2
1Hot powdered lead(II) oxide is reduced by methane, a flammable gas. The products are lead,
steam and carbon dioxide gas.
Fig. 1.1 shows the apparatus used to reduce lead(II) oxide using excess methane.
powdered lead(II) oxide
methane
waste gases
A
B
ice
Fig. 1.1
(a)Name the item of apparatus labelled A.
.............................................................................................................................................. [1]
(b)Draw an arrow on Fig. 1.1 to show where the apparatus should be heated.
[1]
(c)Explain why powdered lead(II) oxide is used and not a large lump of lead(II) oxide.
....................................................................................................................................................
.............................................................................................................................................. [1]
(d)Explain what happens at the point labelled B, on Fig. 1.1.
....................................................................................................................................................
....................................................................................................................................................
.............................................................................................................................................. [2]
(e)The waste gases contain methane.
State why the waste gases should not be released into the laboratory.
....................................................................................................................................................
.............................................................................................................................................. [1]
© UCLES 2023
[Total: 6]
0620/62/M/J/23
3
2A student investigates how the rate of the reaction between aqueous iron(III) nitrate and aqueous
sodium thiosulfate changes with temperature.
The student does five experiments using the apparatus shown in Fig. 2.1.
eye
5 cm3 of aqueous sodium thiosulfate
100 cm3 beaker
50 cm3 of aqueous iron(III) nitrate
printed sheet
printed text
Fig. 2.1
(a) Experiment 1
●
●
●
●
●
●
●
se a 50 cm3 measuring cylinder to pour 50 cm3 of aqueous iron(III) nitrate into a 100 cm3
U
beaker.
Stand the beaker on a printed sheet as shown in Fig. 2.1.
Use a 10 cm3 measuring cylinder to pour 5 cm3 of aqueous sodium thiosulfate into the
beaker and at the same time start a stop-clock.
Use a thermometer to stir the contents of the beaker.
Look down from above the beaker and when the text on the printed sheet becomes visible,
stop the stop-clock.
Use the thermometer to measure the temperature of the solution when the text becomes
visible.
Rinse the beaker and thermometer with water.
Experiment 2
●
●
●
●
●
●
●
●
se the 50 cm3 measuring cylinder to pour 50 cm3 of aqueous iron(III) nitrate into the
U
100 cm3 beaker.
Heat the beaker on a gauze over a Bunsen burner until the temperature of the iron(III) nitrate
has increased by about 5 °C.
Stand the beaker on the printed sheet as shown in Fig. 2.1.
Use the 10 cm3 measuring cylinder to pour 5 cm3 of aqueous sodium thiosulfate into the
beaker and at the same time start a stop-clock.
Use the thermometer to stir the contents of the beaker.
Look down from above the beaker and when the text on the printed sheet becomes visible,
stop the stop-clock.
Use the thermometer to measure the temperature of the solution when the text becomes
visible.
Rinse the beaker and thermometer with water.
Experiment 3
●
epeat Experiment 2, this time heating the aqueous iron(III) nitrate until the temperature
R
has increased by about 10 °C.
Experiment 4
●
© UCLES 2023
epeat Experiment 2, this time heating the aqueous iron(III) nitrate until the temperature
R
has increased by about 15 °C.
0620/62/M/J/23
[Turn over
4
Experiment 5
●
epeat Experiment 2, this time heating the aqueous iron(III) nitrate until the temperature
R
has increased by about 25 °C.
Use the thermometer diagrams and stop-clock diagrams to complete Table 2.1.
Table 2.1
experiment
stop-clock diagram
0
seconds
0
1
time taken for
the text to
become visible
/s
45 15
5
10
temperature of the
solution when the
text becomes
visible / C
30
25
15
minutes
30
thermometer
diagram
20
0
30
0
2
45 15
5
25
15
10
20
30
0
30
0
3
45 15
5
25
15
10
20
30
0
40
0
4
45 15
5
35
15
10
30
30
0
50
0
5
45 15
5
45
15
10
40
30
© UCLES 2023
[4]
0620/62/M/J/23
5
(b)Write a suitable scale on the y-axis and plot your results from Experiments 1 to 5 on Fig. 2.2.
Draw a smooth curve of best fit.
time taken for the
text to become
visible / s
10
20
30
40
50
60
temperature of the solution
when the text becomes visible / C
Fig. 2.2
[4]
(c)Deduce the experiment in which the rate of reaction is fastest.
.............................................................................................................................................. [1]
(d)Use your graph to predict the temperature of the solution when the text becomes visible after
55 seconds.
Show your working on Fig. 2.2.
© UCLES 2023
temperature = .............................. °C [2]
0620/62/M/J/23
[Turn over
6
(e)Explain why wrapping the beaker in cotton wool after it has been heated will improve the
accuracy of the results obtained.
