Example Responses – Paper 6
Cambridge IGCSE™ / IGCSE (9–1)
Biology 0610 / 0970
For examination from 2023
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Contents
Introduction........................................................................................................................................................................4
Question 1.........................................................................................................................................................................5
Question 2.......................................................................................................................................................................10
Question 3.......................................................................................................................................................................13
Question 4.......................................................................................................................................................................16
Question 5.......................................................................................................................................................................18
Question 6.......................................................................................................................................................................21
Example Responses – Paper 6
Introduction
The main aim of this booklet is to exemplify standards for those teaching Cambridge IGCSE / IGCSE (9-1)
Biology 0610 / 0970.
This booklet contains responses to all questions from June 2023 Paper 61, which have been written by a Cambridge
examiner. Responses are accompanied by a brief commentary highlighting common errors and misconceptions where
they are relevant.
The question papers and mark schemes are available to download from the School Support Hub
0610 / 0970 June 2023 Question Paper 61
0610 / 0970 June 2023 Mark Scheme 61
Past exam resources and other teaching and learning resources are available from the School Support Hub
4
Example Responses – Paper 6
Question 1
3
1
A student investigated the effect of temperature on the rate of respiration in yeast cells.
When yeast cells respire they release carbon dioxide gas.
The student used this method:
Step 1
Fill a syringe with 15 cm3 of yeast suspension.
Step 2
Gently lower the syringe into the measuring cylinder, as shown in Fig. 1.1.
Step 3
Fill the measuring cylinder with hot water. Ensure that the water level in the measuring
cylinder is above the syringe nozzle.
bubble of carbon
dioxide gas
measuring cylinder
water
syringe nozzle
yeast suspension
Fig. 1.1
Step 4
Measure the temperature of the water in the measuring cylinder.
Step 5
Start the stop-clock and wait for two minutes.
Step 6
After two minutes, reset the stop-clock to zero.
Step 7
Start the stop-clock again and count the number of bubbles produced by the yeast
suspension in three minutes.
Step 8
Pour the hot water in the measuring cylinder into the waste container. The syringe
containing the yeast suspension should remain in the measuring cylinder.
Step 9
Fill the measuring cylinder with cold water. Ensure that the water level in the measuring
cylinder is above the syringe nozzle.
Step 10 Repeat steps 4 to 7.
5
Example Responses – Paper 6
4
Fig. 1.2 shows the thermometer during step 4 and step 10.
50
50
40
40
30
30
20
20
10
10
0
0
°C
°C
cold water
hot water
Fig. 1.2
Fig. 1.3 shows the number of bubbles the student counted in three minutes in step 7 and step 10.
hot water – 54 bubbles
cold water – 12 bubbles
Fig. 1.3
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6
(a) (i)
Prepare a table for the results and record the temperatures shown in Fig. 1.2 and the
5
results shown in Fig. 1.3.
(a) (i)
Prepare a table for the results and record the temperatures shown
in Fig.Responses
1.2 and –the
Example
Paper 6
results shown in Fig. 1.3.
5
(a) (i)
Prepare a table for the results and record the temperatures shown in Fig. 1.2 and the
5
results shown in Fig. 1.3.
(a) (i)
Prepare a table for the results and record the temperatures shown in Fig. 1.2 and the
results shown in Fig. 1.3.
temperature / oC
number of bubbles
42
54
18
12
[3]
Examiner comment
•
•
(ii) State
a conclusion
Some candidates
included
units in for
the the
dataresults.
cells, usually ºC, or did not put units for temperature in the headings, or
gave ‘bubbles’ rather than ‘number of bubbles’ for the heading.
...........................................................................................................................................
Some misread the thermometers in Fig. 1.2, often as 41 ºC and 19 ºC.
...........................................................................................................................................
[3]
(ii)
(iii)
(ii)
.....................................................................................................................................
[1]
State
a conclusion for the results.
[3]
the higher
thecalculate
temperature
greater
the rate
of respiration
Using
the results,
the rate the
of bubble
production
in bubbles
per minute for the
...........................................................................................................................................
State
conclusioninfor
the
results.
yeast a
suspension
hot
water
and in cold water.
...........................................................................................................................................
[3]
...........................................................................................................................................
.....................................................................................................................................
[1]
State
a conclusion for the results.
...........................................................................................................................................
[3]
(iii) Using
the
results,
calculate
the
rate
of
bubble
production
in
bubbles
per
minute
for
the
...........................................................................................................................................
