COMBINED SCIENCE
Paper 5129/01
Multiple Choice
Question
Number
Key
Question
Number
Key
1
B
21
B
2
B
22
C
3
D
23
A
4
C
24
C
5
A
25
C
6
B
26
B
7
C
27
D
8
B
28
B
9
C
29
B
10
A
30
C
11
A
31
A
12
A
32
C
13
D
33
B
14
C
34
C
15
B
35
D
16
D
36
A
17
C
37
B
18
D
38
C
19
C
39
D
20
C
40
A
Physics, Questions 1 – 13
General comments
A mean score of 17.8 with a standard deviation of 5.2 was achieved by the candidates. Question 13 was
the only question to prove particularly easy, with Questions 5 and 7 proving particularly difficult.
Comments on specific questions
Questions 1 and 2
In both questions, the correct option, B, was chosen by candidates who performed well overall. In Question
1, however, some of these candidates chose option D, which was the correct formula, but an incorrect
rearrangement! In both questions, almost as many candidates chose another option viz. C in Question 1
and A in Question 2.
Question 3
This question discriminated well, with the majority of the weaker candidates opting for B.
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Question 4
Some of the more able candidates chose option A.
Question 5
Confusion and widespread guessing was evident. All the incorrect options attracted more responses than
the correct one, option A. Some of the more able candidates opted for either option C or D.
Question 6
With waves, the usual misconception among candidates concerns amplitude but on this occasion, it was
wavelength, with the majority choosing either option A or B; more correctly opting for B.
Question 7
This question proved difficult because candidates did not read the question carefully enough. Over four
times as many, 67%, chose option B, the S-pole proving too tempting, than chose the correct option, C. The
popular misconception that copper is magnetic may have also played a part, as a tiny number of able
candidates chose option A!
Questions 8 and 9
Weaker candidates were equally divided between incorrect options A and C in Question 8 and options A
and B in Question 9.
Questions 10 and 11
In both questions, approximately 50% of candidates correctly opted for option A.
alternative for weaker candidates in both questions was option C.
The most popular
Question 12
This question discriminated well, with the less able candidates undecided and spread fairly evenly between
the three incorrect options.
Chemistry, Questions 14 – 27
Comments on specific questions
Question 14
The better candidates found this question easy, although a significant number of candidates chose option A,
in which substance 1 was a gas. The question had stated that substance 1 is brittle, which is a property of
solids.
Question 15
This was another easy question for the better candidates. A large number of candidates however thought
that the temperature of the liquid in the flask was 100ºC and chose option A.
Question 16
A large proportion of the candidates chose option A, which gave the data for a calcium atom and not the ion.
Candidates should appreciate the difference between the electronic structure of an atom and a positive ion.
Positive ions have more protons than electrons.
Question 17
The majority of the candidates recognised that an ionic compound is formed between a metal and a nonmetal, magnesium and chlorine. A significant proportion of the candidates thought that carbon and oxygen
would produce an ionic compound.
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Question 18
There was evidence of guesswork from all but the best candidates
Question 19
Again, there was evidence of guesswork. Many candidates did not know that an amphoteric oxide reacts
with both an acid and an alkali, hydrochloric acid and sodium hydroxide. Over 50% of the candidates chose
option A or option D where the oxide reacted with either the hydrochloric acid or the sodium hydroxide.
Question 20
This was another easy question for the better candidates, although there was evidence of guesswork
amongst the weaker candidates.
Question 21
The majority of candidates recognised that caesium is more reactive than lithium but the most popular option
for the weaker candidates was A, which stated that caesium lost an electron when it forms an ion.
Question 22
There was evidence of guesswork even amongst the better candidates. A large number of candidates
thought that limestone was the reducing agent in the production of iron.
Question 23
Over 40% of the candidates chose option D. Candidates were not aware that an alloy is an element with a
small amount of another element mixed with it.
Question 24
A large proportion of the candidates chose option D. Whist respiration and combustion cause an increase in
the carbon dioxide content of the atmosphere, rusting does not. The better candidates recognised that
oxygen is used up in all three processes.
Question 25
The better candidates correctly deduced that oxygen is more soluble than nitrogen in water from the
information. There was evidence that the weaker candidates used guesswork.
Question 26
The better candidates were able to count up the atoms in the substances and deduce the molecular
formulae of the four structures. Option A was the most popular distractor.
Question 27
This proved to be a difficult question for many candidates. Many candidates did not recognise the reaction
as an addition reaction with an alkene, consequently the reaction of propane with steam to produce
propan-1-ol was a popular distractor.
Biology, Questions 28 – 40
Comments on specific questions
Question 28
This was a straightforward question on cell structure, although it proved slightly more difficult than similar
questions in past papers where a diagram has been given.
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Question 29
This question was on a similar theme, but in a particular context. Some of the better candidates were
confused.
Question 30
This question, which required the interpretation of simple information in a table, discriminated well between
candidates.
