oLEVEl Chemistry
32
This document consists of 16 printed pages. DC (SJF/SW) 58088/4 © UCLES 2013 [Turn over UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONS General Certificate of Education Ordinary Level *2325388848* CHEMISTRY 5070/21 Paper 2 Theory October/November 2013 1 hour 30 minutes Candidates answer on the Question Paper. No Additional Materials are required. READ THESE INSTRUCTIONS FIRST 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 a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. DO NOT WRITE IN ANY BARCODES. Section A Answer all questions. Write your answers in the spaces provided in the Question Paper. Section B Answer any three questions. Write your answers in the spaces provided in the Question Paper. Electronic calculators may be used. You may lose marks if you do not show your working or if you do not use appropriate units. A copy of the Periodic Table is printed on page 16. 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.
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Transcript of oLEVEl Chemistry
This document consists of 16 printed pages.
DC (SJF/SW) 58088/4© UCLES 2013 [Turn over
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONSGeneral Certificate of Education Ordinary Level
*2325388848*
CHEMISTRY 5070/21
Paper 2 Theory October/November 2013
1 hour 30 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
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 a soft pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Section AAnswer all questions.Write your answers in the spaces provided in the Question Paper.
Section BAnswer any three questions.Write your answers in the spaces provided in the Question Paper.
Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.
A copy of the Periodic Table is printed on page 16.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.
2
5070/21/O/N/13© UCLES 2013
ForExaminer’s
Use
Section A
Answer all the questions in this section in the spaces provided.
The total mark for this section is 45.
A1 Choose from the following compounds to answer the questions below.
calcium oxidecarbon dioxide
carbon monoxidecopper(II) sulfate
ethanolethene
iron(II) chlorideiron(III) chloridenitrogen dioxidesilver chloridesilver iodide
sulfur dioxide
Each compound can be used once, more than once or not at all.
Which compound is
(a) a solid, which when dissolved in water, gives a green precipitate with aqueous ammonia,
...................................................................................................................................... [1]
(b) a colourless gas which is formed when limestone is heated strongly,
...................................................................................................................................... [1]
(c) a gas which is formed in the atmosphere by lightning activity,
...................................................................................................................................... [1]
(d) a basic oxide,
...................................................................................................................................... [1]
(e) formed when ethane undergoes complete combustion,
...................................................................................................................................... [1]
(f) a white salt which is insoluble in water?
...................................................................................................................................... [1]
[Total: 6]
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A2 Alkenes are a homologous series of unsaturated hydrocarbons.
(a) Give the general formula of alkenes.
...................................................................................................................................... [1]
(b) In addition to having a general formula, state two other characteristics of a homologous series.
1 .......................................................................................................................................
2 ................................................................................................................................... [2]
(c) Alkenes can be made by cracking alkanes.
(i) Give one condition required for cracking.
.............................................................................................................................. [1]
(ii) Tetradecane, C14H30, can be cracked to form an alkene containing eight carbon atoms and an alkane.
Construct an equation for this reaction.
[1]
(d) Ethene reacts with bromine to form 1,2-dibromoethane, CH2BrCH2Br.
Name this type of reaction.
...................................................................................................................................... [1]
(e) Ethene reacts with hydrogen chloride to form the covalent compound chloroethane, CH3CH2Cl.
Suggest two physical properties of chloroethane.
1 .......................................................................................................................................
2 ................................................................................................................................... [2]
(f) Halogenoalkanes such as CCl2F2 are responsible for the depletion of ozone in the upper atmosphere.
Describe the importance of the ozone layer in the upper atmosphere.
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [2]
[Total: 10]
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A3 Calcium, proton number 20, is an element in Group II of the Periodic Table. (a) Give the electronic configuration for calcium.
...................................................................................................................................... [1]
(b) Calcium has six naturally-occurring isotopes.
(i) State the meaning of the term isotopes.
..................................................................................................................................
.............................................................................................................................. [1]
(ii) Complete the following table to show the number of sub-atomic particles in two of these isotopes.
isotope number of protons
number of electrons
number of neutrons
42Ca
48Ca
[3]
(c) Calcium chloride can be formed by reacting calcium carbonate with dilute hydrochloric acid.
(i) Construct an equation for this reaction.