..................................................................................................................................... [1]
Examiner
yeast a
suspension
hot
water
and in cold water.
(ii) comment
State
conclusioninfor
the
results.
(ii)
...........................................................................................................................................
The conclusion
to
the independent
variable
to bubble
the dependent
variable.
The aim per
of the
investigation
(iii) needed
Using
therelate
results,
calculate the
rate of
production
in bubbles
minute
for theis
...........................................................................................................................................
often stated at theyeast
start suspension
of the method.
was measured by counting bubbles, but the dependent
inThe
hot dependent
water and variable
in cold water.
[1]the
variable itself was.....................................................................................................................................
the rate of respiration. Many candidates concluded that the higher the temperature, the higher
...........................................................................................................................................
number of bubbles
produced, but did not relate this to the rate of respiration.
(iii)
Using the results, calculate the rate of bubble production in bubbles per minute for the
rate of bubble production in hot water ............................... bubbles per minute
.....................................................................................................................................
[1]
yeast
suspension in hot water and in cold water.
(iii)
of bubble
production
in cold
waterproduction
...............................
per minute
Using therate
results,
calculate
the rate
of bubble
in bubblesbubbles
per minute
for the
[1]
yeast suspension in hot water and in cold water.
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rate of bubble production in hot water ............................... bubbles per minute
rate of bubble production in cold water ...............................
bubbles per minute
18
rate of bubble production in hot water ...............................
bubbles per minute
[1]
4
rate of bubble production in cold water ...............................
bubbles per minute
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[Turn over
[1]
rate
of
bubble
production
in
hot
water
...............................
bubbles
per
minute
Examiner comment
© UCLES 2023
© UCLES 2023
[Turn over
Some
candidates divided the
number
of bubbles
by0610/61/M/J/23
2 minutes,
or 60 seconds.
rate
of bubble
production
in cold water
............................... bubbles per minute
rate of bubble production in hot water ............................... bubbles per minute
[1]
© UCLES 2023
rate of bubble production in cold water ............................... bubbles per minute
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[Turn over
[1]
7
Example Responses – Paper 6
6
(iv)
State the independent variable in this investigation.
temperature
...........................................................................................................................................
..................................................................................................................................... [1]
6
(v) State two variables that were kept constant in this investigation.
Examiner
(iv) comment
State the independent variable in this investigation.
1 ........................................................................................................................................
• Some candidates
gave constant variables such as time, or volume of yeast.
...........................................................................................................................................
• A few candidates gave the dependent variable, number of bubbles, instead.
...........................................................................................................................................
..................................................................................................................................... [1]
2 ........................................................................................................................................
(v) State two variables that were kept constant in this investigation.
...........................................................................................................................................
volume (15 cm3) of yeast 6
[2]
1 ........................................................................................................................................
(vi)
(iv)
Suggest
the yeastvariable
suspension
left for two minutes in step 5 before starting to
...........................................................................................................................................
State
thewhy
independent
in thiswas
investigation.
count the number of bubbles.
time (3 minutes) for counting bubbles
2...........................................................................................................................................
........................................................................................................................................
...........................................................................................................................................
...........................................................................................................................................
.....................................................................................................................................
[1]
...........................................................................................................................................
[2]
(v) State two variables that were kept constant in this investigation.
.....................................................................................................................................
(vi) Suggest
why the yeast suspension was left for two minutes in step 5 before starting [1]
to
count
the number of bubbles.
Examiner comment
1 ........................................................................................................................................
(vii) Suggest why counting bubbles is not the most accurate method of determining the rate
• Step 3 of the investigation stated that the water level in the measuring cylinder should be above the syringe nozzle,
respiration
in yeast.
...........................................................................................................................................
but did not sayof
that
the volume
of water must be constant.
•
Answers needed to be as precise as possible. When giving time as a constant variable, the answer needed to refer
2...........................................................................................................................................
........................................................................................................................................
to what the time
was for. In this case, the answer needed to give the ‘time for equilibration’ or the ‘time for counting
bubbles’ as the answer.
(vii)
(vi)
(vii)
..................................................................................................................................... [1]
...........................................................................................................................................
[2]
.....................................................................................................................................
[1]
Suggest
why counting bubbles is not the most accurate method of determining the rate
of
respiration
Suggest
why in
theyeast.
yeast suspension was left for two minutes in step 5 before starting to
count the number of bubbles.
...........................................................................................................................................
the yeast was left for two minutes to allow the temperature of the
...........................................................................................................................................
