Cambridge IGCSE™
*5423893260*
CHEMISTRY
0620/43
Paper 4 Theory (Extended)
May/June 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB24 06_0620_43/3RP
© UCLES 2024
[Turn over
2
1
Name the process used to:
(a) produce ammonia from nitrogen
.............................................................................................................................................. [1]
(b) produce lead from molten lead(II) bromide
.............................................................................................................................................. [1]
(c) separate an insoluble solid from a mixture of an insoluble solid and a solution
.............................................................................................................................................. [1]
(d) produce ethanol from ethene
.............................................................................................................................................. [1]
(e) identify the components of a mixture of soluble coloured substances
.............................................................................................................................................. [1]
(f) separate a mixture of several liquids with different boiling points
.............................................................................................................................................. [1]
(g) determine the volume of an acid required to neutralise a given volume of an alkali.
.............................................................................................................................................. [1]
[Total: 7]
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3
2
Complete Table 2.1.
Table 2.1
atom or ion
number of
protons
63
29Cu
29
number of
electrons
37
–
17Cl
number of
neutrons
20
30
28
34
[5]
© UCLES 2024
0620/43/M/J/24
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4
3
This question is about elements and compounds.
(a) Some properties of graphite, oxygen and carbon monoxide are shown in Table 3.1.
Table 3.1
(i)
melting point
/ °C
boiling point
/ °C
conduction of
electricity when
solid
graphite
3652
4827
good
oxygen
–218
–183
poor
carbon monoxide
–199
–191
poor
Explain why graphite conducts electricity when solid.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
Complete the dot-and-cross diagram in Fig. 3.1 of a molecule of oxygen.
Show outer shell electrons only.
O
O
Fig. 3.1
[2]
(iii)
Deduce the physical state of carbon monoxide at –195 °C. Use the data in Table 3.1 to
explain your answer.
physical state ......................................................................................................................
explanation .........................................................................................................................
.............................................................................................................................................
[2]
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5
(iv)
Explain in terms of structure and bonding why graphite has a much higher melting point
than carbon monoxide.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(b) Potassium reacts with chlorine to form potassium chloride.
Write a symbol equation for this reaction.
.............................................................................................................................................. [2]
(c) A dilute aqueous solution of potassium chloride undergoes electrolysis.
Oxygen is produced at the anode.
(i)
State what is meant by the term electrolysis.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Write an ionic half-equation for the production of oxygen at the anode.
....................................................................................................................................... [2]
[Total: 14]
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4
Dinitrogen tetroxide, N2O4, decomposes into nitrogen dioxide, NO2.The reaction is reversible.
N2O4(g)
colourless gas
2NO2(g)
brown gas
Fig. 4.1 shows a gas syringe containing a mixture of dinitrogen tetroxide and nitrogen dioxide. The
gas syringe is sealed. The mixture reaches equilibrium and the colour of the mixture of gases is a
pale brown.
mixture of dinitrogen tetroxide
and nitrogen dioxide
end sealed
plunger
Fig. 4.1
(a) Describe a reversible reaction at equilibrium in terms of:
●
the rate of the forward reaction and the rate of the reverse reaction
....................................................................................................................................................
●
the concentration of reactants and products.
....................................................................................................................................................
[2]
(b) The pressure of the mixture is increased. All other conditions stay the same.
The mixture immediately turns darker brown before the position of equilibrium changes.
Explain in terms of particles why the mixture immediately turns darker brown.
.............................................................................................................................................. [1]
(c) The temperature of the mixture is increased. All other conditions stay the same.
The mixture turns darker brown.
State what can be deduced about the forward reaction from this information.
.............................................................................................................................................. [1]
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(d) Sulfur is converted into sulfuric acid, H2SO4, by a series of reactions.
Sulfur dioxide, SO2, and oxygen, O2, react to form sulfur trioxide, SO3. The reversible reaction
reaches equilibrium.
2SO2(g) + O2(g)
(i)
2SO3(g)
Complete Table 4.1 using only the words, increases, decreases or no change.
Table 4.1
effect on the rate of
the forward reaction
effect on the
equilibrium yield of SO3(g)
add a catalyst
increase the pressure
[4]
(ii)
Deduce the oxidation number of sulfur in:
S ..................................................
SO3 ..............................................
[2]
[Total: 10]
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5
(a) Barium sulfate, BaSO4, is an insoluble salt and is made by precipitation.
(i)
Name two aqueous solutions that produce a precipitate of barium sulfate when they are
mixed.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(ii)
Describe how to produce a pure sample of barium sulfate from the mixture of aqueous
solutions in (a)(i).
.............................................................................................................................................
....................................................................................................................................... [2]
(iii)
Write an ionic equation for the precipitation reaction which produces barium sulfate.
Include state symbols.
....................................................................................................................................... [3]
(b) Soluble salts are made from dilute acids.
Name the dilute acid and one other substance that react together to make copper(II) sulfate.
dilute acid ..................................................................................................................................
other substance .........................................................................................................................
[2]
(c) Nitrates decompose when they are heated.
When hydrated copper(II) nitrate is heated, oxygen gas is produced.
(i)
Describe a test for oxygen.
test ......................................................................................................................................
observations .......................................................................................................................
[1]
(ii)
Complete the equation for the decomposition of hydrated copper(II) nitrate.
2Cu(NO3)2•3H2O → .....CuO + .....NO2 + O2 + .....H2O
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[2]
9
(d) Hydrated zinc sulfate gives off water when it is heated.
ZnSO4•xH2O(s) → ZnSO4(s) + xH2O(g)
A student does an experiment to determine the value of x in ZnSO4•xH2O.
step 1
The student weighs a sample of hydrated zinc sulfate.
step 2
The student heats the sample of hydrated zinc sulfate.
step 3
The student weighs the solid after heating.
step 4
The student repeats step 2 and step 3 until the mass of solid after heating is constant.
(i)
State why the student does step 4.
....................................................................................................................................... [1]
(ii)
In an experiment, 0.574 g of ZnSO4•xH2O is heated until the mass is constant.
The mass of ZnSO4 that remains is 0.322 g.
[Mr: ZnSO4, 161; H2O, 18]
Determine the value of x using the following steps.
●
Calculate the number of moles of ZnSO4 remaining.
.............................. mol
●
Calculate the mass of H2O given off.
.............................. g
●
Calculate the number of moles of H2O given off.
.............................. mol
●
Determine the value of x.
x = ..............................
[4]
[Total: 17]
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6
This question is about iron.
(a) Fig. 6.1 shows a blast furnace used to extract iron from its ore.
waste gases
raw materials:
coke,
iron ore,
limestone
A
molten iron
Fig. 6.1
(i)
Name the main ore of iron used in the blast furnace.
....................................................................................................................................... [1]
(ii)
Name the substance that enters the blast furnace at A.
....................................................................................................................................... [1]
(iii)
Name the reducing agent in the extraction of iron in the blast furnace.
....................................................................................................................................... [1]
(iv)
Explain why limestone is added to the blast furnace. Give details of the chemical reactions
that are involved.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
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11
(b) The list shows the properties of some elements.
●
●
●
●
●
●
act as catalysts
have low densities
have low melting points
form acidic or basic oxides
form coloured compounds
form positive or negative ions
Iron is a transition metal. Sodium is a Group I metal.
State which property from the list:
(i)
is true for sodium but not iron
....................................................................................................................................... [1]
(ii)
is true for iron but not sodium
....................................................................................................................................... [1]
(iii)
is true for both sodium and iron
....................................................................................................................................... [1]
(iv)
is not true for sodium and not true for iron.
....................................................................................................................................... [1]
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12
(c) Steel consists mainly of iron.
Iron rusts when it reacts with water and oxygen.
Fig. 6.2 shows magnesium blocks attached to the bottom of a steel boat. The magnesium does
not completely cover the steel.
The magnesium blocks provide sacrificial protection for the steel.
steel boat
water containing
dissolved oxygen
magnesium
blocks
Fig. 6.2
(i)
Explain, in terms of electrons, why magnesium is used for sacrificial protection.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Name a metal that cannot provide sacrificial protection for steel.
....................................................................................................................................... [1]
[Total: 13]
© UCLES 2024
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13
7
Many organic compounds contain carbon and hydrogen only.
(a) (i)
An organic compound A has the following composition by mass.
C, 83.33%;
H, 16.67%
Calculate the empirical formula of compound A.
empirical formula = .............................. [3]
(ii)
Compound B has the empirical formula C2H5 and a relative molecular mass of 58.
Determine the molecular formula of compound B.
molecular formula = .............................. [2]
(b) Fig. 7.1 shows a section of a polymer formed from an alkene.
(i)
Identify the functional group in alkenes that reacts when alkenes form polymers.
....................................................................................................................................... [1]
(ii)
A section of a polymer is shown in Fig. 7.1.
C 2H 5 H
C 2H 5 H
C
C
C
C
H
H
H
H
Fig. 7.1
●
Draw the displayed formula of the monomer that forms this polymer.
●
Name the monomer used to form this polymer.
.............................................................................................................................................
[3]
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14
(c) Alkenes are produced by cracking alkanes.
When C12H26 is cracked, the products are ethene and an alkane which form in a 2 : 1 mole ratio.
Write a symbol equation for this reaction.
C12H26 → ........................ + ...................................................
(d) (i)
[2]
State the general formula for alcohols.
....................................................................................................................................... [1]
(ii)
Draw the displayed formula of one alcohol with the molecular formula C3H8O. Name the
alcohol you have drawn.
name of alcohol ..................................................................................................................
[2]
[Total: 14]
© UCLES 2024
0620/43/M/J/24
15
BLANK PAGE
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publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
© UCLES 2024
0620/43/M/J/24
© UCLES 2024
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/43/M/J/24
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
16
* 0019654852401 *
,
,
Cambridge IGCSE™
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*7071668735*
CHEMISTRY
0620/42
Paper 4 Theory (Extended)
May/June 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB24 06_0620_42/4RP
© UCLES 2024
[Turn over
DO NOT WRITE IN THIS MARGIN
* 0019654852402 *
2
,
A list of gases is shown.
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ammonia
helium
hydrogen
carbon dioxide
carbon monoxide
chlorine
methane
nitrogen dioxide
propene
sulfur dioxide
Answer the following questions about these gases.
Each gas may be used once, more than once or not at all.
(a) State one gas which:
(i)
is the main constituent of natural gas
....................................................................................................................................... [1]
(ii)
is responsible for both photochemical smog and acid rain
....................................................................................................................................... [1]
(iii)
is unsaturated
....................................................................................................................................... [1]
(iv)
has monatomic particles
....................................................................................................................................... [1]
(v)
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1
reduces iron(III) oxide in a blast furnace.
....................................................................................................................................... [1]
(b) Nitrogen dioxide, NO2, and carbon monoxide are removed from a car exhaust by a catalytic
converter.
Write the symbol equation for this reaction.
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,
[Total: 7]
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* 0019654852403 *
3
,
2
,
A list of five metals is shown.
copper
iron
magnesium
potassium
silver
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(a) All metals form positive ions.
(i)
Describe how atoms form positive ions.
....................................................................................................................................... [1]
(ii)
State which of the five metals in the list has the greatest tendency to form positive ions.
....................................................................................................................................... [1]
(iii)
Suggest one of the five metals in the list which is not likely to show catalytic properties.
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....................................................................................................................................... [1]
(iv)
State which of the five metals in the list is a major component of stainless steel.
....................................................................................................................................... [1]
(b) A student adds a sample of a metal to an aqueous metal salt in a beaker to see if a displacement
reaction takes place.
Complete Table 2.1 to show the colour of the solution in the beaker at the start and at the end
of the experiment.
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Table 2.1
metal
aqueous solution
colour at the start
magnesium
iron(II) sulfate
green
silver
copper(II) sulfate
colour at the end
[3]
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4
,
,
(c) Most Group II metals form a gas when placed into cold water. An alkaline solution is also
formed.
(i)
Name the gas formed when strontium is added to cold water.
....................................................................................................................................... [1]
(ii)
Name the alkaline solution formed when strontium is added to cold water.
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* 0019654852404 *
One Group II metal reacts very slowly when placed in cold water. When heated, the metal
reacts with steam to form a white solid.
Identify this metal and name the white solid formed.
metal ...................................................................................................................................
white solid ...........................................................................................................................
[2]
(d) Under certain conditions, iron will react with steam to form an oxide of iron with the formula
Fe3O4.
Fe3O4 reacts with dilute hydrochloric acid to form a mixture of iron(II) and iron(III) salts and
water.
Deduce the symbol equation for the reaction between Fe3O4 and dilute hydrochloric acid.
.............................................................................................................................................. [3]
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[Total: 14]
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(iii)
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....................................................................................................................................... [1]
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* 0019654852405 *
5
,
3
,
The symbol equation for the industrial production of ammonia is shown.
N2(g) + 3H2(g)
2NH3(g)
∆H = –90 kJ / mol
(a) Name this industrial process.
.............................................................................................................................................. [1]
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(b) State the meaning of ∆H.
.............................................................................................................................................. [1]
(c) State the typical conditions and name the catalyst used in the industrial production of ammonia.
temperature and units ........................................
pressure and units .............................................
catalyst used ......................................................
(d) State two methods of increasing the rate of this reaction.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
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[3]
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6
,
,
(e) The symbol equation for the reaction can be represented as shown in Fig. 3.1.
N
H
N + H
H
H
H
H H
N
H
H
N
H
+
H
H = –90 kJ / mol
H
Fig. 3.1
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* 0019654852406 *
Table 3.1
bond
N≡N
H–H
bond energy in kJ / mol
945
435
Use the bond energies in Table 3.1 and ∆H to calculate the bond energy of an N–H bond, in
kJ / mol.
Use the following steps.
.............................. kJ
Calculate the energy released when bonds form in the products.
.............................. kJ
●
Calculate the energy of an N–H bond.
.............................. kJ / mol
[3]
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●
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Calculate the energy needed to break bonds in the reactants.
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●
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Table 3.1 shows some bond energies.
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* 0019654852407 *
7
,
,
(f) An incomplete symbol equation for the preparation of ammonia in the laboratory is shown.
CaO + 2NH4Cl → CaCl 2 + ......................... + 2NH3
(i)
Complete the symbol equation.
(ii)
Name NH4Cl.
[1]
(iii)
Calculate the volume of ammonia, NH3, measured at room temperature and pressure,
which forms when 1.12 g of CaO is heated with excess NH4Cl.
[Mr: CaO, 56]
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....................................................................................................................................... [1]
.............................. cm3 [3]
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[Total: 15]
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[Turn over
8
,
4
,
A carboxylic acid reacts with an alcohol to produce an ester and water.
Under certain conditions, this reaction can be reversed so an ester reacts with water to produce a
carboxylic acid X and an alcohol Y.
The reaction reaches an equilibrium.
CH3CH2COOCH3 + H2O
X + Y
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* 0019654852408 *
(a) Deduce the empirical formula of the ester.
