Download pdfInt 2 Homework Unit 2 1 MB

1.
(2.1)
The American space shuttle is propelled into space by
rocket boosters which contain aluminium as the fuel.
What is a fuel?
2.
(2.1)
1
Dinitrogen monoxide can be used to boost the performance of
racing car engines.
When dinitrogen monoxide decomposes it forms a mixture of
nitrogen and oxygen.
2N2O(g)
2N2(g) + O2(g)
An experiment was set up as shown below.
Why will the candle burn for longer in gas jar A?
3.
(2.2)
1
Biogas is a renewable fuel which consists of 70% methane and
30% carbon dioxide.
Name the two products which would be formed when biogas is
burned in a good supply of air.
1
1
4.
(2.3)
Candle wax is a hydrocarbon.
Blue cobalt chloride paper and limewater can be used to detect
products formed when candle wax is burned.
a)
Draw and complete the diagram to show the arrangement you
would use.
2
b) Name the product detected using the blue cobalt chloride paper.
1
c)
As the candle burns the funnel becomes coated with soot.
Why does this happen?
1
(4)
2
5.
(2.4)
In some American states, chemicals called oxygenates are added
to petrol to improve combustion.
One such compound is MTBE.
a)
Write the molecular formula for MTBE.
1
b) Name a pollutant in car exhausts which is due to incomplete
combustion of the petrol.
1
c)
Why must cars fitted with catalytic converters use unleaded
petrol?
1
d) Leaded petrol has been a major source of lead pollution in the
soil near to roads.
The graph shows how the mass of lead in one gram samples of
soil varies.
State two conclusions that can be drawn from these graphs.
2
(5)
3
6.
(2.4)
Scientists have been experimenting to find ways of reducing
carbon dioxide in the atmosphere. One of these ways involves
placing concrete balls on the sea bed. They hope that green
plants called algae will grow on the balls and this will help to
reduce the carbon dioxide level.
Give a reason why the amount of carbon dioxide in the air is
increasing.
7.
(2.4)
A compound burns in air. The only products of the reaction are
carbon dioxide, sulphur dioxide and water vapour.
The compound must contain:
8.
(2.6)
A
carbon and hydrogen only
B
carbon and sulphur only
C
carbon, hydrogen and sulphur
D
carbon, hydrogen, sulphur and oxygen
Which molecule would most likely be present in petrol?
A
CH4
B
C3 H 8
C
C8H18
D
C14H30
4
1
Questions 9 and 10 refer to the following information.
The fractional distillation of crude oil produces a number of different
fractions.
9.
(2.6)
10.
(2.7)
Which molecule is most likely to be present in kerosene?
A
C5H12
B
C12H26
C
C19H40
D
C26H54
Which properties apply to a fraction which has a high boiling point?
A
high viscosity and low flammability
B
low viscosity and low flammability
C
high viscosity and high flammability
D
low viscosity and high flammability
5
11.
(2.7)
12.
(2.7)
The fractional distillation of crude oil depends on the fact that
different hydrocarbons have different:
A
densities
B
solubilities
C
boiling points
D
ignition temperatures
The properties of fractions obtained from crude oil depend on the
sizes of molecules in the fractions.
Compared with a fraction containing small molecules a fraction
containing large molecules will:
13.
(2.7)
A
be more viscous
B
be more flammable
C
evaporate more readily
D
have a lower boiling point range
The fractional distillation of crude oil depends on the fact that the
different hydrocarbons have different:
A
boiling points
B
flammabilities
C
solubilities
D
viscosities
6
14.
The grid shows some sulphur compounds.
(2.10)
A
B
CH3 – S – C2H5
C
D
CH3
|
CH3 – C – S – H
|
H
a)
C2H5 – S – C2H5
CH2 – CH2
|
|
CH2 CH2
\
/
S
Identify the two compounds which have the same molecular
formula.
b) Identify the compound which has the general formula CnH2nS.
15.