[1]
(ii) Write both the formula and the electronic configuration for the ions present in calcium chloride.
[2]
(d) (i) Name the products formed at the anode and cathode when molten calcium chloride is electrolysed.
anode .......................................................................................................................
cathode ................................................................................................................ [1]
(ii) Predict the product formed at the cathode when a dilute aqueous solution of calcium chloride is electrolysed.
.............................................................................................................................. [1]
(iii) Explain why solid calcium chloride does not conduct electricity.
.............................................................................................................................. [1]
[Total: 11]
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A4 Nitrogen and oxygen are present in dry air. (a) What is the percentage composition by volume of each of these gases in dry air?
nitrogen ............................................................................................................................
oxygen ......................................................................................................................... [2]
(b) What method is used to separate these gases from each other?
...................................................................................................................................... [1]
(c) In a petrol engine, nitrogen and oxygen combine to form oxides of nitrogen such as nitrogen dioxide, NO2.
State one harmful effect that nitrogen dioxide has on the environment.
...................................................................................................................................... [1]
(d) One of the hydrocarbons in petrol is octane, C8H18. In a petrol engine, some of the octane reacts to form carbon monoxide and water.
Construct an equation for this reaction.
[2]
(e) Catalytic converters are used to remove carbon monoxide and nitrogen dioxide from the exhaust gases of petrol engines.
A catalyst containing rhodium and platinum or palladium is present in a catalytic converter.
What is the function of a catalyst?
...................................................................................................................................... [1]
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(f) In a catalytic converter, carbon monoxide and nitrogen dioxide undergo redox reactions. These reactions reduce the amount of carbon monoxide and nitrogen dioxide in car exhausts.
(i) What is meant by the term redox reaction?
..................................................................................................................................
.............................................................................................................................. [1]
(ii) Explain how the redox reactions in the catalytic converter decrease the amounts of carbon monoxide and nitrogen dioxide in car exhausts.
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [2]
[Total: 10]
A5 Hydrogen peroxide, H2O2, is a colourless liquid.
(a) Calculate the percentage by mass of oxygen in hydrogen peroxide.
..............................................% [2]
(b) The enzyme catalase is present in yeast. The enzyme catalyses the decomposition of aqueous hydrogen peroxide.
2H2O2(aq) 2H2O(l) + O2(g)
The apparatus below is used to monitor this reaction.
wateryeast
+ hydrogenperoxide solution
water
What measurements should be taken in order to monitor the rate of this reaction?
..........................................................................................................................................
...................................................................................................................................... [2]
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(c) Describe and explain the effect of increasing the concentration of hydrogen peroxide on the rate of this reaction.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [3]
(d) The graph below shows how the rate of decomposition of hydrogen peroxide, catalysed by yeast, varies with temperature. All other conditions are kept constant.
20100 30 40temperature / °C
rate ofreaction
50 60
Suggest why the rate of reaction decreases rapidly from 45 °C to 60 °C.
...................................................................................................................................... [1]
[Total: 8]
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Section B
Answer three questions from this section in the spaces provided.
The total mark for this section is 30.
B6 Iron is extracted from its ore (haematite, Fe2O3) in a blast furnace. Coke (carbon) and limestone (calcium carbonate) are also added to the furnace. (a) Describe the essential reactions taking place in the blast furnace.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [4]
(b) Steel is an alloy made by the addition of carbon or metals to iron. Use the diagrams below to explain why an alloy of iron and manganese is less malleable
than pure iron.
iron
iron atoms
manganese atoms
Key
alloy of iron and manganese
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [2]
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(c) Iron reacts with dilute hydrochloric acid to form iron(II) chloride.
Fe(s) + 2HCl (aq) FeCl2(aq) + H2(g)
A student added 2.1 g of iron to 50 cm3 of 0.10 mol / dm3 hydrochloric acid.
(i) Calculate the amount, in moles, of iron present.
........................................... mol [1]
(ii) Calculate the amount, in moles, of hydrochloric acid present.
........................................... mol [1]
(iii) Calculate the volume of hydrogen formed in this reaction, measured at room temperature and pressure.
...........................................cm3 [2]
[Total: 10]
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B7 (a) A compound of carbon, hydrogen and chlorine contains 0.48 g of carbon, 0.08 g of hydrogen and 1.42 g of chlorine.
