Cambridge Assessment International Education
Cambridge International General Certificate of Secondary Education
0620/43
CHEMISTRY
October/November 2019
s.
Paper 4 Theory (Extended)
rc
e
1 hour 15 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
re
so
u
*4049433183*
co
m
SOLVED BY SMART EXAM RESOURCES
te
xa
m
Write your centre number, candidate number and name on all the work you hand in.
Write in dark blue or black pen.
You may use an HB pencil for any diagrams or graphs.
Do not use staples, paper clips, glue or correction fluid.
DO NOT WRITE IN ANY BARCODES.
Answer all questions.
Electronic calculators may be used.
A copy of the Periodic Table is printed on page 16.
You may lose marks if you do not show your working or if you do not use appropriate units.
w
w
w
.s
m
ar
At the end of the examination, fasten all your work securely together.
The number of marks is given in brackets [ ] at the end of each question or part question.
This syllabus is regulated for use in England, Wales and Northern Ireland as a Cambridge International Level 1/Level 2 Certificate.
This document consists of 14 printed pages and 2 blank pages.
IB19 11_0620_43/2RP
© UCLES 2019
[Turn over
2
1
(a)Atoms are made of smaller particles called electrons, neutrons and protons.
Complete the table.
relative charge
Note: You will be able
to answer this
question if and only
if you have learnt by
heart your conceptsreally well!
relative mass
1
1840
electron
-1
neutron
0
1
proton
+1
1
co
m
particle
rc
e
(b)The table gives information about atoms and ions A, B and C.
s.
[2]
Complete the table.
number of
neutrons
number of
protons
symbol
A
13
14
13
27
13Al
B
10
13
12
25
2+
12Mg
te
xa
m
C
re
so
u
number of
electrons
10
10
9
19 9
F
Explanation
For row A;
27-14=13 electrons
w
w
w
.s
m
ar
For row B :
If there are 12 protons then there should have been 12 electrons. But the symbol of
the ion shows +2. Hence it indicates the loss of 2 electrons
© UCLES 2019
0620/43/O/N/19
[6]
[Total: 8]
3
2The table shows the melting points, boiling points and electrical conductivities of six substances
D, E, F, G, H and I.
melting point
/ °C
boiling point
/ °C
electrical conductivity
when solid
electrical conductivity
when liquid
D
1610
2230
non-conductor
non-conductor
E
801
1413
non-conductor
good conductor
F
–119
43
non-conductor
non-conductor
G
1535
2750
good conductor
good conductor
H
114
184
non-conductor
non-conductor
I
–210
–196
non-conductor
non-conductor
s.
co
m
substance
rc
e
Choose
substances from the table which match the following descriptions. Each substance may be
used once, more than once or not at all.
F
(a)Which substance is a liquid at 25 °C? ...................................................................................
[1]
I
re
so
u
(b)Which substance is a gas at 25 °C? ������������������������������������������������������������������������������������ [1]
(c)Which three substances contain simple molecules?
F,H and I
............................................................................................................................................... [3]
te
xa
m
(d)Which substance could be a metal? Give a reason for your answer.
G
substance ...................................................................................................................................
is a good conductor when in the solid state.
reason ..It
.......................................................................................................................................
ar
.....................................................................................................................................................
[2]
(e)Which substance has a macromolecular structure? Give two reasons for your answer.
m
D
substance ...................................................................................................................................
It has a high melting point.
.s
reason 1 ......................................................................................................................................
w
w
It is a non-conductor of elecricity when it is a solid or a liquid.
reason 2 ......................................................................................................................................
[3]
w
(f)Which substance is an ionic solid? Give one reason for your answer.
substance E
...................................................................................................................................
It only conducts electricity when it is a liquid
or
It only conducts electricity when it is a liquid but not when it is a solid.
.....................................................................................................................................................
reason .........................................................................................................................................
[2]
[Total: 12]
© UCLES 2019
0620/43/O/N/19
[Turn over
4
3
(a)Name the ore of aluminium which mainly consists of aluminium oxide.
Bauxite
...............................................................................................................................................
[1]
(b)Aluminium is produced by the electrolysis of aluminium oxide dissolved in molten cryolite.
co
m
waste gases
positive electrode
molten mixture of
aluminium oxide and cryolite
s.
negative electrode
rc
e
aluminium
It improves conductivity
re
so
u
(i)Give two reasons why the electrolysis is done using a molten mixture of aluminium oxide
and cryolite instead of molten aluminium oxide only.
or
It is a better conductor
1 ...........................................................................................................................................
