addition polymer.
B It is used to make bottle for carbonated
drinks.
C It is formed from two different monomers.
D Covalent bonds exist between its polymer
chains.
C
44 The repeating unit of polymer X is shown
below:
O
O
C
C
O
CH2
CH2
O
Which of the following statements concerning
polymer X is INCORRECT?
A
B
C
D
It
It
It
It
is a thermoplastic.
is formed by condensation polymerization.
contains ester linkages.
is used in flavourings and perfumes.
D
45 What is the best description of the benefits of
using jute as a replacement for polythene in
bags?
A It is made from renewable sources and it will
not rot.
B It saves on the use of petroleum and helps
reduce the waste that goes to landfill.
C It is made from non-renewable sources
that remove carbon dioxide from the
atmosphere.
D It saves the customer money and it is
biodegradable.
B
Directions: Questions 46 and 47 refer to butadiene and
pentadiene, both containing two carboncarbon double bonds. Their structures are
shown below.
H
H
H
H
H
H
H
H
H
C
C
C
C
C
C
C
C
C
H
H
H
H
Pentadiene
Butadiene
(1) Cellulose
(2) Nylon
(3) Starch
A
B
C
D
H
46 Butadiene and pentadiene belong to a family of
compounds having the general formula
A
B
C
D
49 Which of the following is / are natural
polymer(s)?
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
50 Which of the following compounds is / are likely
to undergo addition polymerization?
(1) HO–(CH2)2–OH
(2) CH2=CHCH3
O
CnH2n–2.
CnH2n.
CnH2n+2.
CnH2n–4.
A
47 Butadiene can be polymerized to form a polymer,
polybutadiene, whose structure is represented
by
CH2
CH
CH
CH2
n
(3) CH3
A
B
C
D
(1)
(2)
(1)
(2)
C
OH
only
only
and (3) only
and (3) only
B
H
Cl
H
Cl
H
Cl
H
Cl
(1) They are unsaturated.
(2) They can react with bromine dissolved in
an organic solvent.
(3) They can be formed by cracking certain
petroleum fractions.
C
C
C
C
C
C
C
C
Cl
H
Cl
H
Cl
H
Cl
H
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
(1) CO2
(2)
CH2CH2
Which of the following statements concerning X
are correct?
(1) The monomer of X is chloroethene.
(2) X is a thermoplastic.
(3) The flue gas produced by the incineration
of X can cause the formation of acid
rain.
A
48 Which of the following compounds can be
obtained from ethene in a single reaction?
Unit 28
Which of the following statements regarding
butadiene and polybutadiene are correct?
Part A
51 Polymer X has the following structure:
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
C
n
(3) HOCH2CH2OH
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
35
Directions: Questions 52 and 53 refer to the following
experiment.
Polystyrene can be prepared from styrene using the
set-up shown below.
54 Which of the following statements concerning
thermosetting plastics and thermoplastics are
correct?
(1) Thermosetting plastics are less flammable
than thermoplastics.
(2) Thermosetting plastics do not soften on
heating while thermoplastics do.
(3) Thermosetting plastics are formed by
addition polymerization while thermoplastics
are not.
XBUFSPVU
A
B
C
D
XBUFSJO
BTPMVUJPOPGTUZSFOF
JOLFSPTFOF
BOUJCVNQJOH
HSBOVMFT
(1) Making clothes
(2) Making bottles for carbonated drinks
(3) For surfacing of non-stick frying pans
52 Which of the following statements concerning
polystyrene are correct?
Part A
(1) It is a thermoplastic.
(2) It can be remoulded.
(3) The repeating unit of polystyrene is as
shown below:
H
Unit 28
A
B
C
D
C
H
H
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
36
only
only
and (3) only
and (3) only
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
(1) It is a thermoplastic.
(2) It is an addition polymer.
(3) It contains nitrogen.
A
(1) As a catalyst
(2) As an oxidizing agent
(3) As a solvent for styrene
(1)
(2)
(1)
(2)
A
B
C
D
56 Which of the following statements concerning
nylon is / are correct?
53 What is / are the function(s) of kerosene in the
preparation?
A
B
C
D
A
55 Which of the following are common uses of
poly(ethylene terephthalate)?
IFBU
C
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
57 Which of the following statements concerning
poly(ethylene terephthalate) are correct?
(1) It is a condensation polymer.
(2) It has cross-links between the polymer
chains.
(3) It is a thermoplastic.
C
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
58 Which of the following statements concerning
urea-methanal is / are correct?
(1) It softens in hot water.
(2) It consists of cross-links between polymer
chains.
(3) Urea-methanal waste can be recycled by
melting and remoulding.
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
Which of the following statements are correct?
(1) Compound X contains carboxyl groups.
(2) Compound Y contains hydroxyl groups.
(3) Polyester A is an addition polymer.
A
B
C
D
B
(1) Most plastics are non-biodegradable.
(2) Burning plastics may give off toxic
fumes.
(3) M o s t p l a s t i c p ro d u c t s c a n n o t b e
remoulded.
O
CH2
N
C
N
H
(2)
A
B
C
D
n
H
O
C
C
C
H
CH3
O
CH3
(1) Plastic waste is decomposed by bacteria
quickly.
(2) The process may cause pollution of the
underground water.
(3) A lot of plastic waste can be treated in a
short period of time.
C
C
O
CH2
CH2
O
n
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
A
B
C
D
Y
HOOC
HO
CH2
OH
D
(1) petroleum can be conserved.
(2) it can reduce pollution problems.
(3) it can arouse the public’s awareness of
conservation.
COOH
CH2
only
only
and (3) only
and (3) only
63 It is important to recycle plastics because
60 The most common polyester A is made from
compound X and compound Y.
X
(1)
(2)
(1)
(2)
Unit 28
O
A
62 Which of the following statements concerning
the landfilling of plastic waste is / are correct?
n
O
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
Part A
(3)
H
A
61 Which of the following are problems associated
with plastics?
59 Which of the following polymers is / are made
by condensation polymerization?
(1)
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
37
64 Which of the following statements concerning
pyrolysis of plastic waste are correct?
(1) It is necessary to separate different plastics
before pyrolysis.
(2) The plastics are heated in the absence of
air.
(3) Plastics are converted into simple
hydrocarbons.
Directions :
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
C
Each question (Questions 65 – 74) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
1st statement
Part A
Unit 28
38
A
B
C
D
2nd statement
65 Polythene is used for making electric sockets.
Polythene is a thermoplastic.
C
66 Polystyrene is expanded before it is used to
make disposable lunch boxes.
Expanded polystyrene has good heat insulating
property.
A
67 Polystyrene is commonly used to make floor
tiles.
Polystyrene is opaque and flexible.
D
68 Nylon is commonly used for making ropes.
Nylon has a great strength.
A
69 Polythene can decolorize bromine dissolved in
an organic solvent.
Polythene belongs to the alkene series.
D
70 All thermoplastics are made by addition
polymerization.
Thermoplastics consist of long polymer chains
without cross-links.
C
71 Thermosetting plastics melt only at very high
temperatures.
Thermosetting plastics are hard and rigid.
C
72 All condensation polymers are thermosetting
plastics.
All condensation polymers have cross-links
between polymer chains.
D
73 Polyester is a condensation polymer.
Polyester softens on heating.
B
74 Urea-methanal is hard and rigid.
Urea-methanal has cross-links between polymer
chains.
A
Part B
Topic-based exercise
Multiple choice questions
Consider the fractional distillation of crude oil in
the laboratory. Four fractions are collected at the
temperature ranges listed below:
Fraction
Boiling point range
1
room temperature – 100 °C
2
100 °C – 150 °C
3
150 °C – 200 °C
4
200 °C – 250 °C
2
D
Which of the following substances burns most
easily when ignited?
A
B
C
D
4
Bitumen
Kerosene
Lubricating oil
Naphtha
Bitumen
Diesel oil
Kerosene
Lubricating oil
C
The table shows the components of the exhaust
gas from a typical petrol engine.
Gas
Percentage
Carbon dioxide
15.0
Carbon monoxide
1.0
Hydrocarbons
0.05
Nitrogen oxides
0.2
Sulphur dioxide
0.007
A
B
C
D
5
Hydrogen
Methane
Nitrogen
Water vapour
C
The following graph shows some information
about nitrogen dioxide emission.
Part B
3
Fraction 1 burns with a very sooty flame.
Fraction 2 is more viscous than fraction 3.
Fraction 3 burns more easily than fraction 4.
Fraction 4 evaporates more easily than
fraction 1.
C
Which of the following petroleum fractions has
the lowest carbon content?
A
B
C
D
0.7
Which of the following substances will make up
most of the remainder of the exhaust gas?
Which of the following statements is correct?
A
B
C
D
Oxygen
The gases in the table make up less than 20%
of the exhaust gas.
&NJTTJPOPGOJUSPHFO
EJPYJEFLHQFSQFSTPO
1
.FYJDP )VOHBSZ
6,
64
"VTUSBMJB
Which of the following conclusions can be drawn
from this graph?
A Mexico has the lowest population of
people.
B Australia produces more nitrogen dioxide than
the US.
C Every individual person in the UK produces
less nitrogen dioxide than any person living
in the US.
D On average, each person in Hungary produces
less nitrogen dioxide than each person in the
UK.
D
39
6
7
Which of the following is NOT affected by acid
rain?
What is the general formula for this homologous
series?
A
B
C
D
A
B
C
D
Installing catalytic converters
Installing electrostatic precipitators
Installing scrubbers
Increasing the height of the chimney
C
Rainwater samples collected in urban areas have
pH lower than those collected in the countryside.
Which of the following air pollutants is responsible
for this phenomenon?
A
B
C
D
9
C
Which of the following measures can reduce
the emission of sulphur dioxide from a coal-fired
power staton?
A
B
C
D
8
Building made of limestone
Forests
Human respiratory system
Water lives
Carbon monoxide
Nitrogen dioxide
Particulates
Unburnt hydrocarbons
Part B
1
2
3
4
A
H
C
C
H
H
C
C
C
H
H
40
C
C
11 Which of the following statements concerning
members of a homologous series is correct?
A The members have the same general
formula.
B Each successive member differs by a –CH–
unit.
C The volatility of the members increases with
relative molecular mass.
D The members with more carbon atoms in their
molecules dissolve in water more readily. A
12 Consider the following two compounds:
Compound X
10 The first three members of the alkyne homologous
series are shown below.
H
D
H
H
H
H
C
C
C
H
H
H
H
H
H
H
C
C
C
C
H
H
H
H
H
B
A carbon compound X has the molecular formula
C2H3Cl. How many possible structure(s) does X
have?
A
B
C
D
CnHn
CnHn+1
CnHn+2
CnH2n–2
H
H
C
C
H
H
H
H
Compound Y
H
H
Which of the following statements concerning
the compounds is correct?
A They undergo addition reaction with bromine
dissolved in an organic solvent.
B They are alkanes.
C They are the major components of diesel
oil.
D They have the same structural formula. B
13
H
17 Cyclohexa-1,4-diene is treated with bromine
dissolved in an organic solvent.
H
Br
H
C
C
C
H
H
C
H
cyclohexa-1,4-diene
H
Which of the following products is formed?
What is the IUPAC name of the above
compound?
A
B
C
D
2-bromobut-1-ene
3-bromobut-3-ene
2-bromo-1-methylpropene
2-bromo-3-methylpropene
14
Br
C
Br
What is the IUPAC name of the above
compound?
1,1-diethylethanol
1-ethyl-1-methylpropan-1-ol
2-ethylbutan-2-ol
3-methylpentan-3-ol
D
A
B
C
D
Ammonia
Carbon dioxide
Methane
Nitrogen
monoxide
Br
Br
Br
Br
Br
D
Br
Br
Property
odourless
can burn in air
dissolves readily in water
changes from colourless
to brown when exposed
to air
D
16 Which of the following statements concerning
ethene is INCORRECT?
A It burns with a luminous flame.
B It is a liquid at room temperature and
pressure.
C It decolorizes acidified dilute potassium
permanganate solution.
D It can be polymerized.
B
Br
Br
Br
B
18 A carbon compound X has the molecular
formula C4H8. Which of the following statements
concerning X is correct?
A
B
C
D
It has at least four possible structures.
It must be an unsaturated compound.
It is soluble in water.
It can turn acidified dilute potassium
dichromate solution from orange to green.
Part B
15 Which of the following combinations concerning
the properties of gases is correct?
Gas
Br
C2H5
C
OH
A
B
C
D
B
Br
A
C2H5
CH3
A
A
19 Which of the following processes would NOT give
an obvious colour change?
A Bubbling ethene into acidified dilute potassium
permanganate solution
B Adding potassium iodide solution to aqueous
chlorine
C Adding hot concentrated sulphuric acid to
copper
D Electrolyzing dilute magnesium sulphate
solution using carbon electrodes
D
41
20 2-methylbut-1-ene reacts with bromine dissolved
in an organic solvent. The product is
H
CH3 H
H
C
C
C
C
H
H
Br
H
H
CH3 H
H
C
C
C
C
H
Br
H
H
H
H
CH3 H
C
C
C
C
H
Br
Br
H
Br
H
CH3 H
C
C
C
C
H
Br
H
H
A
Br
B
Br
C
H
D
H
23 Consider the following compounds:
methane, ethane, ethanol, methanol
The boiling points of the compounds are in the
order of
H
A
B
C
D
A
H
24 Consider the preparation of propanoic acid using
the set-up shown.
XBUFSPVU
H
DPOEFOTFS
H
XBUFSJO
Part B
A It is soluble in water.
B It undergoes incomplete combustion to give
carbon monoxide.
C It can form a polymer with
C2H5 H
C
as the repeating unit.
H
H
D It can form the following product upon reaction
with chlorine:
H
H
H
H
Cl
C
C
C
C
H
H
H
H
Cl
B
22 Which of the following energy sources is
renewable?