(i) Deduce the empirical formula of this compound.
[2]
(ii) The relative molecular mass of this compound is 99.
Deduce the molecular formula of this compound.
[1]
(b) Chloroethene is another compound containing carbon, hydrogen and chlorine. The structure of chloroethene is shown below.
C
H
H
Cl
H
C
Draw a section of the polymer formed when chloroethene undergoes polymerisation to form poly(chloroethene).
[2]
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(c) Poly(chloroethene) is an addition polymer but nylon is a condensation polymer.
Describe the difference between an addition polymer and a condensation polymer in terms of how they are formed from their monomers.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [1]
(d) Chloroethene is made by reacting ethene with hydrogen chloride and oxygen in the presence of a catalyst of copper(II) chloride, CuCl2. The other product of the reaction is water.
(i) Construct an equation for this reaction.
[1]
(ii) Copper(II) chloride is made by heating copper(II) oxide, CuO, with hydrochloric acid.
Construct an equation for this reaction.
[1]
(iii) Copper is a transition element.
State two physical properties of copper which are different from those of a typical Group I element such as sodium.
1 ...............................................................................................................................
2 ........................................................................................................................... [2]
[Total: 10]
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B8 Zinc sulfide is a compound that can be made by heating zinc powder with sulfur powder. (a) Describe two differences between a mixture of zinc and sulfur and a compound of zinc
and sulfur.
1 .......................................................................................................................................
..........................................................................................................................................
2 .......................................................................................................................................
...................................................................................................................................... [2]
(b) The reaction between zinc and sulfur is exothermic.
Complete the energy profile diagram for this reaction. On your diagram label the product, the enthalpy change for the reaction, ΔH.
zinc + sulfurenergy
progress of reaction
[2]
(c) Part of the structure of zinc sulfide is shown below.
Zn ions
Key
S ions
Deduce the empirical formula of zinc sulfide from this structure.
...................................................................................................................................... [1]
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(d) Zinc sulfide reacts with hydrochloric acid to form hydrogen sulfide. An aqueous solution of hydrogen sulfide behaves as a weak acid.
Describe what is meant by the term weak acid.
..........................................................................................................................................
...................................................................................................................................... [1]
(e) Zinc sulfate can be made by reacting zinc with dilute sulfuric acid.
Zn(s) + H2SO4(aq) ZnSO4(aq) + H2(g)
(i) Write an ionic equation for this reaction.
[1]
(ii) Describe how you would prepare crystals of pure, dry zinc sulfate using this reaction.
..................................................................................................................................
..................................................................................................................................
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [3]
[Total: 10]
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B9 Ethanoic acid reacts with sodium hydroxide to form water and a salt.
(a) Give the formula of the salt.
...................................................................................................................................... [1]
(b) The reaction between ethanoic acid and sodium hydroxide is described as a neutralisation reaction.
Write the simplest ionic equation for this reaction.
...................................................................................................................................... [1]
(c) Ethanoic acid reacts with methanol to form an ester and water.
CH3CO2H + CH3OH CH3CO2CH3 + H2O
The reaction is endothermic.
(i) Describe what happens to the position of this equilibrium when the concentration of methanol is increased. Explain your answer.
..................................................................................................................................
.............................................................................................................................. [1]
(ii) Describe what happens to the position of this equilibrium when the temperature of the reaction mixture is decreased. Explain your answer.
..................................................................................................................................
.............................................................................................................................. [1]
(d) The structure of the ester methyl benzoate is shown below.
H
C
COC
C
O
CH
H
HH
H
H
HC
CC
Deduce the molecular formula for methyl benzoate.
...................................................................................................................................... [1]
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(e) Sodium hydroxide is an alkali.
Give the formula of the ion present in sodium hydroxide which causes it to be alkaline.
...................................................................................................................................... [1]
(f) A student titrated a metal hydroxide with 0.200 mol/dm3 hydrochloric acid. It required 12.5 cm3 of hydrochloric acid to neutralise 25.0 cm3 of 0.0500 mol / dm3 metal
hydroxide solution.
(i) Calculate the amount, in moles, of hydrochloric acid used.
........................................... mol [1]
(ii) Calculate the amount, in moles, of metal hydroxide present.