Iodine can react with propene in the following way.
(2.10)
Name the homologous series to which propene belongs.
7
1
16.
A very hot flame is produced when ethyne gas (C2H2) burns in a
(2.11) plentiful supply of oxygen.
a)
Name the products formed in this reaction.
1
b) Ethyne is the first member of a homologous series called the
alkynes. Ethyne has the following structure.
H – CC – H
All the members of the alkyne series have a triple carbon to
carbon bond. Draw and complete the table below.
Position in series Name
1st
Molecular formula
ethyne
C2 H 2
2nd
3rd
C3 H 4
butyne
2
(3)
17.
(2.12)
The name of the above compound is:
A
but-2-ene
B
pent-2-ene
C
but-3-ene
D
pent-3-ene
8
18.
Which of the following compounds belong to the same homologous
(2.12) series as the compound with the molecular formula C3H8?
9
19.
Alkenes can be made from bromoalkanes. Bromoalkanes are
(2.12) alkane molecules in which a hydrogen atom has been replaced
by a bromine atom, e.g.
Draw the full structural formula for the two alkenes which can be
found from 2-bromobutane.
20.
The molecular formula for cyclohexane is:
(2.13)
A C6 H 6
B
C6H10
C
C6H12
D
C6H14
10
21.
Which of the following could be the molecular formula of a
(2.13) cycloalkane?
A
C7H16
B
C7H14
C
C7H12
D
C7H10
22.
Alkanes can be made by the reaction of sodium with iodoalkanes.
(2.14) This is called the Wurtz synthesis. For example, ethane can be made
from iodomethane.
H
H
|
|
H – C – I + 2Na + I – C – H
|
|
H
H
iodomethane
a)
H H
| |
H – C – C – H + 2NaI
| |
H H
iodomethane
Name the alkane which forms when sodium reacts with
iodoethane.
b) Two different iodoalkanes are used to make propane.
Name the two iodoalkanes.
c)
1
1
The Wurtz synthesis can also be used to make cycloalkanes.
Draw the full structural formula for the compound which could
be used to make cyclobutane.
1
(3)
11
23.
(2.15)
The name of the above compound is:
A
2,3-dimethylpentane
B
3,4-dimethylpentane
C
2,3-dimenthylpropane
D
3,4-dimenthylpropane
24.
Name the alkane shown below.
(2.15)
1
25.
Ethers are useful chemicals.
(2.15) Some ethers are listed in the table below.
Structural formula
Name of ether
CH3CH2 – O – CH2CH3
ethoxyethane
CH3 – O – CH2CH2CH3
methoxypropane
CH3 – O – CH2CH3
methoxyethane
X
CH3CH2 – O – CH2CH2CH3
Suggest a name for ether X.
1
12
26.
(2.15)
H H
H
| |
|
H–C–C–C=C–C–H
| | | | |
H H H H H
The name of the above compound is:
A
but-2-ene
B
pent-2-ene
C
but-3-ene
D
pent-3-ene
27.
Which of the following compounds has an isomer?
(2.16)
13
28.
Two isomers of butene are:
(2.16)
Which of the following structures represents a third isomer of
butene?
14
29.
Which of the following molecules is an isomer of heptane?
(2.16)
B
H H H H H H
| | | | | |
H–C–C–C–C–C–C–H
| | |
| |
H H H
H H
H–C–H
|
H
15
30.
(2.16)
Which of the following compounds is an isomer of the one shown
above?
16
31.
Which of the following alcohols has the highest boiling point?
(2.17) (You may wish to use page 6 of the data booklet to help you.)
17
32.
(2.17)
The above molecule is an example of
A
a saturated alcohol
B
an unsaturated alcohol
C
a saturated carboxylic acid
D
an unsaturated carboxylic acid
33.
The first four members of the alkanal homologous series are:
(2.17)
The general formula for this homologous series is:
A
C2H2n-2O
B
CnH2nO
C
CnH2n+1O
D
CnH2n+2O
18
34.