A
B
C
D
42
Energy from rubbish
Natural gas
Nuclear energy
Solar energy
BNJYUVSFPGQSPQBOPM
BOEBDJEJGJFEQPUBTTJVN
EJDISPNBUFTPMVUJPO
B
BOUJCVNQJOH
HSBOVMFT
21 Which of the following statements concerning
but-2-ene is correct?
C
methane < ethane < methanol < ethanol.
ethane < methane < methanol < ethanol.
ethanol < ethane < methane < methanol.
methanol < methane < ethane < ethanol.
D
IFBU
Which of the following statement concerning this
experiment is INCORRECT?
A The reaction mixture is undergoing reflux.
B The acidified potassium dichromate solution
acts as a catalyst.
C The reaction mixture gradually turns green.
D Propanoic acid can be obtained from the
reaction mixture by distillation.
B
25 A carbon compound can decolorize acidified
potassium permanganate solution on warming,
but cannot decolorize bromine dissolved in an
organic solvent.
What could the carbon compound be?
A
B
C
D
Propane
Propene
Propan-1-ol
Propanoic acid
C
26 How many esters are there with the molecular
formula C4H8O2?
A
B
C
D
3
4
5
6
29 Acarol is sold as an insecticide.
Br
CH2
Reaction 1
+ Cl2
C
C
CH3
O
C
H
CH3
Br
Acarol
CH3CH2OH
Reaction 3
Reaction 2
compound A
CH3COOH
compound B
(with a
pleasant
smell)
27 What are the IUPAC names of compounds A and
B?
A
B
C
D
O
B
Directions: Questions 27 and 28 refer to the following
reaction scheme.
CH2
OH
compound A
compound B
1,2-dichloroethane
1,1-dichloroethane
1,2-dichloroethene
1,2-dichloroethane
ethyl ethanoate
ethyl methanoate
ethyl ethanoate
methyl propanoate
A
Reaction 2
A Acidified K2Cr2O7
solution
B Acidified KMnO4
solution
C Concentrated H2SO4
D Concentrated H2SO4
Which of the following alcohols is used to form
the ester?
A
B
C
D
Dibromophenylethanol
Ethanol
Propan-1-ol
Propan-2-ol
30 Compound X can decolorize bromine dissolved in
an organic solvent. When X is added to sodium
hydrogencarbonate solution, effervescence occurs.
Which of the following compound may X be?
A
H
Reaction 3
acidified KMnO4
solution
concentrated H2SO4
B
H
acidified K2Cr2O7
solution
concentrated H2SO4
D
H
H
H
C
C
C
H
H
H
H
H
H
C
C
C
C
C
O
Part B
28 What are the reagents required for carrying out
Reactions 2 and 3?
The final stage in its manufacture is an
esterification.
OH
O
OH
H
C
B
H
D
H
H
C
C
H
H
O
C
O
H
C
C
H
H
O
H
O
C
H
H
H
C
C
H
H
B
43
31 Poly(ethylene terephthalate) (PET) is a polymer used
in making soft drink bottles. The flow diagram
below shows a route for the synthesis of PET.
CH3
COOH
Step 1
34 Plastic X has the following structure:
COOCH3
O
O
C
C
O
CH2
CH2
O
n
Step 2
Which of the following statements concerning X
is correct?
CH3
COOH
H2C
CH2
COOCH3
Step 3
Step 4
PET
HOCH2CH2OH
Which of the following types of reactions is NOT
involved in the synthesis route?
A
B
C
D
Dehydration
Esterification
Oxidation
Polymerization
A
A
B
C
D
It is a thermosetting plastic.
It is a condensation polymer.
It is formed from urea and methanal.
There are cross-links between the polymer
chains.
B
35 Which of the following statements concerning
nylon is correct?
A
B
C
D
It
It
It
It
is a thermosetting plastic.
contains ester linkages.
has cross-links between polymer chains.
is formed by condensation polymerization.
32 Which of the following combinations is correct?
Plastic
Part B
A
B
C
D
Uses
Polypropene
Polythene
Polystyrene
Urea-methanal
margarine tubs
disposable lunch boxes
clothing
fishing lines
A
D
Directions: Questions 36 and 37 refer to the following
experiment.
Ethene can be prepared by heating ethanol in the
set-up shown below.
CSPLFOQPSPVTQPU
33 The structure of polymer X is shown below.
H
CH3 H
CH3 H
CH3
C
C
C
C
H
CH3 H
DPUUPOXPPM
TPBLFEXJUIFUIBOPM
CPJMJOHUVCF
C
C
CH3 H
CH3
Which of the following statements concerning X
is INCORRECT?
A X is an addition polymer.
B X is a thermoplastic.
C X can be used to make the handle of a frying
pan.
D The monomer of X is methylpropene.
C
44
The reaction involved can be represented by the
equation:
CH3CH2OH(l)
CH2=CH2(g) + H2O(l)
36 The type of reaction involved in the preparation
is
A
B
C
D
addition.
condensation.
dehydration.
substitution.
C
37 Which of the set-ups shown below can be used
to collect the ethene produced?
40 Which of the following statements concerning
fractional distillation is / are correct?
(Relative atomic masses: H = 1.0, C = 12.0,
N = 14.0, O = 16.0)
(1) HBT
(1) The process involves a physical change.
(2) The process can convert large alkane
molecules to small alkane molecules.
(3) The process involves breaking and forming
of covalent bonds.
(2) HBT
XBUFS
A
B
C
D
(3) HBT
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
C
Directions: Questions 38 and 39 refer to polyethenol
which is used to cover dishwasher
tablets.
A section of the polyethenol polymer is shown
below.
CH
CH2
OH
CH
CH2
OH
CH2=CH(OH)
CH2=C(OH)2
CH(OH)=CH(OH)
C(OH)2=C(OH)2
(1) Biodegradation of animal faeces
(2) Treatment of car exhaust gas in a catalytic
converter
(3) Respiration of trees
A
B
C
D
OH
A
A
B
C
D
A
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
43 Which of the following statements concerning
acid rain are correct?
(1) Acid rain refers to rain with pH less than
5.6.
(2) One major air pollutant that causes the
formation of acid rain is carbon dioxide.
(3) Installing catalytic converters in motor
vehicles can help reduce acid rain
formation.
(1) It is an addition polymer.
(2) It is soluble in water.
(3) It contains carboxyl groups.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
(1) Rivers and lakes become more acidic
(2) The formation of photochemical smog
(3) A higher incidence of liver diseases
39 Which of the following statements concerning
polyethenol are correct?
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
42 Which of the following problems are caused by
excessive burning of fossil fuels?
CH
38 Which of the following compounds is a monomer
of polyethenol?
A
B
C
D
A
Part B
CH2
only
only
and (3) only
and (3) only
41 In which of the following processes will carbon
dioxide be produced?
TZSJOHF
A
B
C
D
(1)
(2)
(1)
(2)
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
45
44 Which of the following statements concerning
the measures to reduce air pollutants is / are
correct?
47 Propane reacts with bromine under suitable
conditions. Which of the following statements
concerning this reaction is / are correct?
(1) Scrubber can be used to reduce nitrogen
dioxide.
(2) Catalytic converter can be used to reduce
carbon monoxide.
(3) Electrostatic precipitator can be used to
reduce sulphur dioxide.
(1) The reaction occurs readily in the dark.
(2) The colour of the reaction mixture
fades.
(3) The reaction gives a mixture of carbon
compounds.
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
48 C10H22
H
H
O
C
C
C
H
OH
Part B
only
only
and (3) only
and (3) only
46
A
B
C
D
C8H18 + X
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
B
(1) Chlorine
(2) Acidified dilute potassium dichromate
solution
(3) Acidified dilute potassium permanganate
solution
C
(1) Petroleum is toxic.
(2) Petroleum interferes with the insulation
provided by the feathers of sea birds.
(3) Petroleum can cause the outbreak of fire
on the sea.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
catalyst
49 Which of the following substances can react with
propene?
46 Which of the following statements concerning
oil spillage on the sea are correct?
A
B
C
D
D
(1) It is a substitution reaction.
(2) It is an endothermic process.
(3) X is propene.
OH
(1) Carboxyl group
(2) Hydrogen group
(3) Hydroxyl group
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
Which of the following statements concerning
the above process is / are correct?
What functional group(s) does a lactic acid
molecule contain?
A
B
C
D
(1)
(2)
(1)
(2)
B
45 The structure of lactic acid is shown below.
H
A
B
C
D
D
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
50 Carbon compound X has the molecular formula
C 3H 4Cl 2. Which of the following statements
concerning X is / are correct?
(1) X has at least four possible structures.
(2) X must have a carbon-carbon double
bond.
(3) X can turn acidified dilute potassium
dichromate solution from orange to
green.
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
53 Consider the experimental set-up shown below:
XBUFSPVU
A
51 The structures of two compounds are shown
below.
SFGMVYDPOEFOTFS
XBUFSJO
X
Which of the following statements are correct?
(1) They are hydrocarbons.
(2) They are insoluble in water.
(3) X burns with a more sooty flame than
Y.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
[O]
CH3CHO
[O]
CH3COOH
(1) In order to produce a high yield of ethanoic
acid, an excess of oxidizing agent should
be used under reflux.
(2) Acidified potassium dichromate solution
can be used as the oxidizing agent.
(3) Ethanal can be distilled off as it is formed
because it has a lower boiling point than
either ethanol or ethanoic acid.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
IFBU
After refluxing for an hour, the reaction mixture
is poured into a beaker of sodium carbonate
solution. Which of the following would be
observed?
(1) Gas bubbles are given off.
(2) Two immiscible layers are formed.
(3) A pleasant smell is detected.
D
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
D
54 The structure of compound X is shown below:
Part B
Which of the following statements about this
oxidation of ethanol are correct?
A
B
C
D
BOUJCVNQJOH
HSBOVMFT
A
52 Ethanal and ethanoic acid can be produced by
the sequence of reactions shown below.
C2H5OH
FUIBOPMFUIBOPJDBDJE
DPODFOUSBUFETVMQIVSJDBDJE
Y
OH
HOOCCH2C(CH3)CH2CH2OH
Which of the following statements about X are
correct?
(1) It contains one carboxyl group.
(2) It contains three hydroxyl groups.
(3) It can be esterified both by ethanoic
acid and by ethanol, in the presence of
concentrated sulphuric acid.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
47
55 Which of the following processes require a
catalyst?
(1) Fermentation of glucose to give ethanol
(2) Oxidation of ethanol to ethanoic acid
(3) Preparation of ethyl ethanoate from
ethanoic acid and ethanol
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
59 Teflon is a plastic that can be used to make
artificial hip joints. The repeating unit of Teflon
is shown below.
B
56 Which of the following statements concerning
thermoplastics are correct?
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
Part B
(1) Handles of electric irons
(2) Wallpapers
(3) Advertising displays
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
B
C
D
D
A
B
C
D
48
CH3
F
F
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
B
61 Condensation polymerization differs from addition
polymerization in that
(1) it involves the elimination of small
molecules.
(2) the monomers are unsaturated.
(3) cross-links are formed between polymer
chains.
CH3 H
H
C
(1) They are non-flammable.
(2) They can be moulded many times.
(3) They do not conduct electricity.
(1) X is a thermoplastic.
(2) X is an electrical insulator.
(3) The repeating unit of X is as shown
below:
C
C
60 Which of the following statements concerning
thermosetting plastics are correct?
58 The monomer of polymer X is methylpropene.
Which of the following statements concerning
X are correct?
C
F
(1) It is an addition polymer.
(2) It is a thermoplastic.
(3) The monomer of Teflon is
1,2-difluoroethene.
57 Which of the following items is / are made of
thermoplastics?
A
B
C
D
F
Which of the following statements concerning
Teflon are correct?
(1) They soften upon heating.
(2) Covalent bonds exist in them.
(3) They are all soft and flexible.
A
B
C
D
A
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
62 Which of the following statements concerning
nylon and urea-methanal are correct?
Which of the following statements are correct?
(1) The monomer contains two functional
groups.
(2) PHB is a condensation polymer.
(3) Water molecules are released during the
formation of PHB.
(1) They are thermosetting plastics.
(2) They are condensation polymers.
(3) They are nitrogen-containing
compounds.
A
B
C
D
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
C
63 Polymer A is made using the two monomers
shown below:
H2N(CH2)6NH2
amine X
A
B
C
D
(1) Plastic waste are decomposed by
microorganisms readily.
(2) The process does not cause much air
pollution.
(3) The process helps conserve non-renewable
petroleum.
Which of the following statements is / are
correct?
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
B
66 Which of the following is / are advantage(s) of
using incineration to treat plastic waste?
A
(1) The process produces energy.
(2) The process causes no air pollution.
(3) The cost of operating a controlled
incineration plant is low.
64 PHB stands for polyhydroxybutanoate. The
formation of PHB from its monomer is shown
below.
monomer
2HOCH2CH2CH2COOH
Part B
A
B
C
D
D
65 Which of the following is / are advantage(s) of
landfilling plastic waste?
HOOC(CH2)4COOH
acid Y
(1) The systematic name of amine X is hexane1,6-diamine.
(2) The systematic name of acid Y is butan1,4-dioic acid.
(3) Polymer A is a polyester.
(1) and (2) only
(1) and (3) only
(2) and (3) only
(1), (2) and (3)
A
B
C
D
(1)
(2)
(1)
(2)
only
only
and (3) only
and (3) only
A
HOCH2CH2CH2COOCH2CH2CH2COOH
repeated reaction
CH2CH2CH2
COO
n
49
Directions :
A
B
C
D
Each question (Questions 67 – 80) consists of two separate statements. Decide whether each
of the two statements is true or false; if both are true, then decide whether or not the second
statement is a correct explanation of the first statement. Then select one option from A to D
according to the following table :
Both statements are true and the 2nd statement is a correct explanation of the 1st statement.
Both statements are true but the 2nd statement is NOT a correct explanation of the 1st statement.
The 1st statement is false but the 2nd statement is true.
Both statements are false.
1st statement
Part B
50
2nd statement
67 Fractional distillation of petroleum is a physical
change.
There is a gradual change in physical properties B
as the number of carbon atoms in molecules of
hydrocarbons in petroleum fractions increases.