It has a lower operating temperature.
2 ...........................................................................................................................................
[2]
te
xa
m
(ii)Write ionic half-equations for the reactions occurring at the electrodes.
2O2- --> O + 4e-
2
positive electrode .................................................................................................................
Al3+ + 3e- --> Al
negative electrode ...............................................................................................................
[2]
ar
(iii)The anodes are made of carbon and have to be replaced regularly.
Explain why the carbon anodes have to be replaced regularly.
m
carbon) react with oxygen to form carbondioxide.Hence they
..Anodes(or
............................................................................................................................................
.s
need to be replaced.
w
w
w
........................................................................................................................................ [2]
© UCLES 2019
0620/43/O/N/19
5
(c)The positions of some common metals in the reactivity series are shown.
most reactive
magnesium
aluminium
least reactive
copper
Write an ionic equation for the reaction. Include state symbols.
Mg(s) + Cu2+ (aq) --> Cu (s) + Mg2+ (aq)
co
m
(i)When magnesium is placed in aqueous copper(II) sulfate a displacement reaction occurs
********You lose one mark if you do not write the state symbols********
immediately.
s.
........................................................................................................................................ [2]
[1]mark->Writing correct ionis equation and another [1] mark for writing the state symbols.
rc
e
(ii)State two observations you would make when magnesium is placed in aqueous
copper(II) sulfate.
The solid dissolves [ or] The solid disappears
1 ...........................................................................................................................................
re
so
u
The blue colour of the solution fades [or] The solution becomes paler
2 ...........................................................................................................................................
[2]
Other accepted options: 1)Solution becomes colourless 2) Pink/Orange/Brown solid is formed
Explain why.
te
xa
m
(iii)When aluminium foil is added to aqueous copper(II) sulfate no immediate reaction takes
place.
Beacuse an unreactive coating of aluminium oxide is formed.
........................................................................................................................................ [1]
m
ar
(d)Aluminium powder reacts with iron(III) oxide to produce aluminium oxide and iron.
Note: As per the marking scheme, even if your
Write a chemical equation for this reaction. complete equation is not correct, still you get [1]
mark for simply mentioning Fe2O3 and Al2O3
+ Fe2O3 --> 2Fe + Al2O3
..2Al
.............................................................................................................................................
[2]
w
w
w
.s
[Total: 14]
© UCLES 2019
0620/43/O/N/19
[Turn over
6
4This question is about phosphorus and compounds of phosphorus.
(a)A phosphorus molecule contains four phosphorus atoms only.
What is the formula of a phosphorus molecule?
P4
............................................................................................................................................... [1]
co
m
(b)Phosphorus reacts with chlorine gas to produce phosphorus(III) chloride, PCl 3.
(i)Write a chemical equation for the reaction between phosphorus and chlorine to produce
phosphorus(III) chloride, PCl 3. Even if you do incorrect balancing, you still score a mark for
s.
writing correct symbols of reactants and products.
P........................................................................................................................................
4+ 6Cl2 --> 4 PCl3
[2]
re
so
u
rc
e
(ii)Complete the dot-and-cross diagram to show the electron arrangement in a molecule of
phosphorus(III) chloride, PCl 3. Show outer shell electrons only.
. ..
.
X
.. X.
. .
..
..
X
X
te
xa
m
..
Cl
P
w
w
w
.s
m
ar
Cl
© UCLES 2019
0620/43/O/N/19
Cl
[2]
7
(c)Gaseous phosphorus(III) chloride, PCl 3, reacts with gaseous chlorine to form gaseous
phosphorus(V) chloride, PCl 5.
PCl 3(g) + Cl 2(g)
PCl 5(g)
The chemical equation for this reaction can be represented as shown.
Cl
P
Cl
+
Cl
Cl
Cl
Cl
BOND BREAKING
Cl
P
Cl
Cl
co
m
Cl
BOND MAKING
P– Cl
326
Cl – Cl
243
rc
e
bond energy in kJ / mol
re
so
u
●●
bond
s.
(i)Use the bond energies in the table to calculate the energy change, in kJ / mol, of the
reaction.
Energy needed to break bonds.
●●
te
xa
m
Bond breaking=3(P-Cl) + 1(Cl-Cl)= (3 x 326) + (243)=1221
1221
.............................. kJ
Energy released when bonds are formed.