........................................... mol [1]
(iii) Construct an equation for this reaction. Use the letter M to represent the metal in the metal hydroxide solution.
[1]
(g) Name a metal hydroxide which can be used to treat excess acidity in soils.
...................................................................................................................................... [1]
[Total: 10]
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.
University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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5070/21/O/N/13© UCLES 2013
Gro
up
Th
e P
erio
dic
Tab
le o
f th
e E
lem
ents
140
Ce
Cer
ium
58
141
Pr
Pra
seod
ymiu
m
59
144
Nd
Neo
dym
ium
60
Pm
Pro
met
hium
61
150
Sm
Sa
ma
riu
m
62
152
Eu
Eur
opiu
m
63
157
Gd
Gad
olin
ium
64
159
Tb
Terb
ium
65
162
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m
67
167
Er
Erb
ium
68
169
Tm
Thu
lium
69
173
Yb
Ytte
rbiu
m
70
175
Lu
Lute
tium
71
232
Th
Tho
rium
90
Pa
Pro
tact
iniu
m
91
238
231
147
237
244
243
247
247
251
252
257
258
259
260
UU
rani
um
92
Np
Nep
tuni
um
93
Pu
Plu
toni
um
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m
97
Cf
Cal
iforn
ium
98
Es
Ein
stei
nium
99
Fm
Fer
miu
m
100
Md
Men
dele
vium
101
No
Nob
eliu
m
102
Lr
Law
renc
ium
103
1 HH
ydro
gen
1
7 Li
Lith
ium
3
23 Na
Sod
ium
11
24 Mg
Mag
nesi
um
12
40 Ca
Cal
cium
20
45 Sc
Sca
ndiu
m
21
48 Ti
Tita
nium
22
51 VV
anad
ium
23
52 Cr
Chr
omiu
m
24
55 Mn
Man
gane
se
25
56 Fe
Iron
26
59 Co
Cob
alt
27
59 Ni
Nic
kel
28
64 Cu
Cop
per
29
65 Zn
Zin
c
30
70 Ga
Gal
lium
31
27 Al
Alu
min
ium
13
11 BB
oron
5
12 CC
arbo
n
6
14 NN
itrog
en
7
16 OO
xyge
n
8
19 FF
luor
ine
9
28 Si
Sili
con
14
31 PP
hosp
horu
s
15
32 SS
ulfu
r16
35.5
Cl
Chl
orin
e17
40 Ar
Arg
on18
20 Ne
Neo
n10
4 He
Hel
ium
2
73 Ge
Ger
man
ium
32
75 As
Ars
enic
33
79 Se
Sel
eniu
m
34
80 Br
Bro
min
e
35
84 Kr
Kry
pton
36
39 KP
otas
sium
19
88 Sr
Str
ontiu
m
38
89 YY
ttriu
m
39
91 Zr
Zirc
oniu
m
40
93 Nb
Nio
bium
41
96 Mo
Mol
ybde
num
42
Tc
Tech
netiu
m
43
101
Ru
Rut
heni
um
44
103
Rh
Rho
dium
45
106
Pd
Pal
ladi
um
46
108
Ag
Silv
er
47
112
Cd
Cad
miu
m
48
115
In Indi
um
49
119
Sn
Tin
50
122
Sb
Ant
imon
y
51
128
TeTe
lluriu
m
52
127 I
Iodi
ne
53
131
Xe
Xen
on
54
137
Ba
Bar
ium
56
139
La
Lant
hanu
m
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um
73
184
WTu
ngst
en
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192 Ir
Irid
ium
77
195
Pt
Pla
tinum
78
197
Au
Gol
d
79
201
Hg
Mer
cury
80
204
Tl
Tha
llium
81
207
Pb
Lead
82
209
209
210
222
Bi
Bis
mut
h
83
Po
Pol
oniu
m
84
At
Ast
atin
e
85
Rn
Rad
on
86
Fr
Fran
cium
87
227
Ac
Act
iniu
m
89†
9 Be
Ber
ylliu
m
4
III
IIIIV
VV
IV
II0
85 Rb
Rub
idiu
m
37
133
Cs
Cae
sium
55
226
223
Ra
Rad
ium
88 a Xb
a =
rel
ativ
e at
omic
mas
s
X =
ato
mic
sym
bol
b =
ato
mic
(pr
oton
) nu
mbe
r
Key
DA
TA S
HE
ET
* 58
–71
Lant
hano
id s
erie
s†
90–1
03 A
ctin
oid
serie
s
The
vol
ume
of o
ne m
ole
of a
ny g
as is
24
dm3
at r
oom
tem
pera
ture
and
pre
ssur
e (r
.t.p.