68 Kerosene has a supply that outweighs the
demand in modern society.
Fractional distillation of kerosene can produce
petrol which has a high demand.
D
69 The exhaust gas of diesel engine contains a
higher concentration of particulates than that of
petrol engine.
Compared with petrol, diesel has a higher
carbon content and incomplete combustion
of it gives a greater amount of particulates.
A
70 The boiling point of butane is higher than that
of ethane.
Van der Waals’ forces between butane
molecules are stronger than those between
ethane molecules.
A
71 Ethane and chlorine can react when exposed to
sunlight.
Energy is required to split the chlorine
molecules into free radicals for the reaction.
A
72 Propene can be manufactured by fractional
distillation of petroleum.
Fractional distillation of petroleum convert
large alkane molecules to smaller alkane
molecules and alkene molecules.
D
73 Propan-1-ol is more volatile than ethanol.
The volatility of the members of a homologous
series increases with relative molecular mass.
D
74 To prepare propanal, heat propan-1-ol and
acidified potassium dichromate solution under
reflux.
Acidified potassium dichromate solution
oxidizes propan-1-ol in the reaction.
C
75 To prepare methyl ethanoate, heat ethanol,
methanoic acid and concentrated sulphuric acid
under reflux.
An esterification reaction occurs when ethanol,
methanoic acid and concentrated sulphuric
acid are heated under reflux.
C
76 Propan-1-ol and propanoic acid can be
distinguished by mixing with sodium
hydrogencarbonate solution.
Effervescence occurs when propanoic acid is
mixed with sodium hydrogencarbonate solution
while there is no observable change for
propan-1-ol.
A
77 Thermosetting plastics contain strong covalent
bonds while thermoplastics do not.
Thermosetting plastics are formed via addition
polymerization while thermoplastics are not.
D
78 Thermoplastics are biodegradable while
thermosetting plastics are non-biodegradable.
There are cross-links between polymer chains
in thermosetting plastics.
C
79 Thermoplastics are used for making the handle
of frying pans.
The shape of a thermoplastic handle remains
unchanged during the frying process.
D
80 The rigidity of PVC can be reduced by the
addition of plasticizers.
Van der Waals’ forces exist between PVC
polymer chains.
B
Part B
51
Short questions
81 Petroleum is a mixture of mostly hydrocarbons. The hydrocarbons can be divided into three major classes as
listed in the table below.
Complete the table by giving the structural formula and systematic name of one example in each class.
(6 marks)
Example
Class
Structural formula
Systematic name
any alkane
name of the alkane shown
Alkanes
(1)
H
H
C
Part B
H
Cycloalkanes
H
H
H
C
C
H
H
C
C
H
H
H
H
H
C
H
C
H
C
C
H
C
H
cyclopentane /
cyclohexane /
name of the cycloalkane shown
/
C
H
H
(1)
H
H
H
/ other appropriate cycloalkane
(1)
(1)
H
H
H
Aromatic
hydrocarbons
H
H
C
H
C
C
C
C
C
H
H
C
C
C
H
H
benzene /
methylbenzene /
name of the aromatic
hydrocarbon shown
H
C
C
/
H
C
C
H
H
/ other appropriate aromatic hydrocarbon
(1)
52
(1)
82 Complete the following figure on the name, properties and use(s) of each main petroleum fraction.
(18 marks)
/BNFPG
GSBDUJPO
SFGJOFSZHBTFT
GSBDUJPOBUJOH
UPXFS
QFUSPM
OBQIUIB
6TFT
#PJMJOHQPJOU /VNCFSPGDBSCPO
SBOHFž$
BUPNTQFSNPMFDVMF
PGIZESPDBSCPOJO
FBDIGSBDUJPO
CFMPX
m
m
BTHBTFPVTGVFM
BTGVFMGPSDBST
m
NBOVGBDUVSJOHUPXOHBT LFSPTFOF
m
mŞ
BTGVFMGPSBJSDSBGU
EPNFTUJDGVFM
EJFTFMPJM
mŞ
m
BTGVFMGPSIFBWZWFIJDMFTGBDUPSJFT
ž$
GVFMPJM
PWFS
BCPWF
BTGVFMGPSTIJQTQPXFSTUBUJPOT
QFUSPMFVN
MVCSJDBUJOH
PJMBOEXBY
GVSOBDF
BTMVCSJDBUJOHPJMGPSNBDIJOFT
NBLJOHDBOEMFT
TVSGBDJOHSPBETSPPGT
CJUVNFO
Structure
(a)
H
H
CH3 CH3
C
C
C
H
H
CH3
H
Part B
83 Write down the IUPAC name of each of the following compounds.
(10 marks)
IUPAC name
2,3-dimethylbutane
(1)
(b)
benzene
(1)
53
Structure
(c)
H
H
H
H
H
C
C
C
C
H
H
H
O
IUPAC name
H
butan-1-ol
H
(1)
CH3
(d)
H
(e)
H
(f)
H
(g)
Cl
Part B
(h)
H
H
CH2
C
C
H
OH
H
H
O
C
C
C
H
H
H
CH3 O
C
C
H
H
H
H
C
C
H
H
H
H
H
H
C
C
C
C
H
H
Br
H
(i)
2-methylbutan-2-ol
CH3
(1)
propanal
H
(1)
C
O
H
methylpropanoic acid
(1)
chloroethane
H
(1)
H
2-bromobutane
(1)
Cl
C
H3C
2-chloro-2-methylbutane
CH3
C2H5
(j)
H
(1)
H
H
Br
C
C
C
H
H
C
H
H
54
3-bromobut-1-ene
(1)
84 From the information listed, give the structural formula and systematic name of each carbon compound. All
of the compounds consist of molecules which have four carbon atoms.
(8 marks)
(a) A hydrocarbon that rapidly decolorizes
bromine dissolved in an organic solvent
Any one of the following:
• CH3CH2CH=CH2 (1), but-1-ene (1)
• CH3CH=CHCH3 (1), but-2-ene (1)
CH3
l
• CH3C=CH2 (1), methylpropene (1)
(b) An alkanol
Any one of the following:
• CH3CH2CH2CH2OH (1), butan-1-ol (1)
OH
l
• CH3CH2CHCH3 (1), butan-2-ol (1)
CH3
l
• CH3CHCH2OH (1), methylpropan-1-ol (1)
(c) An alkanoic acid
Any one of the following:
• CH3CH2CH2COOH (1), butanoic acid (1)
CH3
l
• CH3CHCOOH (1), methylpropanoic acid (1)
(d) A hydrocarbon that reacts with chlorine only
when exposed to sunlight
Any one of the following:
• CH3CH2CH2CH3 (1), butane (1)
CH3
l
• CH3CHCH3 (1), methylpropane (1)
Part B
85 The photograph below shows a burning candle. It burns with a yellow flame.
a) What type of compounds is mainly present in the candle wax?
Alkanes
(1 mark)
(1)
55
b) Why does the candle burn with a yellow flame?
(2 marks)
The candle burns with a yellow flame due to incomplete combustion.
(1)
The yellow colour of the flame is due to the presence of tiny carbon particles.
(1)
c) Why is it dangerous to add cold water to a tray containing molten wax at a high temperature?
(2 marks)
The hot molten wax causes the water to vaporize rapidly.
(1)
The steam will cause the molten wax to spurt out.
(1)
86 In Hong Kong, the older public light buses use diesel fuel. However, the newer ones use liquefied petroleum
gas (LPG).
a) What is the source of these fuels?
(1 mark)
Petroleum
(1)
b) Explain why LPG burns with a clearer flame than diesel.
(2 marks)
Part B
LPG contains hydrocarbons with a smaller number of carbon atoms in their molecules.
(1)
It burns more completely than diesel.
(1)
87 For each of the following experiments, state the expected observation and write a relevant chemical
equation.
a) Passing ethene into cold acidified dilute potassium permanganate solution
The purple solution of cold acidified dilute potassium permanganate becomes colourless quickly.
H
H
56
C
C
H
H
(g) + [O] + H2O(l)
H
H
H
C
C
O
O
H
H
(2 marks)
(1)
H(aq)
(1)
b) Passing propene into bromine dissolved in an organic solvent
(2 marks)
The orange solution of bromine becomes colourless quickly.
H
H
H
H
C
C
C
(1)
H
H(g) + Br2 (in organic solvent)
H
H
H
H
C
C
C
H
Br
Br
H (in organic solvent)
(1)
c) Exposing a mixture of propane and bromine vapour to sunlight
(2 marks)
The reddish brown colour of the mixture fades.
(1)
C3H8(g) + Br2(g)
(1)
C3H7Br(l) + HBr(g)
88 Five structures of alkanols with the same molecular formula, C4H10O, are shown below.
H
H
CH3
C
C
H
CH3
H
OH
H
CH3
C
C
H
OH
CH3 H
H
H
CH3
C
C
C
H
H
H
B
A
H
H
H
C
C
C
C
H
H
H
H
OH
C
H
H
CH3 H
C
C
C
H
H
H
D
a) Name the functional group present in the alkanols.
Hydroxyl group
b) Name alkanols A and B.
OH
Part B
H
H
OH
E
(1 mark)
(1)
(2 marks)
A
methylpropan-2-ol
(1)
B
butan-2-ol
(1)
c) Which TWO of the structures, A to E, represent the same alkanol?
B and C (both parts must be correct for 1 mark)
(1 mark)
(1)
57
d) Draw the structure and give the systematic name of the organic product formed in each of the following
reactions.
i) Heating alkanol D and acidified potassium dichromate solution under reflux
H
H
H
H
O
C
C
C
C
H
H
H
(2 marks)
OH
(1)
butanoic acid
(1)
ii) Heating alkanol E and ethanoic acid in the presence of concentrated sulphuric acid
O
CH3
C
O
H
CH3 H
C
C
C
H
H
H
(2 marks)
H
(1)
2-methylpropyl ethanoate
(1)
89 Analysis shows that a compound has a molecular formula C4H8O2. It is known that the compound could be
either X or Y.
CH3CH2CH2COOH
X
or
HOCH2CH=CHCH2OH
Y
a) Describe ONE test which would give a positive result for X but NOT for Y.
(2 marks)
Any one of the following:
Part B
•
•
Add solid sodium hydrogencarbonate (or solution).
(1)
X gives a gas that turns limewater milky.
(1)
Use blue litmus paper / pH paper for testing.
(1)
X turns blue litmus paper / turns pH paper orange (or red).
(1)
b) Describe ONE test which would give a positive result for Y but NOT for X.
(2 marks)
Any one of the following:
•
•
•
58
Add bromine dissolved in an organic solvent.
(1)
Y turns the solution of bromine from orange to colourless quickly.
(1)
Add cold acidified dilute potassium permanganate solution.
(1)
Y turns the permanganate solution from purple to colourless quickly.
(1)
Heat with acidified potassium dichromate solution.
(1)
Y turns the dichromate solution from orange to green.
(1)
90 Each of the products listed in the table below can be made by using material A or B.
Materials
Product
(i)
Toy bicycles
(ii) Sheets for packaging
(iii) Drain pipes
(iv) Lenses
(v) Gear wheel
A
B
polypropene
mild steel
polythene
paper
polyvinyl chloride
iron
Perspex
glass
nylon
steel
In each case, state an advantage of
a) using A over B to make the product.
b) using B over A to make the product.
(You are NOT required to consider the price of the materials.)
Product
(i)
Toy bicycles
(10 marks)
Advantage of using A over B
Polypropene
• is lighter in weight.
• does not corrode easily.
• is self-coloured.
• has no sharp edges.
any one
(1)
Advantage of using B over A
Mild steel is stronger.
(1)
(iii) Drain pipes
PVC
• does not corrode
easily.
• can be shaped more
easily.
Paper
• is biodegradable.
• can be made from
renewable materials.
any one
(1)
any one
(1)
Part B
(ii) Sheets for packaging
Polythene is
• more durable.
• stronger.
• waterproof.
any one
(1)
Iron is stronger.
(1)
(iv) Lenses
Perspex is
• not easily broken.
• lighter in weight.
any one
(1)
Glass is not easily scratched.
(1)
59
Product
(v) Gear wheel
Advantage of using A over B
Nylon
• is lighter in weight.
• does not corrode easily.
• needs no lubricant.
• can be moulded into
different shapes easily.
any one
(1)
Advantage of using B over A
Steel
• is stronger.
• can withstand higher
temperatures.
any one
(1)
91 Explain the following:
a) To keep the house warm in a winter night, Joe shut all the windows and turned the paraffin heater up
high. He was found dead the next morning.
(2 marks)
There was insufficient oxygen for the fuel to burn completely. Carbon monoxide formed due to incomplete combustion
of fuel.
(1)
Carbon monoxide is a very poisonous gas.
(1)
b) Heptadecane (C17H36) found in diesel oil is more viscous than heptane (C7H16) found in petrol. (3 marks)
A heptadecane molecule has a larger molecular mass / size (or a greater number of electrons) than a heptane
molecule.
(1)
Therefore heptadecane has stronger van der Waals’ forces than heptane.
(1)
Part B
Also heptadecane molecules in the form of long chains can become entangled. Hence the relative motion between the
molecules will be hindered.
(1)
Therefore heptadecane is more viscous than heptane.
c) Alkanes are insoluble in water.
There are strong attractions between water molecules.
(2 marks)
(1)
The weak attractions between molecules of alkanes and water are not strong enough to overcome the strong
attractions between water molecules.
d) Ethyl ethanoate can dissolve iodine but cannot dissolve sodium iodide.
60
(1)
(3 marks)
Weak van der Waals’ forces exist between iodine molecules.
(1)
Strong ionic bonds exist between sodium ions and iodide ions in sodium iodide.
(1)
Strength of attraction between iodine molecules is similar to those between ethyl ethanoate molecules.
(1)
Hence iodine molecules and ethyl ethanoate molecules mix together easily.
e) Explain, in terms of bonding, why objects made of polythene are durable.