....................................................................................................................................................
.............................................................................................................................................. [2]
(f) (i)Explain why it would be an improvement to measure the volume of aqueous iron(III) nitrate
in a burette rather than a measuring cylinder.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(ii)Suggest why it would not be an improvement to add the aqueous sodium thiosulfate using
a pipette.
. ............................................................................................................................................
. ...................................................................................................................................... [1]
(g)Suggest why the aqueous sodium thiosulfate must be added after the aqueous iron(III) nitrate
has been heated and not before it is heated.
....................................................................................................................................................
.............................................................................................................................................. [1]
(h)Describe how the results of the experiment would change when the experiment is repeated
using a 250 cm3 beaker in place of the 100 cm3 beaker.
Explain your answer.
change in results ........................................................................................................................
explanation .................................................................................................................................
....................................................................................................................................................
[2]
[Total: 18]
© UCLES 2023
0620/62/M/J/23
11
Notes for use in qualitative analysis
Tests for anions
anion
test
test result
carbonate, CO32–
add dilute acid, then test for carbon
dioxide gas
effervescence, carbon dioxide
produced
chloride, Cl –
[in solution]
acidify with dilute nitric acid, then
add aqueous silver nitrate
white ppt.
bromide, Br –
[in solution]
acidify with dilute nitric acid, then
add aqueous silver nitrate
cream ppt.
iodide, I–
[in solution]
acidify with dilute nitric acid, then
add aqueous silver nitrate
yellow ppt.
nitrate, NO3–
[in solution]
add aqueous sodium hydroxide,
then aluminium foil; warm carefully
ammonia produced
sulfate, SO42–
[in solution]
acidify with dilute nitric acid, then
add aqueous barium nitrate
white ppt.
sulfite, SO32–
add a small volume of acidified
aqueous potassium manganate(VII)
the acidified aqueous potassium
manganate(VII) changes colour
from purple to colourless
Tests for aqueous cations
cation
effect of aqueous sodium hydroxide
effect of aqueous ammonia
aluminium, Al 3+
white ppt., soluble in excess, giving
a colourless solution
ammonium, NH4+
ammonia produced on warming
calcium, Ca2+
white ppt., insoluble in excess
no ppt. or very slight white ppt.
chromium(III), Cr3+
green ppt., soluble in excess
green ppt., insoluble in excess
copper(II), Cu2+
light blue ppt., insoluble in excess
light blue ppt., soluble in excess,
giving a dark blue solution
iron(II), Fe2+
green ppt., insoluble in excess,
ppt. turns brown near surface on
standing
green ppt., insoluble in excess,
ppt. turns brown near surface on
standing
iron(III), Fe3+
red-brown ppt., insoluble in excess
red-brown ppt., insoluble in excess
zinc, Zn2+
white ppt., soluble in excess, giving
a colourless solution
white ppt., soluble in excess, giving
a colourless solution
© UCLES 2023
0620/62/M/J/23
white ppt., insoluble in excess
–
12
Tests for gases
gas
test and test result
ammonia, NH3
turns damp red litmus paper blue
carbon dioxide, CO2
turns limewater milky
chlorine, Cl 2
bleaches damp litmus paper
hydrogen, H2
‘pops’ with a lighted splint
oxygen, O2
relights a glowing splint
sulfur dioxide, SO2
turns acidified aqueous potassium manganate(VII) from purple to colourless
Flame tests for metal ions
metal ion
flame colour
lithium, Li+
red
sodium, Na+
yellow
potassium, K+
lilac
calcium, Ca2+
orange-red
barium, Ba2+
light green
copper(II), Cu2+
blue-green
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.
To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge
Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download
at www.cambridgeinternational.org after the live examination series.
Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge
Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge.
© UCLES 2023
0620/62/M/J/23
5
2
A student investigates the temperature change when solid citric acid reacts with solid
sodium carbonate.
The student does six experiments.
(a) Experiment 1
●
●
lace 5.0 g of solid sodium carbonate in a 100 cm3 beaker.
P
Use a thermometer to stir the solid sodium carbonate for 30 seconds. Measure the
temperature of the solid sodium carbonate.
Experiment 2
●
●
●
Add 1.0 g of solid citric acid to the solid sodium carbonate in the beaker from Experiment 1.
se the thermometer to stir the mixture for 30 seconds. Measure the temperature of the
U
mixture.
Rinse the beaker and thermometer with water.
Experiment 3
●
●
●
●
lace 5.0 g of solid sodium carbonate in the 100 cm3 beaker.
P
Add 2.0 g of solid citric acid to the solid sodium carbonate in the beaker.
Use the thermometer to stir the mixture for 30 seconds. Measure the temperature of the
mixture.
Rinse the beaker and thermometer with water.