.............................................................................................................................................. [1]
(b) Name the ester.
.............................................................................................................................................. [1]
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The forward reaction is endothermic.
name ..........................................................................................................................................
displayed formula
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(c) Name carboxylic acid X and draw its displayed formula.
name ..........................................................................................................................................
structural formula .......................................................................................................................
[2]
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0620/42/M/J/24
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(d) Name alcohol Y and give its structural formula.
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[2]
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* 0019654852509 *
9
,
,
(e) Complete Table 4.1 to show the effect, if any, for each change of condition.
Table 4.1
effect on the concentration of
carboxylic acid X at equilibrium
change of condition
temperature is decreased
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concentration of CH3CH2COOCH3
is decreased
more alcohol Y is added
a catalyst is added
[4]
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(f) At the beginning of the reaction between the ester and water, no carboxylic acid is present in
the reaction mixture.
(i)
pH at start of reaction .........................................................................................................
pH at equilibrium .................................................................................................................
[2]
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(ii)
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Suggest how the pH of the reaction mixture changes from the start of the reaction until
equilibrium is reached.
Assume alcohols and esters are neutral.
Identify the ion that causes the change in pH.
....................................................................................................................................... [1]
(iii)
Name an indicator which can be used to follow the change in pH.
....................................................................................................................................... [1]
[Total: 14]
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10
5
,
Sulfur is a Group VI element.
(a) A sample of sulfur contains two isotopes, 32S and 34S.
(i)
Complete Table 5.1 to show the number of protons and neutrons in one atom of each
isotope of sulfur.
Table 5.1
32
34
S
S
protons
neutrons
[2]
(ii)
State why these isotopes have identical chemical properties.
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,
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* 0019654852510 *
....................................................................................................................................... [1]
....................................................................................................................................... [1]
State the name of the amount of substance which contains 6.02 × 1023 atoms.
....................................................................................................................................... [1]
(v)
Table 5.2 shows the relative abundance of these isotopes of sulfur in the sample.
Table 5.2
atom
32
S
34
relative abundance
95%
5%
S
Calculate the relative atomic mass of sulfur in this sample to one decimal place.
relative atomic mass = .............................. [2]
© UCLES 2024
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(iv)
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State the mass of 6.02 × 1023 atoms of 34S. Include units in your answer.
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(iii)
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* 0019654852511 *
11
,
,
(b) Sulfur reacts with magnesium to form magnesium sulfide, MgS, an ionic compound.
(i)
Complete the dot-and-cross diagram in Fig. 5.1 of the ions in magnesium sulfide.
Give the charges on the ions.
........
........
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Mg
S
Fig. 5.1
[3]
(ii)
State why MgS has a high melting point.
....................................................................................................................................... [1]
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(iii)
State why molten MgS conducts electricity.
....................................................................................................................................... [1]
(c) An acid containing sulfur reacts with sodium hydroxide, NaOH, to form a salt and water. The
salt has the formula Na2SO3.
(i)
Deduce the formula of this acid.
....................................................................................................................................... [1]
(ii)
Deduce the formula of the anion in Na2SO3.
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....................................................................................................................................... [1]
(d) Na2SO3 is oxidised by acidified aqueous potassium manganate(VII).
(i)
State what VII refers to in the name potassium manganate(VII).
....................................................................................................................................... [1]
(ii)
State the colour change when this reaction happens.
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from ............................................................ to ............................................................. [2]
.
[Total: 17]
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12
6
,
Glucose is involved in two processes.
(a) Glucose, C6H12O6, is made in plants from carbon dioxide and water.
(i)
Name this process.
....................................................................................................................................... [1]
(ii)
Write the symbol equation for this process.
....................................................................................................................................... [1]
(iii)
State two essential conditions needed for this process to happen.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
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,
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* 0019654852512 *
(b) Glucose is converted to ethanol.
....................................................................................................................................... [1]
Name the other product formed when glucose is converted to ethanol.
....................................................................................................................................... [1]
(c) Ethanol is made by reacting ethene with steam in an industrial process.
(i)
State the conditions and type of catalyst used in this industrial production of ethanol.
temperature and units ...........................................
pressure and units ................................................
type of catalyst used .............................................
[3]
(ii)
Explain why this reaction is an addition reaction.
....................................................................................................................................... [1]
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0620/42/M/J/24
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(ii)
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Name this process.
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(i)
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* 0019654852513 *
13
,
(iii)
,
Complete the dot-and-cross diagram in Fig. 6.1 of a molecule of ethanol.
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H
H
H
C
C
H
H
O
H
Fig. 6.1
[3]
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[Total: 13]
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[Turn over
© UCLES 2024
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27
28
29
30
73
72
57–71
lanthanoids
56
91
55
zirconium
89
88
yttrium
strontium
85
–
–
cerium
140
90
Th
thorium
232
lanthanum
139
89
Ac
actinium
–
231
protactinium
Pa
91
141
praseodymium
Pr
59
58
Ce
57
–
–
La
Db
dubnium
Rf
Sg
238
uranium
U
92
144
neodymium
Nd
60
–
seaborgium
–
neptunium
Np
93
–
promethium
Pm
61
–
bohrium
Bh
107
186
rhenium
Re
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
Sm
62
–
hassium
Hs
108
190
osmium
Os
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
Eu
63
–
meitnerium
Mt
109
192
iridium
Ir
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
Gd
64
–
darmstadtium
Ds
110
195
platinum
Pt
78
106
palladium
Pd
46
59
nickel
Ni
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–
berkelium
Bk
97
159
terbium
Tb
65
–
roentgenium
Rg
111
197
gold
Au
79
108
silver
Ag
47
64
copper
Cu
–
einsteinium
Es
99
165
holmium
Ho
67
–
nihonium
Nh
113
204
thallium
Tl
81
115
indium
In
49
70
gallium
Ga
–
115
114
Fl
–
fermium
Fm
100
167
erbium
Er
68
–
flerovium
–
mendelevium
Md
101
169
thulium
Tm
–
–
–
–
lawrencium
Lr
103
175
lutetium
Lu
71
Og
oganesson
Ts
tennessine
118
–
radon
Rn
86
131
xenon
Xe
54
84
krypton
Kr
36
40
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nobelium
No
102
173
ytterbium
Yb
70
–
–
69
Lv
livermorium
Mc
moscovium
117
–
209
207
116
At
astatine
Po
polonium
lead
Pb
Bi
85
127
iodine
I
53
80
bromine
Br
84
128
tellurium
Te
52
79
selenium
Se
35
83
122
antimony
Sb
51
75
arsenic
As
34
bismuth
82
119
tin
Sn
50
73
germanium
Ge
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–
californium
Cf
98
163
dysprosium
Dy
66
–
copernicium
Cn
112
201
mercury
Hg
80
112
cadmium
Cd
48
65
zinc
Zn
33
,
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The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
Ra
radium
Fr
francium
106
184
tungsten
W
74
96
molybdenum
Mo
42
52
chromium
Co
32
argon
Ar
18
20
neon
Ne
16
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0620/42/M/J/24
rutherfordium
105
104
actinoids
181
178
89–103
88
87
137
133
Ta
tantalum
Hf
Ba
barium
Cs
caesium
hafnium
93
niobium
Nb
rubidium
Zr
Sr
Rb
Y
38
41
51
vanadium
37
40
48
45
39
titanium
scandium
Fe
40
Mn
calcium
V
23
Cr
39
Ti
Sc
potassium
26
Ca
25
K
24
31
22
21
20
35.5
32
31
28
19
chlorine
sulfur
phosphorus
silicon
27
24
23
aluminium
magnesium
sodium
Cl
S
P
Si
Al
Mg
17
16
15
14
Na
relative atomic mass
13
12
11
19
16
14
12
11
9
F
fluorine
O
oxygen
N
nitrogen
C
carbon
B
boron
7
name
atomic symbol
Be
10
4
9
8
7
6
5
beryllium
atomic number
helium
1
VIII
hydrogen
VII
Li
4
3
Key
VI
2
V
He
IV
1
III
H
Group
,
lithium
II
I
The Periodic Table of Elements
* 0019654852516 *
Cambridge IGCSE™
*1182455718*
CHEMISTRY
0620/41
Paper 4 Theory (Extended)
May/June 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB24 06_0620_41/2RP
© UCLES 2024
[Turn over
2
1
Name the process that is used to:
(a) convert sulfur dioxide into sulfur trioxide in the manufacture of sulfuric acid
.............................................................................................................................................. [1]
(b) obtain water from aqueous sodium chloride
.............................................................................................................................................. [1]
(c) extract aluminium from purified bauxite
.............................................................................................................................................. [1]
(d) separate petroleum into useful substances
.............................................................................................................................................. [1]
(e) produce ethanol from aqueous glucose
.............................................................................................................................................. [1]
(f) manufacture alkenes and hydrogen from large alkane molecules
.............................................................................................................................................. [1]
(g) separate a mixture of soluble coloured substances.
.............................................................................................................................................. [1]
[Total: 7]
© UCLES 2024
0620/41/M/J/24
3
2
Complete Table 2.1.
Table 2.1
atom or ion
number of
protons
number of
electrons
37
17Cl
number of
neutrons
17
63
+
29Cu
34
16
18
17
[5]
© UCLES 2024
0620/41/M/J/24
[Turn over
4
3
This question is about the elements sodium and fluorine and the compound sodium fluoride.
(a) Sodium reacts with fluorine to form sodium fluoride.
Write a symbol equation for this reaction.
.............................................................................................................................................. [2]
(b) Some properties of sodium, fluorine and sodium fluoride are shown in Table 3.1.
Table 3.1
melting point
/ °C
boiling point
/ °C
conduction of
electricity when
solid
sodium
98
883
good
fluorine
–220
–188
poor
sodium fluoride
993
1695
poor
(i)
conduction of
electricity in
aqueous solution
good
Explain why sodium conducts electricity when it is a solid.
....................................................................................................................................... [1]
(ii)
Complete the dot-and-cross diagram in Fig. 3.1 of a molecule of fluorine.
Show outer shell electrons only.
F
F
Fig. 3.1
[2]
(iii)
Deduce the physical state of fluorine at –200 °C. Use the data in Table 3.1 to explain your
answer.
physical state ......................................................................................................................
explanation .........................................................................................................................
.............................................................................................................................................
[2]
© UCLES 2024
0620/41/M/J/24
5
(iv)
Explain in terms of structure and bonding why sodium fluoride has a much higher melting
point than fluorine.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(c) Dilute aqueous sodium fluoride undergoes electrolysis.
Hydrogen is produced at the cathode.
(i)
State what is meant by the term electrolysis.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Write an ionic half-equation for the production of hydrogen at the cathode.
....................................................................................................................................... [2]
[Total: 14]
© UCLES 2024
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[Turn over
6
4
Hydrogen iodide thermally decomposes into iodine and hydrogen. The reaction is reversible.
I2(g)
+
H2(g)
purple gas
colourless gas
2HI(g)
colourless gas
Fig. 4.1 shows a gas syringe containing a mixture of hydrogen iodide, iodine and hydrogen gases.
The gas syringe is sealed and the mixture is heated to 300 °C. The mixture of gases reaches
equilibrium and is purple.
equilibrium mixture of hydrogen iodide,
iodine and hydrogen
end sealed
plunger
Fig. 4.1
(a) State what is meant by the term equilibrium.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) The pressure of the mixture is increased. All other conditions stay the same. The position of
equilibrium does not change.
The colour of the gaseous mixture turns darker purple.
The temperature remains constant.
2HI(g)
colourless gas
(i)
I2(g)
+
H2(g)
purple gas
colourless gas
Explain why the position of equilibrium does not change.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
Suggest why the colour of the mixture of gases turns darker purple.
.............................................................................................................................................
....................................................................................................................................... [1]
© UCLES 2024
0620/41/M/J/24
7
(c) The temperature of the mixture of gases is decreased. All other conditions stay the same.
The mixture of gases turns lighter purple.
State what can be deduced about the forward reaction from this information.
.............................................................................................................................................. [1]
(d) Deduce the oxidation number of iodine, I, in:
HI ...............................................................................................................................................
I2. ...............................................................................................................................................
[2]
(e) Methanol is manufactured by reacting carbon monoxide with hydrogen.
CO(g) + 2H2(g)
CH3OH(g)
The rate of formation of methanol increases when a catalyst is used.
(i)
Choose from the list the element that is most likely to be used as the catalyst.
Draw a circle around your chosen answer.
calcium
(ii)
carbon
copper
sodium
sulfur
[1]
State the effect on the position of equilibrium when a catalyst is used.
....................................................................................................................................... [1]
(iii)
State the effect that a catalyst has on the activation energy, Ea, of a reaction.
....................................................................................................................................... [1]
[Total: 10]
© UCLES 2024
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[Turn over
8
5
(a) Lead(II) bromide, PbBr2, is an insoluble salt and is made by precipitation.
(i)
Name two aqueous solutions that produce a precipitate of lead(II) bromide when they are
mixed.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(ii)
Describe how to produce a pure sample of lead(II) bromide from the mixture of aqueous
solutions in (a)(i).
.............................................................................................................................................
....................................................................................................................................... [2]
(iii)
Write an ionic equation for the precipitation reaction which produces lead(II) bromide.
Include state symbols.
....................................................................................................................................... [3]
(b) When iron(II) sulfate crystals are heated strongly, sulfur dioxide gas is given off.
Describe a test for sulfur dioxide gas.
test .............................................................................................................................................
observations ..............................................................................................................................
[2]
(c) Complete the equation for the thermal decomposition of hydrated cobalt(II) nitrate.
2Co(NO3)2•4H2O → ....CoO + ....NO2 + O2 + ....H2O
© UCLES 2024
0620/41/M/J/24
[2]
9
(d) Hydrated cobalt(II) sulfate, CoSO4•xH2O, produces water when it is heated.
CoSO4•xH2O(s) → CoSO4(s) + xH2O(g)
A student does an experiment to determine the value of x in CoSO4•xH2O.
step 1
The student weighs a sample of hydrated cobalt(II) sulfate.
step 2
The student heats the sample of hydrated cobalt(II) sulfate.
step 3
The student weighs the remaining solid after heating.
(i)
Describe what else the student should do to ensure that all the water has been given off.
No other substances are required.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
In an experiment, 1.405 g of CoSO4•xH2O is heated until all the water is given off.
The mass of CoSO4 that remains is 0.775 g.
[Mr: CoSO4, 155; H2O, 18]
Determine the value of x using the following steps.
●
Calculate the number of moles of CoSO4 that remains.
.............................. mol
●
Calculate the mass of H2O given off.
.............................. g
●
Calculate the number of moles of H2O given off.
.............................. mol
●
Determine the value of x.
x = ..............................
[4]
[Total: 17]
© UCLES 2024
0620/41/M/J/24
[Turn over
10
6
This question is about metals.