Question 31
Many candidates, even the better ones, chose D, showing that they do not really understand the meaning of
the term transpiration.
Question 32
This question discriminated well between candidates,
Question 33
Many candidates chose A, indicating a misunderstanding (or a misreading) or ‘high humidity’.
Question 34
As in Question 30, it was pleasing to see that most candidates could interpret the information given to them
accurately.
Question 35
This question required candidates to deal with an unfamiliar context, and it caused much confusion. To
arrive at the correct answer, candidates only had to realise that all parts of a germinating seed will be
undergoing active respiration.
Question 36
Over one third of candidates chose D on this question, evidently believing that light rays cross over within the
eye for normal focusing.
Question 37
This question was easy, but discriminated satisfactorily. Some candidates thought that alcohol speeds up
reactions, but it only seems that way.
Question 38
There was some evidence of guessing here, but the better candidates were able to interpret the diagram
accurately.
Question 39
This question worked well, but a common error was to think that asexual reproduction is a way of developing
new varieties of plants.
Question 40
Weaker candidates were guessing here, indicating a poor understanding of such terms as fertilisation and
implantation.
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Paper 5129/02
Theory
General comments
The majority of candidates could make some attempt at most of the questions. The candidates’ responses
to the Chemistry section of the paper were better than the Biology or Physics. Many candidates found the
calculations in the Physics section difficult and frequently the units were omitted from the answers. In
addition, a significant number of candidates could state the formula required for a calculation but could not
transpose the formula to allow the calculation to be completed. The definitions and meaning of words in the
Biology section were not well known and were frequently imprecise.
Comments on specific questions
Question 1
Most candidates could work out the proton number, the number of protons, neutrons and electrons for the
atoms but the vast majority of candidates could not work out the number of electrons in a sodium ion. The
most common answer was the number of electrons in a sodium atom. The formula of magnesium chloride
was invariably written as MgCl rather than MgCl2. The bonding in magnesium chloride was not well known,
with a large number of candidates stating that it was covalent rather than ionic.
Question 2
This question was done well by a large number of candidates. The gases used in welding were less well
known than the others. The gases in parts (c) and (d) were particularly well known, although some
candidates suggested that the pollutant was carbon monoxide and the gas produced by the incomplete
combustion of petrol was sulphur dioxide, instead of the other way round.
Question 3
The calculation in part (a) was disappointingly done by all but the best candidates. A greater number of
candidates could calculate the Mr of nitrogen than the Mr of ammonia. The Mr of ammonia was frequently
quoted as being 34 or 31, rather than 17. The candidates who had calculated it as 34 had included the 2
from the equation, rather than calculating the Mr as required by the question. The calculation in part (a)(ii)
proved difficult for the majority of candidates. Candidates should be able to calculate quantities from given
balanced equations. Of those candidates who correctly calculated the quantity required, some were
penalised for either not stating the units or stating the units as grams rather than kilograms. Candidates who
failed to calculate the correct values of Mr in part (a)(i), but used the number correctly in the calculation were
given credit for the calculation. Candidates were unaware that ammonium sulphate is used as a fertiliser
because it contains the essential element nitrogen. A large number of candidates did not gain credit for this
question because they simply stated that ammonium sulphate helps plant growth, with no explanation.
Answers: (a)(i) 28, 17, (ii) 7kg.
Question 4
Candidates rarely mentioned the word ‘atoms’ in their answers. In order to define an element, it is essential
to state that it is made up of one type of atom. Compounds are made up of two different types of atom. The
two different atoms, which make up a compound, are chemically combined together. Candidates frequently
stated that the atoms in a compound are mixed together and were not given credit for their answer. The
homologous series to which methane belongs was well known. The structure of methane was drawn
correctly by a large number of candidates, but some gave the structure of ethane.
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Question 5
A majority of the candidates were able to identify sodium and hydrogen correctly. However, sodium chloride
was less well known as salt C. Gas D was only rarely identified as ammonia. The better candidates
disappointingly only stated the reaction between sodium hydroxide and hydrochloric acid as neutralisation.
The equation for the reaction was poorly done, with many candidates not being able to state the correct
formulae of the reactants and products. Some candidates gave the word equation rather than the symbol
equation. Candidates should be able to construct a balanced chemical equation for a reaction when they are
given the reactants and products.
Question 6
The majority of candidates identified B or E as a metal. The reasons for the choice of substance were
frequently imprecise. The commonest answer was to state that metals conduct electricity, without qualifying
the statement with ‘when solid’. A large number of candidates recognised that metals have high melting
points. A majority of candidates could identify A or D as covalent compounds and state that covalent
compounds have low melting points. The second reason was again, frequently imprecise, in that candidates
simply stated that covalent compounds do not conduct electricity, without qualifying the statement with ‘in
ether solid or liquid’.
