Cambridge IGCSE: CHEMISTRY 0620/62
Cambridge IGCSE: CHEMISTRY 0620/62
Cambridge IGCSE: CHEMISTRY 0620/62
*8713532268*
CHEMISTRY0620/62
Paper 6 Alternative to Practical February/March 2024
1 hour
INSTRUCTIONS
● Answer all questions.
● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
● Write your name, centre number and candidate number in the boxes at the top of the page.
● Write your answer to each question in the space provided.
● Do not use an erasable pen or correction fluid.
● Do not write on any bar codes.
● You may use a calculator.
● You should show all your working and use appropriate units.
INFORMATION
● The total mark for this paper is 40.
● The number of marks for each question or part question is shown in brackets [ ].
● Notes for use in qualitative analysis are provided in the question paper.
IB24 03_0620_62/5RP
© UCLES 2024 [Turn over
2
step 1 step 2
add excess aqueous calcium chloride stir the mixture
to aqueous sodium carbonate
aqueous A
calcium chloride stir
aqueous
sodium carbonate
Fig. 1.1
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(c) After step 2 the student filters the mixture to remove the solid calcium carbonate formed and
collect the filtrate.
Draw a labelled diagram to show the apparatus used for this filtration.
[2]
(i) Identify one substance, other than water, which is mixed with the calcium carbonate and
makes it impure.
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(ii) Describe how the substance you have identified in (d)(i) can be removed from the
calcium carbonate.
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(e) D
escribe a test the student can do on the filtrate obtained in (c) to show that the
calcium chloride used is in excess. Give the result the student obtains if the calcium chloride
is in excess.
test ..............................................................................................................................................
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result ...........................................................................................................................................
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[2]
[Total: 8]
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2 student investigates the reaction between aqueous sodium carbonate and two different solutions
A
of dilute hydrochloric acid, labelled A and B.
Experiment 1
● inse a burette with distilled water and then with dilute hydrochloric acid A.
R
● Rinse a conical flask with distilled water.
● Fill the burette with dilute hydrochloric acid A. Run some of the dilute hydrochloric acid out of
the burette so that the level of the dilute hydrochloric acid is on the burette scale.
● Record the initial burette reading.
● Use a measuring cylinder to pour 25 cm3 of aqueous sodium carbonate into the conical flask.
● Add five drops of methyl orange indicator to the conical flask.
● Stand the conical flask on a white tile.
● Slowly add dilute hydrochloric acid A from the burette to the conical flask, while swirling the
flask, until the solution becomes orange.
● Record the final burette reading.
Experiment 2
● efill the burette with dilute hydrochloric acid A. Run some of the dilute hydrochloric acid out of
R
the burette so that the level of the dilute hydrochloric acid is on the burette scale.
● Record the initial burette reading.
● Empty the conical flask and rinse it with distilled water.
● Use the measuring cylinder to pour 25 cm3 of aqueous sodium carbonate into the conical flask.
● Add five drops of thymolphthalein indicator to the conical flask.
● Stand the conical flask on a white tile.
● Slowly add dilute hydrochloric acid A from the burette to the conical flask, while swirling the
flask, until the solution becomes colourless.
● Record the final burette reading.
Experiment 3
● Repeat Experiment 1, using dilute hydrochloric acid B instead of dilute hydrochloric acid A.
(a) U
se the burette diagrams in Fig. 2.1, Fig. 2.2 and Fig. 2.3 to record the readings for Experiments
1, 2 and 3 in Table 2.1 and complete Table 2.1.
Experiment 1
0 25
1 26
2 27
Fig. 2.1
Experiment 2
0 12
1 13
2 14
Fig. 2.2
Experiment 3
0 38
1 39
2 40
Fig. 2.3
Table 2.1
[4]
(b) (i) tate which solution of dilute hydrochloric acid, A or B, is the more concentrated.
S
Explain your answer.
explanation ..........................................................................................................................
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[1]
(ii) educe how many times more concentrated this solution of dilute hydrochloric acid is than
D
the other solution of dilute hydrochloric acid.
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(c) (i) Compare the volume of dilute hydrochloric acid A used in Experiment 1 to the volume of
dilute hydrochloric acid A used in Experiment 2.
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(ii) educe the volume of dilute hydrochloric acid B required to reach the end-point if
D
Experiment 3 is repeated using thymolphthalein indicator instead of methyl orange
indicator. Use your answer to (c)(i) to help you.
(d) A
t the start of Experiment 3 the burette is rinsed with distilled water and then with dilute
hydrochloric acid B.
(i) Identify the substance removed from the burette when it is rinsed with distilled water at the
start of Experiment 3.
........................................................................................................................................ [1]
(ii) Describe how the result of the titration would change if the burette was not rinsed with
dilute hydrochloric acid B after it had been rinsed with water.
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(iii) xplain why the conical flask is not rinsed with aqueous sodium carbonate after it is rinsed
E
with water.
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(f) D
escribe the effect on the result of warming the aqueous sodium carbonate used in Experiment 1
before carrying out the titration. Explain your answer.
effect ...........................................................................................................................................
explanation .................................................................................................................................
[2]
[Total: 16]
Tests on solid C
he student dissolves solid C in water to form solution C. The student divides solution C into three
T
approximately equal portions.
(a) T
o the first portion of solution C, the student adds about 1 cm3 of dilute nitric acid followed by a
few drops of aqueous barium nitrate.
observations ...............................................................................................................................
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(b) To the second portion of solution C, the student adds about 1 cm3 of dilute nitric acid followed
by a few drops of aqueous silver nitrate.
observations ...............................................................................................................................
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(c) (i) To the third portion of solution C, the student adds an excess of aqueous sodium hydroxide.
observations ........................................................................................................................
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(ii) The student warms the product from (c)(i) and tests any gas given off.
observations ........................................................................................................................
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Tests on solid D
Table 3.1 shows the tests and the student’s observations for solid D.
Table 3.1
tests observations
test 1
test 2
Gently heat about half of the remaining solid D. steam is given off and condensation
forms at the top of the boiling tube
test 3
To the first portion of solution D, add aqueous green precipitate which is insoluble in excess
ammonia dropwise until in excess.
test 4
Heat the mixture formed and hold damp red the red litmus paper remains red
litmus paper at the mouth of the boiling tube.
test 5
Bubble any gas formed through limewater. the limewater becomes milky
(d) State the final colour of the cobalt(II) chloride paper in test 2.
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(e) State what ion the observations in test 4 show is not present.
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[Total: 10]
4 When excess dilute sulfuric acid is added to solid zinc, hydrogen gas and aqueous zinc sulfate are
made.
lan an experiment to show that copper is a catalyst for this reaction. Your plan should include how
P
the results of the experiment will show that copper is a catalyst for this reaction.
ou are provided with zinc powder, dilute sulfuric acid, copper powder and common laboratory
Y
apparatus.
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