Experiment 4
●
Repeat Experiment 3, using 4.0 g of solid citric acid instead of 2.0 g.
Experiment 5
●
Repeat Experiment 4, using 5.0 g of solid citric acid instead of 4.0 g.
Experiment 6
●
© UCLES 2023
Repeat Experiment 5, using 6.0 g of solid citric acid instead of 5.0 g.
0620/63/M/J/23
[Turn over
6
Use the information in the description of the experiments and the thermometer diagrams to
complete Table 2.1.
Table 2.1
experiment
mass of
solid sodium
carbonate / g
mass
of solid
citric acid / g
thermometer
diagram after
30 seconds
temperature after
30 seconds / °C
30
1
5.0
0.0
25
20
20
2
5.0
1.0
15
10
10
5
3
0
10
5
4
0
0
–5
5
–10
0
–5
6
–10
[4]
© UCLES 2023
0620/63/M/J/23
7
(b)Complete a suitable scale on the y-axis and plot the results from Experiments 1 to 6 on Fig. 2.1.
Draw a line of best fit through your points.
temperature
/ C
0
0
1
2
3
4
5
6
mass of
citric acid
/g
Fig. 2.1
[4]
(c)State whether the reaction between solid sodium carbonate and solid citric acid is exothermic
or endothermic.
Explain your answer.
.....................................................................................................................................................
............................................................................................................................................... [1]
(d)Deduce which experiment had the greatest temperature change compared to the temperature
in Experiment 1.
............................................................................................................................................... [1]
(e)
From your graph, deduce the temperature, after stirring for 30 seconds, that is obtained when
3.5 g of solid citric acid is added to 5.0 g of solid sodium carbonate.
Show clearly on the grid how you worked out your answer.
© UCLES 2023
temperature = .............................. °C [2]
0620/63/M/J/23
[Turn over
8
(f) S
uggest why the solid sodium carbonate and solid citric acid are stirred before the temperature
is measured.
.....................................................................................................................................................
............................................................................................................................................... [2]
(g) E
xplain why using a polystyrene cup in place of the glass beaker would increase the accuracy
of the results.
.....................................................................................................................................................
............................................................................................................................................... [2]
© UCLES 2023
[Total: 16]
0620/63/M/J/23
2
1Sulfur dioxide gas is toxic, denser than air and soluble in water. Sulfur dioxide gas can be made by
adding dilute hydrochloric acid to solid sodium sulfite and heating the mixture. The gas made can
be dried by passing it through concentrated sulfuric acid.
The diagram shows the apparatus a student used to try and collect some dry sulfur dioxide gas.
There are two errors in the way the apparatus has been set up.
inverted gas jar
dilute
hydrochloric acid
A
concentrated
sulfuric acid
B
(a)Indicate with an arrow on the diagram where heat should be applied.
[1]
(b)Give the name of the item of apparatus labelled A.
............................................................................................................................................... [1]
(c)Give the name of the substance labelled B.
............................................................................................................................................... [1]
(d)Suggest why this experiment should be carried out in a fume cupboard.
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2022
0620/61/O/N/22
3
(e)Identify the two errors in the way the apparatus has been set up.
1 ..................................................................................................................................................
.....................................................................................................................................................
2 ..................................................................................................................................................
.....................................................................................................................................................
[2]
© UCLES 2022
[Total: 6]
0620/61/O/N/22
[Turn over
5
2A student investigated how the solubility of sodium sulfate in water changes with temperature.
Eight experiments were done.
Experiment 1
● The mass of an empty evaporating basin was found.
● An excess of solid sodium sulfate was placed in a beaker.
● 100 cm3 of cold water was added to the beaker.
● The mixture in the beaker was stirred and heated until it had reached a temperature of 15 °C.
Some of the sodium sulfate had dissolved to form a saturated solution.
● A 25.0 cm3 portion of the saturated solution was removed from the beaker and transferred to
the evaporating basin.
● The evaporating basin was heated until no more steam could be seen and solid sodium sulfate
remained in the evaporating basin.
● The mass of the evaporating basin and the solid sodium sulfate remaining was found.
Experiment 2
● Experiment 1 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 1.
Experiment 3
● Experiment 2 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 2.
Experiment 4
● Experiment 3 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 3.
Experiment 5
● Experiment 4 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 4.
Experiment 6
● Experiment 5 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 5.
Experiment 7
● Experiment 6 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 6.
Experiment 8
● Experiment 7 was repeated but the mixture in the beaker was heated to a higher temperature
than in Experiment 7.