...........................................................................................................................................
yeast to become the same as the water temperature
...........................................................................................................................................
..................................................................................................................................... [1]
..................................................................................................................................... [1]
Suggest why counting bubbles is not the most accurate method of determining the rate
Examiner comment
of respiration in yeast.
Some candidates thought that this waiting time was needed so the yeast could start respiring or start producing
bubbles. Yeast will...........................................................................................................................................
always be respiring so this is not true.
...........................................................................................................................................
..................................................................................................................................... [1]
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8
...........................................................................................................................................
...........................................................................................................................................
Example Responses – Paper 6
..................................................................................................................................... [1]
(vii)
Suggest why counting bubbles is not the most accurate method of determining the rate
of respiration in yeast.
counting bubbles is not an accurate method of determining the rate
...........................................................................................................................................
of respiration as the bubbles are different sizes so contain different
...........................................................................................................................................
volumes of gas
.....................................................................................................................................
[1]
Examiner comment
•
Answers that referred to the difficulty in counting bubbles were also accepted.
•
Some candidates referred to human error or subjectivity, but did not link this to errors in counting.
7
(b) Measuring the volume of a gas is more accurate than counting bubbles. Using a gas syringe
is one method of collecting a volume of gas.
Fig. 1.4 shows part of the apparatus that can be used to measure the volume of a gas by a
different method.
Complete the diagram in Fig. 1.4 by drawing and labelling the two pieces of apparatus that
are missing.
delivery tube
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0610/61/M/J/23
measuring
cylinder
bung
yeast
suspension
container
of water
Fig. 1.4
(c) Yeast can respire reducing sugars.
9
[2]
yeast
suspension
Example Responsesyeast
– Paper 6
suspension
Examiner comment
•
•
•
•
•
•
container
of water
container
of water
Many candidates did not answer this question.
The question asked candidates to show a different method to measure volume of gas apart from use of a gas
syringe, but many drew a gas syringe.
Fig. 1.3
Many drawings included a thermometer in the container of water.
[2]
Some candidates included a delivery tube, but some of these were labelled as ‘pipes’ or the tube did not enter the
measuring
cylinder
water.
(c) Yeast
can under
respire
reducing sugars.
Many drawings did not include a second piece of equipment to measure volume.
Describedid
thenot
method
youdrawings.
would use to test a substance for the presence of reducing sugars.
Some candidates
label their
Fig. 1.4
[2]
...................................................................................................................................................
(c) Yeast
can respire reducing sugars.
...................................................................................................................................................
Describe
the method you would use to test a substance for the presence of reducing sugars.
...................................................................................................................................................
Take a sample of the substance and add Benedict’s solution. Heat the
...................................................................................................................................................
mixture at 80 ºC in a water bath and look for a colour change.
...................................................................................................................................................
.............................................................................................................................................
[2]
...................................................................................................................................................
Examiner
comment
•
•
The Benedict’s
test was well known and most candidates knew that Benedict’s reagent should be heated with the
...................................................................................................................................................
sample.
Candidates
were not expected to give the results of the test, although a large number did.
.............................................................................................................................................
[2]
© UCLES 2023
© UCLES 2023
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10
[Turn over
Example Responses – Paper 6
8
(d) Bread is made from flour, water and yeast which are mixed to form a dough.
Fig. 1.5 shows a person making bread.
dough
Fig. 1.5
The carbon dioxide gas produced by yeast causes the volume of the dough to increase.
Sodium chloride (salt) is often added to dough when making bread. The sodium chloride
affects the rate at which the yeast respire.
Plan an investigation to determine the effect of the mass of sodium chloride on the volume of
dough.
Make three balls of dough each containing the same volume and type of
...................................................................................................................................................
flour, yeast and water.
...................................................................................................................................................
Mix a different mass of sodium chloride (1 g, 2 g and 3 g) into each ball
...................................................................................................................................................
of dough and knead to combine. Use a balance to measure the mass of
...................................................................................................................................................
sodium chloride.
...................................................................................................................................................
Measure the initial volume of dough using a measuring cylinder.
...................................................................................................................................................
Leave the dough for 30 minutes at 20 ºC.
...................................................................................................................................................
After this time measure the final volume of dough, using the measuring
...................................................................................................................................................
cylinder and calculate the change in volume.
...................................................................................................................................................
Repeat this investigation two more times.
...................................................................................................................................................
...................................................................................................................................................
...................................................................................................................................................
