0620 Chemistry June 2025 Question Paper 62

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. A X clean magnesium ribbon water and mineral wool Fig. 1.1

(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]

[Total: 7] , ,

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.

(a) Use the information in the description of the experiments and the thermometer diagrams to complete Table 2.1. , , Table 2.1 experiment mass of anhydrous lithium chloride / g volume of distilled water / cm3 initial temperature / °C thermometer diagram for highest temperature reached / °C highest temperature reached / °C temperature change / °C 1 2.0 40 22.5 30 25 20 2 30 22.5 30 25 20 3 25 22.5 30 35 25 4 20 22.0 30 35 25 5 15 22.0 35 40 30

[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. 0 10 15 20 25 30 volume of water / cm3 35 40 45 temperature change / °C Fig. 2.1

[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]

(ii) Explain why standing the beaker in a water-bath is not an improvement [1]

[Total: 18] , ,

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] , ,

Tests on solid K

Table 3.1 shows the tests and the student’s observations for solid K. Table 3.1 tests observations test 1 Carry out a flame test on solid K. lilac coloured flame test 2 The remaining solid K is dissolved in water to form solution K. Solution K is divided into two portions. To the first portion of solution K in a boiling tube, add 1 cm3 aqueous sodium hydroxide. Warm the product and hold damp red litmus paper at the mouth of the boiling tube. the damp red litmus paper remains red test 3 To the second portion of solution K in a boiling tube, add about 1 cm3 of aqueous sodium hydroxide and a piece of aluminium foil. Warm the mixture and test any gas given off. effervescence is seen damp red litmus paper turns blue

(e) 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]

[Total: 9] , ,