AQA GCSE Chemistry Paper 2 Higher June 2019 question paper 8462/2H

This question is about crude oil and hydrocarbons.

Figure 1 shows a fractionating column used to separate crude oil into fractions.

Table 1 gives information about some of the fractions.

Suggest a suitable temperature for the furnace in Figure 1.

Explain why diesel oil collects above heavy fuel oil but below kerosene in the fractionating column.

Use Table 1.

Suggest two reasons why bitumen is not used as a fuel.

Petrol contains mainly alkanes.

Which of the following compounds is an alkane?

Tick (✓) one box.

Large hydrocarbon molecules in the diesel oil fraction are cracked to produce smaller hydrocarbon molecules.

Describe the conditions needed to crack hydrocarbon molecules from the diesel oil fraction.

Explain why large hydrocarbon molecules in the diesel oil fraction are cracked to produce smaller hydrocarbon molecules.

Complete the equation for the cracking of C₁₅H₃₂

This question is about lithium carbonate.

Lithium carbonate is used in medicines.

Figure 2 shows a tablet containing lithium carbonate.

Lithium carbonate contains lithium ions and carbonate ions.

A student tested the tablet for lithium ions and for carbonate ions.

The student used:

• a metal wire

• dilute hydrochloric acid

• limewater.

Plan an investigation to show the presence of lithium ions and of carbonate ions in the tablet.

You should include the results of the tests for the ions.

The tablet also contains other substances.

The substances in tablets are present in fixed amounts.

What name is given to mixtures like tablets?

The tablet has a mass of 1.20 g and contains 700 mg of lithium carbonate.

Calculate the percentage by mass of lithium carbonate in this tablet.

This question is about rate of reaction.

A student investigated the rate of the reaction between magnesium and dilute hydrochloric acid.

The equation for the reaction is:

Which state symbol in the equation for the reaction does not represent one of the three states of matter?

The student determined the rate of production of hydrogen gas.

What two pieces of measuring apparatus could the student use to find the rate of production of hydrogen gas?

Table 2 shows the results of the investigation.

Plot the data from Table 2 on Figure 3.

You should draw a line of best fit.

Give three conclusions that can be drawn about the rate of reaction between magnesium and dilute hydrochloric acid in this investigation.

Use data from Figure 3 and Table 2.

The student repeated the investigation using dilute hydrochloric acid at a higher temperature.

All the other variables were kept the same.

Which two statements are correct?

Tick (✓) two boxes.

This question is about the corrosion of metals.

The corrosion of iron is called rusting.

A student investigated the rusting of iron.

This is the method used.

1. Set up the test tubes as shown in Figure 4.

2. Leave the test tubes for 1 week.

3. Examine the nails for signs of rust.

Explain what would happen to the nails in each of the test tubes.

Magnesium is fixed to some steel ships.

Explain how this prevents the steel from rusting.

Explain why aluminium window frames do not corrode after they are made.

This question is about combustion of fuels.

Some central heating boilers use wood as a fuel.

Suggest two reasons why wood is more sustainable than natural gas as a fuel for central heating boilers.

Natural gas is mainly methane.

When methane burns it can produce both carbon monoxide and carbon dioxide.

Explain the process by which carbon monoxide can be produced when methane is burned.

Balance the equation for the combustion of methane to produce carbon monoxide.

Propane burns to form carbon dioxide and water.

The equation for the reaction is:

3.60 dm³ carbon dioxide is produced when a sample of propane is burned in

Calculate the volume of unreacted oxygen.

Give your answer in cm³

Figure 5 shows a surfer on a surfboard.

Surfboards are made from polymers.

Surfboards have a poly(styrene) core and an outer skin.

Figure 6 shows the displayed structural formula of poly(styrene).

Figure 7 shows an incomplete displayed structural formula of the monomer styrene.

Complete Figure 7.

The outer skin of surfboards contains a polyester.

Two monomers, A and B, are needed to make the polyester.

Figure 8 shows how these two monomers are represented.

Figure 8

Monomer A
Monomer B

Name the functional group in monomer B.

Monomers A and B join together to produce a polyester and a small molecule.

Name the small molecule.

Why does this type of polyester melt when it is heated?

The outer skin of surfboards is a composite material.

The composite material contains glass fibres surrounded by a polyester.

