CHEMISTRY
Paper 5070/01
Multiple Choice
Question
Number
Key
Question
Number
Key
1
D
21
B
2
D
22
B
3
D
23
A
4
B
24
B
5
A
25
B
6
A
26
D
7
B
27
B
8
C
28
A
9
C
29
C
10
C
30
D
11
A
31
A
12
D
32
C
13
B
33
B
14
A
34
C
15
A
35
B
16
B
36
B
17
C
37
C
18
A
38
C
19
C
39
C
20
D
40
D
General comments
All questions all produced good discrimination with respect to the abilities of the candidates. Candidates
found Questions 34 and 40 to be the most straightforward.
Comments on Individual Questions
Question 2
This was really a question about relative rates of diffusion. Ammonia having a lower Mr than hydrogen
chloride reached the litmus paper first and turned the litmus paper blue. Eventually the hydrogen chloride,
which diffuses more slowly, reaches the litmus paper and turns the litmus red.
5070 Chemistry November 2007
1
Question 8
Sodium chloride was the only ionic compound in the question and the answer to the question. All the other
compounds were covalent compounds.
The answer relied on the knowledge that in general ionic compounds have high melting points and covalent
compounds have low melting points.
Question 9
Graphite conducts electricity due to the movement of electrons and does not contain any ions, thus the very
popular alternative D was incorrect.
Question 13
Alternatives A and C were popular distractors. When an element burns in oxygen it always combines with
the oxygen and therefore the product has a mass equal to the original mass of the element plus the mass of
the oxygen which has combined with the element.
Question 22
A solution of sulphuric acid contains a large number of hydrogen ions. Neutralisation of the acid involves
reducing the number of hydrogen ions in the solution. The only reaction where the number of hydrogen ions
is not reduced is in alternative B and here the hydrogen i