).
This document consists of 16 printed pages.
DC (SJF/SW) 58087/5© UCLES 2013 [Turn over
UNIVERSITY OF CAMBRIDGE INTERNATIONAL EXAMINATIONSGeneral Certificate of Education Ordinary Level
*4178971357*
CHEMISTRY 5070/22
Paper 2 Theory October/November 2013
1 hour 30 minutes
Candidates answer on the Question Paper.
No Additional Materials are required.
READ THESE INSTRUCTIONS FIRST
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 a soft pencil for any diagrams, graphs or rough working.Do not use staples, paper clips, highlighters, glue or correction fluid.DO NOT WRITE IN ANY BARCODES.
Section AAnswer all questions.Write your answers in the spaces provided in the Question Paper.
Section BAnswer any three questions.Write your answers in the spaces provided in the Question Paper.
Electronic calculators may be used.You may lose marks if you do not show your working or if you do not use appropriate units.
A copy of the Periodic Table is printed on page 16.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.
2
5070/22/O/N/13© UCLES 2013
ForExaminer’s
Use
Section A
Answer all the questions in this section in the spaces provided.
The total mark for this section is 45.
A1 Choose from the following elements to answer the questions below.
chlorine
hydrogen
iron
lithium
nickel
nitrogen
oxygen
potassium
silver
sulfur
vanadium
zinc
Each element can be used once, more than once or not at all.
Which element
(a) is liberated at the anode when an aqueous solution of potassium sulfate is electrolysed,
...................................................................................................................................... [1]
(b) is used as a catalyst in the manufacture of margarine,
...................................................................................................................................... [1]
(c) is a non-metallic solid, an atom of which contains only six valency electrons,
...................................................................................................................................... [1]
(d) is higher than sodium in the reactivity series,
...................................................................................................................................... [1]
(e) is in Period 5 of the Periodic Table,
...................................................................................................................................... [1]
(f) forms a white oxide which is amphoteric?
...................................................................................................................................... [1]
[Total: 6]
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A2 Carboxylic acids are a homologous series containing the –CO2H group. The table shows some properties of the first four carboxylic acids in the series.
carboxylic acid molecular formula
densityin g / cm3
boiling pointin °C
methanoic acid CH2O2 1.220 101
C2H4O2 1.049 118
propanoic acid C3H6O2 0.993 141
butanoic acid C4H8O2 0.958 165
(a) (i) Describe how the density of these carboxylic acids varies with the number of carbon atoms in the molecule.
.............................................................................................................................. [1]
(ii) Name the carboxylic acid with the molecular formula C2H4O2.
.............................................................................................................................. [1]
(iii) Draw the structure of propanoic acid, showing all atoms and bonds.
[1]
(b) The next carboxylic acid in this homologous series is pentanoic acid. Pentanoic acid has five carbon atoms.
(i) Deduce the molecular formula for pentanoic acid.
.............................................................................................................................. [1]
(ii) Suggest a value for the boiling point of pentanoic acid.
............................................. °C [1]
(c) Butanoic acid, C3H7CO2H, reacts with sodium to form a salt and a gas. (i) Name the gas.
.............................................................................................................................. [1]
(ii) Give the formula of the salt.
.............................................................................................................................. [1]
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(d) Esters are formed when carboxylic acids react with alcohols. The reaction is catalysed by hydrogen ions.
(i) Describe and explain the effect of a catalyst on reaction rate.
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [2]
(ii) State one commercial use of esters.
.............................................................................................................................. [1]
(iii) The structure of an ester is shown below.
C
HO
H
H
H
OCH C
H
H
C H
Name this ester.
.............................................................................................................................. [1]
[Total: 11]
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A3 Silicon is an element in Group IV of the Periodic Table.
(a) Give the electronic configuration for a silicon atom.