(1 mark)
Polythene is a hydrocarbon with C–C and C–H bonds. These bonds are strong / not readily attacked by chemicals.
(1)
Structured questions
92 Petroleum is an important fossil fuel.
a) How was petroleum formed in nature?
(2 marks)
Petroleum was formed from dead remains of marine animals and plants that lived millions of years ago.
(1)
High temperature, high pressure and bacterial action gradually changed the remains into petroleum.
(1)
Hydrocarbon
Formula
Boiling point (°C)
Pentane
C5H12
36
Hexane
C6H14
69
Heptane
C7H16
99
Octane
C8H18
126
i) What is a ‘hydrocarbon’?
A hydrocarbon is a compound which contains only atoms of hydrogen and carbon.
ii) State what is meant by the term ‘saturated’, as applied to hydrocarbons.
Part B
b) In an oil refinery, petroleum is separated into several fractions. One of these is the petrol fraction. This
fraction contains the saturated hydrocarbons shown in the table.
(1 mark)
(1)
(1 mark)
A hydrocarbon in which all the carbon atoms are connected to each other by single bonds is a saturated
hydrocarbon.
(1)
61
iii) Why does octane have a higher boiling point than the other compounds shown in the table?
(1 mark)
The van der Waals’ forces between octane molecules are stronger than those between molecules of the other
compounds.
(1)
iv) Write a chemical equation for the complete combustion of pentane.
C5H12(g) + 8O2(g)
(1 mark)
5CO2(g) + 6H2O(l)
(1)
v) Which compound, pentane or octane, will burn with a more sooty flame? Explain your answer.
(2 marks)
Octane will burn with a more sooty flame.
(1)
Octane has a higher percentage of carbon by mass. Its possibility of undergoing incomplete combustion to give
carbon is higher.
(1)
vi) Petrol contains a mixture of the hydrocarbons shown in the table. Different mixtures of these hydrocarbons
are used in petrol sold in winter compared to that sold in summer.
Explain why the petrol mixture used in summer is different from that used in winter.
(2 marks)
To prevent excessive vaporization of petrol at high temperatures in summer,
(1)
the petrol must contain more hydrocarbons with a greater number of carbon atoms in their molecules.
(1)
OR
Part B
To ensure adequate vaporization at low temperatures in winter,
(1)
the petrol must contain more hydrocarbons with a smaller number of carbon atoms in their molecules.
(1)
c) Apart from as fuels for transportation, suggest THREE other uses of refined petroleum.
(3 marks)
•
As fuels for generating electricity
(1)
•
As fuels for heating
(1)
•
As raw materials in the petrochemical industry
(1)
93 Petroleum can be separated into different products such as petrol, diesel oil and fuel oil by process A. The
fuel oil obtained can then be converted into smaller molecules by another process B.
a) Name process A and process B.
62
(2 marks)
A
fractional distillation
(1)
B
cracking
(1)
b) State the two physical changes which occur during process A.
(2 marks)
Change 1 liquid to gas / boiling / vaporization
(1)
Change 2 gas to liquid / condensation
(1)
c) Suggest ONE use of each of the following petroleum products.
(2 marks)
i) Diesel oil
As fuel for heavy vehicles / factories
(1)
ii) Fuel oil
As fuel for ships / power stations
(1)
d) State THREE properties in which you would expect petrol and diesel oil to differ from one another.
(3 marks)
Any three of the following:
•
boiling point range
(1)
•
colour
(1)
•
viscosity
(1)
•
volatility
(1)
•
flammability
(1)
•
clearness of flame when burnt
(1)
Explain the environmental benefits of using biodiesel as a sustainable fuel.
Part B
e) Diesel obtained from petroleum is often called fossil diesel. Biodiesel can be made from many vegetable
oils.
(2 marks)
Any two of the following: • Biodiesel is renewable. (1) / • Use less fossil fuels / diesel. (1) / • Use waste oil. (1) /
• Biodiesel is more biodegradable. (1) / • Biodiesel does not contain sulphur which causes the formation of acid rain. (1) /
• Biodiesel burns with a less sooty flame. (1) / • The exhaust gas produced does not contribute much to global
warming (burning biodiesel returns carbon dioxide which has only recently been removed from the atmosphere during
the photosynthesis of plants). (1)
63
94 Petroleum is a fossil fuel. The following experimental set-up is used to separate a sample of petroleum into
different fractions.
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ž$mž$
NJOFSBMXPPM
TPBLFEXJUI
QFUSPMFVN
EFMJWFSZUVCF
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IFBU
DPMEXBUFS
GSBDUJPOPCUBJOFE
a) Why is petroleum considered as a fossil fuel?
(1 mark)
Petroleum originates from dead remains of marine animals and plants that lived millions of years ago.
b) i) Name the process shown in the above diagram.
(1)
(1 mark)
Fractional distillation
ii) Why can petroleum be separated into different fractions by this process?
(1)
(1 mark)
It is because the components in petroleum have different boiling points.
Part B
c) i) What is the function of cold water in the experimental set-up?
(1)
(1 mark)
To condense the vapour given off into liquid.
ii) Why should the thermometer be placed exactly next to the opening of the delivery tube?
(1)
(1 mark)
To ensure that the temperature measured is exactly the boiling point of the vapour leaving the boiling tube.
iii) Suggest TWO safety precautions for carrying out the process in the laboratory.
(1)
(2 marks)
Any two of the following: • Wear safety glasses and protective gloves. (1) / • Ensure good ventilation in the
laboratory. (1) / • Avoid skin contact with the petroleum and its fractions as they may contain harmful substances. (1) /
• Ensure secure clamping of the apparatus. (1) / • Be careful of burns. (1) /
• Avoid heating the mineral wool with a stationary hot flame. (1)
64
d) Two fractions, A and B, are collected at 100 °C and 250 °C respectively. State how these two fractions
differ in
i) the sootiness of flame when burnt;
(1 mark)
Fraction A burns with a less sooty flame than fraction B.
ii) viscosity;
(1)
(1 mark)
Fraction A is less viscous than fraction B.
iii) size of molecules.
(1)
(1 mark)
Molecules in fraction A are smaller than those in fraction B.
e) Suggest TWO advantages of using petroleum over other energy sources.
(1)
(2 marks)
Any two of the following: • Petroleum is readily available at a relatively cheap price. (1) /
• The production of electricity from petroleum is not dependent on the time of day, weather variations or seasonal effects. (1) /
• Petroleum can be transported easily by pipeline, ship, road and rail. (1) / • Petroleum can be used to power cars. (1) /
• Petroleum can be refined to provide raw materials for the production of other products, such as plastics. (1)
f) Many countries are developing alternative energy sources.
i) Suggest THREE reasons for this action.
(3 marks)
Any three of the following:
Burning of petroleum produces a lot of air pollutants.
(1)
•
The resource of petroleum is limited.
(1)
•
Supply and price of petroleum may be unstable in times of political unstability in petroleum-producing
•
countries.
(1)
Petroleum spills during drilling or transport cause major damage to ecosystems both on land and at sea.
(1)
Part B
•
ii) Biogas containing a high proportion of methane can be obtained from organic waste, an alternative
energy source.
(1) Suggest ONE organic waste that can be used for this purpose.
Livestock manure
(1)
(2) Write a chemical equation for the complete combustion of methane.
CH4(g) + 2O2(g)
(1 mark)
CO2(g) + 2H2O(l)
(1 mark)
(1)
65
(3) Suggest ONE advantage and ONE disadvantage of using organic waste as an energy source.
(2 marks)
Advantage:
•
Biogas burns completely and produces no soot.
(1)
Disadvantage:
•
It reduces the amount of manure which can be used as fertilizers.
(1)
95 Fractional distillation of petroleum gives different petroleum fractions. The table below lists the length of
carbon chain of the alkanes in some of the fractions.
Fraction
Length of carbon chain
Petrol
C5 – C10
Kerosene
C10 – C14
X
C14 – C25
a) Describe briefly what happens inside the fractionating towers in an oil refinery.
(4 marks)
Petroleum is first heated to about 400 °C in a furnace. The petroleum is turned into a mixture of liquid and vapour. The
Part B
mixture is then pumped into a fractionating tower.
(1)
The liquid portion flows to the bottom of the tower and is collected as residue.
(1)
The higher levels of the tower are cooler than the lower levels.
(1)
The vapour portion rises up the tower and as it cools it turns back to liquid, collecting in trays at various heights.
(1)
b) Suggest ONE use of kerosene.
(1 mark)
As fuel for aircraft / as domestic fuel
(1)
c) Suggest ONE use of fraction X.
(1 mark)
As fuel for heavy vehicles / factories
(1)
d) In an oil refinery, one of the compounds in fraction X, C24H50, is cracked as shown in the equation
below.
C24H50
C16H34 + 2Y
i) What is the meaning of the term ‘cracking’?
Cracking is the breaking down of larger hydrocarbon molecules to produce smaller hydrocarbon molecules.
66
(1 mark)
(1)
ii) Account for the importance of cracking in petrochemical industry.
(2 marks)
Producing extra petrol
(1)
As a source of alkenes
(1)
iii) Suggest a possible structure of Y, and give its systematic name.
(2 marks)
Any one of the following:
•
CH3CH2CH=CH2
(1)
but-1-ene
(1)
•
CH3CH=CHCH3
(1)
but-2-ene
(1)
(1)
methylpropene
(1)
CH3
•
CH3C=CH2
iv) Suggest a chemical test to distinguish Y from C16H34. State your expected observations.
(3 marks)
Any one of the following:
•
•
(1)
The orange solution of bromine becomes colourless quickly when mixed with Y.
(1)
The orange solution of bromine becomes colourless slowly when mixed with C16H34 under sunlight.
(1)
Mix with cold acidified dilute potassium permanganate solution.
(1)
The purple solution of potassium permanganate becomes colourless quickly when mixed with Y.
(1)
There is no observable change for C16H34.
(1)
Burn Y and C16H34 separately.
(1)
Y gives less dark smokes.
(1)
C16H34 gives more dark smokes.
(1)
Part B
•
Mix with bromine dissolved in an organic solvent.
96 The diagram shows some of the processes involved in the carbon cycle.
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67
a) i) Name processes A, B and C.
(3 marks)
A
photosynthesis
(1)
B
respiration
(1)
C
combustion / burning
(1)
ii) Name rock D.
(1 mark)
Limestone / chalk / marble
(1)
b) i) Name a combination of TWO processes which could allow carbon dioxide to be taken out of the
atmosphere and returned to it within a few days.
(1 mark)
Photosynthesis and respiration / combustion (both parts must be correct for 1 mark)
(1)
ii) Name a combination of TWO processes which could lead to carbon being taken out of the circulation
for millions of years.
(1 mark)
Photosynthesis and fossil fuel formation (1) OR
Solution in water and limestone formation (1) (both parts must be correct for 1 mark)
c) Carbon dioxide is a major greenhouse gas. The presence of greenhouse gases in the atmosphere is
important to life on Earth. However, too much greenhouse gases in the atmosphere can cause global
warming, which may lead to severe environmental consequences.
i) State the importance of greenhouse gases to life on Earth.
(3 marks)
Part B
The Earth receives energy from incoming sunlight and radiates energy back into space.
(1)
Greenhouse gases can trap some of the infrared energy / heat radiated back into space.
(1)
The heat keeps the atmosphere warm for life to sustain on Earth.
(1)
ii) State ONE severe environmental consequence associated with global warming.
(1 mark)
Increase in temperature of the atmosphere can cause melting of polar ice caps / flooding / change in rainfall
pattern.
(1)
iii) Suggest TWO possible ways to prevent further increase in the concentration of carbon dioxide in the
atmosphere without sacrificing our present standard of living.
(2 marks)
Any two of the following:
68
•
Reduce the use of fossil fuel by using alternative energy sources to generate electricity, e.g. wind energy.
(1)
•
Use hydrogen as fuel in fuel cells for cars.
(1)
•
Stop cutting down or burning forests.
(1)
•
Plant more trees.
(1)
97 The combustion of petrol in a car can lead to the formation of carbon monoxide and nitrogen monoxide.
a) Write an equation for the incomplete combustion of the hydrocarbon nonane (C9H20) to give carbon
monoxide and water as the only products.
(1 mark)
2C9H20(g) + 19O2(g)
18CO(g) + 20H2O(l)
b) i) State ONE essential condition for the formation of nitrogen monoxide from air in a car.
High temperature / spark
(1 mark)
(1)
ii) Write a chemical equation for the reaction in which nitrogen monoxide is formed.
N2(g) + O2(g)
(1)
2NO(g)
(1 mark)
(1)
c) The exhaust gas of a car contains also unburnt hydrocarbons and particulates. State ONE potential health
hazard associated with each of the air pollutants.
i) Unburnt hydrocarbons
(1 mark)
They may cause cancer.
(1)
ii) Particulates
(1 mark)
Irritate the respiratory system.
(1)
d) A catalytic converter may be fitted to the car exhaust system to reduce the emission of air pollutants.
Part B
i) Explain, with the aid of chemical equations, how the emission of carbon monoxide and nitrogen
monoxide is reduced.
(4 marks)
Nitrogen monoxide reacts with carbon monoxide as they pass through the catalyst in a catalytic converter. Nitrogen
and carbon dioxide are formed.
catalyst
2CO(g) + 2NO(g)
N2(g) + 2CO2(g)
The excess carbon monoxide is oxidized to carbon dioxide by air.
2CO(g) + O2(g)
catalyst
2CO2(g)
(1)
(1)
(1)
(1)
ii) Explain, with the aid of a chemical equation, how the emission of unburnt hydrocarbons is reduced.
(2 marks)
The unburnt hydrocarbons are oxidized to water and carbon dioxide by air.
2C8H18(l) + 25O2(g)
catalyst
16CO2(g) + 18H2O(l)
(1)
(1)
octane
69
e) Do you agree with the following statement? Explain your answer.
‘The exhaust gas of a diesel engine contains a higher concentration of particulates than that of a petrol
engine.’
(2 marks)
Yes.
The hydrocarbons in diesel contain a much higher percentage of carbon by mass.