............................................................................................................................................. [6]
[Total: 20]
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11
Example Responses – Paper 6
Examiner comment
•
•
•
•
•
Candidates needed to be precise when describing the constant variables. For example, saying ‘the experiment is
left for about half an hour’ is not enough.
Some candidates did not describe a valid dependent variable. Some described the need to measure how much
the dough had risen, but did not state that this could be done by measuring the volume of dough before and after.
Some candidates thought the volume of carbon dioxide produced needed to be measured using a gas syringe.
Many candidates needed to include more detail in their method. For instance, by describing the use of a balance to
measure the mass of the dough ingredients and describing a method to measure the volume of dough, e.g. using a
measuring cylinder.
For the investigation design question, candidates were awarded a mark for stating that the experiment should be
repeated at least two more times. Some candidates did not mention repetitions, or only repeated the experiment
once.
Some candidates stated the name of the independent variable, but gave no indication as to how this variable would
be changed.
12
Example Responses – Paper 6
8
2
Fig. 2.1 is a2photograph of a cross-section of a root from a carrot plant, Daucus carota.
Question
P
2
10
Q
Fig. 2.1 is a photograph of a cross-section of a root from a carrot plant, Daucus carota.
P
Q
magnification ×6
Fig. 2.1
(a) (i)
Draw a large diagram of the carrot root cross-section
that shows×6
the layers visible in
magnification
Fig. 2.1.
Fig. 2.1
(a) (i)
Draw a large diagram of the carrot root cross-section that shows the layers visible in
Fig. 2.1.
[4]
© UCLES 2023
13
0610/51/M/J/23
Example Responses – Paper 6
Examiner comment
•
•
Some candidates included shading or cells in their diagram, so were not awarded the first marking point.
Occasionally, candidate drawings were too big and crossed
into the text at the top or bottom of the question.
11
(ii)
11
Line PQ on Fig. 2.1 represents the diameter
of the carrot root cross-section.
(ii)
Line
PQ on
2.1 of
represents
theFig.
diameter
Measure
theFig.
length
line PQ on
2.1. of the carrot root cross-section.
Measure
the length
of line PQ on Fig. 2.1. mm
length of PQ
...............................................
109of the carrot root
length
of PQ
mmcross-section using the formula and your
Calculate
the...............................................
actual diameter
measurement.
Calculate the actual diameter of the carrot root cross-section using the formula and your
length of line PQ in Fig. 2.1
measurement.
magnification = actual diameter of the carrot root cross-section
length of line PQ in Fig. 2.1
magnification
Give your
answer to=one
decimal
place.
actual
diameter
of the carrot root cross-section
Give
your
Space
for answer
working.to one decimal place.
Space for working.
109
= 18.1667
6
18.2
...................................................................
mm
[3]
................................................................... mm
[3]
Examiner comment
•
•
The question asked for the answer to be given to one decimal place, but some candidates did not give an answer
to one decimal place.
Some candidates incorrectly multiplied by 6 rather than dividing by 6 and some had difficulties converting cm to
mm.
12
(b) A student investigated the effect of the concentration of a salt solution on the mass of carrot
cubes. The student used this method:
•
•
•
•
•
•
(i)
Carrots were cut into cubes. Each side of the cube was 1 cm in length.
The initial mass of each carrot cube was measured and recorded.
Each carrot cube was put into a different concentration of salt solution.
The carrot cubes were left in the salt solutions for one hour.
After one hour, the carrot cubes were removed from the salt solution and dried with
a paper towel.
The final mass of each carrot cube was measured and recorded.
State the dependent variable in the investigation described in 2(b).
the dependent variable was the mass of the carrot cubes
...........................................................................................................................................
..................................................................................................................................... [1]
(ii)
State two variables that were kept constant
in this investigation.
14
•
•
•
Each carrot cube was put into a different concentration of salt solution.
The carrot cubes were left in the salt solutions for one hour.
Exampleand
Responses
– Paper 6
After one hour, the carrot cubes were removed from the salt solution
dried with
a paper towel.
12
•
The final mass of each carrot cube was measured and recorded.
(b) A student investigated the effect of the concentration of a salt solution on the mass of carrot
Examiner
(i) comment
State
dependent
variable
in the investigation described in 2(b).
cubes.
Thethe
student
used this
method:
Common incorrect answers included ‘mass’, which was not enough, or ‘concentration of salt solutions’ which was the
•...........................................................................................................................................
Carrots were cut into cubes. Each side of the cube was 1 cm in length.
independent variable.