(a) Fig. 6.1 shows a blast furnace used to extract iron from its ore.
waste gases
air
air
slag
A
Fig. 6.1
(i)
Coke and iron ore are added at the top of the blast furnace.
Name one other substance that is added at the top of the blast furnace.
....................................................................................................................................... [1]
(ii)
Name the substance that leaves the blast furnace at A.
....................................................................................................................................... [1]
(iii)
Slag is produced from an impurity in iron ore.
Name the impurity in iron ore that is converted into slag.
....................................................................................................................................... [1]
(iv)
Name two substances that react together to produce the high temperature in the blast
furnace.
................................................................ and ............................................................... [1]
(v)
Name two waste gases that leave the blast furnace.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
© UCLES 2024
0620/41/M/J/24
11
(b) Zinc is produced from zinc oxide in a furnace.
The zinc is produced as a gas. It then forms molten zinc.
(i)
Suggest why the zinc produced inside the furnace is a gas.
....................................................................................................................................... [1]
(ii)
State the name of the physical change that occurs when gaseous zinc is converted into
molten zinc.
....................................................................................................................................... [1]
(c) Zinc is used to coat iron to prevent rusting.
(i)
Name the process used to coat iron with zinc as a method of rust prevention.
....................................................................................................................................... [1]
(ii)
When the zinc coating is scratched, the iron underneath does not rust.
Explain why the iron underneath the zinc does not rust.
.............................................................................................................................................
....................................................................................................................................... [2]
(d) Zinc oxide neutralises both acids and bases.
(i)
State the general name given to oxides that neutralise both acids and bases.
....................................................................................................................................... [1]
(ii)
When zinc oxide neutralises aqueous sodium hydroxide, sodium zincate is formed.
The formula of the zincate ion is ZnO22–.
Deduce the formula of sodium zincate.
....................................................................................................................................... [1]
(iii)
Name the zinc compound that forms when zinc oxide neutralises dilute sulfuric acid.
....................................................................................................................................... [1]
[Total: 14]
© UCLES 2024
0620/41/M/J/24
[Turn over
12
7
Many organic compounds contain carbon and hydrogen only.
(a) (i)
Organic compound A has the following composition by mass.
C, 82.76%;
H, 17.24%
Calculate the empirical formula of compound A.
empirical formula = .............................. [3]
(ii)
Compound B has the empirical formula CH2 and a relative molecular mass of 70.
Determine the molecular formula of compound B.
molecular formula = .............................. [1]
(b) Fig. 7.1 shows a section of polymer Q.
CH3 CH3 CH3 CH3
C
C
C
C
H
H
H
H
Fig. 7.1
●
Draw the displayed formula of the monomer that forms polymer Q.
●
Name the monomer used to form polymer Q.
.............................................................................................................................................
[3]
© UCLES 2024
0620/41/M/J/24
13
(c) Propene, C3H6, can be produced by heating C11H24. The products of the reaction are propene,
hydrogen and one other product in a 1 : 1 : 1 mole ratio.
Complete the symbol equation for this reaction.
C11H24 → C3H6 + H2 + ..................
[1]
(d) Carboxylic acids and esters contain carbon, hydrogen and oxygen only.
An ester X and a carboxylic acid Y both contain 3 carbon atoms.
X and Y have the same molecular formula.
(i)
State the name given to compounds with the same molecular formula but different structural
formulae.
....................................................................................................................................... [1]
(ii)
Esters are made by the reaction between carboxylic acids and alcohols.
Ester X is methyl ethanoate.
Name the carboxylic acid and the alcohol used to make methyl ethanoate.
carboxylic acid ....................................................................................................................
alcohol ................................................................................................................................
[2]
(iii)
Draw the displayed formula of carboxylic acid Y. Name the carboxylic acid.
name ...................................................................................................................................
[2]
[Total: 13]
© UCLES 2024
0620/41/M/J/24
[Turn over
© UCLES 2024
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/41/M/J/24
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
16
Cambridge IGCSE™
*5375001254*
CHEMISTRY
0620/42
Paper 4 Theory (Extended)
February/March 2023
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 12 pages.
IB23 03_0620_42/3RP
© UCLES 2023
[Turn over
2
1
This question is about gases found in clean, dry air and gases found in polluted air.
(a) Name one gas found in clean, dry air which contributes to global warming.
.............................................................................................................................................. [1]
(b) State the percentage of nitrogen in clean, dry air.
.............................................................................................................................................. [1]
(c) Name the substance used to remove sulfur dioxide in flue gas desulfurisation.
.............................................................................................................................................. [1]
(d) Nitrogen dioxide, NO2, is formed in car engines.
Name the equipment in a car exhaust used to remove the NO2 formed in car engines.
.............................................................................................................................................. [1]
(e) All gases diffuse.
(i)
Choose from the list of formulae the gas which diffuses most quickly.
Draw a circle around your answer.
CO
(ii)
CO2
CH4
NO2
SO2
[1]
Explain your answer to (i).
....................................................................................................................................... [1]
(f) State one adverse effect of carbon monoxide on human health.
.............................................................................................................................................. [1]
(g) Carbon dioxide, CO2, is a reactant in photosynthesis.
Name the two products of photosynthesis.
................................................................... and ................................................................... [2]
© UCLES 2023
0620/42/F/M/23
3
(h) Complete the dot-and-cross diagram in Fig. 1.1 for a molecule of CO2.
Show outer shell electrons only.
O
C
O
Fig. 1.1
[2]
[Total: 11]
© UCLES 2023
0620/42/F/M/23
[Turn over
4
2
Lithium, sodium and potassium are Group I elements.
(a) Name the type of bonding in these elements.
.............................................................................................................................................. [1]
(b) Sodium reacts with cold water to form hydrogen gas and a solution of a strong alkali.
(i)
State the test for hydrogen gas.
test ......................................................................................................................................
positive result ......................................................................................................................
[1]
(ii)
Suggest the pH of a solution of a strong alkali.
pH = .............................. [1]
(iii)
Name a substance which can be used to confirm the pH of a solution of a strong alkali.
....................................................................................................................................... [1]
(iv)
Write the symbol equation for the reaction between sodium and cold water.
Include state symbols.
....................................................................................................................................... [3]
(c) Lithium has two naturally occurring types of atoms, 6Li and 7Li.
(i)
State the name given to atoms of the same element with different nucleon numbers.
....................................................................................................................................... [1]
(ii)
Complete Table 2.1 to show the number of protons, neutrons and electrons in the atom
and ion of lithium shown.
Table 2.1
6
Li
7
Li+
protons
neutrons
electrons
[3]
© UCLES 2023
0620/42/F/M/23
5
(iii)
Table 2.2 shows the relative abundance of the two naturally occurring atoms of lithium.
Table 2.2
atom
6
Li
7
Li
relative abundance
10%
90%
Calculate the relative atomic mass of lithium to one decimal place.
relative atomic mass = .............................. [2]
(d) Potassium oxide, K2O, is an ionic compound.
Complete Fig. 2.1 to show the electronic configurations of the ions in potassium oxide.
Show the charges on the ions.
......
K
......
O
......
K
Fig. 2.1
[3]
[Total: 16]
© UCLES 2023
0620/42/F/M/23
[Turn over
6
3
The Haber process is used to manufacture ammonia.
(a) State the main source of each gas used in the Haber process.
nitrogen ......................................................................................................................................
hydrogen ....................................................................................................................................
[2]
(b) The equation for the Haber process is shown.
N2(g) + 3H2(g)
2NH3(g)
∆H = –92 kJ / mol
The reaction is reversible. The forward reaction is exothermic.
(i)
State what is meant by the symbol ∆H.
....................................................................................................................................... [1]
(ii)
∆H for the forward reaction is –92 kJ / mol.
State why this value shows that the forward reaction is exothermic.
....................................................................................................................................... [1]
(iii)
State the typical conditions and name the catalyst used in the Haber process.
temperature ............................. °C
pressure ................................. kPa
catalyst .........................................
[3]
(iv)
Complete Table 3.1 to show the effect, if any, when the typical conditions in the Haber
process are changed. Use only the words increases, decreases or no change.
Table 3.1
change to
typical conditions
effect on the rate of
the forward reaction
temperature increases
increases
effect on the concentration
of NH3(g) at equilibrium
pressure decreases
no catalyst
decreases
[4]
© UCLES 2023
0620/42/F/M/23
7
(v)
Explain in terms of collision theory why increasing the temperature increases the rate of
the reaction.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(c) Ammonia reacts with an acid to form ammonium sulfate, (NH4)2SO4.
(i)
State the formula of the acid used.
....................................................................................................................................... [1]
(ii)
State one use of ammonium sulfate.
....................................................................................................................................... [1]
(iii)
Calculate the percentage composition by mass of nitrogen in (NH4)2SO4.
percentage of nitrogen = ............................... % [2]
[Total: 18]
© UCLES 2023
0620/42/F/M/23
[Turn over
8
4
Copper is element 29 in the Periodic Table.
(a) Brass contains copper.
(i)
Name the other metal in brass.
....................................................................................................................................... [1]
(ii)
State the term given to a mixture of a metal with another element.
....................................................................................................................................... [1]
(b) Copper can be stretched into wires. Copper wires conduct electricity.
(i)
Name the property of metals which means that they can be stretched into wires.
....................................................................................................................................... [1]
(ii)
Name the particles responsible for the conduction of electricity in solid copper.
....................................................................................................................................... [1]
(c) Copper is a transition element.
Some physical and chemical properties of transition elements are shown.
physical properties:
● high density
● high strength
chemical properties:
● form coloured compounds
● have ions with variable oxidation numbers
(i)
State one other physical property of transition elements.
....................................................................................................................................... [1]
(ii)
State one other chemical property of transition elements.
....................................................................................................................................... [1]
© UCLES 2023
0620/42/F/M/23
9
(d) Hydrated copper(II) sulfate is a coloured compound. It exists as hydrated crystals which
contain water molecules.
(i)
State the term given to water molecules present in hydrated crystals.
....................................................................................................................................... [1]
(ii)
State the colour of hydrated copper(II) sulfate crystals.
....................................................................................................................................... [1]
(iii)
Write the formula of hydrated copper(II) sulfate.
....................................................................................................................................... [2]
(e) Copper(II) oxide is formed when copper(II) nitrate, Cu(NO3)2, is heated.
2Cu(NO3)2(s) → 2CuO(s) + 4NO2(g) + O2(g)
(i)
State the class of oxide to which copper(II) oxide belongs.
....................................................................................................................................... [1]
(ii)
State the meaning of the Roman numeral (II) in the name copper(II) oxide.
....................................................................................................................................... [1]
(iii)
0.0200 moles of Cu(NO3)2 is heated.
Calculate the mass of 0.0200 moles of Cu(NO3)2.
mass = .............................. g [2]
(iv)
Calculate the total volume of gas, in dm3 at r.t.p., produced when 0.0200 moles of
Cu(NO3)2 is heated.
volume = .............................. dm3 [2]
(v)
Powdered aluminium reduces copper(II) oxide.
Write the symbol equation for this reaction.
....................................................................................................................................... [2]
[Total: 18]
© UCLES 2023
0620/42/F/M/23
[Turn over
10
5
Propane, propene, propan-1-ol and propanoic acid are members of different homologous series.
Molecules of these substances contain three carbon atoms.
(a) Explain why members of a homologous series have similar chemical properties.
.............................................................................................................................................. [1]
(b) Name the homologous series to which propanoic acid belongs.
.............................................................................................................................................. [1]
(c) State the general formula of the homologous series to which propanoic acid belongs.
.............................................................................................................................................. [1]
(d) Propan-1-ol has an unbranched isomer.
●
Name this isomer.
....................................................................................................................................................
●
Draw the displayed formula of this isomer.
[2]
(e) Propane and propene can be manufactured by heating decane, C10H22, in the presence of a
catalyst. One other product is formed.
(i)
Complete the equation for this reaction.
C10H22 → ........................... + ........................... + ...........................
(ii)
[2]
Name this manufacturing process.
....................................................................................................................................... [1]
© UCLES 2023
0620/42/F/M/23
11
(f) Propene forms a polymer named poly(propene).
(i)
Draw the displayed formula of a section of poly(propene) showing three repeat units.
[2]
(ii)
State the type of polymerisation that occurs when propene forms poly(propene).
....................................................................................................................................... [1]
(g) Propanoic acid reacts with aqueous sodium carbonate to form a salt.
(i)
Suggest the name of the salt formed.
....................................................................................................................................... [1]
(ii)
Suggest the formula of the anion in this salt.
....................................................................................................................................... [1]
(h) Propanoic acid forms an ester when it reacts with ethanol in the presence of a catalyst.
(i)
Suggest a suitable catalyst.
....................................................................................................................................... [1]
(ii)
Name the ester formed.
....................................................................................................................................... [1]
(iii)
Draw the displayed formula of this ester.
[2]
[Total: 17]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
© UCLES 2023
0620/42/F/M/23
© UCLES 2023
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/42/F/M/23
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
12
Cambridge IGCSE™
*3062140036*
CHEMISTRY
0620/41
Paper 4 Theory (Extended)
May/June 2023
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB23 06_0620_41/3RP
© UCLES 2023
[Turn over
2
1
Some symbol equations and word equations, A to J, are shown.
A
Fe3+ + 3OH– → Fe(OH)3
B
H+ + OH– → H2O
C
ethane + chlorine → chloroethane + hydrogen chloride
D
C12H26 → C8H18 + C4H8
E
ethene + steam → ethanol
F
chlorine + aqueous potassium iodide → iodine + aqueous potassium chloride
G
C6H12O6 → 2C2H5OH + 2CO2
H
ethanoic acid + ethanol → ethyl ethanoate + water
I
calcium carbonate → calcium oxide + carbon dioxide
J
6CO2 + 6H2O → C6H12O6 + 6O2
Use the equations to answer the questions that follow.
Each equation may be used once, more than once, or not at all.
Give the letter, A to J, for the equation that represents:
(a) a neutralisation reaction ...................................................................................................... [1]
(b) a precipitation reaction ........................................................................................................ [1]
(c) the formation of an ester ...................................................................................................... [1]
(d) photosynthesis ..................................................................................................................... [1]
(e) fermentation ......................................................................................................................... [1]
(f) cracking. .............................................................................................................................. [1]
[Total: 6]
© UCLES 2023
0620/41/M/J/23
3
2
(a) The symbols of the elements in Period 2 of the Periodic Table are shown.
Li
Be
B
C
N
O
F
Ne
Use the symbols of the elements in Period 2 to answer the questions that follow.
Each symbol may be used once, more than once or not at all.
Give the symbol of the element that:
(i)
makes up approximately 78% of clean, dry air ............................................................. [1]
(ii)
contains atoms with only three electrons in the outer shell .......................................... [1]
(iii)
contains atoms with only nine protons .......................................................................... [1]
(iv)
exists as graphite .......................................................................................................... [1]
(v)
is an alkali metal ........................................................................................................... [1]
(vi)
only has an oxidation number of zero. ......................................................................... [1]
(b) Boron, B, has two isotopes.