Draw one line from each material to the description of that material.

Material
Description of the material

The outer skin makes the surfboard more expensive.

Suggest two reasons why an outer skin is added to the poly(styrene) core.

A large amount of aluminium sulfate was accidentally added to the drinking water supply at a water treatment works.

Describe a test to show that the drinking water contained aluminium ions.

Give the result of the test.

Describe a test to show that the drinking water contained sulfate ions.

Give the result of the test.

Plan an investigation to find the total mass of dissolved solids in a 100 cm³ sample of the drinking water.

Your investigation should produce valid results.

Titan is a moon of the planet Saturn.

Table 3 shows the percentages of the gases in the atmosphere of Titan.

Some scientists think that living organisms could have evolved on Titan.

Explain why these organisms could not have evolved in the same way that life is thought to have evolved on Earth.

Use Table 3.

Saturn has other moons.

The other moons of Saturn have no atmosphere.

Titan is warmer than the other moons of Saturn because its atmosphere contains the greenhouse gas methane.

Explain how this greenhouse gas keeps Titan warmer than the other moons of Saturn.

The atmosphere of Titan contains small amounts of propene.

Describe a test to show that propene is an unsaturated hydrocarbon.

Give the result of the test.

Some students investigated the rate of decomposition of hydrogen peroxide, H₂O₂

The equation for the reaction is:

The catalyst for the reaction is manganese dioxide.

Describe a test to identify the gas produced in the reaction.

Give the result of the test.

Student A investigated the effect of the particle size of manganese dioxide on the rate of the reaction.

This is the method used.

1. Measure 25 cm³ of 0.3 mol/dm³ hydrogen peroxide solution into a conical flask.

2. Add a spatula of fine manganese dioxide powder to the conical flask.

3. Measure the volume of gas produced every minute for 10 minutes.

4. Repeat steps 1 to 3 with some coarse manganese dioxide lumps.

The method student A used did not give valid results.

What two improvements could student A make to the method to give valid results?

Tick (✓) two boxes.

Student B used a method which gave valid results.

Figure 9 shows student B ’s results.

Determine the mean rate of reaction in cm³/s between 2 and 4 minutes for coarse manganese dioxide lumps.

Give your answer to 2 significant figures.

Use data from Figure 9.

Hydrogen peroxide molecules must collide with manganese dioxide particles for catalysis to take place.

Student B repeated the experiment with coarse lumps of manganese dioxide.

Student B used the same volume of 0.2 mol/dm³ hydrogen peroxide instead of 0.3 mol/dm³ hydrogen peroxide.

Sketch on Figure 9 the curve you would expect to see.

Assume that the reaction is complete after 9 minutes.

The rate of reaction is different when manganese dioxide is used as a fine powder rather than coarse lumps.

Explain why.

You should answer in terms of collision theory.

This question is about reversible reactions and equilibrium.

Hydrogen is used to produce ammonia in the Haber process.

The hydrogen is made in two stages.

Stage 1 is the reaction of methane and steam to produce carbon monoxide and hydrogen.

The equation for the reaction is:

Calculate the atom economy for the formation of hydrogen in stage 1.

Relative atomic masses (A_r): H = 1 C = 12 O = 16

Explain why a low pressure is used in stage 1.

Give your answer in terms of equilibrium.

Stage 2 uses the carbon monoxide produced in stage 1.

The carbon monoxide is reacted with more steam to produce carbon dioxide and more hydrogen.

The equation for the reaction in stage 2 is:

What is the effect of increasing the pressure on the equilibrium yield of hydrogen in stage 2 ?

Figure 10 shows the percentage yield of ammonia produced at different temperatures and pressures in the Haber process.

A temperature of 450 °C and a pressure of 200 atmospheres are used in the Haber process.

A student suggested that a temperature of 350 °C and a pressure of 285 atmospheres could be used instead of those used in the Haber process.

Determine how many times greater the percentage yield of ammonia obtained would be.

Use Figure 10.

A pressure of 285 atmospheres is not used in the Haber process instead of 200 atmospheres.

Give one reason why.

How does Figure 10 show that the forward reaction in the Haber process is exothermic?

World production of ammonia is now about 30 times greater than it was in 1950.

Suggest why the demand for ammonia has increased.