•
The initial mass of each carrot cube was measured and recorded.
.....................................................................................................................................
[1]
•
Each carrot cube was put into a different concentration of salt solution.
•
The carrot cubes were left in the salt solutions for one hour.
(ii) •StateAfter
two one
variables
were kept
constant
in this investigation.
hour, that
the carrot
cubes
12were removed from the salt solution and dried with
a paper towel.
the
initial
volume
of the carrot
cube
•1 ........................................................................................................................................
The
final massthe
of effect
each carrot
was measured
and
recorded.
(b) A student
investigated
of the cube
concentration
of a salt
solution
on the mass of carrot
cubes. The
student
used
this
method:
thethetime
that variable
the carrot
were described
left in the
salt solution
2 ........................................................................................................................................
(i) State
dependent
in thecubes
investigation
in 2(b).
[2]
•
Carrots were cut into cubes. Each side of the cube was 1 cm in length.
...........................................................................................................................................
•
The initial mass of each carrot cube was measured and recorded.
Examiner
(iii) comment
why
it was
important
dry athe
carrot cubes
before measuring
the final mass.
•Explain
Each
carrot
cube
was puttointo
different
concentration
of salt solution.
3
[1]
• The initial volume
of
thecarrot
carrot cubes
cube was
theleft
same
for all
carrot
cubes for
(1 cm
). hour.
However, the volume of the cubes
•.....................................................................................................................................
The
were
in the
salt
solutions
one
...........................................................................................................................................
would have changed
over
the
course
of
the
investigation.
Therefore,
it
was
not
enough
to
state
that
the
size
or
•
After one hour, the carrot cubes were removed from the salt solution and dried with
•
•
volume of
cubes
was
kept
constant.
(ii)the State
variables
that were kept constant in this investigation.
atwo
paper
towel.
...........................................................................................................................................
The initial mass
notfinal
constant,
in Tablecube
2.1. was measured and recorded.
• was
The
massas
ofshown
each carrot
1
........................................................................................................................................
Some gave ‘time’, unqualified. Descriptions of a variable needed to be sufficiently detailed to be unambiguous and
.....................................................................................................................................
[1]
awarded (i)
a mark.
State
the dependent variable in the investigation described in 2(b).
2 ........................................................................................................................................
The results
of the investigation are shown in Table 2.1.
[2]
...........................................................................................................................................
(iii)
Table
2.1cubes before measuring the final mass. [1]
Explain
why it was important to dry the
carrot
.....................................................................................................................................
the extra water on the carrot cube will add to the final mass, so
of salt that initial
of
mass of
...........................................................................................................................................
(ii) concentration
State
two variables
were mass
kept constant
in final
this investigation.
change in mass / g
solution / mol per dm3
carrot cube / g
carrot cube / g
the cubes should be dried before measuring the final mass
1...........................................................................................................................................
........................................................................................................................................
0.0
0.97
1.04
0.07
0.2
0.98
0.99
0.01
[1]
2.....................................................................................................................................
........................................................................................................................................
0.4
0.96
0.90
–0.06
[2]
0.98
–0.12
The results 0.6
of the investigation are
shown in Table 2.1. 0.86
Examiner
0.84
–0.15
(iii) comment
Explain0.8
why it was important 0.99
to dry the carrot cubes
before measuring the
final mass.
Table
2.1
• Many candidates referred
accuracy or reliability. Their
refer to how the extra
1.0 to improvements in0.95
0.79 answer needed to–0.16
...........................................................................................................................................
water would have
contributed
to the final mass
of the carrot cube.
1.2
0.96
0.80
–0.16
concentration
of
salt
initial
mass
ofbe dried tofinal
massthe
ofexcess salt solution, but did not
• Some candidates said that the carrot
cubes
needed
to
remove
change in mass / g
3
per dm
carrot cube / g
...........................................................................................................................................
explain thatsolution
this
extra/ mol
solution
would addcarrot
to the cube
mass./ g
0.0
0.97
1.04
0.07
..................................................................................................................................... [1]
0.2
0.98
0.99
0.01
0.4
0.96
0.90
–0.06
The results of the investigation are shown in Table 2.1.