© UCLES 2022
0620/61/O/N/22
[Turn over
6
(a)Complete the table by using the thermometer diagrams and calculating the mass of solid
sodium sulfate remaining in the evaporating basin at each temperature.
experiment
thermometer
diagram
temperature
/ °C
mass of empty
evaporating
basin / g
mass of evaporating
basin and solid
sodium sulfate
remaining / g
15
54.2
58.1
56.3
62.2
57.1
66.7
58.0
69.7
57.6
69.9
56.4
68.1
55.9
67.1
57.6
68.4
mass of solid
sodium sulfate
remaining / g
20
1
15
10
30
2
25
20
30
3
25
20
35
4
30
25
40
5
35
30
50
6
45
40
65
7
60
55
90
8
85
80
[4]
© UCLES 2022
0620/61/O/N/22
7
(b)Plot the results from Experiments 1 to 8 on the grid.
Draw two curves of best fit, one through the first four points and one through the second four
points. Extend the two curves so that they cross.
14
12
mass of solid
sodium sulfate
remaining / g
10
8
6
4
2
10
20
30
40
50
60
70
80
90
temperature / C
[4]
(c) (i)
From your graph, deduce the mass of solid sodium sulfate that remains in the evaporating
basin when the mixture in the beaker is heated to 55 °C.
Show clearly on the grid how you worked out your answer.
mass of solid sodium sulfate remaining = .............................. g [2]
(ii)The mass of solid sodium sulfate remaining in (c)(i) is the mass of sodium sulfate that will
dissolve in 25.0 cm3 of solution at 55 °C.
Use your answer to (c)(i) to calculate the concentration, in g / dm3, of saturated aqueous
sodium sulfate at 55 °C.
(1 dm3 = 1000 cm3)
© UCLES 2022
concentration = .............................. g / dm3 [1]
0620/61/O/N/22
[Turn over
8
(d)The student repeated the experiment and found 11.0 g of solid sodium sulfate remained in the
evaporating basin.
Use your graph to deduce the two possible temperatures to which the mixture in the beaker
may have been heated.
................................................................. and ��������������������������������������������������������������������� [2]
(e)Name an item of apparatus that can be used to remove the 25.0 cm3 portion of saturated
solution from the beaker.
............................................................................................................................................... [1]
(f) (i)Suggest why it is important that an excess of sodium sulfate is added to the water in the
beaker.
........................................................................................................................................ [1]
(ii)Suggest why the mixture in the beaker was stirred as it was heated.
........................................................................................................................................ [1]
(g)The saturated solution was heated until no more steam could be seen and solid sodium sulfate
remained in the evaporating basin.
Suggest a better way of ensuring that all of the water has been evaporated.
.....................................................................................................................................................
.....................................................................................................................................................
............................................................................................................................................... [2]
(h)
Use your graph in (b) to deduce what would be observed if a saturated solution of sodium sulfate
at 80 °C is cooled to 50 °C.
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2022
[Total: 19]
0620/61/O/N/22
2
1Silver chloride is an ionic compound and is insoluble in water. Molten silver chloride breaks down
during electrolysis. The products are chlorine and silver.
Chlorine gas is soluble in water and toxic.
A student suggests using the apparatus shown to break down silver chloride.
power
supply
silver chloride
(a)Draw an arrow on the diagram to show where heat must be applied so that the silver chloride
can break down.
[1]
(b)Complete the diagram to show how chlorine gas can be collected and the volume of the
chlorine measured. Label any apparatus you have drawn.
[2]
(c)Give two observations that are made as the silver chloride breaks down.
1 ..................................................................................................................................................
2 ..................................................................................................................................................
[2]
© UCLES 2021
0620/62/F/M/21
3
(d)The person doing the experiment followed all normal laboratory safety rules.
State one additional safety precaution that should be taken when doing this experiment. Give
a reason for your answer.
safety precaution ........................................................................................................................
reason .........................................................................................................................................
[2]
(e)Suggest one reason why zinc is not a suitable material to use as the electrodes.
.....................................................................................................................................................
............................................................................................................................................... [1]
(f)The chlorine gas was bubbled into an aqueous solution of a sodium salt. The colour of the
solution changed from colourless to orange.
Identify the sodium salt and explain what has happened to cause the colour change.
sodium salt .................................................................................................................................
explanation..................................................................................................................................
.....................................................................................................................................................
[2]
© UCLES 2021
[Total: 10]
0620/62/F/M/21
[Turn over
5
2A student investigated the time taken to collect 40 cm3 of hydrogen gas when magnesium reacts
with dilute sulfuric acid.
Five experiments were done using the apparatus shown.
inverted 50 cm3
measuring cylinder
dilute sulfuric acid
and distilled water
water
Experiment 1
●● Using a measuring cylinder, 8 cm3 of dilute sulfuric acid was poured into the boiling tube.
●● Using a second measuring cylinder, 12 cm3 of distilled water was added to the acid in the
boiling tube.
●● The apparatus was set up as shown in the diagram, ensuring the inverted measuring cylinder
was full of water.