...................................................................................................................................... [1]
(b) Silicon has three naturally occurring isotopes. Complete the following table for two of these isotopes.
isotope 28Si 30Si
number of protons
number of electrons
number of neutrons[3]
(c) Silicon reacts with chlorine on heating to form silicon(IV) chloride, SiCl4. Construct an equation for this reaction.
[1]
(d) Silicon(IV) chloride is a simple molecular compound.
(i) Suggest two physical properties of silicon(IV) chloride other than solubility.
1 ...............................................................................................................................
2 ........................................................................................................................... [2] (ii) Draw a ‘dot-and-cross’ diagram for silicon(IV) chloride. You only need to show the outer shell electrons for each atom.
[2]
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(e) Silicon(IV) chloride reacts with water to form silicon(IV) oxide. Part of the structure of silicon(IV) oxide is shown below.
silicon atomoxygen atom
Key
Explain, in terms of structure and bonding, why silicon(IV) oxide has a very high melting point.
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...................................................................................................................................... [2]
[Total: 11]
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A4 The carbon cycle regulates the amount of carbon dioxide in the atmosphere. (a) (i) State two processes which release carbon dioxide into the atmosphere.
1 ...............................................................................................................................
2 ........................................................................................................................... [2]
(ii) Name one process which removes carbon dioxide from the atmosphere.
.............................................................................................................................. [1]
(b) Carbon dioxide is a greenhouse gas. (i) What is the meaning of the term greenhouse gas?
..................................................................................................................................
.............................................................................................................................. [1]
(ii) Name another greenhouse gas and give a natural source of this gas.
name ........................................................................................................................
source .................................................................................................................. [2]
(c) Carbon dioxide dissolves in water to form a weakly acidic solution.
CO2(g) + H2O(l) HCO3–(aq) + H+(aq)
(i) What is the meaning of the term weak acid ?
..................................................................................................................................
.............................................................................................................................. [1]
(ii) Describe how you could measure the pH of this solution other than by using a pH meter.
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [2]
(d) Sodium hydrogencarbonate, NaHCO3, decomposes on heating to form a carbonate, water and a gas which turns limewater milky.
Construct an equation for this reaction.
[2][Total: 11]
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A5 A student reacts magnesium ribbon with excess hydrochloric acid. She follows the course of the reaction by measuring the volume of gas produced against
time.
(a) Write the equation for the reaction of magnesium with hydrochloric acid.
...................................................................................................................................... [1]
(b) (i) On the axes below draw a sketch graph to show how the volume of gas produced during the reaction varies with time and label this line ‘A’.
Label the axes with the appropriate units.
[2]
(ii) The student then carries out the experiment at a lower temperature. All the other conditions remain the same.
On the axes above draw another line to show how the volume of gas produced varies with time and label this line ‘B’. [1]
(c) Magnesium reacts with carbon to form the compound magnesium carbide.
Calculate the percentage by mass of magnesium in magnesium carbide, MgC2.
[2]
[Total: 6]
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Section B
Answer three questions from this section in the spaces provided.
The total mark for this section is 30.
B6 Aluminium is extracted from purified bauxite by electrolysis. (a) Describe how this electrolysis is carried out and construct equations for the reactions
occurring at both the anode and cathode.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [4]
(b) What properties of aluminium make it useful for
(i) making aircraft, .........................................................................................................
(ii) making electricity cables. ...................................................................................... [2]
(c) Aluminium is high in the reactivity series. (i) Explain why aluminium does not react with aqueous copper(II) sulfate.
..................................................................................................................................
.............................................................................................................................. [2]
(ii) When a few drops of aqueous sodium chloride are added to a mixture of aluminium and aqueous copper(II) sulfate, a vigorous reaction occurs.
copper(II) sulfate + aluminium aluminium sulfate + copper
What type of reaction is this?
.............................................................................................................................. [1]
(iii) State the formula of aluminium sulfate.
.............................................................................................................................. [1]
[Total: 10]
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B7 Ethene is an unsaturated hydrocarbon.
(a) What is the meaning of each of these terms?
unsaturated ......................................................................................................................
hydrocarbon ................................................................................................................. [2]
(b) Ethene can be manufactured by cracking.
(i) State the conditions used for cracking.
..................................................................................................................................
