AQA GCSE Chemistry Paper 2 Higher June 2022 question paper 8462/2H

This question is about copper wire and copper compounds.

Copper is used to make electrical wires. Figure 1 shows how copper electrical wire is insulated using an addition polymer called poly(butene).

The addition polymer poly(butene) has the displayed structural formula:

Poly(butene) is produced from the monomer butene. Complete Figure 2 to show the displayed structural formula of butene.

Copper can be obtained by recycling scrap copper wire.

Suggest why poly(butene) insulation must be removed from scrap copper wire before the copper is recycled.

Describe how scrap copper wire can be recycled to make new copper water pipes.

Suggest two reasons why recycling scrap copper is more sustainable than extracting copper from copper ores.

Copper sulfate is a compound of copper. Copper sulfate solution contains copper(II) ions and sulfate ions.

A solution can be added to copper sulfate solution to show the presence of copper(II) ions. Name the solution added. Give the result of the test. Name of solution added

Describe one test to show the presence of sulfate ions in copper sulfate solution. Give the result of the test.

A student investigated the change in mass when hydrated cobalt chloride was heated. The word equation for the reaction is: hydrated cobalt chloride ⇌ anhydrous cobalt chloride + water

This is the method used.

1. Add 2.0 g of hydrated cobalt chloride to an empty test tube.

2. Measure the mass of the test tube and contents.

3. Heat the test tube and contents gently for 30 seconds.

4. Allow the test tube and contents to cool.

5. Measure the mass of the test tube and contents.

6. Repeat steps 3 to 5 until the mass of the test tube and contents does not change.

Table 1 shows the results.

Determine the mass of the empty test tube.

Explain why the mass of the test tube and contents decreased.

Suggest why the test tube and contents were heated until the mass did not change.

Energy is taken in from the surroundings when hydrated cobalt chloride is heated.

When 238 g of hydrated cobalt chloride is heated until the mass does not change, 88.1 kJ of energy is taken in. The student heated 2.00 g of hydrated cobalt chloride until the mass did not change.

Calculate the energy taken in during this reaction. Give your answer to 3 significant figures.

What type of reaction takes place when hydrated cobalt chloride is heated?

This question is about life cycle assessments (LCAs).

Milk bottles can be made from glass or from a polymer. Table 2 shows information about milk bottles of equal volume.

Evaluate the use of glass for milk bottles compared with the use of a polymer for milk bottles. Use features of life cycle assessments (LCAs) in your answer. Use Table 2.

Milk is also sold in cardboard cartons. A carton is made using 40 cm³ of cardboard.

Calculate the mass of the carton. Use the equation:

This question is about the fractions obtained from crude oil.

Crude oil is separated into fractions by fractional distillation. The fractions obtained from crude oil include:

• lubricating oil

• naphtha

• petroleum gases.

Table 3 shows the boiling point range of these fractions.

Explain how these fractions are obtained from crude oil by fractional distillation.

Fractions from crude oil can be processed to produce feedstock for the petrochemical industry. Which two are useful materials produced from this feedstock? Tick (✓) two boxes.

Another fraction obtained from crude oil is petrol.

Petrol contains a hydrocarbon with the formula C₉H₂₀ Complete the equation for the complete combustion of C₉H₂₀ You should balance the equation.

Petrol obtained from crude oil contains sulfur impurities. Explain why sulfur impurities are removed before petrol is burned in car engines.

Table 4 shows information about two more fractions obtained from crude oil.

A student predicted that heavy fuel oil is more viscous than kerosene. The student’s prediction was correct.

Justify the student’s prediction.

The heavy fuel oil fraction can be processed to produce smaller hydrocarbon molecules.

Name the process which produces smaller hydrocarbon molecules from heavy fuel oil. Give the conditions used in this process.

Hydrocarbon molecules containing seven and eight carbon atoms can be produced when heavy fuel oil is processed. Which pair of hydrocarbon molecules would both turn bromine water colourless? Tick (✓) one box.

This question is about water.

Sewage is waste water. Sewage contains organic matter.

Describe how sewage is treated to remove organic matter.

Sea water and ground water are treated to make them potable. Table 5 shows information about the composition and treatment of sea water and of ground water.

Sea water is desalinated during Process 1. Which pair of concentrations could represent X in Table 5 ? Tick (✓) one box.

Explain why the concentrations of sodium ions and of chloride ions in the ground water in Table 5 are unchanged by Process 1.

Explain why the ground water in Table 5 requires Process 2 before the water is safe to drink.

After treatment the ground water in Table 5 is sold by a company as pure water. The ground water in Table 5 is not chemically pure because the water contains sodium ions and chloride ions.