(i)
State the meaning of the term isotopes.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Table 2.1 shows the relative masses and the percentage abundances of the two isotopes
of boron.
Table 2.1
relative mass of isotope
percentage abundance of isotope
10
20
11
80
Calculate the relative atomic mass of boron to one decimal place.
relative atomic mass = .............................. [2]
[Total: 10]
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3
This question is about ionic and covalent compounds.
(a) (i)
Sodium reacts with oxygen to form the ionic compound sodium oxide.
The electronic configurations of an atom of sodium and an atom of oxygen are shown in
Fig. 3.1.
sodium atom
oxygen atom
Na
O
Fig. 3.1
Ions are formed by the transfer of electrons from sodium atoms to oxygen atoms.
Complete the dot-and-cross diagrams in Fig. 3.2 to show the electronic configuration of
one sodium ion and one oxide ion. Show the charges on the ions.
sodium ion
oxide ion
.....
.....
Na
O
Fig. 3.2
[3]
(ii)
Write the formula of sodium oxide.
....................................................................................................................................... [1]
(b) Carbon dioxide, CO2, is a covalent compound.
Complete the dot-and-cross diagram in Fig. 3.3 to show the electronic configuration in a
molecule of carbon dioxide. Show outer shell electrons only.
O
C
O
Fig. 3.3
[2]
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(c) The melting points of sodium oxide and carbon dioxide are shown in Table 3.1.
Table 3.1
melting point / °C
(i)
sodium oxide
1275
carbon dioxide
–78
Explain, in terms of bonding, why sodium oxide has a high melting point.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Carbon dioxide has a low melting point.
State the general term for the weak forces that cause carbon dioxide to have a low melting
point.
....................................................................................................................................... [1]
[Total: 9]
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4
Oxygen is produced by the decomposition of aqueous hydrogen peroxide. Manganese(IV) oxide,
MnO2, is a catalyst for this reaction.
(a) State the meaning of the term catalyst.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) A student adds powdered manganese(IV) oxide to aqueous hydrogen peroxide in a conical
flask as shown in Fig. 4.1. The mass of the conical flask and its contents is measured at regular
time intervals. The mass decreases as time increases.
loosely fitting
cotton wool plug
aqueous
hydrogen peroxide
powdered
manganese(IV) oxide
(catalyst)
balance
Fig. 4.1
(i)
State why the mass of the conical flask and its contents decreases as time increases.
....................................................................................................................................... [1]
(ii)
The rate of reaction is highest at the start of the reaction. The rate decreases and eventually
becomes zero.
Explain why the rate of reaction is highest at the start of the reaction.
.............................................................................................................................................
....................................................................................................................................... [1]
(iii)
Explain why the rate of reaction eventually becomes zero.
.............................................................................................................................................
....................................................................................................................................... [1]
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(c) The experiment is repeated at an increased temperature.
All other conditions stay the same.
Explain in terms of collision theory why the rate of reaction is higher at an increased temperature.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(d) The equation for the decomposition of aqueous hydrogen peroxide, H2O2(aq), is shown.
2H2O2(aq) → 2H2O(l) + O2(g)
50.0 cm3 of a 0.200 mol / dm3 solution of H2O2(aq) is used.
Calculate the mass of O2 that forms.
Use the following steps.
●
Calculate the number of moles of H2O2 used.
.............................. mol
●
Determine the number of moles of O2 produced.
.............................. mol
●
Calculate the mass of O2 produced.
.............................. g
[3]
(e) State the effect on the mass of oxygen produced if the mass of powdered manganese(IV) oxide
catalyst is increased.
.............................................................................................................................................. [1]
(f) Oxygen can also be produced by the decomposition of mercury(II) oxide, HgO.
The only products of this decomposition are mercury and oxygen.
Write a symbol equation for this decomposition.
.............................................................................................................................................. [2]
[Total: 14]
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5
This question is about electricity and chemical reactions.
(a) The electrolysis of concentrated aqueous potassium bromide using graphite electrodes forms:
● hydrogen at the cathode
● bromine at the anode.
The electrolyte becomes aqueous potassium hydroxide.
(i)
State what is meant by the term electrolysis.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
State why graphite is suitable for use as an electrode.
....................................................................................................................................... [1]
(iii)
Write an ionic half-equation for the formation of hydrogen at the cathode.
....................................................................................................................................... [2]
(iv)
Name the type of particle responsible for the transfer of charge in the conducting wires.
....................................................................................................................................... [1]
(v)
Name the type of particle responsible for the transfer of charge in aqueous
potassium bromide.
....................................................................................................................................... [1]
(vi)
State the names of the products formed when electricity is passed through dilute aqueous
potassium bromide using graphite electrodes.
at the anode ........................................................................................................................
at the cathode ......................................................................................................................
[2]
(b) Bauxite is an ore containing aluminium.
Aluminium is extracted by electrolysis of purified bauxite in molten cryolite using carbon
electrodes.
(i)
Name the aluminium compound in purified bauxite.
....................................................................................................................................... [1]
(ii)
State two reasons why cryolite is used in this electrolysis.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
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(iii)
The anode is made from carbon.
Explain why the carbon anode has to be replaced regularly.
.............................................................................................................................................
....................................................................................................................................... [1]
(c) Hydrogen–oxygen fuel cells can be used to produce electricity in vehicles.
(i)
Write the symbol equation for the overall reaction in a hydrogen–oxygen fuel cell.
....................................................................................................................................... [2]
(ii)
State one advantage of using hydrogen–oxygen fuel cells instead of petrol in vehicle
engines.
....................................................................................................................................... [1]
[Total: 16]
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6
This question is about sulfur and compounds of sulfur.
Sulfur is converted into sulfuric acid, H2SO4, by the Contact process.
The process involves four stages.
stage 1
Molten sulfur is converted into sulfur dioxide.
stage 2
Sulfur dioxide reacts with oxygen to form sulfur trioxide.
stage 3
Sulfur trioxide combines with concentrated sulfuric acid to form oleum, H2S2O7.
stage 4
Oleum reacts to form concentrated sulfuric acid.
(a) (i)
In stage 1, iron pyrites, FeS2, can be used instead of molten sulfur.
The iron pyrites is heated strongly in air.
Balance the equation for the reaction occurring when iron pyrites reacts with oxygen in the
air.
.....FeS2 + .....O2 → .....Fe2O3 + .....SO2
(ii)
[1]
Name Fe2O3. Include the oxidation number of iron.
....................................................................................................................................... [1]
(b) The equation for stage 2 is shown.
2SO2(g) + O2(g)
2SO3(g)
The forward reaction is exothermic.
The reaction is carried out at a temperature of 450 °C and a pressure of 2 atm.
Using explanations that do not involve cost:
(i)
explain why a temperature greater than 450 °C is not used
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
explain why a pressure lower than 2 atm is not used.
.............................................................................................................................................
....................................................................................................................................... [1]
(c) When sulfuric acid reacts with ammonia the salt produced is ammonium sulfate.
Write the symbol equation for this reaction.
.............................................................................................................................................. [2]
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(d) Lead(II) sulfate is an insoluble salt.
Lead(II) sulfate can be made from aqueous ammonium sulfate using a precipitation reaction.
(i)
Name a solution that can be added to aqueous ammonium sulfate to produce a precipitate
of lead(II) sulfate.
....................................................................................................................................... [1]
(ii)
Write an ionic equation for this precipitation reaction. Include state symbols.
....................................................................................................................................... [3]
(iii)
The precipitate of lead(II) sulfate forms in an aqueous solution.
Describe how pure lead(II) sulfate can be obtained from the mixture.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
[Total: 13]
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7
This question is about organic compounds.
(a) Butane reacts with chlorine in a photochemical reaction.
C4H10 + Cl 2 → C4H9Cl + HCl
(i)
State the meaning of the term photochemical.
....................................................................................................................................... [1]
(ii)
An organic compound with the formula C4H9Cl is formed when one molecule of butane
reacts with one molecule of chlorine.
Draw the displayed formulae of two possible structural isomers with the formula C4H9Cl
formed in this reaction.
[2]
(b) The structure of compound A is shown in Fig. 7.1.
COOH H
C
C
H
CH2OH
Fig. 7.1
(i)
Deduce the molecular formula of compound A.
....................................................................................................................................... [1]
(ii)
There are three functional groups in compound A.
Name the homologous series of compounds that contain the following functional groups:
–C=C– ................................................................................................................................
–OH ....................................................................................................................................
–COOH. ..............................................................................................................................
[3]
(iii)
State what is observed when compound A is added to:
aqueous bromine ................................................................................................................
aqueous sodium carbonate. ...............................................................................................
[2]
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(iv)
Compound A can be used as a single monomer to produce two different polymers.
Draw one repeat unit of the addition polymer formed from compound A.
[2]
(v)
Compound A can be converted into a dicarboxylic acid.
Name the type of condensation polymer formed from a dicarboxylic acid and a diol.
....................................................................................................................................... [1]
[Total: 12]
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15
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Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
© UCLES 2023
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© UCLES 2023
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/41/M/J/23
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
16
Cambridge IGCSE™
*5023388906*
CHEMISTRY
0620/43
Paper 4 Theory (Extended)
October/November 2023
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB23 11_0620_43/3RP
© UCLES 2023
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1
A list of substances is shown.
barium nitrate
carbon monoxide
hydrated cobalt(II) chloride
copper(II) oxide
anhydrous copper(II) sulfate
ethane
potassium iodide
propene
sodium bromide
sulfur dioxide
zinc oxide
Answer the following questions using only the substances from the list.
Each substance may be used once, more than once or not at all.
Give the name of the substance that:
(a) gives a lilac colour in a flame test
.............................................................................................................................................. [1]
(b) forms a cream precipitate when its aqueous solution reacts with acidified aqueous silver nitrate
.............................................................................................................................................. [1]
(c) is an acidic oxide
.............................................................................................................................................. [1]
(d) is an unsaturated hydrocarbon
.............................................................................................................................................. [1]
(e) is a product of incomplete combustion of fossil fuels
.............................................................................................................................................. [1]
(f) is used to test for the presence of water.
.............................................................................................................................................. [1]
[Total: 6]
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2
Table 2.1 gives information about particles A, B, C, D, E and F.
Table 2.1
particle
number of
electrons
number of
neutrons
number of
protons
A
5
6
5
B
10
11
10
C
10
14
13
D
18
17
16
E
18
17
17
F
15
16
15
(a) Give the letters of all the particles which are:
(i)
atoms
....................................................................................................................................... [1]
(ii)
ions with a charge of 2–
....................................................................................................................................... [1]
(iii)
cations.
....................................................................................................................................... [1]
(b) State the atomic number of A.
.............................................................................................................................................. [1]
(c) Determine the number of nucleons in D.
.............................................................................................................................................. [1]
(d) State the electronic configuration of D.
.............................................................................................................................................. [1]
(e) State the group number of F.
.............................................................................................................................................. [1]
(f) State the period number of B.
.............................................................................................................................................. [1]
[Total: 8]
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3
This question is about nitrogen and some of its compounds.
(a) Nitrogen is converted into ammonia, NH3, in the Haber process.
(i)
Nitrogen is obtained from air.
State the percentage of nitrogen in clean, dry air.
....................................................................................................................................... [1]
(ii)
State the source of hydrogen for the Haber process.
....................................................................................................................................... [1]
(iii)
Complete the dot-and-cross diagram in Fig. 3.1 for a molecule of ammonia.
Show the outer shell electrons only.
H
H
N
H
Fig. 3.1
[2]
(iv)
Write a chemical equation for the reaction occurring in the Haber process and give the
typical reaction conditions. Include units where appropriate.
chemical equation ...............................................................................................................
reaction conditions:
temperature ........................................................................................................................
pressure ..............................................................................................................................
catalyst ...............................................................................................................................
[5]
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(b) Ammonia is converted into nitric acid.
The first stage of this conversion uses a catalyst and occurs at a temperature of 900 °C and a
pressure of 5 atmospheres.
4NH3(g) + 5O2(g)
4NO(g) + 6H2O(g)
The forward reaction is exothermic.
(i)
Suggest which of the following elements is most likely to be used as a catalyst.
Draw a circle around your answer.
calcium
(ii)
lead
platinum
sodium
sulfur
[1]
State the oxidation number of nitrogen in:
NH3 .....................................................................................................................................
NO ......................................................................................................................................
[2]
(iii)
Use your answer to (ii) to explain whether the nitrogen in ammonia undergoes oxidation
or reduction.
.............................................................................................................................................
....................................................................................................................................... [1]
(iv)
Complete Table 3.1 using the words increases, decreases or no change.
Table 3.1
effect on the equilibrium
yield of NO(g)
effect on the rate of
the forward reaction
decreasing the pressure
decreasing the temperature
decreases
removing the catalyst
decreases
[4]
(v)
Decreasing the temperature causes the rate of the forward reaction to decrease.
Explain, using collision theory, why the rate of the reaction is slower at the decreased
temperature.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
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(c) In the second stage, nitric acid is produced.
Balance the symbol equation for this reaction.
.....NO + .....O2 + .....H2O → .....HNO3
[1]
[Total: 21]
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4
This question is about sulfuric acid and salts that are made from sulfuric acid.
(a) Zinc reacts with dilute sulfuric acid. Aqueous zinc sulfate is one of the products.
Powdered zinc is added to dilute sulfuric acid. The mixture is stirred. More zinc is added, with
stirring, until the zinc is in excess.
Zn(s) + H2SO4(aq) → ZnSO4(aq) + H2(g)
The mixture is then filtered.
(i)
Name the limiting reactant.
....................................................................................................................................... [1]
(ii)
State two observations that indicate the zinc is in excess.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(iii)
Name the filtrate.
....................................................................................................................................... [1]
(iv)
Name two compounds which both react with dilute sulfuric acid to produce aqueous
zinc sulfate.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(b) Zinc sulfate crystals are produced by heating aqueous zinc sulfate until a saturated solution is
formed. When the saturated solution cools down, crystals of zinc sulfate start to form.
(i)
State what is meant by the term saturated solution.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
Explain why crystals form when the saturated solution cools down.
....................................................................................................................................... [1]
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(c) Nickel(II) sulfate crystals contain water of crystallisation.
When nickel(II) sulfate crystals, NiSO4•xH2O, are heated, they give off water.
NiSO4•xH2O(s) → NiSO4(s) + xH2O(g)
A student carries out an experiment to determine the value of x in NiSO4•xH2O.
step 1
Nickel(II) sulfate crystals are weighed.
step 2
Nickel(II) sulfate crystals are heated.
step 3
The remaining solid is allowed to cool and is then weighed.
step 4
The remaining solid is heated again, allowed to cool and is then weighed.
step 5
Step 4 is repeated until there is no change in mass.
(i)
State the term used to describe crystals that contain water of crystallisation.
....................................................................................................................................... [1]
(ii)
State why step 4 is repeated until there is no change in mass.