.............................................................................................................................. [2]
(ii) Construct an equation for the cracking of tetradecane, C14H30, to form ethene and one other hydrocarbon.
.............................................................................................................................. [1]
(c) Alkenes such as ethene can undergo addition polymerisation. (i) State one use of poly(ethene).
.............................................................................................................................. [1]
(ii) The diagram below shows a section of a polymer chain.
CH CH2
C2H5 C2H5 C2H5
CH CH2 CH CH2
Deduce the structure of the monomer which is used to make this polymer.
[1]
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(d) Ethanol can be manufactured by the catalytic addition of steam to ethene.
C2H4 + H2O C2H5OH
If the reactants are not recycled, only 5% of the ethene is converted to ethanol.
Calculate the mass of ethanol formed from 0.4 tonnes of ethene when only 5% of the ethene is converted to ethanol.
[1 tonne is 1 000 000 grams]
mass of ethanol ...................................... tonnes [3]
[Total: 10]
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B8 When hydrogen iodide, HI, is heated in a closed tube, the following dynamic equilibrium is established.
2HI(g) H2(g) + I2(g) ΔH = + 9.6 kJ / mol
(a) What is meant by the term dynamic equilibrium?
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [2]
(b) The table shows the concentrations of HI(g), H2(g) and I2(g) in the equilibrium mixture at 25 °C and 450 °C.
substance concentration at 25 °C/ mol / dm3
concentration at 450 °C/ mol / dm3
HI(g) 0.94 0.79
H2(g) 0.033 0.11
I2(g) 0.033 0.11
(i) The tube has a volume of 50 cm3.
Calculate the mass of hydrogen iodide in the equilibrium mixture at 25 °C.
[2]
(ii) Describe and explain the differences in the concentrations of reactant and products at 25 °C and 450 °C.
..................................................................................................................................
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [2]
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(c) Complete the energy profile diagram for the decomposition of hydrogen iodide. On your diagram label • the products, • the enthalpy change of the reaction, ΔH.
progress of reaction
energyreactants
[2]
(d) An aqueous solution of hydrogen iodide contains iodide ions. Describe a test for iodide ions.
..........................................................................................................................................
...................................................................................................................................... [2]
[Total: 10]
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B9 The compounds ammonium nitrate and ammonium sulfate are both fertilisers.
(a) Explain why farmers add these fertilisers to soils.
..........................................................................................................................................
...................................................................................................................................... [1]
(b) Ammonium sulfate can be prepared by adding sulfuric acid to aqueous ammonia. Construct the equation for this reaction.
...................................................................................................................................... [1]
(c) Excess acidity in soils can be treated by adding calcium hydroxide.
(i) Give the formula of the ion present in calcium hydroxide which causes it to be alkaline.
.............................................................................................................................. [1]
(ii) Explain why adding calcium hydroxide causes loss of nitrogen from fertilisers such as ammonium nitrate, which have been previously added to the soil.
..................................................................................................................................
..................................................................................................................................
.............................................................................................................................. [2]
(d) A student titrated 10.0 cm3 of aqueous calcium hydroxide with hydrochloric acid.
Ca(OH)2(aq) + 2HCl(aq) CaCl2(aq) + 2H2O(l)
It required 4.00 cm3 of 0.0100 mol / dm3 hydrochloric acid to neutralise 10.0 cm3 of aqueous calcium hydroxide.
Calculate the concentration of the calcium hydroxide.
................................... mol/ dm3 [3]
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(e) Describe how to obtain pure dry crystals of calcium chloride from an aqueous solution of calcium chloride.
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
..........................................................................................................................................
...................................................................................................................................... [2]
[Total: 10]
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.
University of Cambridge International Examinations is part of the Cambridge Assessment Group. Cambridge Assessment is the brand name of University of Cambridge Local Examinations Syndicate (UCLES), which is itself a department of the University of Cambridge.