Suggest what the company means by ‘pure’.

Chlorine is also used to treat some ground water. Describe the test for chlorine gas. Give the result of the test.

This question is about the chemistry of the Earth’s atmosphere. Figure 3 shows how the percentages of gases in the Earth’s atmosphere may have changed since the atmosphere was formed.

Explain the change in the percentage of gas in the region labelled A on Figure 3.

Explain the change in the percentage of gas in the region labelled B on Figure 3.

Compare the changes in the percentages of gases in the region labelled C on Figure 3.

What process caused the changes in the percentages of gases in the region labelled C on Figure 3 ?

Natural gas is a fossil fuel. Describe how deposits of natural gas were formed.

Ammonia is produced in the Haber process. The raw materials for the Haber process are nitrogen and hydrogen. The equation for the reaction is:

Give the sources of the nitrogen and of the hydrogen used in the Haber process.

How does the equation for the reaction show that the atom economy of the forward reaction is 100%?

Figure 4 represents the Haber process.

Explain how the ammonia produced is separated from the unreacted nitrogen and hydrogen in X.

The Haber process uses a temperature of 450 °C and a pressure of 200 atmospheres. Table 6 shows the percentage yield of ammonia produced at 450 °C using different pressures.

Complete Figure 5. The first two points have been plotted. You should:

• use a suitable scale for the x-axis

• plot the remaining data from Table 6

• draw a line of best fit.

Determine the percentage yield of ammonia at 450 °C and 500 atmospheres. Show your working on Figure 5.

The equation for the production of ammonia in the Haber process is:

The forward reaction is exothermic. The conditions used are:

• a temperature of 450 °C

• a pressure of 200 atmospheres

• the presence of an iron catalyst.

Explain why these conditions are chosen for economical production of ammonia in the Haber process. You should include references to the rate of reaction and the position of equilibrium.

This question is about the reaction between sodium thiosulfate solution and hydrochloric acid. When hydrochloric acid is added to sodium thiosulfate solution, the mixture gradually becomes cloudy. The equation for the reaction is:

Sulfur is produced in the reaction. Why does the mixture become cloudy?

A student investigated the effect of changing the concentration of sodium thiosulfate solution on the rate of the reaction. Figure 6 shows the apparatus used.

A smaller percentage of light from the light source reaches the light sensor as the mixture becomes more cloudy. This is the method used.

1. Measure 50 cm³ of 0.10 mol/dm³ sodium thiosulfate solution into the beaker.

2. Add 10 cm³ of hydrochloric acid to the sodium thiosulfate solution.

3. Immediately start a timer.

4. Record the percentage of light from the light source that reaches the light sensor every 20 seconds for 120 seconds.

5. Repeat steps 1 to 4 using 0.20 mol/dm³ sodium thiosulfate solution.

Figure 7 shows the results for 0.10 mol/dm³ sodium thiosulfate solution.

The percentage of light reaching the light sensor decreases by 1% when 7.1 × 10⁻⁵ moles of sulfur is produced. Determine the rate of reaction in mol/s for the production of sulfur at 30 seconds. You should draw a tangent on Figure 7.

Explain why the rate of reaction changes between 0 and 60 seconds. Answer in terms of concentration. Use Figure 7.

Figure 8 is a repeat of Figure 7.

Figure 8 shows the results for 0.10 mol/dm³ sodium thiosulfate solution. Sodium thiosulfate solution was in excess in the investigation.

The line of best fit on Figure 8 is horizontal between 80 and 120 seconds because the reaction stopped. Why did the reaction stop?

Sketch a line on Figure 8 to show the results you would predict for 0.20 mol/dm³ sodium thiosulfate solution.

The same student did the investigation again the next day. The student found that the same method produced different results for the percentage of light reaching the light sensor.

How could the student improve the method so that the same percentages of light reached the light sensor?

Tick (✓) one box.

The student improved the method so that similar results were obtained on different days. What name is given to similar results obtained on different days under the same conditions by the same student? Tick (✓) one box.

Figure 9 shows the volumes of:

• sodium thiosulfate solution of concentration 0.10 mol/dm³

• hydrochloric acid of concentration 0.05 mol/dm³

which completely react to produce different masses of sulfur.

Which expression represents the relationship between the volume (V) of sodium thiosulfate solution used and the mass (m) of sulfur produced? Use Figure 9. Tick (✓) one box.

Determine the simplest whole number ratio of the volumes of sodium thiosulfate solution: hydrochloric acid which completely react with each other. Use Figure 9.