0.6
0.98
0.86
–0.12
Table 2.1
0.8
0.99
0.84
–0.15
1.0
0.95
0.79
–0.16
concentration of salt
initial mass of
final mass of
change–0.16
in mass / g
1.2
0.96
0.80
© UCLES 2023 solution / mol per dm3
0610/61/M/J/23
carrot cube
/g
carrot cube / g
0.0
0.2
0.4
0.6
0.8
1.0
1.2
© UCLES 2023
0.97
0.98
0.96
0.98
0.99
0.95
0.96
1.04
0.99
0.90
0.86
0.84
0.79
0.80
0610/61/M/J/23
15
0.07
0.01
–0.06
–0.12
–0.15
–0.16
–0.16
Example Responses – Paper 6
11
(iv)
Using the data in Table 2.1, plot a line graph on the grid to show the effect of concentration
of salt solution on the change in mass of the carrot cubes.
One axis has been started for you.
0.1
0.05
concentration
of salt solution
/ mol per dm3
Using the data in Table 2.1, plot a line graph on the grid to show the effect of concentration
0.0 of salt solution on the change in mass of the carrot cubes.
0.2
0.4
0.6
0.8
1.0
1.1
1.2
13
change in
mass / g
(iv)
One axis has been started for you.
-0.05
-0.1
-0.15
0.0
-0.2
[4]
Examiner comment
•
•
•
•
(v)
Using your graph, estimate the concentration of salt solution at which there is no change
Many candidates made the scale for the y-axis too small, so the data points did not cover at least half the available
in the mass of the carrot cube.
space.
Some candidates
gave
on the
y-axis
were your
out byestimate.
a factor of 10, for example giving 0.5 rather than
Show
onvalues
the graph
how
youwhich
obtained
0.05.
Some candidates gave a non-linear scale and some had the axes the
wrong way round. The independent
...........................................
mol per variable
dm3
needed to be on the x-axis.
[2]
As osmosis experiments involve mass loss and negative values, candidates needed more practice constructing
and plotting
this information
nature would in
beTable
useful.2.1, calculate the percentage change in mass of the
(vi) graphs
Usingofthe
carrot cube that was placed in the 0.4 mol per dm3 salt solution.
(v)
[4]
Space for working.
Using your graph, estimate the concentration of salt solution at which there is no change
in the mass of the carrot cube.
Show on the graph how you obtained your estimate.
(vi)
0.23
...........................................
mol per dm3
[2]
............................................................ %
Using the information in Table 2.1, calculate the percentage change in mass of the
[2]
carrot cube that was placed in the 0.4 mol per dm3 salt solution.
16
Space for working.
Example Responses – Paper 6
Examiner comment
•
•
•
•
•
The example response shows the intercept as a cross on the x-axis. This is the ideal answer. However, most
graphs were drawn with the x-axis labelled along the bottom of the graph paper. In this case it was expected that a
line would be drawn from where the graph crossed the zero change in mass, down to the x-axis.
[4]
A significant number of intercepts were shown where the mass of carrot cubes became constant, i.e. at 1.1 mol per
dm3, rather
where
their
line crossed
their
at zero change
in mass.
(v) than
Using
your
graph,
estimate
thex-axis
concentration
of salt
solution at which there is no change
Those candidates
who
did
not
answer
the
previous
question
were
unable
to answer this question too.
in the mass of the carrot cube.
More practice is needed for this skill, as some candidates were unsure as to what they were being asked to do.
Show to
onfollow
the graph
how you carefully,
obtainedas
your
estimate.
Candidates needed
the instructions
there
were many answers given where there was no
indication of an intercept on their graph.
........................................... mol per dm3
[2]
(vi)
Using the information in Table 2.1, calculate the percentage change in mass of the
carrot cube that was placed in the 0.4 mol per dm3 salt solution.
Space for working.
( 0.9 0.96)
100 6.25
0.96
© UCLES 2023
Examiner comment
0610/51/M/J/23
-6.25
............................................................
%
[2]
[Turn over
Some candidates divided -0.06 by 0.9 rather than 0.96 and some divided 0.96 by 0.9.
14
(vii)
The student did not repeat the investigation and only collected one set of results.
Explain why it is better to collect several sets of results.
it is better to collect several sets of results so that anomalous results
...........................................................................................................................................
can be identified and then discarded from the results before an
...........................................................................................................................................
average is calculated
.....................................................................................................................................
[1]
[Total: 20]
Examiner comment
•
•
Some candidates gave explanations that referred to preventing anomalies, increasing reliability or stated that it was
so that an average could be calculated, but these were ignored.
Candidates needed to use correct vocabulary when describing anomalies. They referred to ‘abnormal results’,
‘errors’, ‘mistakes’, etc. in their answers, that showed the right understanding, but some candidates had not used
the correct term.
17
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