(1)
Incomplete combustion will give a greater amount of particulates.
(1)
98 The following diagram shows the formation of acid rain.
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OJUSPHFO
Part B
a) i) Explain how oxides of nitrogen are formed inside car engines.
(1 mark)
Inside the car engine, the air gets so hot that nitrogen and oxygen react together, forming oxides of nitrogen.
ii) Suggest ONE effect of oxides of nitrogen on health.
(1 mark)
Irritate and attack the respiratory system / the lungs.
iii) Explain, with the aid of a chemical equation, how nitrogen dioxide leads to acid rain.
70
(1)
(1)
(2 marks)
Nitrogen dioxide reacts with rainwater to form acids that lower the pH of rainwater. This gives rise to acid rain.
(1)
2NO2(g) + H2O(l)
(1)
HNO3(aq) + HNO2(aq)
iv) Suggest a device that can be installed in motor cars to reduce the emission of oxides of nitrogen.
(1 mark)
Catalytic converter
(1)
b) i) Explain why sulphur dioxide is present in power station gas.
(1 mark)
Power stations burn either coal or low-grade petroleum, both containing sulphur. When these fuels are burnt, they
give off sulphur dioxide to the air.
ii) Explain, with the aid of a chemical equation, how sulphur dioxide leads to acid rain.
(1)
(2 marks)
Sulphur dioxide reacts with rainwater to form sulphurous acid. The acid lowers the pH of rainwater. This gives rise
to acid rain.
SO2(g) + H2O(l)
(1)
H2SO3(aq)
(1)
iii) Suggest a device that can be installed in power stations to reduce the emission of sulphur dioxide.
(1 mark)
Flue gas desulphurization system / scrubber
c) State TWO undesirable effects of acid rain.
(1)
(2 marks)
Any two of the following:
•
It can cause surface waters and lakes to become too acidic.
(1)
•
Acid rain can cause damage to plants, including crops and forests.
(1)
•
Acid rain also damages metal / limestone structures.
It corrodes metals / wears away the limestone.
Part B
This is harmful to water lives and even kills them.
(1)
d) i) Some scientists believe that we should use more wind energy rather than continuing to burn fossil
fuels as much as we do now.
Suggest TWO reasons for this.
(2 marks)
Any two of the following:
•
Wind energy is a renewable energy source and hence will not run out like fossil fuels.
(1)
•
Wind energy produces no carbon dioxide and hence does not add to greenhouse effect.
(1)
•
Wind energy produces no sulphur dioxide and hence does not add to acid rain.
(1)
•
Less environmental impact of extraction / transport of fuels due to the decreasing use of fossil fuels.
(1)
71
ii) The picture shows a poster put up by a group of people protesting against a plan to build a
windfarm.
OFFSHORE
NOT
ONSHORE
NO WINDFARM NEXT TO OUR HOMES!
(1) Suggest TWO reasons why some people are against windfarms.
(2 marks)
Any two of the following:
Part B
•
Noise which may cause disturbance / stress.
(1)
•
Visual impact may deter tourists / spoil landscape beauty.
(1)
•
Risks to wildlife, e.g. bird strike.
(1)
•
Disruption to TV signals by interference.
(1)
(2) Suggest ONE reason why the protesters may think that it is better to build windfarms offshore
rather than on land.
(1 mark)
Any one of the following:
•
Further away from people (hence reduction of noise, visual impact, etc.)
(1)
•
Higher wind speeds / more wind
(1)
99 Carbon dioxide and methane are two major greenhouse gases in the atmosphere. The table below shows
the average concentrations of the two gases in the atmosphere in 1900 and in 2000.
Gas
72
Average concentration in the atmosphere (arbitrary units)
Year 1900
Year 2000
Carbon dioxide
300 000
400 000
Methane
1 000
2 000
a) Suggest TWO reasons why there was a large increase in concentration of carbon dioxide in the atmosphere
in the past ten decades.
(2 marks)
The number of motor vehicles increases rapidly. Burning large amount of petrol / diesel produces carbon dioxide.
(1)
The rapid growth in population leads to deforestation, providing more land for housing. Less carbon dioxide is removed
from the atmosphere by photosynthesis.
(1)
b) Suggest ONE reason why there was a large increase in concentration of methane in the atmosphere in
the past ten decades.
(1 mark)
There is an increase in the number of rice paddies / cattle. The manure / remains decay to give methane.
c) Explain why carbon dioxide and methane can cause greenhouse effect.
(1)
(2 marks)
The Earth receives energy from incoming sunlight and radiates energy back into space.
(1)
Carbon dioxide and methane in the atmosphere can trap some of the infrared energy / heat radiated back into space. (1)
d) Too much greenhouse gases in the atmosphere can cause global warming. An increase in the Earth’s
temperature causes carbon dioxide to be given off from oceans.
Suggest why carbon dioxide is released from oceans when they become warmer.
(1 mark)
higher temperatures.
Part B
Carbon dioxide is less soluble in oceans at higher temperatures. / The respiration of marine organisms increases at
(1)
e) Suggest ONE possible way to prevent further increase in the concentration of each of the following
greenhouse gases in the atmosphere without sacrificing our present standard of living:
i) Carbon dioxide
(1 mark)
Any one of the following:
• Reduce the use of fossil fuel by using alternative energy sources to generate electricity, e.g. wind energy. (1) /
• Use hydrogen as fuel in fuel cells for cars. (1) / • Stop cutting down or burning forests. (1) / • Plant more trees. (1)
ii) Methane
Use natural gas / methane from biomass as a fuel.
(1 mark)
(1)
73
100 Both pentane (C5H12) and decane (C10H22) are members of the same homologous series.
a) Using pentane and decane as examples, illustrate TWO characteristics of the members of a homologous
series.
(4 marks)
Any two of the following:
•
Members of the same homologous series have the same general formula.
(1)
The general formula for pentane and decane is CnH2n+2. / Each member in a homologous series differs from the
•
•
next by a –CH2– unit.
(1)
Members of the same homologous series show a gradual change in physical properties.
(1)
The boiling point / melting point / viscosity / density of decane is higher than that of pentane.
(1)
Members of the same homologous series show similar chemical properties.
(1)
Both pentane and decane can undergo substitution reaction with bromine / chlorine.
(1)
b) Give the molecular formula of the alkane which contains 14 carbon atoms.
C14H30
(1 mark)
(1)
c) Besides pentane, draw the structural formulae of TWO other compounds with the molecular formula
C5H12. Give the IUPAC name of each compound drawn.
(4 marks)
H
H
CH3 H
H
C
C
C
C
H
H
H
H
H
(1)
Part B
2-methylbutane
H
(1)
H
CH3 H
C
C
H
CH3 H
C
H
(1)
2,2-dimethylpropane
(1)
d) The cracking of alkanes gives useful products.
i) Write a chemical equation for the cracking of decane to produce a different alkane and propene
only.
(1 mark)
Any one of the following: C10H22(l)
C10H22(l)
74
C7H16(l) + C3H6(g) (1) /
C4H10(g) + 2C3H6(g) (1) / C10H22(l)
CH4(g) + 3C3H6(g) (1)
ii) Draw a labelled diagram to show how the cracking of decane can be carried out in the laboratory,
including the collection of the gaseous product.
(3 marks)
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HBTFPVTQSPEVDU
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(1 mark for correct set-up; 1 mark for correct gas collection method; 1 mark for labelling of decane and porcelain
pieces; award 0 mark if the set-up is not workable)
(3)
iii) Apart from bromine, suggest ONE reagent which can be used to show the presence of propene in
the product mixture. State the expected observation and an equation for the reaction involved.
(3 marks)
Cold acidified dilute potassium permanganate solution
(1)
It turns from purple to colourless quickly in the presence of propene.
(1)
H
H
H
H
C
C
C
H(g) + [O] + H2O(l)
H
H
H
C
C
C
H
OH
OH
H(aq)
(1)
Part B
H
H
iv) The propene obtained from the cracking of decane can be used to make a polymer.
(1) Draw the structure of the polymer.
H
CH3
C
C
H
H
n
(1 mark)
(1)
(2) Can the polymer produced decolorize bromine dissolved in an organic solvent? Explain briefly.
(2 marks)
No.
(1)
It does not contain carbon-carbon multiple bonds.
(1)
75
101 The graph below shows the boiling points of some alkanes.
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a) i) State the trend in the boiling points of the alkanes.
(1 mark)
The boiling points of alkanes rise as the number of carbon atoms in the alkane molecules increases.
ii) Explain the trend in the boiling points of the alkanes.
(1)
(2 marks)
An alkane molecule becomes larger and heavier as the number of carbon atoms in the molecule increases.
(1)
Hence the van der Waals’ forces between the molecules increase.
(1)
Part B
Therefore more heat is needed to separate the molecules during boiling.
b) Use the above graph to estimate the boiling points of
i) octane (C8H18);
(1 mark)
~400 K
(1)
ii) hexadecane (C16H34).
(1 mark)
~545 K
(1)
c) Dodecane (C12H26) reacts with chlorine to produce a compound with molecular formula C12H25Cl.
C12H26 + Cl2
C12H25Cl + HCl
The reaction is initiated by the formation of chlorine free radicals from chlorine.
i) What is meant by the term ‘free radical’?
A species containing an unpaired electron
76
(1 mark)
(1)
ii) State the conditions necessary to bring about the formation of the chlorine free radicals from
chlorine.
(1 mark)
Ultraviolet light / heat
(1)
iii) The chlorine free radicals react with dodecane to produce C12H25Cl. Write equations for the TWO
propagation steps involved.
(2 marks)
C12H26 + Cl•
C12H25• + HCl
C12H25• + Cl2
(1)
C12H25Cl + Cl•
(1)
iv) Suggest why this reaction is NOT an effective way for the preparation of C12H25Cl.
The reaction gives a mixture of products (C12H25Cl, C12H24Cl2, etc.).
(1 mark)
(1)
102 In an experiment, a mixture of bromine vapour and ethane was exposed to sunlight.
a) State the expected observation in the experiment.
(1 mark)
The reddish brown colour of the mixture fades.
(1)
b) The reaction of bromine with ethane is similar to that of chlorine with ethane.
i) Name the type of reaction involved.
(1 mark)
Substitution reaction
(1)
ii) Write equations for the following steps in the reaction of bromine and ethane to produce
bromoethane.
(1) Initiation step
Br• + Br•
(1)
(2) First propagation step
CH3CH3 + Br•
(1 mark)
CH3CH2• + HBr
(1)
(3) Second propagation step
CH3CH2• + Br2
Part B
Br •• Br
(1 mark)
(1 mark)
CH3CH2Br + Br•
(1)
iii) In the reaction between bromine and ethane, another type of steps occurs in which free radicals
combine.
(1) Name this type of steps.
(1 mark)
Termination step
(1)
(2) Write an equation to illustrate this type of steps.
CH3CH2• + Br•
CH3CH2Br (1) OR 2CH3CH2•
(1 mark)
C4H10 (1)
77
c) The reaction of bromine and ethane produces a mixture of liquid carbon compounds.
i) Name a technique which could be used to separate the different compounds in this mixture.
(1 mark)
Fractional distillation
(1)
ii) Write a chemical equation for the conversion of ethane into hexabromoethane, C2Br6.
C2H6 + 6Br2
C2Br6 + 6HBr
(1 mark)
(1)
iii) State how the reaction conditions would have to be adjusted to produce the highest possible yield of
hexabromoethane.
(1 mark)
Use excess bromine.
(1)
103 A student carried out an experiment to convert octane (C8H18) into smaller molecules and collected the
gaseous products by using a boiling tube.
a) Name the chemical process involved in this experiment.
(1 mark)
Cracking
(1)
b) Draw a labelled diagram to show how this experiment can be performed in the laboratory.
(3 marks)
VOHMB[FEQPSDFMBJOQJFDFT
HBTFPVTQSPEVDUT
Part B
NJOFSBMXPPM
TPBLFEXJUI
PDUBOF
CFBLFS
IFBU
XBUFS
(1 mark for correct set-up; 1 mark for correct gas collection method; 1 mark for labelling octane and porcelain pieces;
award 0 mark if the set-up is not workable)
(3)
c) i) The student added a few drops of bromine dissolved in an organic solvent into the boiling tube
containing the gaseous products. The orange colour of the bromine solution disappeared immediately.
Why?
(2 marks)
The products of cracking contained alkenes / unsaturated hydrocarbons
(1)
which decolorized the bromine solution immediately by addition reaction.
(1)
ii) The student then dropped more bromine solution into the boiling tube until the orange colour of the
bromine solution persisted. After about 10 minutes, the orange colour disappeared. Why? (2 marks)
78
The products of cracking also contained alkanes / saturated hydrocarbons
(1)
which decolorized the bromine solution slowly by substitution reaction.
(1)
104 But-1-ene reacts as shown below.
A
CH3CH2CH2CH3
H2 / Ni catalyst
150 °C
CH3CH2CH
B
CH3CH2CHBrCH2Br
CH2
but-1-ene
steam / catalyst
CH3CH2CH(OH)CH3
C
a) Name compounds A and C.
(2 marks)
A is butane.
(1)
C is butan-2-ol.
(1)
b) Consider the conversion of but-1-ene to compound B.
i) Suggest how but-1-ene can be converted to compound B.
Mix but-1-ene with bromine dissolved in an organic solvent.
The orange colour of the bromine solution becomes colourless quickly.
(1)
(1 mark)
Part B
ii) State your expected observation during the reaction.
(1 mark)
(1)
c) But-1-ene can form a polymer.
i) What characteristic in the structure of but-1-ene enables it to act as a monomer?
It contains C=C bond.
(1)
ii) Write an equation for the polymerization of but-1-ene.
n
H
H
H
H
C
C
C
C
CH3CH2 H
(1 mark)
CH3CH2 H
n
(1 mark)
(1)
iii) The polymer is a thermoplastic.
Explain what is meant by the term ‘thermoplastic’.
A plastic that can be melted or softened by heat. / A plastic that can be remoulded when warmed.