●● The bung was removed from the boiling tube.
●● A coiled length of magnesium ribbon was added to the boiling tube, the bung was immediately
replaced and a timer started.
●● The time taken for 40 cm3 of gas to be collected was measured.
●● The student felt the outside of the boiling tube.
(a) (i)The student noticed that the boiling tube was warm.
What does this tell you about the type of reaction?
........................................................................................................................................ [1]
(ii)Describe one change that could be made to the apparatus to help keep the temperature
of the contents of the boiling tube constant during the reaction.
........................................................................................................................................ [1]
Experiment 2
●● The boiling tube was rinsed out with distilled water.
●● Experiment 1 was repeated using 10 cm3 of dilute sulfuric acid and 10 cm3 of distilled water.
Experiment 3
●● Experiment 2 was repeated using 12 cm3 of dilute sulfuric acid and 8 cm3 of distilled water.
Experiment 4
●● Experiment 2 was repeated using 16 cm3 of dilute sulfuric acid and 4 cm3 of distilled water.
Experiment 5
●● Experiment 2 was repeated using 20 cm3 of dilute sulfuric acid and no distilled water.
© UCLES 2020
0620/62/F/M/20
[Turn over
6
(b)Use the information in the description of the experiments and the timer diagrams to complete
the table. Record the time in seconds.
experiment
volume of
dilute sulfuric
acid / cm3
volume of
distilled water
/ cm3
0
seconds
0
1
8
time to collect
40 cm3 of gas / s
timer diagram
45 15
5
10
15
minutes
30
0
0
2
10
45 15
5
15
5
15
5
15
5
15
10
30
0
0
3
12
45 15
10
30
0
0
4
16
45 15
10
30
0
0
5
20
45 15
10
30
[4]
© UCLES 2020
0620/62/F/M/20
7
(c)Add a suitable scale to the y-axis and plot the results from Experiments 1 to 5 on the grid.
Draw a smooth line graph.
time to collect
40 cm3 of gas / s
6
8
10
12
14
16
18
20
volume of dilute sulfuric acid / cm
3
[4]
(d) (i)
From your graph, deduce the time taken to collect 40 cm3 of gas if the experiment was
repeated using 9 cm3 of dilute sulfuric acid.
Show clearly on the grid how you worked out your answer.
.............................. s
[2]
(ii)
What volume of distilled water would be needed if the experiment was repeated
using 9 cm3 of dilute sulfuric acid?
.............................. cm3 [1]
© UCLES 2020
0620/62/F/M/20
[Turn over
8
(e)The rate of reaction can be calculated using the equation shown.
rate of reaction =
volume of gas collected
time taken to collect the gas
(i)Use this equation to calculate the rate of reaction in Experiment 1. Give the units for the
rate of reaction you have calculated.
rate of reaction = .............................. units = ..............................
[2]
(ii)In which Experiment, 1, 2, 3, 4 or 5, was the rate of reaction greatest?
........................................................................................................................................ [1]
(f)Why would measuring the volume of dilute sulfuric acid with a burette rather than a measuring
cylinder be an improvement?
.....................................................................................................................................................
............................................................................................................................................... [1]
(g)The magnesium starts to react with the dilute sulfuric acid as soon as it is added.
(i)Why does this decrease the accuracy of the investigation?
........................................................................................................................................ [1]
(ii)Describe one improvement that you could make to overcome this problem.
..............................................................................................................................................
..............................................................................................................................................
........................................................................................................................................ [1]
© UCLES 2020
[Total: 19]
0620/62/F/M/20
2
1
The diagram shows the apparatus used to pass an electric current
concentrated hydrochloric acid. Hydrogen and chlorine were formed at the electrodes.
through
+ power –
supply
switch
A
(a)Name the item of apparatus labelled A.
............................................................................................................................................... [1]
(b)The electrodes were made of platinum.
(i)Give two reasons why platinum is a suitable material for the electrodes.
1 ...........................................................................................................................................
2 ...........................................................................................................................................
[2]
(ii)Suggest another material suitable to use as electrodes in this experiment.
........................................................................................................................................ [1]
(c)The teacher doing this experiment wore safety glasses, gloves, had their hair tied back and
stood up throughout the experiment.
State one other safety precaution that should be taken when doing this experiment.
Explain your answer.
safety precaution ........................................................................................................................
explanation .................................................................................................................................
[2]
© UCLES 2020
[Total: 6]
0620/62/O/N/20
3
2
student investigated the rate of a reaction between sodium metabisulfite and potassium iodate.
A
In the reaction, starch was used as an indicator. At first the reacting mixture remained colourless
but then suddenly changed to a blue-black colour.
Five experiments were done. In each experiment the total volume of liquid was 45 cm3.