....................................................................................................................................... [1]
(iii)
In an experiment, 0.454 g of nickel(II) sulfate crystals, NiSO4•xH2O, is used. The mass of
anhydrous nickel(II) sulfate, NiSO4, remaining is 0.310 g.
[Mr: NiSO4, 155; H2O, 18]
Determine the value of x in NiSO4•xH2O.
Use the following steps.
●
Calculate the number of moles of NiSO4 remaining.
●
Calculate the mass of H2O given off.
moles of NiSO4 = ..............................
mass of H2O = .............................. g
●
Calculate the number of moles of H2O given off.
moles of H2O = ..............................
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●
Calculate the value of x.
x = ..............................
[4]
[Total: 15]
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5
This question is about iron.
(a) (i)
Describe the bonding in a metallic element such as iron.
You may include a labelled diagram as part of your answer.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
(ii)
Explain why iron conducts electricity when it is solid.
....................................................................................................................................... [1]
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(b) Iron is extracted from hematite in the blast furnace as shown in Fig. 5.1.
waste gases
coke,
hematite,
limestone
air
air
slag
molten iron
Fig. 5.1
(i)
Give two reasons why coke is added to the blast furnace.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(ii)
Explain how limestone removes the impurities in the hematite.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iii)
Hematite contains iron(III) oxide.
Write a symbol equation for the conversion of iron(III) oxide to iron in the blast furnace.
....................................................................................................................................... [2]
(iv)
Suggest why the iron produced in the blast furnace is molten.
....................................................................................................................................... [1]
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12
(c) Most iron is converted into steel. Steel is an alloy.
Steel is more useful than pure iron because it is harder and stronger.
Explain why the structure of alloys causes them to be harder and stronger than pure metals.
You may include a diagram as part of your answer.
....................................................................................................................................................
.............................................................................................................................................. [2]
(d) Iron forms rust.
Rusting is prevented by coating iron with zinc.
(i)
Name the substances that react with iron to form rust.
....................................................................................................................................... [1]
(ii)
Name the process in which zinc is used to coat iron to prevent rusting.
....................................................................................................................................... [1]
(iii)
Explain how the coating of zinc prevents rusting if the zinc is not scratched.
....................................................................................................................................... [1]
(iv)
When zinc is scratched the iron becomes exposed.
Explain how the zinc continues to prevent rusting.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
[Total: 18]
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6
(a) Esters are members of a homologous series of organic compounds.
Give two characteristics that are the same for all members of a homologous series.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
(b) Ester X has the structure shown in Fig. 6.1.
H
H
H
C
C
H
H
O
C
O
H
H
C
C
H
H
H
Fig. 6.1
Name ester X.
.............................................................................................................................................. [1]
(c) (i)
Ester Y has the structural formula HCOOCH2CH2CH3.
Name the alcohol and the carboxylic acid used to make ester Y.
alcohol ................................................................................................................................
carboxylic acid ....................................................................................................................
[2]
(ii)
State the molecular formula of ester Y.
....................................................................................................................................... [1]
(d) Ester Z has the molecular formula C4H8O2.
State the empirical formula of ester Z.
.............................................................................................................................................. [1]
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14
(e) Polymers containing ester linkages are known as polyesters.
Polyamides are another type of polymer. Nylon is a polyamide.
The structure of nylon is shown in Fig. 6.2.
O
O
C
C
N
N
H
H
Fig. 6.2
(i)
State the term used to describe the type of polymerisation used to produce polyesters and
polyamides.
....................................................................................................................................... [1]
(ii)
Complete Fig. 6.3 to show the structures of the monomers used to produce nylon. Show
all of the atoms and all of the bonds.
Fig. 6.3
[2]
(f) Naturally occurring polyamides are found in food.
(i)
State the name given to naturally occurring polyamides.
....................................................................................................................................... [1]
(ii)
Name the type of monomer which forms naturally occurring polyamides.
....................................................................................................................................... [1]
[Total: 12]
© UCLES 2023
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© UCLES 2023
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/43/O/N/23
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
16
Cambridge IGCSE™
*0306701071*
CHEMISTRY
0620/41
Paper 4 Theory (Extended)
October/November 2023
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB23 11_0620_41/2RP
© UCLES 2023
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2
1
A list of gases is shown.
ammonia
carbon dioxide
carbon monoxide
ethene
fluorine
oxygen
sulfur dioxide
xenon
Answer the following questions using only the gases from the list.
Each gas may be used once, more than once or not at all.
Give the name of the gas that:
(a) causes acid rain
.............................................................................................................................................. [1]
(b) forms an alkaline solution when dissolved in water
.............................................................................................................................................. [1]
(c) is inert
.............................................................................................................................................. [1]
(d) is a product of photosynthesis
.............................................................................................................................................. [1]
(e) can form a polymer
.............................................................................................................................................. [1]
(f) is produced in the test for nitrate ions.
.............................................................................................................................................. [1]
[Total: 6]
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3
2
Boron and aluminium are Group III elements.
(a) Boron has only two naturally occurring isotopes, 10B and 11B.
Complete Table 2.1 to show the numbers of protons, neutrons and electrons in an atom of 11B.
Table 2.1
number of protons
number of neutrons
number of electrons
[2]
(b) The relative atomic mass of boron to one decimal place is 10.8.
(i)
Determine the relative abundance of 10B present in boron. Give your answer as a
percentage.
.............................. % [1]
(ii)
Use the relative atomic mass of boron to calculate the number of atoms in 0.540 g of
boron. Give your answer in standard form.
number of atoms = .............................. [2]
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4
(c) Aluminium is extracted from its purified ore as shown in Fig. 2.1.
+ power –
supply
anodes
+
+
electrolyte
wires
cathode
molten aluminium
Fig. 2.1
(i)
Name the ore of aluminium.
....................................................................................................................................... [1]
(ii)
The electrolyte contains aluminium oxide and one other substance.
Name the other substance and explain why it is used.
name ...................................................................................................................................
explanation .........................................................................................................................
.............................................................................................................................................
[2]
(iii)
Write the ionic half-equation for the reaction at the cathode.
....................................................................................................................................... [2]
(iv)
Explain why the anodes need frequent replacement.
.............................................................................................................................................
....................................................................................................................................... [2]
(d) State two physical properties of aluminium that make it suitable for use in overhead electrical
cables.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
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5
(e) Explain the apparent unreactivity of aluminium.
....................................................................................................................................................
.............................................................................................................................................. [2]
(f) Aluminium reacts with fluorine to form aluminium fluoride, Al F3, an ionic compound.
(i)
Write the symbol equation for this reaction.
....................................................................................................................................... [2]
(ii)
Complete Fig. 2.2 to show the electronic configuration of one aluminium ion and one
fluoride ion.
Show the charges on the ions.
.....
.....
Al
F
Fig. 2.2
[3]
[Total: 21]
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3
Order of reactivity can be determined by displacement reactions.
(a) A student investigates the reactivities of four metals by carrying out a series of experiments.
Each of the metals lead, manganese, silver and zinc are added separately to aqueous metal
nitrates of the other metals.
(i)
Table 3.1 shows some of the results.
Table 3.1
aqueous solution
lead
Pb
manganese
Mn
lead(II) nitrate
silver
Ag
zinc
Zn
✓
manganese(II) nitrate
silver nitrate
✓
✓
zinc nitrate
✗
✗
✓
key
✓ = displacement reaction occurs
✗ = displacement reaction does not occur
Complete Table 3.1 and place the four metals in their order of reactivity with the most
reactive first.
1 ......................................... most reactive
2 .........................................
3 .........................................
4 .........................................
[3]
(ii)
Suggest why the metal nitrates and not the metal sulfates of these four metals are used
as the aqueous solutions.
....................................................................................................................................... [1]
(iii)
Write the symbol equation for the reaction between zinc and silver nitrate.
....................................................................................................................................... [2]
© UCLES 2023
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7
(b) The reactivity of Group VII elements can be investigated experimentally.
A student bubbles chlorine gas into a test-tube containing aqueous potassium bromide.
(i)
Describe the colour change seen in the test-tube.
from .............................................................. to ........................................................... [2]
(ii)
Complete the ionic equation for this reaction.
Include state symbols.
............ + ....Br –(aq) → .................... + ....................
(iii)
[3]
The reactivity trend seen in Cl, Br and I applies to all the elements in Group VII.
Use the Periodic Table to identify the Group VII element which cannot displace any other
Group VII elements.
....................................................................................................................................... [1]
[Total: 12]
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8
4
Aqueous hydrogen peroxide, H2O2, slowly forms water and oxygen at room temperature and
pressure, r.t.p. This reaction is catalysed by manganese(IV) oxide.
The equation is shown.
2H2O2(aq) → 2H2O(l) + O2(g)
(a) State the test for oxygen gas.
test .............................................................................................................................................
observations ..............................................................................................................................
[1]
(b) A student investigates the rate of formation of oxygen gas when manganese(IV) oxide is
added to aqueous hydrogen peroxide.
The volume of oxygen gas formed is measured at regular time intervals at r.t.p. The results are
plotted onto the graph in Fig. 4.1.
volume of
oxygen gas
0
0
t1
t2
time
Fig. 4.1
(i)
State how the graph in Fig. 4.1 shows the rate of reaction at time t2, is lower than at
time t1.
....................................................................................................................................... [1]
(ii)
Explain, using collision theory, why the rate of reaction at time t2 is lower than at time t1.
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
(iii)
© UCLES 2023
On Fig. 4.1, sketch the graph obtained when the experiment is repeated using aqueous
hydrogen peroxide at a higher temperature. All other conditions remain the same.
[2]
0620/41/O/N/23
9
(c) Manganese(IV) oxide is added to 20 cm3 of aqueous hydrogen peroxide. The total volume of
oxygen gas produced is 72 cm3 at r.t.p.
2H2O2(aq) → 2H2O(l) + O2(g)
Calculate the concentration of the aqueous hydrogen peroxide in g / dm3 using the following
steps.
●
Calculate the number of moles of oxygen gas produced.
.............................. mol
●
Determine the number of moles of hydrogen peroxide which reacts.
.............................. mol
●
Calculate the concentration of aqueous hydrogen peroxide in mol / dm3.
.............................. mol / dm3
●
Calculate the concentration of aqueous hydrogen peroxide in g / dm3.
.............................. g / dm3
[5]
(d) Suggest the identity of one other metal oxide which also catalyses this reaction.
.............................................................................................................................................. [1]
[Total: 12]
© UCLES 2023
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10
5
Methane reacts with steam to produce hydrogen gas.
CH4(g) + H2O(g)
CO(g) + 3H2(g)
∆H = +200 kJ / mol
The reaction takes place at 1000 °C and 100 kPa pressure.
(a) The reaction is reversible and reaches an equilibrium in a closed system.
State two features of an equilibrium.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
(b) State and explain, in terms of equilibrium, what happens to the concentration of hydrogen
when:
(i)
the pressure is increased
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
the temperature is increased
.............................................................................................................................................
....................................................................................................................................... [2]
(iii)
a catalyst is used.
.............................................................................................................................................
....................................................................................................................................... [2]
(c) Methane is a greenhouse gas which contributes to global warming.
(i)
Name a greenhouse gas found in clean, dry air.
....................................................................................................................................... [1]
(ii)
Explain, in terms of thermal energy, how greenhouse gases cause global warming.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
[Total: 12]
© UCLES 2023
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11
6
Ethanol is manufactured by two methods:
method 1
fermentation of aqueous glucose
method 2
catalytic addition of steam to an alkene.
(a) Method 1 takes place at room temperature and pressure.
State two other conditions needed in method 1.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
(b) (i)
State the typical temperature and pressure used in method 2.
temperature .............................. °C
pressure .................................... kPa
[2]
(ii)
Name the alkene used in method 2.
....................................................................................................................................... [1]
(iii)
State why the reaction in method 2 is referred to as an addition reaction.
....................................................................................................................................... [1]
(c) The catalyst in method 2 is phosphoric acid, H3PO4. Dilute phosphoric acid is a weak acid
which contains phosphate ions, PO43–.
(i)
State what is meant by the term acid.
....................................................................................................................................... [1]
(ii)
State the meaning of weak in the term weak acid.
....................................................................................................................................... [1]
(iii)
Determine the oxidation number of phosphorus in the PO43– ion.
Show your working.
oxidation number = .............................. [2]
© UCLES 2023
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12
(d) Give one advantage of each method of production of ethanol.
method 1 ....................................................................................................................................
method 2 ....................................................................................................................................
[2]
(e) Ethanol can be converted to ethanoic acid by reacting it with an acidified oxidising agent.
(i)
Name the acidified oxidising agent.
....................................................................................................................................... [1]
(ii)
State, in terms of redox, what type of reagent ethanol is in this reaction.
....................................................................................................................................... [1]
(f) Ethanoic acid reacts with calcium to form a salt and one other product.
(i)
Name the salt.
....................................................................................................................................... [1]
(ii)
Write the formula of the salt.
....................................................................................................................................... [1]
(iii)
Identify the other product.
....................................................................................................................................... [1]
[Total: 17]
© UCLES 2023
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© UCLES 2023
12
V
Cr
Mn
Co
27
Ni
28
Cu
29
Zn
30
Fe
57–71
56
55
0620/41/O/N/23
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
rutherfordium
La
57
actinoids
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
59
nickel
The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
lanthanoids
–
Ra
radium
Fr
francium
89–103
178
104
137
88
133
87
Hf
hafnium
Ba
barium
lanthanoids
Cs
72
91
zirconium
Zr
40
48
titanium
caesium
89
yttrium
88
strontium
85
rubidium
Y
39
45
Sr
38
40
Ca
Rb
37
39
K
scandium
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
64
copper
–
californium
Cf
98
163
dysprosium
66
Dy
–
Cn
copernicium
112
201
Hg
mercury
80
112
cadmium
Cd
48
65
zinc
calcium
Ti
26
potassium
Sc
25
31
24
–
einsteinium
Es
99
165
holmium
67
Ho
–
Nh
nihonium
113
204
Tl
thallium
81
115
indium
In
49
70
gallium
Ga
27
20
24
19
23
aluminium
Al
13
11
boron
magnesium
23
1
sodium
22
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
Ge
32
28
silicon
Si
14
12
carbon
–
mendelevium
Md
101
169
thulium
69
Tm
–
Mc
moscovium
115
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
nobelium
No
102
173
ytterbium
70
Yb
–
Lv
livermorium
116
–
Po
polonium
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
oxygen
–
Lr
lawrencium
103
175
lutetium
71
Lu
–
Ts
tennessine
117
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
Og
oganesson
118
–
Rn
radon
86
131
xenon
54
Xe
84
krypton
36
Kr
40
argon
18
Ar
20
neon
Ne
10
4
helium
6
V
hydrogen
5
IV
He
Mg
21
relative atomic mass
name
atomic symbol
atomic number
Key
III
H
1
Group
Na
9
11
7
Be
beryllium
Li
4
3
lithium
II
I
The Periodic Table of Elements
16
* 0000800000001 *
,
,
Cambridge IGCSE™
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CHEMISTRY
Paper 4 Theory (Extended)
0620/43
October/November 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 20 pages. Any blank pages are indicated.