5( P-Cl)= 5 X (326) = 1630
ar
Bond forming =
1630
m
.............................. kJ
●●
Energy change of reaction.
w
w
w
.s
Energy Chnage=-409 kJ
-409
energy change = .............................. kJ / mol
Note: Negative sign in the final answer is essential [3]
(ii)Deduce whether the energy change for this reaction is exothermic or endothermic. Explain
your answer.
Exothermic and the energy released when bonds are formed is greater than the
..............................................................................................................................................
energy absorbed to break the bonds.
........................................................................................................................................ [1]
© UCLES 2019
0620/43/O/N/19
[Turn over
8
(d)Under certain conditions the reaction reaches equilibrium.
PCl 3(g) + Cl 2(g)
PCl 5(g)
State
and explain the effect, if any, on the position of equilibrium if the pressure is increased.
All other conditions are unchanged.
There are fewer moles on the right. Hence the equilibrium shifts to the right.
.....................................................................................................................................................
co
m
.....................................................................................................................................................
............................................................................................................................................... [2]
(e)Phosphine, PH3, is produced by the reaction between water and calcium phosphide, Ca3P2.
3
2
...........Ca(OH)
2 + ......PH3
rc
e
6 2O
Ca3P2 + ......H
s.
Balance the chemical equation for this reaction.
[2]
(f)The phosphonium ion, PH4+, is similar to the ammonium ion.
+
NH
re
so
u
4
(i)State the formula of the ammonium ion. �����������������������������������������������������������������������
[1]
PH I
4
(ii)Suggest the formula of phosphonium iodide. ���������������������������������������������������������������
[1]
(g)Calcium phosphate contains the phosphate ion, PO43–.
What is the formula of calcium phosphate?
te
xa
m
Ca PO )
3( 4 2
...............................................................................................................................................
[1]
ar
(h) Phosphorus forms another compound with hydrogen with the following composition by mass:
P, 93.94%; H, 6.06%.
(i)Calculate the empirical formula of the compound.
H
6.06/1=6.06
6.06/3.03=2
PH2
empirical formula = .............................. [2]
w
.s
m
P
93.94 /31=3.03
Moles=Mass/Mr=> 3.03/3.03=1
w
w
(ii)The compound has a relative molecular mass of 66.
Deduce the molecular formula of the compound.
Ar of hydrogen = 1;
Hence: 66 = x (Mr of PH2)
66 = x ( 31 +2(1)
x = 66/33=2
Hence Molecular formula = 2 x (PH2)= P2H4
P2H2
molecular formula = ..............................
[1]
[Total: 19]
© UCLES 2019
0620/43/O/N/19
9
5Nitrates such as ammonium nitrate are used as fertilisers.
The final stage in the production of ammonium nitrate is shown in the equation.
Ca(NO3)2 + 2NH3 + CO2 + H2O
2NH4NO3 + CaCO3
The relative formula mass, Mr, of calcium nitrate, Ca(NO3)2, = 164.
●●
Calculate the number of moles of Ca(NO3)2 in 820 g.
●●
re
so
u
rc
e
s.
Moles= Mass/Mr
= 820/ 164 =5
co
m
Calculate the maximum mass of ammonium nitrate that can be produced from 820 g of
calcium nitrate, Ca(NO3)2, using the following steps.
5
.............................. mol
Deduce the number of moles of NH4NO3 produced.
Ca(NO3)2 + 2NH3 + CO2 + H2O
2NH4NO3 + CaCO3
.............................. mol
Calculate the Mr of NH4NO3.
ar
●●
te
xa
m
According to the above ideal equation:
For every 1 mole of Ca( NO3)2 , there exist 2 moles of NH4NO3
Hence for 5 ''
''
''
''
''
'' 2x5=10moles " "
10
.s
m
Mr of NH4NO3= 14 + 4(1) + 14 + 3(16)=80
w
80
w
Mr of NH4NO3 = ..............................
w
●●
Calculate the maximum mass of ammonium nitrate produced.
Mass= Moles X Mr
= 10 X 80
= 800g
800
..............................
g
[4]
© UCLES 2019
0620/43/O/N/19
[Turn over
6
This question is about sulfuric acid and substances that can be made from sulfuric acid.
(a)Sulfuric acid is a strong acid.
What is meant by the term strong acid ?
A strong acid exists entirely as ions in the solution
strong ..........................................................................................................................................
co
m
Acid is a proton donor
acid .............................................................................................................................................
[2]
re
so
u
dilute sulfuric acid
rc
e
s.
