0620 Chemistry November 2025 Question Paper 63

1 A student uses the apparatus in Fig. 1.1 to show that water is formed as one of the products when a fuel is burned. The gases produced when the fuel is burned are passed through the apparatus using a suction pump. to suction pump solid X U-tube burning fuel ice W Fig. 1.1

(a) Identify the item of apparatus labelled W in Fig. 1.1 [1]

(b) When the fuel is burned, the steam produced passes into the U-tube.

Suggest why the U-tube is surrounded by ice [1]

(c) Water causes solid X in the U-tube to change colour.

Name solid X and state the colour change seen. solid X colour change from to [2] . , ,

The student tries to use the apparatus in Fig. 1.2 to pass the gases produced through acidified aqueous potassium manganate(VII).

There is an error in the apparatus in Fig. 1.2 so that the gases produced will not pass through the acidified aqueous potassium manganate(VII). to suction pump burning fuel Y acidified aqueous potassium manganate(VII) Fig. 1.2

(d) Identify the item of apparatus labelled Y in Fig. 1.2 [1]

(e) On Fig. 1.2, draw a circle around the error in the apparatus. [1]

(f) The error in the apparatus in Fig. 1.2 is corrected.

The student observes that the acidified aqueous potassium manganate(VII) changes colour from purple to colourless.

Suggest why this colour change occurs [1]

[Total: 7] , ,

2 A student investigates the temperature change when a 5 cm length of coiled magnesium ribbon reacts with excess dilute sulfuric acid.

The student does five experiments.

Experiment 1 • Rinse a burette with distilled water and then with dilute sulfuric acid. • Fill the burette with dilute sulfuric acid. Run some of the dilute sulfuric acid out of the burette so that the level of the dilute sulfuric acid is on the 0.0 cm3 mark. • Use the burette to add 30.0 cm3 of dilute sulfuric acid to a boiling tube. • Use a thermometer to measure the initial temperature of the acid. • Record the initial temperature. • Add a coil of magnesium ribbon to the boiling tube. At the same time start a stop-watch. • Continually stir the contents of the boiling tube using the thermometer. • After 1 minute, measure the temperature of the mixture in the boiling tube. • Record this temperature.

Experiment 2 • Refill the burette with dilute sulfuric acid. Run some of the dilute sulfuric acid out of the burette so that the level of the dilute sulfuric acid is on the 0.0 cm3 mark. • Use the burette to add 25.0 cm3 of dilute sulfuric acid to a new boiling tube. • Use the thermometer to measure the initial temperature of the acid. • Record the initial temperature. • Add a coil of magnesium ribbon to the boiling tube. At the same time start the stop-watch. • Continually stir the contents of the boiling tube using the thermometer. • After 1 minute, measure the temperature of the mixture in the boiling tube. • Record this temperature.

Experiment 3 • Repeat Experiment 2, using 20.0 cm3 of dilute sulfuric acid instead of 25.0 cm3.

Experiment 4 • Repeat Experiment 2, using 15.0 cm3 of dilute sulfuric acid instead of 25.0 cm3.

Experiment 5 • Repeat Experiment 2, using 10.0 cm3 of dilute sulfuric acid instead of 25.0 cm3. , ,

(a) Use the thermometer diagrams to complete Table 2.1. Table 2.1 thermometer diagram for initial temperature / °C thermometer diagram for temperature after 1 minute / °C initial temperature / °C experiment 1 2 3 4 5 volume of dilute sulfuric acid / cm3 30.0 25.0 20.0 15.0 10.0 temperature after 1 minute / °C temperature increase / °C 30 25 20 30 25 20 30 25 20 30 25 20 30 25 20 30 25 20 40 35 30 40 35 30 40 35 30 50 45 40

[4] , ,

(b) On Fig. 2.1, complete a suitable scale on the y-axis and plot the results from Experiments 1 to 5. Draw a line of best fit. temperature increase / °C volume of dilute sulfuric acid / cm3 10.0 0.0 15.0 20.0 25.0 30.0 35.0 Fig. 2.1

[4]

(c) Explain why the temperature increase changes as the volume of dilute sulfuric acid changes [2]

(d) Extrapolate the line of best fit on your graph in Fig. 2.1 to deduce the temperature increase if 33.0 cm3 of dilute sulfuric acid is used.

Show clearly on Fig. 2.1 how you worked out your answer.

temperature increase = [3]

(e) The investigation is repeated using 2.5 cm lengths of coiled magnesium ribbon instead of 5 cm lengths.

On Fig. 2.1, sketch a line to show the results you would expect. Label this line E. [1] , ,

(f) (i) Give one reason why a burette, rather than a measuring cylinder, is used to measure the volume of the dilute sulfuric acid [1]

(ii) Explain why the contents of the boiling tube are stirred during each experiment [1]

(g) Describe one change to the apparatus that will give more accurate results.

Explain your answer. change to apparatus explanation [2]

[Total: 18] , ,

3 A student tests two substances: solution A and solid B.

Tests on solution A

Solution A is aqueous iron(III) nitrate.

Record the expected observations.

The student divides solution A into three approximately equal portions.

(a) To the first portion of solution A, the student adds aqueous ammonia dropwise and then in excess. observations when added dropwise observations in excess [2]

(b) (i) To the second portion of solution A, the student adds excess aqueous sodium hydroxide. observations [1]

(ii) To the product from (b)(i), the student adds a small piece of aluminium foil. The student gently warms the mixture formed and tests any gas produced. observations [1]

(iii) Identify the gas produced in (b)(ii) [1]

(c) To the third portion of solution A, the student adds about 1 cm3 of dilute nitric acid followed by a few drops of aqueous barium nitrate. observations [1] , , Tests on solid B Table 3.1 shows the tests and the student’s observations for solid B. Table 3.1 tests observations test 1 Do a flame test on solid B. light green flame colour test 2 Add the remaining solid B to dilute hydrochloric acid. Test any gas produced. effervescence and a colourless solution forms limewater turns milky

(d) Identify the gas produced in test 2 [1]

(e) Identify solid B [2]

[Total: 9] , ,