IB24 11_0620_43/4RP
© UCLES 2024
[Turn over
1
2
,
A list of substances is shown.
bauxite
carbon dioxide
cryolite
ethane
ethanol
ethene
graphite
helium
hematite
hydrogen
silicon(IV) oxide
sodium chloride
Answer the following questions using only the substances from the list.
Each substance may be used once, more than once or not at all.
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(a) is manufactured by fermentation
.............................................................................................................................................. [1]
(b) is monatomic
.............................................................................................................................................. [1]
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State which substance:
(d) is a solvent in the extraction of aluminium
.............................................................................................................................................. [1]
(e) is an ore of iron
.............................................................................................................................................. [1]
(f) is manufactured from methane
.............................................................................................................................................. [1]
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0620/43/O/N/24
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(c) is a reactant in photosynthesis
,
,
3
(g) is a compound with a giant covalent structure
.............................................................................................................................................. [1]
(h) is used as a lubricant
.............................................................................................................................................. [1]
(i) is tested for with limewater.
.............................................................................................................................................. [1]
[Total: 9]
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© UCLES 2024
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0620/43/O/N/24
[Turn over
(a) State the meaning of the term electrolysis.
....................................................................................................................................................
.............................................................................................................................................. [2]
(b) Table 2.1 gives some information about the electrolysis of two electrolytes using graphite
electrodes.
Table 2.1
anode
(positive electrode)
electrolyte
observation
name of product
aqueous
copper(II) sulfate
bubbles of
colourless gas
oxygen
concentrated aqueous
potassium iodide
(i)
(ii)
cathode
(negative electrode)
observation
bubbles of
colourless gas
name of product
pink-brown solid
Complete Table 2.1.
Oxygen is produced at the anode by the electrolysis of aqueous copper(II) sulfate.
[4]
Write the ionic half-equation for this reaction.
....................................................................................................................................... [2]
(c) Aqueous copper(II) sulfate is electrolysed using copper electrodes instead of graphite
electrodes.
(i)
Explain why the mass of the anode decreases during this electrolysis.
....................................................................................................................................... [1]
(ii)
Name the product formed at the cathode.
....................................................................................................................................... [1]
(iii)
State what change, if any, is observed in the appearance of the aqueous copper(II) sulfate.
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This question is about electrolysis.
4
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2
,
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[Total: 11]
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0620/43/O/N/24
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,
3
5
,
This question is about compounds of tin.
(a) Tin(IV) oxide has the formula SnO2.
The relative formula mass, Mr, of SnO2 is 151.
Calculate the percentage by mass of tin in SnO2.
percentage by mass of tin in SnO2 = ..............................% [1]
(b) SnO2 is an amphoteric oxide.
SnO2 reacts with aqueous sodium hydroxide, NaOH, to form a sodium salt and water only.
The sodium salt contains a negative ion with the formula SnO32–.
(i)
State the meaning of the term amphoteric.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
Write the symbol equation for the reaction between SnO2 and NaOH.
....................................................................................................................................... [2]
(c) Tin is a metal that forms both covalent and ionic compounds.
Suggest why this is unusual for a metal.
.............................................................................................................................................. [1]
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0620/43/O/N/24
[Turn over
(d) (i)
6
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,
Tin(IV) chloride, SnCl 4, is covalently bonded.
,
A tin atom has four electrons in its outer shell.
Complete the dot-and-cross diagram in Fig. 3.1 for a molecule of SnCl 4.
Show the outer shell electrons only.
Cl
Sn
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Cl
Cl
Cl
Fig. 3.1
(ii)
[2]
Tin(II) oxide, SnO, is ionically bonded.
The melting points of SnCl 4 and SnO are shown in Table 3.1.
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* 0000800000006 *
SnCl 4
SnO
melting point / °C
–33
1080
Explain, in terms of structure and bonding, why SnCl 4 has a much lower melting point than
SnO.
.............................................................................................................................................
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Table 3.1
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [3]
© UCLES 2024
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,
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,
(e) Part of the reactivity series is shown.
7
magnesium
aluminium
tin
copper
(i)
most reactive
least reactive
When aluminium foil is added to aqueous tin(II) sulfate, a reaction does not occur even
though aluminium is above tin in the reactivity series.
Explain why a reaction does not occur.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
An aqueous solution of tin(II) sulfate contains Sn2+ ions.
Two experiments are carried out.
Experiment 1
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Experiment 2
Copper is added to aqueous tin(II) sulfate.
Magnesium is added to aqueous tin(II) sulfate.
Write an ionic equation for any reaction that occurs in each experiment.
If no reaction occurs, write ‘no reaction’.
Experiment 1 ......................................................................................................................
Experiment 2 ......................................................................................................................
[2]
(f) Hydrated tin(II) nitrate, Sn(NO3)2•20H2O, decomposes when it is heated.
(i)
State what is meant by the term hydrated.
.............................................................................................................................................
....................................................................................................................................... [1]
(ii)
Complete the equation for the decomposition of Sn(NO3)2•20H2O.
2Sn(NO3)2•20H2O → ......SnO + ......NO2 + O2 + ......H2O
[2]
[Total: 16]
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0620/43/O/N/24
[Turn over
(a) Dilute sulfuric acid and aqueous sodium hydroxide can be used to prepare sodium sulfate
crystals using a method that involves titration.
The apparatus for titration is shown in Fig. 4.1.
dilute sulfuric acid
conical flask
25.0 cm3 aqueous
sodium hydroxide
0.100 mol / dm3
Fig. 4.1
Thymolphthalein is used as an indicator for this titration.
(i)
State the colour change of thymolphthalein at the end-point of this titration.
from ............................................................ to ............................................................. [2]
(ii)
Suggest why universal indicator is not used for this titration.
.............................................................................................................................................
....................................................................................................................................... [1]
© UCLES 2024
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0620/43/O/N/24
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This question is about sulfuric acid, H2SO4.
8
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,
The equation for the reaction is shown.
2NaOH + H2SO4 → Na2SO4 + 2H2O
Calculate the concentration of H2SO4 using the following steps.
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Calculate the number of moles of NaOH used.
.............................. mol
●
Determine the number of moles of H2SO4 that react with the NaOH.
.............................. mol
●
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9
,
(b) 25.0 cm3 of aqueous sodium hydroxide, NaOH, of concentration 0.100 mol / dm3 is neutralised
by 20.0 cm3 of dilute sulfuric acid, H2SO4.
●
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Calculate the concentration of H2SO4.
.............................. mol / dm3
[3]
(c) A student is provided with an aqueous solution of sodium sulfate.
Describe how to prepare a pure sample of sodium sulfate crystals from this solution.
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [3]
(d) Potassium hydrogen sulfate, KHSO4, can be prepared by a reaction between aqueous
potassium hydroxide and dilute sulfuric acid. Water is the only other product.
Write a symbol equation for this reaction.
.............................................................................................................................................. [1]
© UCLES 2024
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[Turn over
,
10
,
(e) Potassium hydrogen sulfate, KHSO4, dissolves in water to form solution X.
Solution X contains K+, H+ and SO42– ions.
Name the type of solution that contains H+ ions.
....................................................................................................................................... [1]
A flame test is carried out on X.
.............................................................................................................................................
●
Solid copper(II) carbonate is added to X.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
●
Aqueous barium nitrate acidified with dilute nitric acid is added to X.
.............................................................................................................................................
[5]
(f) 0.325 g of Zn is added to dilute sulfuric acid which contains 0.0100 moles of H2SO4.
The equation for this reaction is shown.
Zn + H2SO4 → ZnSO4 + H2
(i)
Determine whether Zn or H2SO4 is the limiting reactant.
Explain your answer.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
....................................................................................................................................... [2]
© UCLES 2024
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0620/43/O/N/24
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State the observations when the following tests are done.
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(ii)
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(i)
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,
(ii)
,
11
In another experiment, 48.0 cm3 of hydrogen gas, H2, is produced. The experiment is
carried out at room temperature and pressure, r.t.p.
Calculate the number of molecules in 48.0 cm3 of H2 gas measured at r.t.p.
The value of the Avogadro constant is 6.02 × 1023.
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.............................. molecules [2]
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[Total: 20]
© UCLES 2024
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0620/43/O/N/24
[Turn over
The equation for the reaction is shown.
2H2O2(aq) → 2H2O(l) + O2(g)
The student uses the apparatus shown in Fig. 5.1.
loosely fitting cotton wool
manganese(IV) oxide
catalyst
aqueous hydrogen peroxide
container
balance
Fig. 5.1
The student:
● adds the catalyst to the aqueous hydrogen peroxide
● replaces the container on the balance
● starts a stop-watch
● records the mass at regular time intervals.
(a) Table 5.1 shows the mass recorded at regular time intervals.
Table 5.1
time / s
mass / g
30
49.80
0
60
90
120
150
180
210
240
270
(i)
50.64
49.38
49.17
49.07
49.02
48.99
48.97
48.97
48.97
Suggest why the mass decreases as time increases.
....................................................................................................................................... [1]
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0620/43/O/N/24
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A student investigates the rate of decomposition of aqueous hydrogen peroxide, H2O2, using
manganese(IV) oxide as a catalyst.
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This question is about rate of reaction and equilibrium.
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5
12
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,
(ii)
,
13
After a certain time the reaction stops.
Explain why the reaction stops.
....................................................................................................................................... [1]
(iii)
Suggest why it is not possible to use the results in Table 5.1 to determine the exact time
when the reaction stops.
....................................................................................................................................... [1]
(b) Fig. 5.2 shows a graph of the mass against time.
mass / g
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.............................................................................................................................................
0
time / s
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Fig. 5.2
The experiment is repeated at a higher temperature.
All other conditions remain the same.
(i)
Explain, in terms of collision theory, why the rate of reaction is higher at a higher temperature.
.............................................................................................................................................
.............................................................................................................................................
.............................................................................................................................................
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.............................................................................................................................................
....................................................................................................................................... [3]
(ii)
© UCLES 2024
On Fig. 5.2, sketch the line expected when the experiment is repeated at a higher
temperature.
[2]
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0620/43/O/N/24
[Turn over
....................................................................................................................................... [2]
(ii)
State how the mass of the catalyst has changed, if at all, at the end of the experiment.
....................................................................................................................................... [1]
(d) Nitrogen monoxide gas, NO, and oxygen gas, O2, react to produce nitrogen dioxide gas, NO2,
at room temperature.
The reaction can reach equilibrium. The equation is shown.
2NO(g) + O2(g)
2NO2(g)
∆H = –113 kJ / mol
NO(g) and O2(g) are passed into a beaker as shown in Fig. 5.3.
NO(g)
O2(g)
beaker
Fig. 5.3
(i)
Explain why the method shown in Fig. 5.3 will not allow the reaction to reach equilibrium.
....................................................................................................................................... [1]
(ii)
The apparatus is changed and equilibrium is reached.
The temperature of the equilibrium system is then increased and the position of equilibrium
shifts to the left.
Explain why the position of equilibrium shifts to the left.
....................................................................................................................................... [1]
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0620/43/O/N/24
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Explain the meaning of (IV) in manganese(IV) oxide.
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(i)
,
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14
(c) Manganese(IV) oxide is the catalyst in this reaction.
,
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,
(iii)
,
15
The pressure of the equilibrium system is then increased.
State the direction, if any, in which the position of equilibrium shifts.
Explain your answer.
direction ..............................................................................................................................
explanation .........................................................................................................................
[2]
[Total: 15]
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[Turn over
This question is about hydrocarbons.
(a) State the meaning of the term hydrocarbon.
.............................................................................................................................................. [1]
(b) Propene, C3H6, can be made from long-chain alkanes such as dodecane.
Dodecane contains 12 carbon atoms.
(i)
Deduce the molecular formula of dodecane.
....................................................................................................................................... [1]
(ii)
Name the type of reaction that occurs when long-chain alkanes are converted into shorter
chain alkenes.
....................................................................................................................................... [1]
(c) Propene is an unsaturated hydrocarbon.
Propene reacts with bromine.
(i)
State the meaning of the term unsaturated.
....................................................................................................................................... [1]
(ii)
Write the molecular formula of the product formed when propene reacts with bromine.
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0620/43/O/N/24
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6
16
,
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,
17
,
(d) A styrene molecule is represented as shown in Fig. 6.1.
H
C 6H 5
H
H
C
C
(i)
The molecular formula of styrene is C8H8.
Determine the empirical formula of styrene.
....................................................................................................................................... [1]
(ii)
Styrene can be polymerised into poly(styrene).
State the type of polymerisation that occurs when styrene is converted into poly(styrene).
....................................................................................................................................... [1]
(iii)
Draw the structure of one repeat unit of poly(styrene). Include all of the atoms and all of
the bonds.
The C6H5 group should be represented as C6H5.
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Fig. 6.1
[2]
[Total: 9]
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19
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publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
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V
Cr
24
Mn
25
Fe
26
Co
27
Ni
28
Cu
29
Zn
30
57–71
Fr
59
–
actinium
Ac
232
thorium
Th
90
89
140
cerium
139
231
protactinium
Pa
91
141
praseodymium
Pr
58
Ce
–
–
Db
dubnium
Rf
105
181
rutherfordium
lanthanum
57
La
actinoids
178
tantalum
Ta
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
seaborgium
Sg
106
184
tungsten
W
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
bohrium
Bh
107
186
rhenium
Re
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
hassium
Hs
108
190
osmium
Os
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
meitnerium
Mt
109
192
iridium
Ir
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
darmstadtium
Ds
110
195
platinum
Pt
78
106
palladium
Pd
46
59
nickel
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–
berkelium
Bk
97
159
terbium
65
Tb
–
roentgenium
Rg
111
197
gold
Au
79
108
silver
Ag
47
64
copper
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The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
–
Ra
radium
lanthanoids
–
francium
89–103
104
137
88
133
87
Hf
hafnium
Ba
barium
Cs
72
91
zirconium
Zr
40
48
titanium
–
einsteinium
Es
99
165
holmium
67
Ho
–
nihonium
Nh
113
204
thallium
Tl
81
115
indium
In
49
70
gallium
115
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
–
mendelevium
Md
101
169
thulium
69
Tm
–
moscovium
Mc
209
bismuth
114
207
lead
Bi
83
122
antimony
Sb
51
75
arsenic
As
Pb
82
tin
119
Sn
50
73
germanium
Ge
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–
californium
Cf
98
163
dysprosium
66
Dy
–
copernicium
Cn
112
201
mercury
Hg
80
112
cadmium
Cd
48
65
zinc
Ga
33
31
phosphorus
P
15
14
N
nitrogen
7
V
–
–
–
lawrencium
Lr
103
175
lutetium
71
Lu
–
tennessine
Ts
117
astatine
At
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
F
fluorine
9
VII
2
4
–
oganesson
Og
118
–
radon
Rn
86
131
xenon
Xe
54
84
krypton
Kr
36
40
argon
Ar
18
20
neon
Ne
10
helium
He
VIII
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nobelium
No
102
173
ytterbium
70
Yb
–
livermorium
Lv
116
–
polonium
Po
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
O
oxygen
8
VI
20
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0620/43/O/N/24
caesium
lanthanoids
89
56
88
55
85
yttrium
Y
39
45
strontium
Sr
38
40
Ca
32
28
silicon
Si
14
12
C
carbon
6
IV
,
rubidium
Rb
37
39
K
scandium
calcium
Ti
23
potassium
Sc
22
31
21
27
20
24
19
23
aluminium
Al
13
11
B
boron
5
magnesium
Mg
relative atomic mass
name
atomic symbol
atomic number
1
hydrogen
sodium
Na
12
11
9
beryllium
lithium
7
Be
4
3
Key
1
H
III
,
Li
II
I
Group
The Periodic Table of Elements
* 0000800000020 *
* 0000800000001 *
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Cambridge IGCSE™
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CHEMISTRY
Paper 4 Theory (Extended)
0620/42
October/November 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB24 11_0620_42/4RP
© UCLES 2024
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BLANK PAGE
0620/42/O/N/24
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2
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* 0000800000003 *
,
1
3
,
The formulae of the molecules A to I are shown in Table 1.1.
