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IGCSE Chemistry 0620 Paper 62, May/June 2025

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Question paper

0620/62 · May/June 2025

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1

When heated, magnesium reacts with steam to make magnesium oxide and hydrogen gas. Fig. 1.1 shows the apparatus a teacher uses to react clean magnesium ribbon with steam and collect the hydrogen gas produced.

Figure 1 of 2 for question 1
Figure 2 of 2 for question 1
a

Name the item of apparatus labelled A in Fig. 1.1.

[1]
b

Suggest how the magnesium ribbon should be cleaned before use.

[1]
c

State the purpose of the mineral wool.

[1]
d

Draw two arrows on Fig. 1.1 to show the two places where the apparatus should be heated.

[2]
e

During the reaction a colourless liquid collects at the point marked X on Fig. 1.1. Suggest the identity of liquid X.

[1]
f

The gas collected in A is not pure hydrogen. Suggest why the gas collected is not pure.

[1]
2

A student investigates the temperature change when anhydrous lithium chloride dissolves in water. The student does five experiments. Experiment 1 • Use a 50 cm3 measuring cylinder to pour 40 cm3 of distilled water into a 100 cm3 beaker. • Use a thermometer to measure the initial temperature of the water. • Add a 2.0 g sample of anhydrous lithium chloride to the water in the beaker. • Continually stir the mixture in the beaker using the thermometer. • Measure the highest temperature reached by the mixture in the beaker. • Empty the beaker and rinse the beaker with distilled water. Experiment 2 • Repeat Experiment 1 using 30 cm3 of distilled water instead of 40 cm3. Experiment 3 • Repeat Experiment 1 using 25 cm3 of distilled water instead of 40 cm3. Experiment 4 • Repeat Experiment 1 using 20 cm3 of distilled water instead of 40 cm3. Experiment 5 • Repeat Experiment 1 using 15 cm3 of distilled water instead of 40 cm3.

Figure 1 of 1 for question 2
a

Use the information in the description of the experiments and the thermometer diagrams to complete Table 2.1.

[4]
b

Complete a suitable scale on the y-axis and plot your results from Experiments 1 to 5 on Fig. 2.1. Draw a line of best fit.

[4]
c

Extrapolate the line on your graph in Fig. 2.1 to deduce the temperature change when Experiment 1 is repeated with 45 cm3 of water instead of 40 cm3 of water. Show clearly on Fig. 2.1 how you worked out your answer. temperature change = ..............................

[3]
d

The energy, in J, given out when 2.0 g of anhydrous lithium chloride dissolves is calculated using the equation shown. energy given out = temperature change ×4.2× volume of water Calculate the energy given out when 2.0 g of anhydrous lithium chloride dissolves in Experiment 5. energy given out = .............................. J

[1]
e

Estimate the temperature change when Experiment 1 is repeated using 4.0 g of anhydrous lithium chloride instead of 2.0 g. Give a reason for your answer. temperature change ................................................................................................................. reason ....................................................................................................................................... ...................................................................................................................................................

[2]
f

Explain why the results obtained would be more accurate if the beaker used in each experiment was replaced by a polystyrene cup.

[2]
g(i)

Explain why using a burette instead of a measuring cylinder is an improvement.

[1]
g(ii)

Explain why standing the beaker in a water-bath is not an improvement.

[1]
3

A student tests two solids: solid J and solid K. Tests on solid J Solid J is iron(II) iodide. The student dissolves solid J in water to form solution J. Solution J is divided into four portions.

a

To the first portion of solution J, the student adds aqueous sodium hydroxide dropwise and then in excess. observations when added dropwise ......................................................................................... observations when added in excess .........................................................................................

[2]
b

To the second portion of solution J, the student adds 1 cm3 of dilute nitric acid followed by a few drops of aqueous barium nitrate. observations ............................................................................................................................. .............................................................................................................................................

[1]
c

To the third portion of solution J, the student adds 1 cm3 of dilute nitric acid followed by a few drops of aqueous silver nitrate. observations ............................................................................................................................. .............................................................................................................................................

[1]
d

To the fourth portion of solution J, the student adds 1 cm3 of aqueous chlorine. observations ............................................................................................................................. .............................................................................................................................................

