Section A (3 marks)
Each question below is provided with four answers. Select the most appropriate answer and fill it in the brackets provided.
1. Iron metal is extracted from iron(III) oxide through a series of reactions in a blast furnace. The five reactions that occur in the blast furnace are:
Reaction 1: C + O2 CO2
Reaction 2: CaCO3 CaO + CO2
Reaction 3: CO2 + C 2CO
Reaction 4: Fe2O3 + 3CO 3CO2 + 2Fe
Reaction 5: CaO + SiO2 CaSiO3
Which of the above reactions are not redox reactions?
A
1 and 3 only
B
2 and 5 only
C
1, 2 and 5 only
D
3, 4 and 5 only
(
)
2. The nickel-cadmium rechargeable battery is based upon the following overall reaction. Cd + 2NiO(OH) + 4H2O Cd(OH)2 + 2Ni(OH)2.H2O
What is the oxidation number of nickel at the beginning and at the end of the reaction? 1
beginning
end
A
+1.5
+2
B
+2
+3
C
+3
+2
D
+3
+4
(
)
3. When substance X is added to aqueous potassium iodide and acidified potassium manganate(VII) solution separately, both resultant solutions appear colourless.
In the two reactions, substance X is acting as
A
an oxidising agent only.
B
a reducing agent only.
C
both an oxidising agent and a reducing agent.
D
neither an oxidising agent nor a reducing agent.
(
)
Section B (12 marks)
Answer all the questions in the spaces provided below.
4.
An oxyacid is an acid that contains oxygen atom(s) bonded to hydrogen atom(s) and at least one other element. Sulfuric acid (H2SO4), phosphoric acid (H3PO4) and nitric acid (HNO3) are all oxyacids.
Chlorine forms several types of oxyacids. The table below shows some properties of oxyacids of chlorine. oxidation state of chlorine
reaction with magnesium
(all acids at equal volume and concentration)
name
formula
perchloric acid
HClO4
very vigorous
hypochlorus acid
HOCl
only a few bubbles seen
chloric acid
HClO3
+5
vigorous
chlorous acid
HClO2
+3
reacts readily
(a)
Complete the table by filling in the oxidation state of chlorine.
2
[2]
(b) (i)
Arrange the acids in ascending order of strength.
…………………………………………………………….…………………
(ii)
[1]
With reference to your answer in (b)(i) and the information from the table, deduce a trend that can be observed.
…………………………………………………………….………………….……
…………………………………………………………….…………………
(c)
[1]
Hypochlorus acid can be made by reacting chlorine with water.
The equation is shown below.
Cl2 + H2O HCl + HOCl
Using oxidation numbers, show that this is a redox reaction.
…………………………………………………………….……………………………...
…………………………………………………………….……………………………...
…………………………………………………………….……………………………...
…………………………………………………………….……………………………...
…………………………………………………………….……………………………...
…………………………………………………………….………………………..
5.
[3]
In an experiment, air from a motorcar exhaust was passed through the apparatus as shown in the diagram.
3
(a)
Fill in the blanks in the table below. reagent change observed
turned from white to blue turned from orange to green white precipitate formed limewater
name of substance causing the change
carbon dioxide gas
[2]
(b)
The presence of carbon monoxide is tested with palladium(II) chloride solution.
Palladium(II) chloride solution reacts with carbon monoxide and water vapour to form palladium metal. Two other acidic products are also formed.
(i)
Write the balanced chemical equation for the reaction.
……………………………………………………………………………..
(ii)
[1]
Identify the oxidising agent. Explain your answer.
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………..
END OF PAPER
4
[2]
Group
I
II
III
IV
V
VI
VII
0
1
4
H
He
Hydrogen
Helium
1
2
7
9
11
12
14
16
19
20
Li
Be
B
C
N
O
F
Ne
Lithium
Beryllium
Boron
4
3
5
Carbon
6
Nitrogen
7
Oxygen
8
Fluorine
9
Neon
10
23
24
27
28
31
32
35.5
40
Na
Mg
Al
Si
P
S
Cl
Ar
Sodium
Magnesium
Aluminium
12
11
13
39
40
45
K
Ca
Sc
Potassium
19
Calcium
20
85
48
Scandium
88
89
Sulfur
16
Chlorine
17
Argon
18
52
55
56
59
59
64
65
70
73
75
79
80
84
V
Cr
Mn
Fe
Co
Ni
Cu
Zn
Ga
Ge
As
Se
Br
Kr
Vanadium
Chromium
Manganese
23
Titanium
22
Phosphorus
15
51
Ti
21
Silicon
14
24
25
91
93
Iron
26
101
96
Cobalt
Nickel
27
103
Copper
28
106
29
108
Zinc
30
112
Gallium
Germanium
31
115
32
119
Arsenic
33
122
Selenium
34
128
Bromine
35
127
Krypton
36
131
Rb
Sr
Y
Zr
Nb
Mo
Tc
Ru
Rh
Pd
Ag
Cd
In
Sn
Sb
Te
I
Xe
Rubidium
Strontium
Yttrium
Zirconium
Niobium
Molybdenum
Technetium
Ruthenium
Rhodium
Palladium
Silver
Cadmium
Indium
Tin
Antimony
Tellurium
Iodine
Xenon
37
133
38
137
39
139
40
178
41
181
42
184
43
186
44
190
45
192
46
195
47
197
48
201
49
204
50
207
51
209
52
53
54
Cs
Ba
La
Hf
Ta
W
Re
Os
Ir
Pt
Au
Hg
Tl
Pb
Bi
Po
At
Rn
Caesium
Barium
Lanthanium
Hafnium
Tantalum
Tungsten
Rhenium
Osmium
Iridium
Platinum
Gold
Mercury
Thallium
Lead
Bismuth
Polonium
Astatine
Radon
55
56
226
57
227
72
Fr
Ra
Radium
74
75
76
77
78
79
80
81
82
83
84
85
86
Ac
Francium
73
Actinium
87
89
88
+
140
*58-71 Lanthanoid series
+90-103 Actinoid series
a
X
Key b a = relative atomic mass
X = atomic symbol b = proton (atomic) number