Carbohydrates in plant and animal waste can be digested by
(2.18) bacteria to produce biogas.
The digestion involves several steps.
carbohydrates
glucose
ethanoic acid
biogas
(70% methane + 30% carbon dioxide)
Draw the full structural formula for ethanoic acid.
1
35. The structural formula for lactic acid is shown below.
(2.18)
Draw the carboxyl group in the lactic acid module.
19
1
36. Which of the following is a structural formula for methyl ethanoate?
(2.19)
37.
(2.19)
The ester with the above structure can be prepared from
A
ethanol and ethanoic acid
B
ethanol and methanoic acid
C
methanol and ethanoic acid
D
methanol and methanoic acid
20
38.
The structural formulae for two of the compounds in lavender are
(2.19) shown below.
linalool
a)
linalyl ethanoate
To show that lavender oil contains unsaturated compounds it can
be tested by shaking s sample with bromine solution.
Bromine solution is corrosive. Apart from wearing safety
goggles, give another safety precaution which should be taken
when shaking the sample with bromine solution.
1
b)
Linalool is an alcohol. Copy the structural formula of linalool.
Draw the alcohol group in the linalool molecule shown above.
1
c)
Linalyl ethanoate is made from an alcohol and ethanoic acid.
To which group of compounds does linalyl ethanoate belong?
1
d)
Draw the full structural formula for ethanoic acid.
1
(4)
21
39. Which of the following structural formulae is that of an ester?
(2.19)
40.
a)
(2.19)
The alcohols are a family of carbon compounds.
Methanol reacts with ethanoic acid to form an ester.
Name the ester formed.
1
b) Propan-1-ol has the following full structural formula.
H H H
| | |
H – C – C – C – OH
| | |
H H H
Draw the full structural formula for an isomer of propan-1-ol.
1
(2)
22
41.
A student’s results are shown below for the PPA ‘Testing for
(2.21) Unsaturation’.
Hydrocarbon
Molecular
formula
Observation with
bromine solution
Saturated or
unsaturated
A
C6H14
no change
B
C6H12
bromine decolourises unsaturated
C
C6H12
no change
D
C6H10
bromine decolourises unsaturated
saturated
saturated
Draw a possible structural formula for hydrocarbon D.
1
42.
Terpenes are important in the perfume industry. One example is
(2.21) called terpinolene. It is an unsaturated hydrocarbon with the
molecular formula C10H16. The structural formula is shown.
CH3
|
C
CH2 CH
|
|
CH2 CH2
C
C
CH3
CH3
Write the molecular formula for the product of the complete reaction
of terpinolene with bromine.
1
23
43.
a) What is meant by an unsaturated hydrocarbon?
(2.21)
b) Bromine solution is used to test for unsaturation.
(i)
(ii)
c)
Briefly describe how the test is carried out giving the
results you would expect.
1
1
State one precaution which should be taken when carrying
out the test.
1
Two hydrocarbons A and B were tested for unsaturation.
Hydrocarbon Molecular formula Result of test
A
C5H10
negative
B
C5H10
positive
Draw a possible structure for each of the hydrocarbons.
1
(4)
24
44.
Students set up the apparatus below to carry out the PPA ‘Cracking’.
(2.21)
a)
The PPA gives special instructions as to how the test tube should
be heated. Describe how the test tube should be heated.
1
b) (i)
(ii)
c)
The bromine solution is decolourised.
What does this tell you about the gases produced by
cracking?
1
How is ‘suck back’ avoided?
1
In this experiment, the aluminium oxide is acting as a
heterogeneous catalyst. What is meant by a heterogeneous
catalyst?
1
(4)
45.
Which type of reaction is represented by the equation?
(2.22)
C2H4 + H2O
catalyst
C2H5OH
25
46.
Name the type of chemical reaction which takes place when iodine
(2.22) reacts with propene.
47.