Experiment 1
●● Using a 10 cm3 measuring cylinder, 5 cm3 of aqueous sodium metabisulfite was poured into a
beaker.
●● Using another 10 cm3 measuring cylinder, 5 cm3 of aqueous starch was poured into the beaker.
●● Using a 25 cm3 measuring cylinder, 15 cm3 of distilled water was poured into the beaker.
●● Using another 25 cm3 measuring cylinder, 20 cm3 of aqueous potassium iodate was poured into
the beaker. At the same time a stop‑clock was started.
●● The mixture in the beaker was stirred until a sudden colour change was seen.
●● The stop‑clock was immediately stopped and the time recorded.
●● The beaker was rinsed with water.
Experiment 2
●● Experiment 1 was repeated
aqueous potassium iodate.
using
17 cm3
of
distilled
water
and
18 cm3
of
Experiment 3
●● Experiment 1 was repeated
aqueous potassium iodate.
using
21 cm3
of
distilled
water
and
14 cm3
of
Experiment 4
●● Experiment 1 was repeated
aqueous potassium iodate.
using
23 cm3
of
distilled
water
and
12 cm3
of
Experiment 5
●● Experiment 1 was repeated
aqueous potassium iodate.
using
25 cm3
of
distilled
water
and
10 cm3
of
© UCLES 2020
0620/62/O/N/20
[Turn over
4
(a)Use the information in the description of the experiments and the stop‑clock diagrams to
complete the table. Record the times in seconds.
experiment
volume of
aqueous sodium
metabisulfite
/ cm3
volume
of distilled
water
/ cm3
volume of
aqueous
potassium
iodate / cm3
stop‑clock diagram
0
seconds
0
1
20
45 15
time to
change
colour
/s
5
10
15
minutes
30
0
0
2
18
45 15
5
15
5
15
5
15
5
15
10
30
0
0
3
14
45 15
10
30
0
0
4
12
45 15
10
30
0
0
5
10
45 15
10
30
[5]
© UCLES 2020
0620/62/O/N/20
5
(b)Plot the results from Experiments 1 to 5 on the grid.
Draw a smooth curve of best fit.
80
70
60
time to change
colour / s
50
40
30
10
12
14
16
18
20
22
volume of aqueous potassium iodate / cm3
[3]
(c) (i)
From your graph, predict the time to change colour if 16 cm3 of aqueous potassium iodate
was used.
Show clearly on the grid how you worked out your answer.
time to change colour = .............................. s [2]
(ii)Calculate the volume of distilled water required if 16 cm3 of aqueous potassium iodate was
used.
volume of distilled water = .............................. cm3 [1]
(d)Sketch on the grid the graph you would expect if Experiments 1 to 5 were repeated at a higher
temperature.[1]
© UCLES 2020
0620/62/O/N/20
[Turn over
6
(e)The concentration of potassium iodate in the reaction mixture in each experiment can be
calculated using the equation shown.
concentration =
0.05 × volume of aqueous potassium iodate
45
(i)Calculate the concentration of potassium iodate in the reaction mixture in Experiment 2.
concentration = .............................. mol / dm3 [1]
(ii)State which experiment, 1, 2, 3, 4 or 5, had the fastest rate of reaction.
........................................................................................................................................ [1]
(f)Suggest why the volume of distilled water added to each experiment was increased as the
volume of aqueous potassium iodate was decreased.
.....................................................................................................................................................
............................................................................................................................................... [1]
(g)Give one change you could make to the apparatus used which would improve the results.
Explain your answer.
change to apparatus ...................................................................................................................
.....................................................................................................................................................
explanation .................................................................................................................................
.....................................................................................................................................................
[2]
(h)How could the reliability of the results of this investigation be checked?
.....................................................................................................................................................