(1 mark)
(1)
79
d) Besides but-1-ene, draw the structural formulae of TWO compounds with the molecular formula C4H8.
(2 marks)
Any two of the following:
H3C
H
H
C
C
H
CH3
(1)
H
H
CH3
C
C
H
C
C
H
H
C
C
H
H
(1)
H
H
H
H
CH2
CH3
C
H
(1)
H
H
C
C
H
(1)
105 Cars in some countries use gasohol as fuel. Gasohol is a mixture of ethanol and petrol. Ethanol can be
obtained from petroleum in the following way.
petroleum
Process X
heavy oil
Process Y
ethene
Process Z
ethanol
a) i) Name Process X.
Fractional distillation
ii) Describe and explain how the hydrocarbons in petroleum is separated by Process X.
(1)
(3 marks)
Part B
Petroleum is a mixture of hydrocarbons with different boiling points.
(1)
Heat the petroleum to obtain a mixture of liquid and vapour.
(1)
Hydrocarbons in the vapour portion condense at different temperatures.
(1)
b) i) Name Process Y and state its principle.
(2 marks)
Cracking.
(1)
Larger hydrocarbon molecules break down to produce smaller hydrocarbon molecules.
(1)
ii) Can the ethanol produced in this way be used to make wine? Explain briefly.
80
(1 mark)
(2 marks)
No.
(1)
It is because the ethanol is contaminated with toxic impurities, e.g. methanol.
(1)
c) Process Z can be represented by the following word equation.
ethene + steam
ethanol
Name the type of reaction involved.
(1 mark)
Addition / hydration
(1)
d) State ONE advantage of using gasohol over each of the following substances as a fuel for cars.
i) Ethanol
(1 mark)
Gasohol is less flammable. / More energy can be obtained from gasohol.
(1)
ii) Petrol
(1 mark)
Any one of the following:
•
Gasohol undergoes complete combustion more readily.
(1)
•
Burning gasohol produces less carbon monoxide / particulates.
(1)
e) Ethanol can also be produced from crops, such as sugar cane. Suggest ONE drawback of producing
ethanol from crops.
(1 mark)
This may lead to diversion of investment from food production, resulting in increased food prices.
(1)
106 X, Y and Z are carbon compounds. X is an alkanol with four carbon atoms and one oxygen atom in its
molecule. The flow diagram below shows the conversion of X to Z.
Part B
BDJEJGJFE,$S0BR
9
:
IFBU
DPODFOUSBUFE)40IFBU
;
Z has a pleasant smell.
a) Write the structural formulae and IUPAC names of X, Y and Z.
(6 marks)
OR
X: H
H
H
H
H
C
C
C
C
H
H
H
H
X: butan-1-ol
O
H
(1)
(1)
X: H
H
CH3 H
C
C
C
H
H
H
X: methylpropan-1-ol
O
H
(1)
(1)
81
Y: H
H
H
H
O
C
C
C
C
H
H
H
OH
(1)
Y: butanoic acid
Z: H
(1)
H
H
H
O
C
C
C
C
H
H
H
O
H
H
H
H
C
C
C
C
H
H
H
H
Z: butyl butanoate
H
(1)
(1)
Y: H
H
CH3 O
C
C
H
H
C
OH
(1)
Y: methylpropanoic acid
Z: H
H
CH3 O
C
C
H
H
C
(1)
O
H
CH3 H
C
C
C
H
H
H
Z: 2-methylpropyl methylpropanoate
b) State the expected observation when X reacts with acidified potassium dichromate solution.
The reaction mixture turns from orange to green.
H
(1)
(1)
(1 mark)
(1)
c) Consider the reaction of X and Y to form Z.
i) State the function of concentrated sulphuric acid in the reaction.
As a catalyst
(1 mark)
(1)
ii) Name the type of reaction involved.
(1 mark)
Esterification
(1)
iii) Suggest a method to separate Z from the reaction mixture.
Part B
Fractional distillation / using separating funnel
(1 mark)
(1)
d) An alkanol has the same molecular formula as X but a different structure. Suggest a structure for this
alkanol. Give also its IUPAC name.
(2 marks)
Any one of the following:
H
H
H
82
H
H
H
H
C
C
C
C
H
OH
H
H
H
CH3 H
C
C
C
H
H
H
H
CH3 H
C
C
C
H
OH
H
(1)
butan-2-ol
(1)
OH
(1)
methylpropan-1-ol
(1)
H
(1)
methylpropan-2-ol
(1)
H
107 Many drinks have a characteristic smell. 2-ethyl-3-methylbutanoic acid gives rum its characteristic aroma.
2-ethyl-3-methylbutanoic acid can be prepared in the laboratory by the oxidation of 2-ethyl-3-methylbutan1-ol.
A student used the following experimental set-up for the preparation.
IPUXBUFSCBUI
FUIZMNFUIZMCVUBOPM
PYJEJ[JOHBHFOU
a) Suggest an oxidizing agent that can be used.
(1 mark)
Acidified potassium dichromate solution / acidified potassium permanganate solution
(1)
b) State ONE advantage of using a hot water bath over direct heating with a Bunsen burner in the
experiment.
(1 mark)
Prevent the alcohol from catching fire. / The alcohol is flammable.
(1)
c) The student failed to obtain 2-ethyl-3-methylbutanoic acid even after a long time.
i) Draw a labelled diagram to show an experimental set-up the student should use.
(2 marks)
XBUFSPVU
Part B
SFGMVYDPOEFOTFS
XBUFSJO
FUIZMNFUIZMCVUBOPM
PYJEJ[JOHBHFOU
BOUJCVNQJOH
HSBOVMFT
IFBU
(1 mark for correct set-up; 1 mark for correct direction of water flow in condenser; award 0 mark if the set-up is not
workable.)
(2)
ii) Explain why the acid could finally be obtained using the new set-up.
The new set-up prevents any loss of the alcohol by evaporation / helps the reaction occur for longer time.
iii) What is the structural formula of 2-ethyl-3-methylbutan-1-ol?
H
H
CH3 C2H5 H
C
C
C
C
H
H
H
H
(1 mark)
(1)
(1 mark)
OH
(1)
83
iv) Using [O] to represent the oxidizing agent, write a balanced chemical equation for this oxidation.
(1 mark)
H
H
CH3 C2H5 H
C
C
C
C
H
H
H
H
OH + 2[O]
H
H
CH3 C2H5 O
C
C
C
H
H
H
C
OH + H2O
(1)
108 Alcohol X (relative molecular mass = 72.0) has the following compound by mass:
C 66.7%
H 11.1%
O 22.2%
a) i) Calculate the empirical formula of X.
(2 marks)
Suppose we have 100 g of compound X, so there are 66.7 g of carbon, 11.1 g of hydrogen and 22.2 g of oxygen.
Carbon
Hydrogen
Oxygen
Mass of element
in the compound
66.7 g
11.1 g
22.2 g
Number of moles
of atoms that
combine
66.7 g
= 5.56 mol
12.0 g mol–1
Simplest ratio of
atoms
5.56 mol
1.39 mol
= 4.00
11.1 g
1.0 g mol–1
11.1 mol
1.39 mol
= 11.1 mol
= 7.99
22.2 g
= 1.39 mol
16.0 g mol–1
1.39 mol
1.39 mol
= 1.00
(1)
(1)
∴ the empirical formula of X is C4H8O.
Part B
ii) Calculate the molecular formula of X.
(1 mark)
Let (C4H8O)n be the molecular formula of X.
Relative molecular mass of X = n(4 x 12.0 + 8 x 1.0 + 16.0)
= 72n
i.e. 72n = 72.0
n = 1
∴ the molecular formula of X is C4H8O.
(1)
b) When X is shaken with bromine dissolved in an organic solvent, the bromine is decolorized quickly.
i) Suggest the type of reaction involved.
Addition reaction
84
(1 mark)
(1)
ii) Deduce TWO possible structures of X.
(2 marks)
Any two of the following:
H
H
H
H
H
C
C
C
C
H
H
OH
H
H
CH3 H
C
C
C
OH
HO
(1)
H
H
OH
H
C
C
C
C
H
H
H
H
H
C
C
C
C
H
H
(1)
H
H
H
H
H
H
CH3 H
C
C
C
OH
(1)
H
H
H
H
H
(1)
H
H
OH
H
C
C
C
C
H
H
(1)
H
H
H
H
C
C
C
C
H
H
H
OH
H
H
C
C
C
C
H
H
OH
(1)
H
(1)
H
(1)
109 Ethanol reacts with ethanoic acid to produce ethyl ethanoate. The preparation of ethyl ethanoate consists of
seven steps as listed below:
Heat 60.0 g of ethanol, 50.0 g of glacial ethanoic acid and some concentrated sulphuric acid under
reflux for 10 minutes.
Step 2
Distil off the crude ester from the reaction mixture.
Step 3
Transfer the distillate to a separating funnel and shake with sodium carbonate solution.
Step 4
Allow the aqueous and organic layers in the separating funnel to settle. Separate the organic layer
from the aqueous layer.
Step 5
Shake the ester with calcium chloride solution. This removes the ethanol remaining as an impurity.
Step 6
Add anhydrous calcium chloride to the ester.
Step 7
Decant the ester from calcium chloride into a flask. Carry out distillation. Collect the fraction with a
boiling point range of 74 – 79 °C.
a) i) Write an equation for the reaction that occurs in Step 1.
CH3CH2OH(l) + CH3COOH(l)
CH3COOCH2CH3(l) + H2O(l)
ii) What is the function of concentrated sulphuric acid in the experiment?
As a catalyst
Part B
Step 1
(1 mark)
(1)
(1 mark)
(1)
85
iii) Draw a labelled diagram to show the experimental set-up used for reflux in Step 1.
(2 marks)
XBUFSPVU
SFGMVYDPOEFOTFS
XBUFSJO
FUIBOPMHMBDJBMFUIBOPJDBDJE
DPODFOUSBUFETVMQIVSJDBDJE
BOUJCVNQJOH
HSBOVMFT
HFOUMFIFBU
(1 mark for correct set-up; 1 mark for correct direction of water flow in condenser; award 0 mark if the set-up is not
workable.)
(2)
b) Explain why the crude ester is shaken with sodium carbonate solution in Step 3.
To remove traces of ethanoic acid and sulphuric acid.
(1 mark)
(1)
–3
c) Given that the density of ethyl ethanoate is 0.9 g cm , explain how the organic layer can be separated
from the aqueous layer in Step 4.
(1 mark)
Separate the organic layer from the aqueous layer by running off the lower aqueous layer.
Part B
d) What is the purpose of adding anhydrous calcium chloride in Step 6?
To remove any remaining traces of water from the product.
(1)
(1 mark)
(1)
e) Draw a labelled diagram to show the experimental set-up used for distillation in Step 7.
(3 marks)
UIFSNPNFUFS
XBUFSPVU
DPOEFOTFS
DSVEFFTUFS
BOUJCVNQJOH
HSBOVMFT
XBUFSJO
HFOUMFIFBU
JDFXBUFSCBUI
FTUFS
(1 mark for correct set-up; 1 mark for correct labels; 1 mark for the correct direction of water flow in condenser; award
0 mark if the set-up is not workable.)
(3)
86
f) In a certain experiment, 45.0 g of ethyl ethanoate were obtained.
i) Calculate the number of moles of each reactant used.
(2 marks)
60.0 g
= 1.30 mol
–1
46.0 g mol
50.0 g
= 0.833 mol
Number of moles of CH3COOH used =
60.0 g mol–1
(1)
ii) Calculate the percentage yield of ester in the experiment.
(2 marks)
Number of moles of CH3CH2OH used =
(1)
(Molar masses of ethanol, ethanoic acid and ethyl ethanoate are 46.0 g mol–1, 60.0 g mol–1 and
88.0 g mol–1 respectively.)
According to the equation for the esterification reaction, 1 mole of CH3CH2OH reacts with 1 mole of CH3COOH to
give 1 mole of CH3COOCH2CH3.
During the reaction, 0.833 moles of CH3COOH would react with 0.833 moles of CH3CH2OH. Therefore CH3CH2OH
was in excess. The amount of CH3COOH limited the amount of ester produced.
Theoretical yield of ester = 0.833 mol x 88.0 g mol–1 = 73.3 g
45.0 g
Percentage yield of ester =
x 100% = 61.4%
73.3 g
(1)
(1)
∴ the percentage yield of ethyl ethanoate was 61.4%.
Part B
g) Suggest a hazard warning label that should be displayed on a bottle of ethyl ethanoate.
Flammable
(1 mark)
(1)
h) Draw the structure of another ester which has the same molecular formula as ethyl ethanoate, and give
its systematic name.
(2 marks)
Any one of the following:
O
H
C
O
CH2CH2CH3
(1)
propyl methanoate
(1)
C
O
(1)
methyl propanoate
(1)
O
CH(CH3)2
(1)
methylethyl methanoate
(1)
O
CH3CH2
CH3
O
H
C
87
110 a) Plastics are very useful materials. Many objects previously made with metals are now made with plastics.
For each of the following objects, suggest ONE advantage of using plastics over using metals in making
the object.
i) The casing for an electric rice cooker
(1 mark)
Any one of the following:
•
Electricity leakage can be prevented.
(1)
•
Plastic does not corrode easily.
(1)
ii) A drain pipe
(1 mark)
Any one of the following:
•
Plastic does not corrode easily.
(1)
•
Plastic can be shaped more easily.
(1)
iii) The bumper of a car
(1 mark)
Any one of the following:
• Plastic does not corrode easily. (1) / • Lightweight. (1) / • No chrome plating required. (1)
iv) A large outdoor slide for children
(1 mark)
Any one of the following:
• Plastic does not corrode easily. (1) / • Lightweight. (1) / • No sharp edges. (1) /
Part B
• Self-coloured / no painting required. (1) / • More durable. (1)
b) Plastic X can be used to manufacture medicine bottles. It has the following structure:
CH3 H
CH3 H
CH3 H
C
C
C
C
C
C
H
H
H
H
H
H
i) (1) Draw the structure of the monomer of plastic X.