A hydrocarbon Y has molecular formula C6H12 and does not react
(2.22) with bromine solution.
A possible full structural formula for hydrocarbon Y is:
26
48.
The diagram below shows the apparatus used in the PPA
(2.23) ‘Cracking’. Liquid paraffin is cracked using an aluminium oxide
catalyst. Bromine solution is used to show that some of the products
are unsaturated.
B
A
C
a)
Name A, B and C in the diagram of the apparatus used to crack
liquid paraffin.
1
b) What safety precaution should be taken before heating is
stopped?
1
(2)
49.
At a refinery, some fractions from crude oil are cracked.
(2.23)
What is meant by cracking?
27
1
50.
One way in which ethanol is produced industrially is shown below:
(2.24)
H H
H H
| |
| |
C=C
catalyst
H – C – C – OH
| |
| |
H H
H H
What name is given to this type of reaction?
A
condensation
B
hydration
C
hydrolysis
D
oxidation
28
51.
Propane can be cracked to produce a mixture of smaller molecules.
(2.24)
a)
Catalysts can be used to speed up a chemical reaction.
Give another advantage of using a catalyst.
1
b) Name the process used at step 2 to separate the product mixture.
1
c)
Name the other product separated from the mixture in the
flowchart.
1
(3)
29
52.
(2.25)
Gas X will:
A
burn with a pop
B
turn limewater cloudy
C
relight a glowing splint
D
rapidly decolourise bromine solution
53.
Sugar can be added after fermentation has taken place to sweeten
(2.26) yogurt.
Suggest why the sugar is added after the fermentation stage and not
before.
1
30
54.
Lavender flowers contain an oil. Lavender oil is produced from the
(2.27) flowers by steam distillation. The flowers are put into a flask with a
little water. Steam from a steam generator is blown through them to
extract the oil. The mixture of lavender oil and steam distils over. It
is condensed and collected.
The pieces of apparatus which are used to carry out this steam
distillation are shown below:
Write down the letters in order to show the order in which the pieces
of apparatus should be arranged to obtain the mixture.
1
31
55.
Ethanol vapour can be dehydrated by passing it over hot aluminium
(2.29) oxide.
Which of the following compounds would be produced?
A
ethane
B
ethane
C
ethanoic acid
D
ethyl ethanoate
56.
An ethoxyethane molecule can be formed when two ethanol
(2.30) molecules join together with the loss of water.
CH3CH2OH + HOCH2CH3  CH3CH2 – O – CH2CH3 + H2O
Name the type of reaction taking place.
57. The apparatus below can be used to dehydrate ethanol.
(2.30)
Gas X will:
A
burn with a pop
B
relight a glowing splint
C
turn limewater cloudy
D
rapidly decolourise bromine solution
32
1
58.
a) Draw the full structural formula for propanoic acid.
(2.30)
b) The diagram below shows how an alkane can be prepared
from an alkanoic acid.
1
The equation for the reaction is:
alkanoic acid  alkane + carbon dioxide
Draw and complete the table to show alkanoic acid could be
used to produce butane.
alkanoic acid
alkane
ethanoic acid
methane
propanoic acid
ethane
butane
1
(2)
59.
Which of the following is a renewable source of energy?
(2.31)
A coal
B
petrol
C
ethanol
D
natural gas
33
60.
Ethyl ethanoate can be made by reacting ethanoic acid and ethanol.
(2.32)
A
a)
Name this type of chemical reaction.
1
b) A method of making ethyl ethanoate from ethanol only has been
developed .
2C2H5OH
catalyst
CH3COOC2H5 + 2X
(i)
Name substance X
1
(ii)
This method was developed for use in countries where
ethanol is made from a renewable source.
Name this source of ethanol.
1
(3)
61.
DIMP is a useful insect repellent.
(2.33) DIMP contains two ester groups as shown by the structure below.
When DIMP is hydrolysed it forms a carboxylic acid and an alkanol.