[1]
e

Tests on solid K Table 3.1 shows the tests and the student’s observations for solid K. State the conclusion about solid K that can be made from the observations in test 2.

[1]
f

Identify the gas given off in test 3.

[1]
g

Identify solid K.

[2]
4

Magnesium sulfate is a salt. Magnesium sulfate is soluble in water. The solubility of a salt is the mass of the salt, in g, that dissolves in 100 cm3 of water at a specified temperature. Plan an investigation to determine the solubility of magnesium sulfate in water at 50 ∘C. Your plan must include how the solubility of magnesium sulfate, in g per 100 cm3 of water, can be found. You are provided with solid magnesium sulfate, distilled water and common laboratory apparatus.

[6]

Mark scheme

0620/62 · May/June 2025

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1a · 1 mark

  • 1 mark

    (gas) syringe

1b · 1 mark

  • 1 mark

    (rub with) sand / emery / abrasive paper

1c · 1 mark

  • 1 mark

    to hold / absorb the water / to prevent the water running along the tube

1d · 2 marks

  • 1 mark

    arrow under (soaked) mineral wool / water

  • 1 mark

    arrow under solid / metal (and X positioned correctly)

1e · 1 mark

  • 1 mark

    water / H2O

1f · 1 mark

  • 1 mark

    contains air (that was in the apparatus at the start)

2a · 4 marks

  • 1 mark

    all experiments have a mass of 2.0 g of lithium chloride

  • 1 mark

    all temperatures and temperature changes recorded to 1 dp

  • 1 mark

    all five highest temperatures recorded correctly (27.0, 29.0, 30.5, 32.5, 35.5)

  • 1 mark

    all temperature changes calculated correctly (4.5, 6.5, 8.0, 10.5, 13.5)

2b · 4 marks

  • 1 mark

    y-axis scale is linear and points extend over halfway up scale

  • 2 marks

    all points plotted correctly

  • 1 mark

    best fit line

2c · 3 marks

  • 1 mark

    extrapolation shown on graph, this must be a smooth continuation of line to at least a volume of 45

  • 1 mark

    correct reading from their extrapolation at 45

  • 1 mark

    °C

2d · 1 mark

  • 1 mark

    850.5 OR 851

2e · 2 marks

  • 1 mark

    (temperature change approximately) doubled / 9 °C

  • 1 mark

    twice as much lithium chloride dissolved / used (so twice as much energy given out)

2f · 2 marks

  • 1 mark

    polystyrene is a better insulator than glass / it is an insulator

  • 1 mark

    less heat loss (to the surroundings)

2g(i) · 1 mark

  • 1 mark

    (burette more) accurate (than measuring cylinder)

2g(ii) · 1 mark

  • 1 mark

    water-bath would keep temperature constant

3a · 2 marks

  • 1 mark

    dropwise: green precipitate

  • 1 mark

    excess: no (further) change / precipitate remains / green precipitate / insoluble

3b · 1 mark

  • 1 mark

    no change

3c · 1 mark

  • 1 mark

    yellow precipitate

3d · 1 mark

  • 1 mark

    (solution / liquid becomes) yellow / orange / brown

3e · 1 mark

  • 1 mark

    does not contain ammonium / NH4+ ions / not ammonium / NH4+

3f · 1 mark

  • 1 mark

    ammonia / NH3

3g · 2 marks

  • 1 mark

    potassium / K+

  • 1 mark

    nitrate / NO3–

4 · 6 marks

  • 1 mark

    100 cm3 of water measured using suitable apparatus and placed into a suitable container

  • 1 mark

    water is heated to 50 °C

  • 1 mark

    water is maintained at this temperature

  • 1 mark

    magnesium sulfate is added in excess or in portions until no more dissolves

  • 1 mark

    the mixture is stirred

  • 1 mark

    the solution is filtered to remove undissolved magnesium sulfate or the mass used is known

  • 1 mark

    the use of appropriate measurements to calculate the solubility.

Questions

  1. 1
    Question 17 marks
    Mark scheme ›
  2. 2
    Question 218 marks
    Mark scheme ›
  3. 3
    Question 39 marks
    Mark scheme ›
  4. 4
    Question 46 marks
    Mark scheme ›

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