............................................................................................................................................... [1]
© UCLES 2020
[Total: 18]
0620/62/O/N/20
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2023
Marks
1(a)
beaker
1
1(b)
arrow pointing upwards towards lead oxide
1
1(c)
(the powder has) larger surface area / reacts faster / rate increases
1
1(d)
M1 (ice) cools (steam / vapour / gas)
1
M2 (steam / vapour / gas) condenses / water (collects / forms)
1
(methane is) flammable
1
1(e)
Question
2(a)
© UCLES 2023
Answer
Marks
M1 all five times correct (116, 80, 69, 46, 21)
1
M2 all times shown in seconds only
1
M3 all temperatures correct (20.5, 27.0, 30.0, 37.0, 46.5)
1
M4 all temperatures shown to 1 dp
1
Page 5 of 7
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(b)
Answer
May/June 2023
Marks
M1 y-axis scale in linear and points extend over halfway up scale
1
M2 and M3 all points plotted correctly
2
M4 best fit line
1
2(c)
experiment 5
1
2(d)
M1 working shown on graph at 55 s
1
M2 correct value for temperature from their graph
1
M1 insulation / reduces heat loss
1
M2 temperature remains (more) constant / changes less / does not change / is maintained
1
2(f)(i)
(burette) (more) accurate (than a measuring cylinder)
1
2(f)(ii)
reaction starts while still adding the sodium thiosulfate / slow (to add)
1
2(g)
otherwise it will react while it is being heated / temperature increases while it is reacting / reaction starts at a lower
temperature
1
2(h)
M1 times shorter / decrease
1
M2 less depth to look through
1
2(e)
Question
3(a)
3(b)
© UCLES 2023
Answer
Marks
M1 use of a wire / splint to get substance into a flame
1
M2 putting sample INTO flame and identifying (Bunsen) flame as roaring / blue / non-luminous / hot
1
ammonia / NH3
1
Page 6 of 7
0620/63
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
May/June 2023
Marks
1(a)(i)
fractional distillation
1
1(a)(ii)
A condenser
1
B beaker
1
1(a)(iii)
An arrow pointing to the round bottom flask anywhere below the top of the liquid
1
1(b)(i)
residue
1
1(b)(ii)
pour (distilled) water through / over it
1
1(b)(iii)
crystallisation (of sodium chloride) / evaporation (of water)
1
Question
2(a)
Answer
Marks
M1 all masses of sodium carbonate and citric acid correct (5.0, 5.0, 5.0, 5.0, 5.0 and 1.0, 2.0, 4.0, 5.0, 6.0)
1
M2 and M3 all temperatures correct
(25.0; 11.5; 5.0; 0.5; –1.0; –2.0)
2
M4 all values shown to 1 dp
1
M1 y-axis scale in linear and points extend over halfway up scale above zero
1
M2 and M3 all points plotted correctly
2
M4 curved line of best-fit
1
2(c)
endothermic
and
because the temperature decreased
1
2(d)
experiment 6
1
2(b)
© UCLES 2023
Page 6 of 9
0620/63
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(e)
Answer
May/June 2023
Marks
M1 working shown on graph at 3.5 g
1
M2 correct value from their graph
1
2(f)
any 2 from:
 so that the sodium carbonate mix together
 so they react
 so the temperature is the same throughout the mixture
2
2(g)
M1 insulation
1
M2 reduces heat being gained from the surroundings / keeps temperature lower / stops temperature going up
OR
M1 prevents heat loss / prevents heat gain / prevents energy exchange with surroundings
M2 stops temperature going up / reduces increase in temperature (after reaction has ended)
1
Question
Answer
Marks
3(a)
hydrated / contains water
1
3(b)
not a sulfite
1
3(c)
M1 aluminium / Al 3+
1
M2 zinc / Zn2+
1
M1 potassium / K+
1
M2 sulfate / SO42–
1
M1 effervescence / bubbles / fizzing
1
M2 lime water turns milky
1
3(d)
3(e)
© UCLES 2023
Page 7 of 9
Cambridge IGCSE – Mark Scheme
PUBLISHED
0620/61
Question
Answer
October/November 2022
Marks
1(a)
arrow upward to bottom of left-hand flask – between lines shown
1
1(b)
(conical) flask
1
1(c)
sodium sulfite
1
1(d)
sulfur dioxide / gas is toxic
1
1(e)
MP1 (tube linking flasks) should go into sulfuric acid / (tube from flask to gas jar) should not go into acid
2
MP2 gas jar should not be inverted
Question
2(a)
2(b)
© UCLES 2022
Answer
Marks
M1 and M2 all temperature readings correct
((15), 22, 29, 32, 34, 46, 61, 84)
2
M3 and M4 all final masses correct
(3.9, 5.9, 9.6, 11.7, 12.3, 11.7, 11.2, 10.8)
2
M1 and M2 all 8 points plotted correctly
2
M3 two lines drawn, one for first four points and one for last four points
1
M4 lines extrapolated so that they cross
1
Page 6 of 8
Cambridge IGCSE – Mark Scheme
PUBLISHED
0620/61
Question
2(c)(i)
Answer
October/November 2022
Marks
M1 appropriate working from 55 °C on graph
1
M2 correct value from their line (expected is 11.2 to 11.4)
1
correct evaluation of answer to c(i)  40
1
M1 two temperatures from graph at 11 g (expected are around 31 and 67)
1
M2 °C
1
(volumetric / graduated) pipette
1
2(f)(i)
to ensure a saturated solution is formed / so that it does not all dissolve
1
2(f)(ii)
to speed up dissolving
1
2(g)
M1 reheat and reweigh
1
M2 until mass stops changing
1
no change / remains colourless
1
2(c)(ii)
2(d)
2(e)
2(h)
Question
3(a)
Answer
Marks
M1 white precipitate
1
M2 dissolves
1
3(b)
no change / (remains) colourless
1
3(c)
cream precipitate
1
sulfur dioxide
1
3(d)(i)
© UCLES 2022
Page 7 of 8
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
Answer
March 2021
Marks
1(a)
an arrow pointing to the bottom of the test tube.