Question 7
This question was poorly done by the majority of the candidates. Only a small number of candidates
correctly identified that switches A and C should be closed to light lamp Q only. The symbol for a fuse was
not well known and those who could draw the symbol correctly rarely placed it in the live part of the circuit.
Many candidates drew the fuse across the power supply. The function of a fuse was seen, by most
candidates, as a means of controlling the current. Candidates should be aware that when the current in the
circuit exceeds the rating of the fuse, the fuse melts and the circuit is broken. The calculation was done
poorly by many candidates. The majority of candidates who knew the formula to calculate the current did not
allow for the fact that there were two bulbs in the circuit, and obtained an answer 0.25A. The energy change
‘electrical to heat or light’ was not well known by candidates, but most did score the mark for heat or light.
Answer: (d) 0.5A.
Question 8
Most candidates identified radio waves as having the lowest frequency, but inevitably gamma rays was a
common alternative. S was correctly named as X-rays by a large number of candidates. The properties of
electromagnetic radiation were not well known. The calculations in part (d) were poorly done. Those
candidates who knew the formulae to answer the questions, frequently let themselves down by their inability
to transpose the formulae and/or poor use of scientific calculators. Those candidates who correctly
calculated the numerical answer, frequently omitted the units.
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Answers: (d)(i) 1.5 x 10 m, (ii) 6 x 10 Hz.
Question 9
Many candidates correctly calculated the value of X and Y, but the number of neutrons proved more difficult
for some candidates. The concept of half life is not well understood by the majority of candidates. Only a
small number of candidates recognised that 4800 years was three half lives, and consequently that the
sample emitted alpha particles at a rate of 3000 per second. Those candidates who recognised that three
half lives had elapsed simply divided 24000 by three and obtained 8000 per second. Only a small number of
candidates recognised that beta particles can be detected by a Geiger Muller tube. A surprisingly large
number of candidates thought the reason for not using alpha particles was that they pass through paper,
rather than they are stopped by paper.
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Answer: (b) 3000s .
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Question 10
A large number of candidates correctly marked the poles on the two magnets. Parts (b) and (c) were
answered poorly by a large number of candidates. Many candidates talked about electrical conduction of
iron, or the electromagnet being stronger than a permanent magnet. Only the good candidates appreciated
the temporary nature of an electromagnet. Many candidates knew of at least one way of increasing the
strength of an electromagnet, with the majority suggesting increasing the number of turns. Some candidates
suggested hitting or stroking the magnet and clearly there is some confusion between induction and
electromagnetism.
Question 11
The type of respiration was well known, particularly by the better candidates. Many candidates recognised
that the limewater went milky in tube B. Candidates who simply stated that bubbles would be seen gained
no credit. The word equation for fermentation was not well known. The majority of the candidates tried to
write an equation for aerobic respiration. The vast majority of candidates suggested, correctly, that the yeast
speeded up the reaction, but this did not answer the question asked. The idea that the reaction provided the
yeast with energy was not well known even amongst the better candidates. The product formed by
anaerobic respiration, lactic acid, was well known, particularly by the better candidates. The majority of
candidates gained credit for suggesting some form of strenuous activity in part (b)(ii).
Question 12
Most candidates gained some credit for part (a), but many were penalised for drawing the arrow heads the
wrong way round. The name of the organisms that are decomposers was not well known, and the function
of decomposers was misunderstood. There were many vague comments about fertilising the soil, which
gained no credit. The explanation required was that decomposers cause the decay of dead animals and
plants, which provide nutrients for the growing plants. The majority of candidates knew that animals eat
green plants and are therefore consumers. A smaller number of candidates stated that green plants make
food through the process of photosynthesis and are therefore producers. Only a small number of candidates
stated that animals were unable to make their own food.
Question 13
This question was poorly answered by the majority of the candidates. The better candidates could define
excretion as the removal of waste, but only a small number of candidates indicated that this waste was the
product of metabolism. Only a small number of candidates correctly identified the products of metabolism as
carbon dioxide and urea. The most common answer was urine. Of those candidates who identified the
products of metabolism, there was confusion as to the organ where the product was produced and where it
was excreted. The kidney was frequently quoted as where urea was produced, rather than the organ from
which it was excreted. The difference between egestion and excretion was not well understood. Few
candidates stated that egestion was the removal of faeces from the anus and that this was undigested
material not absorbed by the body.
Question 14
The definition of osmosis was quite well known, but candidates frequently lost marks by stating that it was
the movement of water molecules from a high concentration to a low concentration. During osmosis, water
moves from a dilute solution to a more concentrated solution through a semi-permeable membrane. The
name of the cell was well known by many candidates. The confusion over the definition of osmosis was
further shown by the fact that the majority of candidates thought that the water in the soil was the more
concentrated solution. The ion absorbed by plants was often stated incorrectly as nitrogen. The majority of
candidates stated that water was lost from the leaves by the stomata, but too many vague answers such as
pores and leaves were seen. The name of the process was known by the better candidates, but many
candidates stated that the process was evaporation or respiration.
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