(b)Dilute sulfuric acid and aqueous sodium hydroxide are used to make aqueous sodium sulfate,
Na2SO4(aq), or aqueous sodium hydrogen sulfate, NaHSO4(aq). The method includes use of
the following apparatus.
te
xa
m
conical flask
25.0 cm3 of aqueous
sodium hydroxide
ar
2
5.0 cm3 of aqueous sodium hydroxide of concentration 0.100 mol / dm3 was neutralised by
25.0 cm3 of dilute sulfuric acid of concentration 0.0500 mol / dm3. The equation for the reaction
is shown. This is reaction 1.
m
2NaOH(aq) + H2SO4(aq)
Na2SO4(aq) + 2H2O(l)
reaction 1
w
.s
The
same technique and the same solutions can be used to make aqueous
sodium hydrogen sulfate. The equation for the reaction is shown. This is reaction 2.
NaOH(aq) + H2SO4(aq)
NaHSO4(aq) + H2O(l)
reaction 2
w
w
Complete
the table to calculate the volume of dilute sulfuric acid that reacts with 25.0 cm3 of
aqueous sodium hydroxide in reaction 2.
volume of 0.0500 mol / dm3
dilute sulfuric acid in cm3
volume of 0.100 mol / dm3
aqueous sodium hydroxide in cm3
reaction 1
25.0
25.0
reaction 2
50.0
25.0
[1]
© UCLES 2019
0620/43/O/N/19
11
(c)
Aqueous sodium hydrogen sulfate, NaHSO4(aq), contains the ions Na+(aq), H+(aq)
and SO42–(aq).
Describe what you would see if the following experiments were done.
(i)
A flame test was done on aqueous sodium hydrogen sulfate.
Yellow flame
........................................................................................................................................ [1]
co
m
(ii)Solid copper(II) oxide was added to aqueous sodium hydrogen sulfate and the mixture
was warmed.
The
solid dissolves and a blue colour solution is obtained
..............................................................................................................................................
s.
........................................................................................................................................ [2]
rc
e
(d)A test can be done to show the presence of SO42–(aq) by adding acidified aqueous barium chloride
or acidified aqueous barium nitrate.
White precipitate
re
so
u
(i)State the observation that would show that SO42– is present.
........................................................................................................................................ [1]
(ii)Write an ionic equation for the reaction that occurs if SO42– is present. Include state
symbols.
22+
te
xa
m
Ba (aq) + SO4 (aq) ---> BaSO4 (s)
........................................................................................................................................ [2]
[Total: 9]
w
w
.s
m
ar
Note: Halide ion test
w
Note: Flame test results:
© UCLES 2019
0620/43/O/N/19
[Turn over
12
7Addition polymerisation and condensation polymerisation are two types of polymerisation.
(a)Which functional group is present in all the monomers which are used to make addition
polymers?
C=C
............................................................................................................................................... [1]
CH3 CH3 CH3 CH3 CH3 CH3
C
C
C
C
C
H
H
H
H
H
H
s.
C
co
m
(b)Part of an addition polymer is shown.
rc
e
(i)How many monomer units are needed to make the part of the addition polymer shown?
.3
....................................................................................................................................... [1]
te
xa
m
Name the monomer.
re
so
u
(ii)Draw the structure of the monomer that is used to make this addition polymer. Show all of
the atoms and all of the bonds.
but-2-ene
name ....................................................................................................................................
[2]
ar
(iii)State the empirical formula of:
CH2
Empirical formula is the same as it is the
reduced formula
m
the monomer .......................................................................................................................
CH2
w
w
w
.s
the polymer. .........................................................................................................................
[2]
© UCLES 2019
0620/43/O/N/19
13
(c)Complex carbohydrates are natural condensation polymers. They can be broken down into
colourless monomers which can then be separated and identified.
X is a complex carbohydrate.
Starting
with a sample of X, describe how to produce, separate, detect and identify the
monomers which make it up.
s.
co
m
Your
answer should include:
●● the name of the process used to break down X into its monomers
●● two types of substance that can be used to break down X
●● the name of the process used to separate the monomers
●● the method used to detect the monomers after they have been separated
●● the method used to identify the monomers after they have been separated and detected.
re
so
u
rc
e
The complex carbohydrates are broken down by the hydrolysis reaction.Acid
and enzymes are used in the process of breaking doen the carbohydrate.The
complex carbohydrates get broken down into colourless monomers. The
monomers are separated through chromatography. As the monomers are
colourless,a suitable locating agent is used to make them visible. The Rf values
of the monomers are calculated and compared against standard Rf values to
identify the mom=nomers.