(1 mark)
CH3 H
C
C
H
H
(2) Name the monomer.
Propene
88
(1)
(1 mark)
(1)
ii) Name the TWO main processes involved in the production of bottles from the monomer of plastic
X.
(2 marks)
•
Addition polymerization
(1)
•
Moulding
(1)
iii) State ONE property of plastic X which makes it suitable for making medicine bottles.
Resistance to chemicals / barrier to moisture
(1 mark)
(1)
iv) A medicine bottle is made of plastic X. Can this bottle be remoulded into other shapes? Explain your
answer.
(2 marks)
Yes
(1)
Plastic X is a thermoplastic (can be softened by heat) and thus can be remoulded.
(1)
c) Landfilling and incineration are two possible methods for treating plastic waste.
i) Explain how landfilling and incineration of plastic waste cause pollution problems.
(2 marks)
Landfilling
Any one of the following:
•
Degradation of plastic takes a long time.
(1)
•
May cause pollution of underground water.
(1)
•
Slow release of toxins from landfill sites.
(1)
Incineration
Toxic gases are produced.
ii) Suggest another way to treat plastic waste.
Recycling / pyrolysis
Part B
•
(1)
(1 mark)
(1)
d) The following was printed on a plastic bag.
100% degradable
From date of production this bag degrades in a
maximum of 18 months, unlike conventional plastic
which potentially lasts one million years
Biodegradable plastics are made from plant materials.
Suggest TWO reasons why it is better for the environment if we use biodegradable rather than nonbiodegradable plastics.
(2 marks)
•
Less waste / less landfill / easier to dispose of / less pollution from burning.
(1)
•
Does not use up crude oil.
(1)
89
111 Complete the table by
i) listing TWO properties of each plastic which make it suitable for making the item stated;
ii) drawing the repeating unit of the plastic.
Plastic
(a) Polypropene
(10 marks)
(5 marks)
Item
Two properties of the
plastic that make it suitable
bottle crate
Any two of the following:
• strong
(1)
• lightweight
(1)
• good resistance to
chemical attack
(1)
• does not deform under
heavy load / stiff
(1)
Repeating unit of the plastic
H
H
C
C
H
CH3
(1)
H
(b) Nylon
parachutes
• strong
• lightweight
(1)
(1)
N
O
(CH2)6
N
C
(CH2)4
H
C
O
(1)
Part B
(c) Polyvinyl
chloride
shower curtain
Any two of the following:
• durable
(1)
• easily coloured
(1)
• flexible
(1)
• does not wrinkle easily (1)
Cl
H
C
C
H
H
(1)
(d) Ureamethanal
electric plug
• excellent electrical
insulator
• can withstand high
temperatures
O
(1)
CH2
(1)
N
C
H
N
H
(1)
(e) Perspex
transparent
advertising
display
Any two of the following:
• strong
(1)
• rigid
(1)
• not easily scratched
(1)
H
CH3
C
C
H
C
O
CH3
O
(1)
90
112 Addition polymers are made by joining lots of monomer molecules together.
a) Look at the table. It shows the structures of some monomers and polymers.
Monomer
H
H
C
Polymer
H
C
H
monomer A
H
H
C
C
F
C
Cl
H
C
H
C
C
H
H
n
polymer A
monomer B
F
H
H
Cl
C
C
H
H
n
(1)
polymer B
F
F
(1)
monomer C
F
F
C
C
F
F
n
polymer C
Complete the above table.
(2 marks)
Part B
b) Ice lollies are made by freezing sugar solutions in moulds made from polymer A.
i) One reason for using polymer A to make ice lolly moulds is that it is easily shaped.
State TWO other properties that make polymer A a good material for making ice lolly moulds.
(2 marks)
Any two of the following:
• Waterproof (1) / • Non-toxic (1) / • Stiff (1) / • Strong (1) / • Non-sticking (1) /
• Does not crack when cold (1) / • Good resistance to chemical attack (1) /
• Does not flavour the solution (1)
91
ii) Suggest a reason why polymer A is NOT suitable for making containers for hot foods.
(1 mark)
It softens / changes shape when heated.
(1)
iii) Explain, in terms of bonding, why objects made of polymer A are durable.
(1 mark)
Polymer A is a hydrocarbon with C–C and C–H bonds. These bonds are strong / not readily attacked by
chemicals.
(1)
iv) Suggest why polymer A does NOT have a constant relative molecular mass.
(1 mark)
Polymer A is a mixture of polymeric molecules of different chain lengths.
(1)
v) Polymer A is a thermoplastic.
Explain, in terms of structure, why polymer A softens upon heating.
(2 marks)
In polymer A, the polymer molecules are in the form of separate long chains.
Only weak van der Waals’ forces hold the chains together.
(1)
Upon heating, these forces are overcome and the chains move over one another.
(1)
c) The fluorinated polymer X is produced from monomer C and hexafluoropropene.
i) Draw the structure of a molecule of hexafluoropropene.
Part B
F
F
F
F
C
C
C
(1 mark)
F
(1)
F
ii) Draw a section of the chain of polymer X, including TWO units of monomer C and ONE unit of
hexafluoropropene.
(2 marks)
F
F
CF3
F
F
F
C
C
C
C
C
C
F
F
F
F
F
F
(2)
(different order of residues is acceptable)
d) Some scientists believe that incineration is a better way of treating plastic waste than landfilling.
Suggest why incineration has less environmental impact than landfilling.
(2 marks)
Any two of the following:
92
•
Incineration can produce energy and the need for burning fossil fuels is reduced.
(1)
•
Landfilling may cause pollution of underground water.
(1)
•
There may be slow release of toxins from landfill sites.
(1)
113 The following flow diagram shows two important plastics that can be made from ethene.
)
)
$
$
)
)
OXJUI
SFBDUJP
ZHFO
OEPY
B
F
JO
DIMPS
NPOPNFS"
SFBDUJP
OXJUI
CFO[F
OF
NPOPNFS#
QPMZNFSJ[BUJPO
QPMZNFSJ[BUJPO
a) Explain the meaning of the term ‘polymerization’.
17$
QMBTUJD9
(1 mark)
Polymerization is the process of repeatedly joining together many small molecules to form very large molecules.
b) Write the structural formulae of monomers A and B.
Monomer A
Monomer B
Cl
H
C
C
H
H
H
H
C
C
(1)
(2 marks)
(1)
H
(1)
Part B
c) Name plastic X.
(1 mark)
Polystyrene
(1)
d) Write a chemical equation for the formation of PVC.
Cl
H
Cl
H
nC
C
C
C
H
H
H
H
(1 mark)
n
(1)
e) PVC is used to cover copper when electrical wires are made.
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One property of PVC, which makes it useful for covering electrical wires, is that it lasts a long time.
93
Give TWO other properties of PVC which make it useful for covering electrical wires.
(2 marks)
Any two of the following:
•
Good insulator of electricity
(1)
•
Flexible
(1)
•
Easy to mould
(1)
•
Easy to colour
(1)
•
Waterproof
(1)
f) Plastic X can be made into an expanded form by adding a blowing agent.
Disposable lunch boxes are usually made of the expanded form of plastic X.
i) Suggest ONE reason why plastic X is expanded before it is used to make lunch boxes.
(1 mark)
To improve the heat insulating property of the material.
(1)
ii) Suggest ONE use of plastic X without blowing agent.
(1 mark)
Making sample bottles / compact disc cases / yogurt pots
(1)
g) Hydrogen chloride is given off when PVC burns in incinerators.
i) Suggest TWO harmful effects of discharging hydrogen chloride into the atmosphere.
(2 marks)
•
Hydrogen chloride can cause the formation of acid rain.
(1)
•
Hydrogen chloride can irritate and attack the respiratory system.
(1)
Part B
ii) Suggest a method for removing the hydrogen chloride from incinerator flue gas.
Pass the gas through a scrubber.
(1)
114 The flow diagram below shows the production processes of two plastic articles.
BEEJUJPOQPMZNFSJ[BUJPO
NPOPNFS"
QMBTUJD9
XJOEPXTPGBHSFFOIPVTF
DPOEFOTBUJPOQPMZNFSJ[BUJPO
NPOPNFST$BOE%
QMBTUJD:
QMBTUJDCPUUMFGPSGJ[[ZESJOL
94
(1 mark)
a) One of the properties that makes plastic X suitable for making windows is that it is transparent.
Suggest THREE other properties of this plastic that make it suitable for making windows in a
greenhouse.
(3 marks)
Any three of the following:
• Does not break when hit. (1) / • Does not corrode / does not react with moist air. (1) /
• Not degraded by sunlight. (1) / • Does not dissolve in water. (1) / • Non-biodegradable (1) / • Lightweight (1) /
• Thermal insulator (1) / • Durable (1) / • High melting point (1) / • Strong (1) / • Rigid (1)
b) Perspex can be used to make the windows in the greenhouse.
i) Draw the structure of the monomer of Perspex.
H
CH3
C
C
H
C
O
(1 mark)
CH3
O
(1)
ii) What characteristic in the structure of the monomer enables it to act as a monomer?
(1 mark)
It contains C=C bond.
(1)
i) Explain the meaning of the term ‘condensation polymerization’.
Part B
c) Poly(ethylene terephthalate) is used to make the bottle for fizzy drink.
(2 marks)
Condensation polymerization is a reaction in which monomer molecules join together repeatedly to form polymer
molecules.
(1)
Small molecules are always formed during the reaction.
(1)
ii) Draw the structures of two monomers for producing the plastic.
HO
O
O
C
C
OH
(1)
HO
CH2
(2 marks)
CH2
OH
(1)
iii) What characteristic in the structures of the monomers enable them to act as monomers?
Each monomer has two functional groups (or reactive sites).
(1 mark)
(1)
95
115 a) Teflon is a plastic that can be used as the coating of non-stick cooking ware. Teflon is an addition polymer
of linear structure consisting of carbon and fluorine only. The ratio of number of carbon atoms : the
number of fluorine atoms in the polymer is 1 : 2.
i) Draw a portion of the Teflon structure with 8 carbon atoms.
(1 mark)
F
F
F
F
F
F
F
F
C
C
C
C
C
C
C
C
F
F
F
F
F
F
F
F
ii) What is the meaning of ‘addition polymerization’?
(1)
(2 marks)
Addition polymerization is a reaction in which monomer molecules join together repeatedly to form polymer
molecules.
(1)
No atoms are lost from the monomer molecules during the reaction.
(1)
iii) Write the repeating unit of Teflon, and suggest a possible monomer of Teflon.
(1) Repeating unit
(1 mark)
F
F
C
C
F
F
(2) Monomer
(1)
(1 mark)
Part B
F
F
C
C
F
F
(1)
iv) Apart from the non-sticking property, give TWO other properties of Teflon which make it suitable for
coating non-stick cooking ware.
(2 marks)
Any two of the following:
96
•
Can withstand high temperature
(1)
•
Flexible
(1)
•
Excellent chemical resistance
(1)
•
Non-toxic
(1)
•
Does not flavour the food
(1)
b) Disposal of plastic waste can cause pollution problems. The pollution problems can be reduced by the
recycling of plastic waste.
i) Besides recycling, suggest THREE other methods for treating plastic waste.
(3 marks)
•
Incineration
(1)
•
Pyrolysis
(1)
•
Landfilling
(1)
ii) State TWO advantages of recycling plastic waste.
(2 marks)
Any two of the following:
•
It reduces the amount of plastic waste.
(1)
•
It helps conserve petroleum which is non-renewable.
(1)
•
It converts plastic waste into useful products.
(1)
iii) State TWO disadvantages of recycling plastic waste.
(2 marks)
Any two of the following:
Difficult to separate plastic waste from other waste.
(1)
•
Difficult to separate different plastic waste.
(1)
•
Difficult to remove additives in the plastic waste.
(1)
•
Many plastics lose their original properties over successive recycling cycles.
(1)
•
The cost is high.
(1)
Part B
•
iv) Suggest how you can help reduce pollution problems associated with the disposal of plastic waste.
(1 mark)
Bring our own bags. / Use substitutes for plastics. / Reduce the use of plastics. / Use biodegradable plastics.
(1)
116 Urea-methanal is a plastic which can be made using coal as a feedstock. The flow diagram below shows the
steps involved in the production process.
DPBM
4UFQ
DBSCPONPOPYJEF
4UFQ
NFUIBOPM
a) Name the type of reaction taking place in Step 3.
Oxidation
4UFQ
NFUIBOBM
4UFQ
VSFBNFUIBOBM
(1 mark)
(1)
97
b) Suggest how Step 4 can be carried out in the laboratory.
(3 marks)
Add powdered urea to methanal solution until some urea remain undissolved.
(1)
Add 1 drop of concentrated sulphuric acid to the solution.
(1)
Keep on stirring until a solid forms.
(1)
c) The structures of urea and methanal are shown below:
O
H2N
C
O
NH2
urea
H
C
H
methanal
Draw the repeating unit of urea-methanal.
(1 mark)
O
CH2
N
C
H
N
H
(1)
d) Urea-methanal does NOT soften on heating.
i) What is the name given to this type of plastic?
(1 mark)
Thermosetting plastic
Part B
ii) Explain why urea-methanal CANNOT be remoulded.
(1)
(3 marks)
When urea-methanal is made from its monomers, polymer chains are first formed. Hence it can be moulded into
the desired shape.
(1)
As heating continues, strong links begin to form between the chains to give a three-dimensional network of
bonds.
(1)
Urea-methanal does not melt or soften on heating due to the cross-link between the polymer chains.
(1)
Thus urea-methanal cannot be remoulded.
98
e) The following diagrams show four plastic items. One of them is made of urea-methanal.
IPUBJSCMPXFSDBTF
DBSQFU
GPPEXSBQQJOH
UIVNCUBDL
i) Which of the above items is made of urea-methanal? Explain your answer.
(2 marks)
Hot air blower case.
(1)
Urea-methanal is a thermosetting plastic and thus can withstand high temperature.