Table 1.1
molecule
formula
B
C2H5OH
D
CO2
F
NO2
H
O2
A
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C
E
G
I
C 2H 4
CO
Cl 2
N2
SO2
Answer the following questions about the molecules, A to I.
Each letter may be used once, more than once or not at all.
State which of the molecules A to I:
(a) is an element with a triple bond ........................................................................................... [1]
(b) is a product of photosynthesis ............................................................................................. [1]
(c) is used as a fuel ................................................................................................................... [1]
(d) turns limewater milky ........................................................................................................... [1]
(e) undergoes a substitution reaction with alkanes ................................................................... [1]
(f) is a colourless liquid at r.t.p. ................................................................................................ [1]
(g) is unsaturated ...................................................................................................................... [1]
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(h) is 21% of clean, dry air ........................................................................................................ [1]
(i) is a reactant in the Haber process. ...................................................................................... [1]
[Total: 9]
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0620/42/O/N/24
[Turn over
2
,
4
Aluminium is manufactured by the electrolysis of aluminium oxide.
(a) State the name of the main ore of aluminium.
.............................................................................................................................................. [1]
(b) Name the substance mixed with aluminium oxide to reduce the operating temperature of the
process.
.............................................................................................................................................. [1]
(c) Explain why the molten mixture in (b) conducts electricity.
.............................................................................................................................................. [1]
(d) Table 2.1 contains some information about the processes which take place at the anode and
the cathode.
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,
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* 0000800000004 *
(i)
(ii)
…………………………………….
Complete Table 2.1:
●
Write the number of electrons needed to balance the ionic half-equation for the
reaction at the anode.
●
Write the ionic half-equation for the reaction at the cathode.
[3]
State why the process at the anode is an oxidation.
....................................................................................................................................... [1]
(iii)
Oxygen is formed at the anode.
Explain why the main gas given off at the anode is carbon dioxide and not oxygen.
.............................................................................................................................................
....................................................................................................................................... [2]
(e) State why aluminium is used in food containers.
.............................................................................................................................................. [1]
© UCLES 2024
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0620/42/O/N/24
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2O2– → O2 + ......e–
cathode
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anode
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Table 2.1
,
5
,
(f) Aluminium reacts with fluorine to form the ionic compound aluminium fluoride.
Complete the dot-and-cross diagram in Fig. 2.1 of the ions in aluminium fluoride.
Give the charges on the ions.
.......
.......
Al
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* 0000800000005 *
F
.......
F
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.......
F
Fig. 2.1
[Total: 13]
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[3]
© UCLES 2024
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0620/42/O/N/24
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3
,
6
Sulfur forms two chlorides, P and Q.
Chloride P has the formula S2Cl 2. Chloride Q has the formula SCl 2.
(a) Both chlorides are covalently bonded and have low melting points.
Suggest, in terms of attraction between particles, why these chlorides have low melting points.
....................................................................................................................................................
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* 0000800000006 *
(b) Chloride P, S2Cl 2, forms when sulfur reacts with chlorine.
Write the symbol equation for this reaction.
.............................................................................................................................................. [1]
(c) Complete the dot-and-cross diagram in Fig. 3.1 of a molecule of chloride Q, SCl 2.
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.............................................................................................................................................. [2]
Cl
Fig. 3.1
[3]
(d) Chloride P is converted to chloride Q by reaction with chlorine in a closed system.
The reversible reaction reaches an equilibrium.
S2Cl 2(g) + Cl 2(g)
P
2SCl 2(g)
Q
The forward reaction is exothermic.
Suggest two changes to the conditions which will result in a decrease in the concentration of
chloride Q at equilibrium.
1 .................................................................................................................................................
2 .................................................................................................................................................
[2]
© UCLES 2024
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0620/42/O/N/24
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S
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Cl
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Show outer electrons only.
,
7
,
(e) The rate of the forward reaction in (d) is determined by collision theory.
The rate of reaction depends upon two factors:
●
●
the frequency of collisions between particles
the proportion of collisions which have energy greater than or equal to the activation
energy.
(i)
Define the term activation energy.
....................................................................................................................................... [1]
(ii)
Give the symbol for activation energy.
....................................................................................................................................... [1]
(iii)
Complete Table 3.1 to show the effect, if any, when the conditions are changed.
Use only the words increases, decreases or no change.
Table 3.1
effect on the
frequency of collisions
between particles
change to conditions
concentration of
chlorine is increased
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effect on the proportion of collisions
which have energy greater than
or equal to the activation energy
temperature is
increased
a catalyst is added
[5]
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© UCLES 2024
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0620/42/O/N/24
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8
,
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(f) The reaction of chloride P with chlorine is a redox reaction.
S2Cl 2(g) + Cl 2(g)
P
2SCl 2(g)
Q
The oxidation number of Cl in chloride P and chloride Q is –1.
Use oxidation numbers to explain why:
●
sulfur is oxidised in the forward reaction
.............................................................................................................................................
.............................................................................................................................................
●
chlorine is oxidised in the reverse reaction.
.............................................................................................................................................
.............................................................................................................................................
[4]
© UCLES 2024
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[Total: 19]
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9
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Question 4 starts on the next page.
© UCLES 2024
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0620/42/O/N/24
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4
10
,
Silver bromide, AgBr, is made when aqueous silver ethanoate, CH3COOAg, is added to aqueous
sodium bromide, NaBr.
The equation for the reaction is shown in equation 1.
equation 1
CH3COOAg + NaBr → CH3COONa + AgBr
The method includes the following steps.
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step 1 Add 200.0 cm3 of 0.0500 mol / dm3 CH3COOAg to a beaker.
This volume contains 0.0100 mol of Ag+ ions.
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* 0000800000010 *
step 2 Add 50.0 cm3 of aqueous NaBr. This volume contains 0.0100 mol of Br – ions.
A precipitate forms.
step 3 Filter the mixture.
step 4 Dry the solid residue until all the water is removed.
step 5 Record the mass of the dry residue.
(b) Name a different aqueous silver salt which could be used in step 1.
.............................................................................................................................................. [1]
(c) Use the information in step 2 to calculate the concentration of aqueous NaBr.
concentration = .............................. mol / dm3 [1]
(d) State the colour of the precipitate which forms in step 2.
.............................................................................................................................................. [1]
© UCLES 2024
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0620/42/O/N/24
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[1]
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Ag+(.......) + Br –(.......) → AgBr(.......)
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(a) Complete the ionic equation for the reaction by adding the missing state symbols.
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* 0000800000011 *
,
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11
(e) Use the information in step 1, step 2 and equation 1 to determine the number of moles of
AgBr formed. Use this value to calculate the mass of AgBr formed.
number of moles of AgBr = ..............................
mass of AgBr = .............................. g
[3]
(f) Name the salt dissolved in the filtrate in step 3.
.............................................................................................................................................. [1]
(g) The recorded mass of the dry residue in step 5 is greater than the mass calculated in (e)
because a step is missing from the procedure.
(i)
Suggest the missing step.
....................................................................................................................................... [1]
(ii)
Name the substance responsible for the greater mass of the dry residue.
....................................................................................................................................... [1]
(h) Barium sulfate can be made by the same method but with different aqueous solutions.
(i)
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,
Suggest two aqueous solutions which can be added together to make barium sulfate.
............................................................... and ................................................................ [2]
(ii)
Write the balanced symbol equation for this reaction.
....................................................................................................................................... [2]
[Total: 14]
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0620/42/O/N/24
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,
5
12
,
Alkenes are manufactured by cracking larger alkane molecules.
(a) State the source of the large alkane molecules used in cracking.
.............................................................................................................................................. [1]
(b) State two conditions needed for cracking large alkane molecules.
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* 0000800000012 *
2 .................................................................................................................................................
[2]
(c) When one molecule of dodecane, C12H26, is cracked, three molecules of but-1-ene and one
other product are formed.
Use molecular formulae to complete the symbol equation for this reaction.
Suggest the type of chemical reaction which happens during cracking.
....................................................................................................................................... [1]
(d) Propene will undergo polymerisation.
(i)
Suggest the name of the polymer formed from propene.
....................................................................................................................................... [1]
(ii)
Draw part of this polymer molecule to show three repeat units.
[3]
(iii)
State the type of polymerisation propene undergoes.
....................................................................................................................................... [1]
[Total: 11]
© UCLES 2024
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0620/42/O/N/24
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(ii)
[2]
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C12H26 → ....................................... + .......................................
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(i)
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1 .................................................................................................................................................
,
,
13
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Question 6 starts on the next page.
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0620/42/O/N/24
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6
14
,
Polyamides and polyesters are polymers.
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,
Polyamides can occur naturally or can be manufactured.
(a) Part of the structure of a polyamide is shown in Fig. 6.1.
O
C
O
C
N
H
N
H
O
C
O
C
N
H
N
H
O
C
Fig. 6.1
On Fig. 6.1, draw a circle around one amide linkage.
[1]
(ii)
Complete Fig. 6.2 to show the structures of the two monomers needed to make the
polymer in Fig. 6.1.
Show all of the atoms and all of the bonds in the functional groups.
(iii)
[2]
Name the other product formed in this polymerisation.
....................................................................................................................................... [1]
(iv)
State the term given to natural polyamides.
....................................................................................................................................... [1]
(v)
Name the type of monomers which are used to make natural polyamides.
....................................................................................................................................... [1]
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Fig. 6.2
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(i)
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* 0000800000014 *
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* 0000800000015 *
,
(vi)
,
15
One of the monomers which forms part of a natural polyamide has three carbon atoms.
Complete Fig. 6.3 to show the displayed formula of this monomer.
C
H
Fig. 6.3
[3]
(b) PET is a polyester.
(i)
Name the two types of monomer molecules needed to make polyesters.
(ii)
Draw part of the structure of PET which shows two repeat units.
Show all of the atoms and all of the bonds in the linkages.
[3]
[Total: 14]
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............................................................... and ................................................................ [2]
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
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[Turn over
© UCLES 2024
ĬÍĊ®Ġ´íÈõÏĪÅĊßü¶Ą×
Ĭć­óÎĥČÿÙĀĉąċòÄÃýĂ
ĥåõÕµĕåõąõÕÅŵĥµåÕ
V
Cr
24
Mn
25
Fe
26
Co
27
Ni
28
Cu
29
Zn
30
57–71
Fr
59
–
actinium
Ac
232
thorium
Th
90
89
140
cerium
139
231
protactinium
Pa
91
141
praseodymium
Pr
58
Ce
–
–
Db
dubnium
Rf
105
181
rutherfordium
lanthanum
57
La
actinoids
178
tantalum
Ta
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
seaborgium
Sg
106
184
tungsten
W
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
bohrium
Bh
107
186
rhenium
Re
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
hassium
Hs
108
190
osmium
Os
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
meitnerium
Mt
109
192
iridium
Ir
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
darmstadtium
Ds
110
195
platinum
Pt
78
106
palladium
Pd
46
59
nickel
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–
berkelium
Bk
97
159
terbium
65
Tb
–
roentgenium
Rg
111
197
gold
Au
79
108
silver
Ag
47
64
copper
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The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
–
Ra
radium
lanthanoids
–
francium
89–103
104
137
88
133
87
Hf
hafnium
Ba
barium
Cs
72
91
zirconium
Zr
40
48
titanium
–
einsteinium
Es
99
165
holmium
67
Ho
–
nihonium
Nh
113
204
thallium
Tl
81
115
indium
In
49
70
gallium
115
–
fermium
Fm
100
167
erbium
68
Er
–
Fl
flerovium
–
mendelevium
Md
101
169
thulium
69
Tm
–
moscovium
Mc
209
bismuth
114
207
lead
Bi
83
122
antimony
Sb
51
75
arsenic
As
Pb
82
tin
119
Sn
50
73
germanium
Ge
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–
californium
Cf
98
163
dysprosium
66
Dy
–
copernicium
Cn
112
201
mercury
Hg
80
112
cadmium
Cd
48
65
zinc
Ga
33
31
phosphorus
P
15
14
N
nitrogen
7
V
–
–
–
lawrencium
Lr
103
175
lutetium
71
Lu
–
tennessine
Ts
117
astatine
At
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
F
fluorine
9
VII
2
4
–
oganesson
Og
118
–
radon
Rn
86
131
xenon
Xe
54
84
krypton
Kr
36
40
argon
Ar
18
20
neon
Ne
10
helium
He
VIII
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nobelium
No
102
173
ytterbium
70
Yb
–
livermorium
Lv
116
–
polonium
Po
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
O
oxygen
8
VI
16
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0620/42/O/N/24
caesium
lanthanoids
89
56
88
55
85
yttrium
Y
39
45
strontium
Sr
38
40
Ca
32
28
silicon
Si
14
12
C
carbon
6
IV
,
rubidium
Rb
37
39
K
scandium
calcium
Ti
23
potassium
Sc
22
31
21
27
20
24
19
23
aluminium
Al
13
11
B
boron
5
magnesium
Mg
relative atomic mass
name
atomic symbol
atomic number
1
hydrogen
sodium
Na
12
11
9
beryllium
lithium
7
Be
4
3
Key
1
H
III
,
Li
II
I
Group
The Periodic Table of Elements
* 0000800000016 *
* 0000800000001 *
,
,
Cambridge IGCSE™
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CHEMISTRY
Paper 4 Theory (Extended)
0620/41
October/November 2024
1 hour 15 minutes
You must answer on the question paper.
No additional materials are needed.