Name the alkanol produced when DIMP is hydrolysed.
1
34
62.
The diagram shows how an ester with a ‘pear drops’ smell can be
(2.35) made.
ethanol + pentanoic acid  ester + water
a)
(i)
Name the ester formed.
1
(ii)
Why can this reaction be described as a condensation
reaction?
1
b) Polyesters are synthetic fibres.
Part of the structure of a polyester fibre is shown below.
(i)
Why are polyester fibres described as synthetic?
1
(ii)
Draw the ester link in the polyester structure.
1
(4)
35
63.
Part of a polymer structure is shown.
(2.37)
Which of the following gases could not be produced when this
polymer is burned?
A
CO
B
CO2
C
HC1
D
HCN
64.
Which polymer dissolves readily in water?
(2.39)
A polystyrene
B
nylon
C
poly(ethanol)
D
Kevlar
65.
Biopol is a polymer which is:
(2.39)
A natural and biodegradeable
B
synthetic and biodegradeable
C
natural and non-biodegradeable
D
synthetic and non-biodegradeable
36
66.
A compound has a relative formula mass of 30 and contains only
(2.40) carbon and hydrogen.
Which statement about the compound is true?
A
It is a gas.
B
It has a high viscosity.
C
It undergoes addition polymerisation.
D
It decolourises bromine water immediately.
67.
Industrial ethanol can be manufactured from ethene by:
(2.40)
A condensation
B
dehydration
C
hydration
D
hydrolysis
37
68.
The flow diagram shows the manufacture of polythene from
(2.40) hydrocarbons in crude oil.
Crude oil
process X
Alkanes
process Y
Ethene
process Z
Polythene
Which line in the table identifies the processes X, Y and Z?
Process X
Process Y
Process Z
A distillation
cracking
hydrolysis
B cracking
combustion
polymerisation
C polymerisation distillation
hydrolysis
D distillation
polymerisation
cracking
38
69.
Part of the structure of an addition polymer is shown below. It is
(2.41) made using two different monomers.
Which pair of alkenes could be used as monomers?
A
ethene and propene
B
ethene and butene
C
propene and butene
D
ethane and pentene
39
70.
Poly(ethenyl ethanoate) is an addition polymer. Part of its structure
(2.41) is shown below:
H
|
C
|
H
a)
OCOCH3
|
C
|
H
H
|
C
|
H
OCOCH3 H
|
|
C
C
|
|
H
H
OCOCH3
|
C
|
H
Draw the structural formula for the monomer used to make this
polymer.
1
b) Poly(ethenyl ethanoate) is used to make the polymer
poly(ethenol).
poly(ethenyl ethanoate) + methanol  poly(ethenol) + methyl ethanoate
Methyl ethanoate is also formed in the reaction.
(i)
What property of poly(ethenol) makes it useful for laundry
bags?
1
(ii)
Draw a structural formula for methyl ethanoate.
1
(3)
71.
To remove small ash and soot particles, emissions are passed
(2.41) through cloth filters coated with the polymer, poly
(tetrafluoroethene). A section of the polymer is shown.
Draw the full structural formula for the monomer from which
poly(tetrafluoroethene) is made.
1
40
72.
The structure below shows a section of an addition polymer.
(2.41)
Which molecule is used to make this polymer?
41
73.
Propene can take part in addition reactions.
(2.41)
a)
(i)
Draw the structural formula for propan-2-ol.
1
(ii)
Give another name for the addition reaction that
produces propan-2-ol.
1
b) Identify substance Y.
c)
1
Draw a section of the polymer formed from propene showing
three monomer units linked together.
1
(4)
42
74.
Polymers are used in the manufacture of glass windscreens. This
(2.42) makes the windscreens less likely to shatter into fragments.
a)
Name the type of polymerisation reaction used to make
polyesters.
1
b) The PVB polymer is made from a monomer with the structure
H H
| |
C=C
| |
H CH2CHO
Draw a section of the polymer showing three monomer units
linked together.