1
1(b)
apparatus that looks like a gas syringe in approximately horizontal orientation connected to delivery tube
1
graduations shown OR labelled as (gas) syringe
1
any 2 from:
• yellow / green gas
• bubbles / effervescence
• shiny liquid / metal / solid / deposit / substance
2
1(c)
max 2
1(d)
M1 Precaution: use a fume cupboard / well ventilated space
1
Reason: chlorine is toxic / poisonous
M2 must link to M1 to score
1
1(e)
(zinc) reacts (with chlorine / silver chloride)
1
1(f)
sodium bromide
1
bromine is displaced by chlorine
OR
chlorine is more reactive than bromine
OR
chlorine oxidises bromide
1
© UCLES 2021
Page 5 of 8
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
Answer
March 2020
Marks
thermometer
1
(round bottom) flask
1
arrow to bottom entry to water jacket on condenser
1
1(c)(i)
flammable
1
1(c)(ii)
water bath / electric heater / heating mantle/ oil bath
1
1(d)
cools (the vapour / alcohol)
1
1(e)
methanol
1
lowest boiling point
1
1(b)
Question
Answer
Marks
2(a)(i)
exothermic
1
2(a)(ii)
use a water bath
1
all volumes of distilled water completed correctly (12, 10, 8, 4, zero / 0 / none / –)
1
all times completed correctly, all five correct scores 2, four correct scores 1 (72, 45, 33, 23, 16)
2
all times to number of seconds only
1
suitable y-axis scale
1
plotting – all five correct scores 2, four correct scores 1
2
suitable best fit line
1
2(b)
2(c)
© UCLES 2020
Page 5 of 7
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(d)(i)
Answer
March 2020
Marks
correct reading from graph (expected 54–56)
1
working shown on graph
1
2(d)(ii)
11 (cm3)
1
2(e)(i)
0.56 ecf from results table (correct calculation of 40 / time for experiment 1)
1
cm3 / s
1
5
1
more accurate
1
2(g)(i)
gas escapes (before bung inserted) / gas not collected
1
2(g)(ii)
any description of method that prevents gas loss such as partitioned container, suspend magnesium on thread, etc.
1
2(e)(ii)
2(f)
Question
3
Answer
Marks
Tests on solution J
1
3(a)
1
1
3(b)
carbon dioxide
1
hydrochloric acid / HCl
hydrogen (ions) / H+
chloride (ions) / Cl–
2
Tests on solid K
1
no change
1
3(c)(i)
3(d)
© UCLES 2020
Page 6 of 7
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
1(a)
1(b)(i)
1(b)(ii)
1(d)
Answer
2(b)
2(c)(i)
2(c)(ii)
2(d)
2(e)(i)
© UCLES 2020
Marks
beaker
1
conduct electricity
1
inert
1
carbon / graphite
1
use a fume cupboard
1
chlorine is toxic
1
Question
2(a)
October/November 2020
Answer
Marks
all volumes of sodium metabisulfite completed as 5
1
all volumes of water (15, 17, 21, 23, 25) correct.
1
all times recorded correctly (38, 42, 53, 61, 72)
2
all five times in seconds only
1
all 5 points plotted correctly
2
suitable best fit curve drawn. Line must go through / within half a square of correctly plotted points
1
correct working shown on graph
1
time correct for their working
1
19
1
line is below plotted line and does not meet / touch plotted line.
1
0.02
1
Page 6 of 8
0620/62
Cambridge IGCSE – Mark Scheme
PUBLISHED
Question
2(e)(ii)
Answer
October/November 2020
Marks
1
1
2(f)
to keep total volume constant / so concentration of sodium metabisulphite does not change
1
2(g)
change: use a pipette / burette (in place of a measuring cylinder)
1
explanation: more accurate / precise (than a measuring cylinder)
1
repeat and compare the results
1
2(h)
Question
3
3(a)
Answer
Marks
Tests on solid Q
fizzing / effervescence / bubbles
1
(some of the) solid dissolves / disappears OR colourless solution
1
limewater turns milky
1
carbon dioxide / CO2
1
white precipitate
1
dissolves / forms a colourless solution
1
3(c)(ii)
aluminium (ions) give the same result
1
3(c)(iii)
add (excess) ammonia (solution)
1
3(b)
3(c)(i)
3(d)
© UCLES 2020
Tests on solid R
sodium / Na+
1
iodide / I–
1
Page 7 of 8