............................................................................................................................................... [6]
te
xa
m
(d)Synthetic polyamides are condensation polymers.
(i)Name a synthetic polyamide.
nylon
........................................................................................................................................ [1]
ar
(ii)Synthetic polyamides can be made by reacting carboxylic acids with amines.
Name the other substance that is produced in this reaction.
water
m
........................................................................................................................................ [1]
w
w
w
.s
[Total: 14]
© UCLES 2019
0620/43/O/N/19
[Turn over
14
w
w
w
.s
m
ar
te
xa
m
re
so
u
rc
e
s.
co
m
BLANK PAGE
© UCLES 2019
0620/43/O/N/19
15
w
w
w
.s
m
ar
te
xa
m
re
so
u
rc
e
s.
co
m
BLANK PAGE
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 the Cambridge Assessment Group. Cambridge Assessment is the brand name of the University of
Cambridge Local Examinations Syndicate (UCLES), which itself is a department of the University of Cambridge.
© UCLES 2019
0620/43/O/N/19
© UCLES 2019
12
11
20
calcium
19
potassium
57–71
56
55
0620/43/O/N/19
88
–
90
89
232
thorium
actinium
–
Th
Ac
140
cerium
139
lanthanum
59
231
protactinium
Pa
91
141
praseodymium
Pr
–
58
Ce
–
Db
dubnium
Rf
105
181
Ta
tantalum
73
93
niobium
Nb
41
51
vanadium
V
23
rutherfordium
104
178
La
57
actinoids
89–103
Hf
hafnium
72
91
zirconium
Zr
40
48
titanium
Ti
22
238
uranium
U
92
144
neodymium
60
Nd
–
Sg
seaborgium
106
184
W
tungsten
74
96
molybdenum
Mo
42
52
Cr
24
chromium
relative atomic mass
name
atomic symbol
atomic number
–
neptunium
Np
93
–
promethium
61
Pm
–
Bh
bohrium
107
186
Re
rhenium
75
–
technetium
Tc
43
manganese
55
Co
27
Ni
28
Cu
29
Zn
30
B
C
N
7
O
8
VI
F
9
VII
2
VIII
–
plutonium
Pu
94
150
samarium
62
Sm
–
Hs
hassium
108
190
Os
osmium
76
101
ruthenium
Ru
44
56
iron
Fe
26
1
–
americium
Am
95
152
europium
63
Eu
–
Mt
meitnerium
109
192
Ir
iridium
77
103
rhodium
Rh
45
59
cobalt
64
copper
–
curium
Cm
96
157
gadolinium
64
Gd
–
Ds
darmstadtium
110
195
Pt
platinum
78
106
palladium
Pd
46
–
berkelium
Bk
97
159
terbium
65
Tb
–
Rg
roentgenium
111
197
gold
Au
79
108
silver
Ag
47
–
californium
Cf
98
163
dysprosium
66
Dy
–
einsteinium
Es
99
69
Tm
209
Bi
bismuth
83
122
antimony
Sb
51
75
arsenic
As
33
31
phosphorus
P
15
14
nitrogen
–
fermium
Fm
100
167
erbium
–
mendelevium
Md
101
169
thulium
co
m
68
Er
–
Fl
flerovium
114
207
lead
Pb
82
tin
119
Sn
50
73
Ge
32
28
silicon
Si
14
12
carbon
germanium
s.
165
holmium
67
Ho
204
Tl
thallium
81
115
indium
In
49
70
gallium
rc
e
–
Cn
copernicium
112
201
Hg
mercury
80
112
Cd
48
65
zinc
cadmium
re
so
u
59
nickel
Ga
31
27
aluminium
Al
13
11
boron
–
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
–
At
astatine
85
127
iodine
I
53
80
bromine
Br
35
35.5
chlorine
Cl
17
19
fluorine
–
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
1
III
H
te
xa
m
Mn
25
ar
m
.s
Key
w
Group
The Periodic Table of Elements
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
137
87
133
Ba
barium
Cs
caesium
lanthanoids
89
yttrium
88
strontium
85
rubidium
Y
39
45
scandium
Sc
Sr
38
40
Ca
21
Rb
37
39
K
24
magnesium
sodium
23
Mg
Na
9
beryllium
lithium
7
Be
4
3
Li
II
I
w
w
16