1
(2)
75.
A section of a polymer is shown below:
(2.43)
The polymer is:
A
a polyamide formed by addition polymerisation
B
a polyamide formed by condensation polymerisation
C
a polyester formed by addition polymerisation
D
a polyester formed by condensation polymerisation
43
76.
Kevlar is a recently developed polymer.
(2.43)
a) State a useful property of Kevlar.
1
b) The monomers used to make Kevlar have the following structural
formulae.
O
O
H
HO – C – C6H4 – C – OH
H
H – N – C6H4 – N – H
Why are these molecules able to take part in condensation
polymerisation?
c)
1
Kevlar is an example of a polyamide.
Draw the structure of an amide link.
1
(3)
77.
Nylon is a polymer.
(2.43) The monomers shown below are used to produce a nylon.
a)
Draw a section of the polymer showing the three monomer units
linked together.
1
b) What feature of their structure makes these molecules suitable
for use as monomers?
1
(2)
44
78.
Which of the following groups can react together to form an amide
(2.43) (peptide) link?
79.
What name is given to the reaction shown by the following equation?
(2.44)
C2H12O6 + 6O2  6CO2 + 6H2O
A
combustion
B
condensation
C
dehydration
D
hydrolysis
45
80.
Which of the following is the molecular formula for a carbohydrate?
(2.45)
A C6H14O
B
C6H12O2
C
C6H10O4
D
C6H12O6
81.
A solution containing two carbohydrates was tested as shown.
(2.46)
The solution could have contained:
A
starch and sucrose
B
starch and glucose
C
glucose and maltose
D
fructose and sucrose
46
82.
Which sugar will not be detected by the Benedict’s test?
(2.46)
A fructose
B
glucose
C
maltose
D
sucrose
83.
In which of the following experiments would both carbohydrates
(2.46) give orange precipitate when heated with Benedict’s solution?
47
84.
Which carbohydrate gives a positive result when tested with iodine
(2.46) solution?
A
glucose
B
maltose
C
sucrose
D
starch
85.
A student was investigating the effect of acid on the hydrolysis of
(2.46) starch.
a)
What colour change would the student have observed?
1
b) A control experiment would be required for the investigation.
Draw a labelled diagram of the control experiment.
1
(2)
48
86.
During digestion starch is broken down to form glucose.
(2.48) What name is given to this type of reaction?
A
combustion
B
condensation
C
fermentation
D
hydrolysis
87.
(2.48)
Which line in the table correctly describes reactions X and Y?
Reaction X
Reaction Y
A
condensation
hydration
B
condensation
hydrolysis
C
dehydration
hydration
D
dehydration
hydrolysis
49
88.
What type of substance is formed when starch is hydrolysed?
(2.48)
A a sugar
B
a carboxylic acid
C
an amino acid
D
an ester
89.
In the PPA ‘Hydrolysis of starch’, dilute hydrochloric acid can be
(2.48) used to break down the starch.
a)
After heating with dilute hydrochloric acid, solid sodium
hydrogencarbonate is added to each reaction mixture.
Why is hydrogencarbonate added at this stage?
1
b) Copy and complete the table to show the results which should be
obtained when the reaction mixtures are tested with Benedict’s
solution.
Reaction mixture
Observation on heating
with Benedict’s solution
A
B
1
(2)
50
90.
Enzymes are biological catalysts. A chemistry class was
(2.49) investigating how the activity of an enzyme changed with pH.
They carried out experiments at different pH values and timed how
long it took for the enzyme to break down starch. The more active
the enzyme, the shorter the time to break down the starch.
Here are their results.
a)
Name the type of chemical reaction taking place when starch
is broken down.
1
b) To which class of compounds do enzymes belong?
c)
What effect does increasing the ph from 5 to 6 have on the
activity of the enzyme?
1
1
d) Some students suggested speeding up the rate of the reaction
by heating the starch and enzyme mixtures in boiling water
baths. Why would this not speed up the reaction rate?