(1)
ii) Nylon can be used to make the carpet.
(1) Draw the structures of two monomers for producing a nylon.
H
H
N
H
(CH2)6
N
(2 marks)
O
H
(1)
HO
C
O
(CH2)4
C
OH
(2) Suggest ONE reason why recycling of used carpets to recover nylon is difficult.
Carpets are made of a variety of materials. Separating nylon from carpets may be difficult.
(1 mark)
(1)
Part B
(3) State ONE disadvantage of disposing of nylon carpets by incineration.
(1)
(1 mark)
Poisonous gas / oxides of nitrogen / carbon monoxide / hydrogen cyanide / soot may evolve.
(1)
117 Polylactide is a polymer whose monomer is lactic acid.
CH3 O
C
HO
C
OH
H
lactic acid
a) Name TWO functional groups in lactic acid.
(2 marks)
Hydroxyl group
(1)
Carboxyl group
(1)
99
b) What is meant by the term ‘polymer’?
(2 marks)
A polymer is a compound which consists of very large molecules
(1)
formed by joining together many small molecules repeatedly.
(1)
c) Polylactide is a thermoplastic.
i) Explain, in terms of structure, why thermoplastics soften upon heating.
(2 marks)
In a thermoplastic, the polymer molecules are in the form of separate long chains. Only weak intermolecular forces
hold the chains together.
(1)
Upon heating, these forces are overcome and the chains move over one another.
(1)
ii) Polylactide is a biodegradable plastic. Explain why it is better for the environment if we use biodegradable
rather than non-biodegradable plastics.
(1 mark)
Less waste / less landfill / easier to dispose of / less pollution from burning
118 Read the following passage and answer the questions that follow.
Chlorofluorocarbons
Chlorofluorocarbons (CFCs) are compounds which contain chlorine, fluorine and carbon.
Part B
CFCs have been used extensively in last five or six decades as refrigerants. In recent years it has been found
that CFCs are quite destructive to the environment. They are a major cause of the depletion of the Earth’s ozone
layer and contribute to the greenhouse effect.
The chlorofluorocarbon CF2Cl2 has been used as a refrigerant. It passes through the lower atmosphere and
reaches the upper atmosphere. There it reacts with the ozone layer.
sunlight
Step 1
CF2Cl2
•CF2Cl + Cl•
Step 2
O3 + Cl•
O2 + ClO•
Step 3
O3 + ClO•
2O2 + Cl•
Because of concern over the depletion of the ozone layer, many nations have agreed to cut down their use of
CFCs. Alternative compounds such as hydrohalocarbons containing at least one hydrogen atom per molecule
are already in production. The C–H bond in these compounds can be attacked by reactive species in the lower
atmosphere and they do not reach the upper atmosphere.
100
(1)
a) Explain why greenhouse gases can cause greenhouse effect.
(2 marks)
The Earth receives energy from incoming sunlight and radiates energy back into space.
(1)
Greenhouse gases can trap some of the infrared energy / heat radiated back into space.
(1)
b) Apart from CFCs, suggest TWO other greenhouse gases.
(2 marks)
Any two of the following:
• carbon dioxide (1) / • methane (1) / • oxides of nitrogen (1) / • ozone (1)
c) State ONE severe environmental consequence associated with global warming.
(1 mark)
Increase in temperature of the atmosphere can cause melting of polar ice caps / flooding / change in rainfall
pattern.
(1)
d) What is the connection between the lack of reactivity of CF2Cl2 and the damage which it does to the
ozone layer?
(1 mark)
CF2Cl2 is not able to react with substances in the lower atmosphere, and thus it reaches the upper atmosphere.
(1)
e) Refer to the steps showing how CF2Cl2 may damage the ozone layer.
i) Name the type of reactive intermediate shown in each of the three steps.
(1)
ii) Name the type of step illustrated by Step 1.
(1 mark)
Initiation
Part B
Free radical
(1 mark)
(1)
iii) Name the type of step illustrated by Step 3.
(1 mark)
Propagation
(1)
f) 1,1,1,2-tetrafluoroethane has been developed to replace CFCs.
i) Draw the structural formula of 1,1,1,2-tetrafluoroethane.
F
F
F
C
C
F
H
(1 mark)
H
ii) Suggest why 1,1,1,2-tetrafluoroethane is believed NOT to destroy the ozone layer.
It contains two H atoms and thus is more reactive than a CFC.
(1)
(1 mark)
(1)
101
119 Read the following passage and answer the questions that follow.
Dissolving plastic bags
Most hospitals put laundry in dissolving plastic bags. Obviously, such laundry bags are not made of ordinary
plastic film. They are made of material that is strong and airtight under room conditions but dissolves quickly in
hot water.
The water-soluble laundry bags are made of polyvinyl alcohol (PVA). The repeating unit of PVA is shown
below.
H
H
C
C
H
OH
PVA is a polymer made by polymerization of the monomer vinyl acetate.
CH2
CH
polymerization
O
C
CH3
vinyl acetate
Part B
102
CH2
NaOH
CH
methanol
O
O
C
CH2
CH
O
O
CH3
polyvinyl acetate
H
n
n
polyvinyl alcohol
PVA films are used for packages that release their contents upon contacting water. Some brands of sanitizers,
dyes and detergents are packaged in dissolving plastic bags.
a) Why do most hospitals put laundry in dissolving plastic bags?
(2 marks)
Laundry bags do not have to be opened and thus prevent the spread of infectious microbes throughout the hospital. (2)
b) Explain the meaning of the term ‘repeating unit’.
(2 marks)
A repeating unit is the smallest part of a polymer molecule,
(1)
and the whole polymer structure can be obtained by repeating it.
(1)
c) Based on the structure of PVA, explain why PVA plastic bags can dissolve in water.
(1 mark)
The –OH groups of the polymer chains of PVA tend to mix with water.
d) Explain the meaning of the term ‘polymerization’.
(1)
(1 mark)
Polymerization is the process of repeatedly joining together many small molecules to form very large molecules.
(1)
e) Farmers usually purchase pesticides and herbicides in concentrated form, and dilute them with water before
applying to crops. At high concentrations, some pesticides and herbicides can be toxic to humans.
Suggest how soluble plastic bags can help solve the problem.
(2 marks)
Farmers can drop powdered insecticides and herbicides packaged in PVA bags into water for preparing the dilute
solutions required. (The farmer is never exposed to the chemicals).
(2)
Part B
f) Suggest a plastic that is commonly used to make plastic bags.
Polythene
(1 mark)
(1)
103
120 Read the following passage and answer the questions that follow.
Treating plastic waste
Landfilling is probably the easiest way to dispose of plastic waste. Household waste does not get sorted into
different materials because it is disposed of in the same hole in the ground.
When the hole is eventually full, the waste is covered by a layer of soil to stop it smelling.
However, recycling of plastic waste is an important goal in many industrialized countries. Simply melting and
shaping plastic waste results in low-quality products. It has been reported that in the presence of a suitable
catalyst, polythene waste can be converted to aromatic hydrocarbons. These aromatic hydrocarbons have a
number of uses in chemical industry.
a) Suggest why melting and shaping plastic waste results in low-quality products.
(1 mark)
The product obtained contains different plastics as well as other substances such as refuse.
(1)
b) Suggest ONE problem that may occur in the conversion of polythene waste to aromatic hydrocarbons.
(1 mark)
It is difficult to isolate polythene from other plastics as the plastics may have very similar densities.
(1)
Part B
c) Draw the structural formula of an aromatic hydrocarbon, and give the systematic name of the aromatic
hydrocarbon.
(2 marks)
CH3
OR
benzene
104
methylbenzene
(2)
d) Suppose town X plans to recycle all the polythene waste rather than landfilling.
i) Suggest ONE economic argument and ONE environmental argument that will be made against
recycling.
(2 marks)
Economic argument
Any one of the following:
•
Polythene waste must be collected / transported / sorted / washed; these processes are expensive.
(1)
•
These processes use fossil fuels which are expensive.
(1)
Environmental argument
Any one of the following:
•
Using fossil fuels that are non-renewable / forms CO2 / CO / SO2 / NOx / particulates
(1)
•
Washing uses / pollutes water.
(1)
ii) For each argument made in (i), how can officials of the town persuade those making the argument
to accept the plan?
(2 marks)
Any two of the following:
Landfill is running out.
(1)
•
Polythene is non-biodegradable / degradation of polythene waste takes a long time.
(1)
•
Landfilling may cause pollution of underground water.
(1)
•
Slow release of toxins from landfill sites.
(1)
•
Collect / transport polythene waste alongside other waste.
(1)
•
Recycling helps conserve petroleum which is non-renewable.
(1)
•
Polythene waste can be converted into useful products.
(1)
•
More jobs / employment for local people.
(1)
Part B
•
105
121 Discuss the impacts of using fossil fuels on our present standard of living and the environment.
(9 marks)
(For this question, you are required to give answers in paragraph form.)
Our high standard of living is due to fossil fuel use.
Any three of the following:
Petrol and diesel oil obtained from the fractional distillation of petroleum are used as fuels to power vehicles.
(1)
Fuels are used to generate electricity.
(1)
Refinery gases and kerosene obtained from the fractional distillation of petroleum are used for cooking and heating.
(1)
Petrochemicals serve as raw materials in the production of many synthetic substances, particularly a wide range of
plastics.
(1)
However, burning fossil fuels causes global warming and serious air pollution problems.
Any three of the following:
Fossil fuel combustion produces carbon dioxide, a major greenhouse gas. Too much carbon dioxide in the atmosphere can
cause global warming.
(1)
Most of the carbon monoxide in the air comes from the exhaust gas of cars, trucks and buses. Carbon monoxide is a very
poisonous gas.
(1)
Not all the petrol in car engines gets burnt. Some unburnt hydrocarbons escape in the car exhaust gas. Unburnt
hydrocarbons give photochemical smog with oxides of nitrogen.
(1)
Part B
Inside car engines, the air gets so hot that nitrogen and oxygen react together, forming oxides of nitrogen. Oxides of
nitrogen can cause the formation of acid rain.
(1)
Incomplete combustion of hydrocarbons produce suspended particulates. These particulates can reduce visibility.
(1)
Combustion of coal or low-grade petroleum in factories and power stations produces sulphur dioxide. Sulphur dioxide can
cause the formation of acid rain.
(1)
(3 marks for organization and presentation)
106
122 Discuss how acid rain arises and suggest measures to reduce its formation.
(9 marks)
(For this question, you are required to give answers in paragraph form.)
Factories and power stations burn either coal or low-grade petroleum, both containing sulphur. When these fuels are burnt,
they give off sulphur dioxide to the air.
(1)
Inside car engines and power station furnaces, the air gets so hot that nitrogen and oxygen react together, forming oxides
of nitrogen.
(1)
Sulphur dioxide reacts with rainwater to form sulphurous acid.
(1)
Nitrogen dioxide reacts with rainwater to form nitric acid and nitrous acid.
(1)
These acids lower the pH of rainwater, giving rise to acid rain.
Measures to reduce acid rain formation
•
For sulphur dioxide
Any one of the following:
•
– using low-sulphur coal instead of high-sulphur coal
(1)
– installing flue gas desulphurization systems or scrubbers in power stations
(1)
For oxides of nitrogen
Any one of the following:
(1)
– installing low nitrogen oxide burners in power stations
(1)
(3 marks for organization and presentation)
Part B
– installing catalytic converters in exhaust systems of motor vehicles
107
123 You are provided with four unlabelled bottles each containing one of the following colourless liquids:
cyclohexane
propanoic acid
cyclohexene
propan-1-ol
Outline a scheme of tests to distinguish the four liquids from one another.
(9 marks)
(For this question, you are required to give answers in paragraph form.)
Add water to the liquids.
(1)
Both propanoic acid and propan-1-ol can mix with water in all proportions.
(1)
Add a piece of pH paper to the aqueous solutions.
(1)
Solution of propanoic acid is acidic while that of propan-1-ol is not.
(1)
OR
Warm each liquid with acidified potassium dichromate solution.
(1)
Propan-1-ol turns the dichromate solution from orange to green.
(1)
There is no observable change for propanoic acid.
Add bromine dissolved in an organic solvent to the remaining two compounds.
(1)
Cyclohexene turns the solution of bromine from orange to colourless quickly.
(1)
There is no observable change for cyclohexane.
(3 marks for organization and presentation)
Part B
108
124 Write an essay on the current practice of household plastic waste treatment in Hong Kong and suggest how
citizens can help reduce plastic waste problems.
(9 marks)
(For this question, you are required to give answers in paragraph form.)
Most plastic waste in Hong Kong are treated by landfilling, others are recycled / incinerated.
Landfilling
Any two of the following:
•
A lot of plastic waste can be treated in a short period of time.
(1)
•
Not enough land for building landfill sites. / The three strategic landfills in Hong Kong will soon be filled up.
(1)
•
Degradation of plastic takes a long time.
(1)
•
May cause pollution of underground water.
(1)
•
There is slow release of toxins from landfill sites.
(1)
Any one of the following:
Recycling
Incineration
Any two of the following:
Any two of the following:
Conserve petroleum which is non-renewable.
(1)
•
Volume of solid waste can be greatly reduced.
(1)
•
Plastic waste can be converted to useful products. (1)
•
Energy can be produced.
(1)
•
It is difficult to separate plastic waste from other
•
Reduce landwastage.
(1)
(1)
waste.
(1)
•
Toxic gases are produced.
•
It is difficult to separate different plastic waste.
(1)
•
The cost of operating a controlled incineration
•
Many plastics lose their original properties over
plant is high.
successive recycling cycles.
(1)
•
It is difficult to remove additives in plastic waste.
(1)
•
The process is uneconomical.
(1)
Part B
•
(1)
How citizens can help reduce plastic waste problems
Any two of the following:
•
Reduce the use of plastic shopping bags; bring our own bags when shopping.
(1)
•
Use items made of biodegradable / degradable plastics.
(1)
•
Separate plastic waste from other waste for recycling.
(1)
(3 marks for organization and presentation)
109