AQA GCSE Trilogy Chemistry Paper 2 Higher June 2018 question paper 8464/C/2H

Crude oil is a mixture of hydrocarbons.

The hydrocarbons in crude oil are separated into fractions by fractional distillation. Figure 1 shows a fractional distillation column.

Crude oil vapour passes up the column. Complete the sentence. Choose the answer from the box.

Why do the fractions separate? Tick one box.

Most of the hydrocarbons in crude oil are alkanes.

Figure 2 represents an alkane molecule.

Name the alkane.

Methane (CH₄) is an alkane. What is the general formula for alkanes? Tick one box.

Alkanes burn in oxygen. Balance the equation for methane burning.

Ethene is an alkene. Which reagent is used to test for alkenes? Tick one box.

Table 1 shows data from a life cycle assessment (LCA) for the disposal of 10 000 biodegradable plastic bags.

Why are life cycle assessments (LCA) done?

Compare the two methods for the disposal of biodegradable plastic bags. Use information from Table 1

This question is about the Earth’s atmosphere.

Carbon dioxide is a greenhouse gas. What is another greenhouse gas?

Tick one box.

Greenhouse gases cause global climate change. Give two effects of global climate change.

4.1 kg of a plastic, used to make plastic bottles, has a carbon footprint of 6.0 kg of carbon dioxide. Calculate the carbon footprint of one plastic bottle of mass 23.5 g

Give one way that carbon dioxide emissions can be reduced when a plastic bottle is manufactured.

Explain how the percentages of nitrogen, oxygen and carbon dioxide in the Earth’s atmosphere today have changed from the Earth’s early atmosphere.

A student investigated the mass of dissolved solids in 5 cm³ samples of water. Figure 3 shows the apparatus.

Table 2 shows the student’s results.

Calculate mass X in Table 2

5 cm³ is a small volume of water for each experiment. Give one advantage and one disadvantage of using a larger volume.

Potable water is not pure water. Describe the difference between potable water and pure water.

Potable water is obtained from both groundwater and from sea water. Describe how groundwater and sea water are treated to produce potable water.

The percentage by mass of dissolved solids in a 6.50 g sample is 2.2% Calculate the mass of the dissolved solids.

Fertilisers are formulations.

What is a formulation?

A bag of fertiliser contains 14.52 kg of ammonium nitrate (NH₄NO₃). Relative formula mass (M_r): NH₄NO₃ = 80 Calculate the number of moles of ammonium nitrate in the bag of fertiliser. Give your answer in standard form to 2 significant figures.

The fertiliser also contains potassium chloride. Explain why potassium chloride has a high melting point.

A student investigated the effect of the size of marble chips on the rate of the reaction between marble chips and hydrochloric acid. This is the method used.

1. Add 10 g of marble chips into the flask.

2. Add 50 cm³ of hydrochloric acid, connect the gas syringe and start a timer.

3. Record the volume of gas produced every 10 seconds.

Figure 4 shows the apparatus.

Complete the equation for the reaction.

Figure 5 shows the student’s results.

Describe the trend shown in Figure 5 Use values in your answer.

Describe how you would use Figure 5 to find the rate of the reaction at 15 seconds. You do not need to do a calculation.

Give the units for the rate of this reaction.

Table 3 shows the results of the investigation.

Give one conclusion about how the size of the marble chips affects the rate of the reaction.

Suggest why all three sizes of marble chips produce a maximum volume of 60 cm³ of gas.

Figure 6 shows eight small cubes, each 1 cm x 1 cm x 1 cm, and one large cube, 2 cm x 2 cm x 2 cm

Total volume of small cubes = 8 cm³ Volume of large cube = 8 cm³ Total surface area of small cubes = 48 cm²

Calculate the surface area of the large cube.

Explain why the size of the marble chips affects the rate of the reaction. Give your answer in terms of ‘collision theory’.

The student repeated the investigation with small marble chips using hydrochloric acid with a lower concentration. Figure 7 shows the volume of gas produced during the first 40 seconds.

Explain why the results for the lower concentration of acid are different from the results for the higher concentration of acid.

Bleach is a solution of sodium hypochlorite (NaClO). Chlorine gas is produced when bleach reacts with hydrochloric acid. NaClO(aq) + 2HCl (aq) NaCl(aq) + H₂O(l) + Cl₂(g)

Give the test and result for chlorine gas.

Figure 8 shows a sealed flask of sodium hypochlorite and hydrochloric acid at equilibrium.

Explain why equilibrium is reached in this reaction.

The stopper in Figure 8 is removed and hydrochloric acid is added. The stopper is replaced. Explain what happens to the equilibrium.

Chlorine gas is also produced when hydrogen chloride decomposes.

The forward reaction is endothermic.

Predict the effect of increasing the temperature on the amount of chlorine gas produced at equilibrium. Explain your answer using Le Chatelier’s Principle.

Explain the effect of increasing the pressure on this equilibrium.