INSTRUCTIONS
●
Answer all questions.
●
Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
●
Write your name, centre number and candidate number in the boxes at the top of the page.
●
Write your answer to each question in the space provided.
●
Do not use an erasable pen or correction fluid.
●
Do not write on any bar codes.
●
You may use a calculator.
●
You should show all your working and use appropriate units.
INFORMATION
●
The total mark for this paper is 80.
●
The number of marks for each question or part question is shown in brackets [ ].
●
The Periodic Table is printed in the question paper.
This document has 16 pages. Any blank pages are indicated.
IB24 11_0620_41/3RP
© UCLES 2024
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,
© UCLES 2024
,
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ĥąµĕõµÅµÕŵąąµąĕõÕ
BLANK PAGE
0620/41/O/N/24
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2
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* 0000800000003 *
,
1
,
3
A list of chemical and physical processes, A to H, is shown.
A
B
C
D
E
F
G
H
combustion
diffusion
melting
neutralisation
photosynthesis
reversible reaction
roasting
thermal decomposition
Answer the following questions about processes A to H.
Each letter may be used once, more than once or not at all.
State which of the processes A to H:
(a) happens when an acid reacts with an alkali
.............................................................................................................................................. [1]
(b) reaches a position of equilibrium
.............................................................................................................................................. [1]
(c) involves particles changing from fixed positions to being mobile, but still touching
.............................................................................................................................................. [1]
(d) are physical changes
................................................................... and ................................................................... [1]
(e) is caused by gas particles colliding with each other.
.............................................................................................................................................. [1]
[Total: 5]
© UCLES 2024
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0620/41/O/N/24
[Turn over
2
4
,
This question is about atomic structure and the Periodic Table.
(a) Define the term nucleon number.
.............................................................................................................................................. [1]
(b) State the connection between the number of occupied electron shells in an atom and the
period number of that element.
.............................................................................................................................................. [1]
(c) Write the electronic configuration of the following atom and ion.
28
14Si ...............................................
37
–
17Cl .............................................
[2]
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,
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* 0000800000004 *
(d) Complete Table 2.1.
19 –
9F
number of
neutrons
9
10
31
38
11
number of
electrons
28
[5]
© UCLES 2024
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0620/41/O/N/24
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23
11Na
number of
protons
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atom or ion
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Table 2.1
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* 0000800000005 *
,
5
(e) A sample of thallium, Tl, contains two isotopes, 203 Tl and 205 Tl.
(i)
Define the term isotopes.
.............................................................................................................................................
....................................................................................................................................... [2]
(ii)
The relative abundance of 203 Tl : 205Tl is in the ratio 3 : 7.
Calculate the relative atomic mass of thallium in the sample to one decimal place.
relative atomic mass = .............................. [2]
(iii)
Suggest why these two isotopes have identical chemical properties.
....................................................................................................................................... [1]
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[Total: 14]
© UCLES 2024
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0620/41/O/N/24
[Turn over
A sample of aqueous copper(II) sulfate is made by adding excess copper(II) oxide, CuO, to hot
dilute sulfuric acid, H2SO4.
(a) Complete the symbol equation for this reaction. Include state symbols.
CuO(..........) + H2SO4(..........) → CuSO4(..........) + ...........................(l)
[2]
(b) State one observation which shows that copper(II) oxide is added in excess.
.............................................................................................................................................. [1]
(c) Describe how aqueous copper(II) sulfate can be separated from the reaction mixture.
.............................................................................................................................................. [1]
(d) Crystals of hydrated copper(II) sulfate can be obtained from aqueous copper(II) sulfate by
crystallisation.
(i)
State what is meant by the term hydrated.
....................................................................................................................................... [1]
(ii)
Write the formula of hydrated copper(II) sulfate.
....................................................................................................................................... [1]
(iii)
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,
Describe how this crystallisation is done.
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3
6
Copper(II) sulfate has the formula CuSO4. Aqueous copper(II) sulfate is a blue solution.
,
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* 0000800000006 *
....................................................................................................................................... [2]
© UCLES 2024
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0620/41/O/N/24
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.............................................................................................................................................
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* 0000800000007 *
7
(e) Aqueous copper(II) sulfate undergoes electrolysis using graphite electrodes.
,
(i)
,
State why aqueous copper(II) sulfate conducts electricity.
....................................................................................................................................... [1]
(ii)
Give two reasons why the electrodes are made of graphite.
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1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
(iii)
Describe how the appearance of the electrolyte changes during the electrolysis of aqueous
copper(II) sulfate.
....................................................................................................................................... [1]
(iv)
Describe what is seen at the cathode during the electrolysis of aqueous copper(II) sulfate.
....................................................................................................................................... [1]
(v)
Write the ionic half-equation for the reaction at the anode.
....................................................................................................................................... [3]
(vi)
State two differences seen if the electrolysis is repeated using copper electrodes instead
of graphite electrodes.
1 ..........................................................................................................................................
2 ..........................................................................................................................................
[2]
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[Total: 18]
© UCLES 2024
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0620/41/O/N/24
[Turn over
4
8
,
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,
When magnesium nitrate is heated strongly, magnesium oxide is formed.
(a) The equation for this reaction is shown.
2Mg(NO3)2 → 2MgO + 4NO2 + O2
(i)
State the change in oxidation number of nitrogen, N, in this reaction.
from ............................ to ............................
(ii)
[2]
Identify the element which is oxidised in this reaction.
....................................................................................................................................... [1]
(iii)
Calculate the volume of NO2 gas, at r.t.p., formed when 7.40 g of Mg(NO3)2 is heated.
Use the following steps.
●
Calculate the Mr of Mg(NO3)2.
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* 0000800000008 *
Calculate the number of moles of Mg(NO3)2 used.
.............................. mol
Determine the number of moles of NO2 formed.
.............................. mol
●
Calculate the volume of NO2 gas, in cm3, at r.t.p.
.............................. cm3
[4]
© UCLES 2024
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0620/41/O/N/24
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●
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..............................
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* 0000800000009 *
,
9
,
(b) Magnesium oxide, MgO, is an ionic compound.
Complete the dot-and-cross diagram in Fig. 4.1 of the ions in magnesium oxide.
Give the charges on each of the ions.
.......
.......
Mg
O
Fig. 4.1
[3]
(c) Oxygen is a covalent molecule.
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Complete the dot-and-cross diagram in Fig. 4.2 of a molecule of oxygen.
The inner shells have been drawn.
O
O
Fig. 4.2
[Total: 12]
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[2]
© UCLES 2024
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0620/41/O/N/24
[Turn over
Hydrogen is the first element of the Periodic Table.
(a) Hydrogen is used in fuel cells to produce electricity in vehicles.
Name the substance which combines with hydrogen in a fuel cell.
....................................................................................................................................... [1]
Give one advantage and one disadvantage of using fuel cells instead of gasoline in vehicle
engines.
advantage ...........................................................................................................................
disadvantage ......................................................................................................................
[2]
(b) Hydrogen gas can be made from petroleum by a two-step procedure.
step 1
Petroleum is separated into different components.
step 2
Large molecules obtained in step 1 are converted into smaller molecules including
hydrogen gas.
(i)
Name the process used in step 1.
....................................................................................................................................... [1]
(ii)
Name the process used in step 2.
....................................................................................................................................... [1]
(c) Organic compounds contain hydrogen atoms.
Calculate the number of hydrogen atoms in 44.0 g of the ester methyl propanoate,
CH3CH2COOCH3.
One mole of CH3CH2COOCH3 contains 6.02 × 1023 molecules.
Give your answer in standard form.
number of hydrogen atoms = .................................................. [4]
© UCLES 2024
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0620/41/O/N/24
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(ii)
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(i)
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5
10
,
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,
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* 0000800000010 *
,
11
,
(d) For each of the homologous series shown, name a member that contains six hydrogen atoms.
●
alkanes ............................................................
●
alkenes ............................................................
●
alcohols ...........................................................
●
carboxylic acids ...............................................
[4]
(e) Unsaturated alkenes are converted into saturated alkanes by reaction with hydrogen gas.
(i)
State why alkenes and alkanes are hydrocarbons.
....................................................................................................................................... [1]
(ii)
State why alkenes are unsaturated.
....................................................................................................................................... [1]
(iii)
Name the catalyst needed to convert alkenes into alkanes.
....................................................................................................................................... [1]
(iv)
Explain why the conversion of alkenes into alkanes is an addition reaction.
....................................................................................................................................... [1]
[Total: 17]
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© UCLES 2024
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Ĭăºñ×ğăöÞöý»÷³ÈěąĂ
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0620/41/O/N/24
[Turn over
,
6
,
12
Natural polyamides are polymers made from amino acid monomers.
(a) State the type of polymerisation reaction that occurs when natural polyamides form.
.............................................................................................................................................. [1]
(b) State the term given to natural polyamides.
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* 0000800000012 *
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.............................................................................................................................................. [1]
(c) An amino acid is represented as shown in Fig. 6.1.
H 2N
COOH
Fig. 6.1
Complete Fig. 6.2 to show the general structure of an amino acid.
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Show all of the atoms and all of the bonds in the functional groups.
C
H
[3]
© UCLES 2024
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0620/41/O/N/24
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Fig. 6.2
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* 0000800000013 *
,
13
,
(d) Three different amino acids are represented as shown in Fig. 6.3.
amino acid A
H 2N
COOH
amino acid B
H 2N
COOH
H2 N
COOH
Fig. 6.3
Complete the diagram in Fig. 6.4 to show the part of the structure of the natural polyamide that
forms when the three amino acids, A, B and C, combine.
Show all of the atoms and all of the bonds in the linkages.
Fig. 6.4
[3]
(e) A mixture of the three amino acids, A, B and C, can be separated and the amino acids
identified using paper chromatography.
Complete the equation for Rf.
Rf =
[2]
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amino acid C
© UCLES 2024
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0620/41/O/N/24
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,
14
(f) A sample of the mixture of the three amino acids, A, B and C, is placed onto the baseline and
a chromatogram is allowed to develop as shown in Fig. 6.5.
mixture
placed here
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The finished chromatogram is shown in Fig. 6.6.
baseline
solvent
Fig. 6.5
Fig. 6.6
The amino acids, A, B and C, are colourless. Water is used as the solvent.
(i)
Explain why the baseline is drawn in pencil.
....................................................................................................................................... [1]
(ii)
State the type of substance used to make the colourless amino acids visible on the
chromatogram in Fig. 6.6.
....................................................................................................................................... [1]
(iii)
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,
Explain why in Fig. 6.6 only two spots are seen from the mixture of three amino acids.
.............................................................................................................................................
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* 0000800000014 *
Suggest how the experiment can be changed to separate all three amino acids.
....................................................................................................................................... [1]
[Total: 14]
© UCLES 2024
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0620/41/O/N/24
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(iv)
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....................................................................................................................................... [1]
,
,
15
BLANK PAGE
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* 0000800000015 *
Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every
reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the
publisher will be pleased to make amends at the earliest possible opportunity.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
© UCLES 2024
ĬÏĊ®Ġ´íÈõÏĪÅĊÞüµĂ×
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0620/41/O/N/24
© UCLES 2024
ĬÍĊ®Ġ´íÈõÏĪÅĊàúµĄ×
Ĭă¹óÖġðþÐôĊĘÛĪÄëýĂ
ĥåõĕµõåµÕąĕąąÕąĕÅÕ
V
Cr
24
Mn
25
Fe
26
Co
27
Ni
28
Cu
29
Zn
30
Fr
59
–
actinium
Ac
232
thorium
Th
90
89
140
cerium
139
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
105
181
rutherfordium
lanthanum
57
La
actinoids
178
tantalum
Ta
73
93
niobium
Nb
41
51
vanadium
238
uranium
U
92
144
neodymium
60
Nd
–
seaborgium
Sg
106
184
tungsten
W
74
96
molybdenum
Mo
42
52
chromium
–
neptunium
Np
93
–
promethium
61
Pm
–
bohrium
Bh
107
186
rhenium
Re
75
–
technetium
Tc
43
55
manganese
–
plutonium
Pu
94
150
samarium
62
Sm
–
hassium
Hs
108
190
osmium
Os
76
101
ruthenium
Ru
44
56
iron
–
americium
Am
95
152
europium
63
Eu
–
meitnerium
Mt
109
192
iridium
Ir
77
103
rhodium
Rh
45
59
cobalt
–
curium
Cm
96
157
gadolinium
64
Gd
–
darmstadtium
Ds
110
195
platinum
Pt
78
106
palladium
Pd
46
59
nickel
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–
berkelium
Bk
97
159
terbium
65
Tb
–
roentgenium
Rg
111
197
gold
Au
79
108
silver
Ag
47
64
copper
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The volume of one mole of any gas is 24 dm3 at room temperature and pressure (r.t.p.).
actinoids
–
Ra
radium
lanthanoids
–
francium
89–103
104
137
88
133
87
Hf
hafnium
Ba
barium
Cs
72
91
zirconium
Zr
40
48
titanium
–
einsteinium
Es
99
165
holmium
67
Ho
–
nihonium
Nh
113
204
thallium
Tl
81
115
indium
In
49
70
gallium
–
fermium
Fm
100
167
erbium
68
Er
–
flerovium
Fl
114
207
lead
Pb
82
tin
119
Sn
50
73
germanium
–
mendelevium
Md
101
169
thulium
69
Tm
–
moscovium
Mc
115
209
bismuth
Bi
83
122
antimony
Sb
51
75
arsenic
As
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–
californium
Cf
98
163
dysprosium
66
Dy
–
copernicium
Cn
112
201
mercury
Hg
80
112
cadmium
Cd
48
65
zinc
Ge
33
31
phosphorus
P
15
14
N
nitrogen
7
V
–
–
–
–
lawrencium
Lr
103
175
lutetium
71
Lu
–
tennessine
Ts
117
astatine
At
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
F
fluorine
9
VII
2
4
–
–
oganesson
Og
118
radon
Rn
86
131
xenon
Xe
54
84
krypton
Kr
36
40
argon
Ar
18
20
neon
Ne
10
helium
He
VIII
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nobelium
No
102
173
ytterbium
70
Yb
–
livermorium
Lv
116
polonium
Po
84
128
tellurium
Te
52
79
selenium
Se
34
32
sulfur
S
16
16
O
oxygen
8
VI
16
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caesium
lanthanoids
57–71
56
55
89
yttrium
85
88
Y
39
45
scandium
strontium
Sr
38
40
Ga
32
28
silicon
Si
14
12
C
carbon
6
IV
,
rubidium
Rb
37
39
K
Ca
calcium
Ti
23
potassium
Sc
22
31
21
20
19
27
aluminium
23
24
Al
13
11
B
boron
5
magnesium
Mg
relative atomic mass
name
atomic symbol
atomic number
1
hydrogen
sodium
Na
12
11
9
beryllium
lithium
7
Be
4
3
Key
1
H
III
,
Li
II
I
Group
The Periodic Table of Elements
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