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5070/22/O/N/13© UCLES 2013
Gro
up
Th
e P
erio
dic
Tab
le o
f th
e E
lem
ents
140
Ce
Cer
ium
58
141
Pr
Pra
seod
ymiu
m
59
144
Nd
Neo
dym
ium
60
Pm
Pro
met
hium
61
150
Sm
Sa
ma
riu
m
62
152
Eu
Eur
opiu
m
63
157
Gd
Gad
olin
ium
64
159
Tb
Terb
ium
65
162
Dy
Dys
pros
ium
66
165
Ho
Hol
miu
m
67
167
Er
Erb
ium
68
169
Tm
Thu
lium
69
173
Yb
Ytte
rbiu
m
70
175
Lu
Lute
tium
71
232
Th
Tho
rium
90
Pa
Pro
tact
iniu
m
91
238
231
147
237
244
243
247
247
251
252
257
258
259
260
UU
rani
um
92
Np
Nep
tuni
um
93
Pu
Plu
toni
um
94
Am
Am
eric
ium
95
Cm
Cur
ium
96
Bk
Ber
keliu
m
97
Cf
Cal
iforn
ium
98
Es
Ein
stei
nium
99
Fm
Fer
miu
m
100
Md
Men
dele
vium
101
No
Nob
eliu
m
102
Lr
Law
renc
ium
103
1 HH
ydro
gen
1
7 Li
Lith
ium
3
23 Na
Sod
ium
11
24 Mg
Mag
nesi
um
12
40 Ca
Cal
cium
20
45 Sc
Sca
ndiu
m
21
48 Ti
Tita
nium
22
51 VV
anad
ium
23
52 Cr
Chr
omiu
m
24
55 Mn
Man
gane
se
25
56 Fe
Iron
26
59 Co
Cob
alt
27
59 Ni
Nic
kel
28
64 Cu
Cop
per
29
65 Zn
Zin
c
30
70 Ga
Gal
lium
31
27 Al
Alu
min
ium
13
11 BB
oron
5
12 CC
arbo
n
6
14 NN
itrog
en
7
16 OO
xyge
n
8
19 FF
luor
ine
9
28 Si
Sili
con
14
31 PP
hosp
horu
s
15
32 SS
ulfu
r16
35.5
Cl
Chl
orin
e17
40 Ar
Arg
on18
20 Ne
Neo
n10
4 He
Hel
ium
2
73 Ge
Ger
man
ium
32
75 As
Ars
enic
33
79 Se
Sel
eniu
m
34
80 Br
Bro
min
e
35
84 Kr
Kry
pton
36
39 KP
otas
sium
19
88 Sr
Str
ontiu
m
38
89 YY
ttriu
m
39
91 Zr
Zirc
oniu
m
40
93 Nb
Nio
bium
41
96 Mo
Mol
ybde
num
42
Tc
Tech
netiu
m
43
101
Ru
Rut
heni
um
44
103
Rh
Rho
dium
45
106
Pd
Pal
ladi
um
46
108
Ag
Silv
er
47
112
Cd
Cad
miu
m
48
115
In Indi
um
49
119
Sn
Tin
50
122
Sb
Ant
imon
y
51
128
TeTe
lluriu
m
52
127 I
Iodi
ne
53
131
Xe
Xen
on
54
137
Ba
Bar
ium
56
139
La
Lant
hanu
m
57
*
178
Hf
Haf
nium
72
181
TaTa
ntal
um
73
184
WTu
ngst
en
74
186
Re
Rhe
nium
75
190
Os
Osm
ium
76
192 Ir
Irid
ium
77
195
Pt
Pla
tinum
78
197
Au
Gol
d
79
201
Hg
Mer
cury
80
204
Tl
Tha
llium
81
207
Pb
Lead
82
209
209
210
222
Bi
Bis
mut
h
83
Po
Pol
oniu
m
84
At
Ast
atin
e
85
Rn
Rad
on
86
Fr
Fran
cium
87
227
Ac
Act
iniu
m
89†
9 Be
Ber
ylliu
m
4
III
IIIIV
VV
IV
II0
85 Rb
Rub
idiu
m
37
133
Cs
Cae
sium
55
226
223
Ra
Rad
ium
88 a Xb
a =
rel
ativ
e at
omic
mas
s
X =
ato
mic
sym
bol
b =
ato
mic
(pr
oton
) nu
mbe
r
Key
DA
TA S
HE
ET
* 58
–71
Lant
hano
id s
erie
s†
90–1
03 A
ctin
oid
serie
s
The
vol
ume
of o
ne m
ole
of a
ny g
as is
24
dm3
at r
oom
tem
pera
ture
and
pre
ssur
e (r
.t.p.
).