1
e) During the experiment, small samples were removed and
tested with iodine solution to see if all the starch had been
broken down. Suggest how the students would have known
that all the starch had been broken down.
1
(5)
51
91.
Which of the following correctly shows the elements present in
(2.50) carbohydrates and proteins?
Carbohydrates
Proteins
A
C and H
C, H and O
B
C and H
C, H, O and N
C
C, H and O
C, H, O and N
D
C, H, O and N
C, H and O
92.
Jelly is made from a protein called gelatin.
(2.51)
a) Name the type of monomers which join together to form proteins.
1
b) A section of the gelatin structure is shown below.
(i)
(ii)
c)
Copy and circle a peptide link in this section of the gelatin
structure.
1
Draw the structure of the monomer which makes this
section of the gelatin structure.
1
Papain, an enzyme found in pineapple juice, can hydrolyse
gelatin. When papain is heated to a high temperature it no
longer hydrolyses the gelatin. Suggest why.
1
(4)
52
93.
Which type of compound is represented by the structure shown?
(2.51)
A
amine
B
protein
C
amino acid
D
carboxylic acid
94.
Proteins are formed from amino acids.
(2.53)
When two amino acids join together
A
an ester link if formed by an addition reaction
B
an ester link is formed by a condensation reaction
C
an amide link is formed by an addition reaction
D
an amide link is formed by a condensation reaction
95
Which type of reaction occurs during the formation of proteins from
(2.53) amino acids?
53
96.
The table below shows the saturated and unsaturated fatty acid
(2.56) content of a fat and an oil.
Source
a)
fat / oil
% Fatty acid in substance
Saturated
Unsaturated
animal
chicken fat
68
32
marine
cod liver oil
25
75
What do fats and oils provide in our diet?
1
b) Name another source of fats and oils.
1
c)
1
Why do oils have a lower melting point than fats?
d) How can oils be converted into hardened fats?
1
(4)
97.
Both fats and oils are mixtures of triglycerides.
(2.56) Each triglyceride is an ester made from glycerol and fatty acids.
The majority of the molecules contain carbon to carbon double
bonds.
a)
Why does a triglyceride molecule have three ester linkages. 1
b) Explain why hardening increases the melting point of a fat
or oil.
c)
2
On exposure to air, oils turn rancid more rapidly than fats.
In this process the triglyceride molecules are broken into
small ‘foul-smelling’ molecules. At what functional group
within the triglyceride is the breaking likely to occur?
1
(4)
54
98.
The mass of iodine that reacts with 100 g of a substance is known
(2.56) as the iodine number.
Explain why oils are likely to have higher iodine numbers than fats.
1
99.
The conversion of an oil into a hardened fat involves the
(2.56)
A addition of water
B
removal of water
C
addition of hydrogen
D
removal of hydrogen
100. Which of the following are polymers?
(2.56)
A plant sugars
B
animal fats
C
marine oils
D
vegetable proteins
55
101. What is the ratio of glycerol molecules to fatty acid molecules
(2.57) produced on the hydrolysis of a fat or oil?
A
1:1
B
1:2
C
1:3
D
1:4
102. Which structure represents a molecule of glycerol?
(2.57)
56
103. Which of the following is a naturally occurring ester?
(2.57)
A fat
B
protein
C
starch
D
sucrose
104. Which compound could be obtained by the hydrolysis of a fat?
(2.57)
A ethanol
B
glucose
C
glycerol
D
propanol
57
105. Fats are broken down in the body by hydrolysis.
(2.57)
a)
When one mole of fat is hydrolysed, how many moles of fatty
acids are produced?
1
b) Name the molecule with the structure shown.
1
c)
Lipase is an enzyme which can catalyse the hydrolysis of
fats in milk. Copy and complete the diagram to show how the
indicator colour would change after lipase was added to the test
tube.
1
(3)
58