AQA GCSE Trilogy Chemistry Paper 2 Higher November 2021 question paper 8464/C/2H

Figure 1 shows the apparatus.

This is the method used.

1. Pour 50 cm³ of hydrochloric acid into a conical flask.

2. Add a piece of magnesium.

3. Insert stopper and delivery tube and start a timer.

4. Collect the gas produced in a gas syringe.

5. Record the volume of gas produced every 20 seconds for 2 minutes.

6. Repeat steps 1 to 5 with higher concentrations of hydrochloric acid.

Give the independent variable and one control variable in this investigation.

Independent variable

Table 1 shows the results from the first experiment using hydrochloric acid with a

low concentration.

Complete Figure 2.

You should:

• plot the data from Table 1 (the point 0,0 has been plotted for you)

• draw a line of best fit.

How does the rate of this reaction change with time?

Use Table 1.

Tick (✓) one box.

The student repeated the experiment using hydrochloric acid with a higher concentration.

Which statement is correct?

Tick (✓) one box.

Temperature also affects the rate of the reaction.

Explain how increasing the temperature affects the rate of the reaction.

You should refer to particles and collisions.

Crude oil is a resource found in rocks.

Most of the compounds in crude oil are hydrocarbons.

Complete the sentence.

Crude oil is formed by the decomposition of

Alkanes are hydrocarbons.

Give the name of the alkane molecule that has three carbon atoms.

Figure 3 shows two alkane molecules.

Table 2 shows the melting points and boiling points of methane and hexane.

Compare the structure and properties of methane and hexane.

Hydrocarbons are cracked to produce more useful alkanes and alkenes.

Decane (C₁₀H₂₂) is cracked to produce two products.

Complete the equation for the reaction.

C₂H₄ is an alkene.

What is the test for alkenes?

Give the result of the test if an alkene is present.

The methods used to produce potable water depend upon available sources of water.

Suggest how copper sulfate can be used as a test for the presence of water.

The boiling point is used to check the purity of a sample of water.

In chemistry, what is meant by a ‘pure substance’?

The boiling point of a 250 g sample of water was 100.60 °C.

The boiling point of pure water in a data book is 100.00 °C.

Each 1% of impurity increases the boiling point of water by 0.12 °C.

Calculate the mass of the impurity in the sample of water.

Explain how distillation is used to obtain potable water from salty water.

Obtaining potable water from salty water is more expensive than obtaining potable water from ground water.

Explain why.

Refer to the processes used in both methods in your answer.

Industries use the Earth’s natural copper resources to produce useful products.

Figure 4 shows the world production of copper from 1900 to 2020.

Describe the trend shown by the graph in Figure 4.

Suggest one reason for the trend in Figure 4.

Suggest one reason why the trend cannot be used to accurately predict the future world production of copper.

High-grade copper resources are now difficult to find.

Phytomining is used to extract copper from low-grade ores.

There are five stages, A, B, C, D and E, in phytomining.

The stages are not in the correct order.

Stage A Copper compounds from ash are dissolved in acid.

Stage B Plants absorb metal compounds.

Stage C Plants are burned.

Stage D Plants are harvested.

Stage E Solution of copper compound is electrolysed.

What is the correct order of stages A, B, C, D, and E ?

Tick (✓) one box.

Give two disadvantages of phytomining compared with traditional mining methods.

Do not refer to cost in your answer.

In one year, 8.89 × 10⁹ kg of copper was produced.

41.0% of this copper was produced from recycled copper.

The energy needed to produce 1 kg of copper from copper ore is 70.4 MJ.

The energy needed to produce 1 kg of recycled copper is 27.2 MJ.

Calculate the difference in energy used if all the copper was produced from recycling.

Give your answer to 3 significant figures.

Atmospheric pollution is emitted by cars.

Some car emissions contain nitrogen dioxide.

Describe how nitrogen dioxide (NO₂) is produced in the engine of a car that burns fossil fuels.

Table 3 shows the concentration of nitrogen dioxide in the air in three different areas for 1 week.

The mean value for nitrogen dioxide in the air for the whole week in the city centre

Calculate the value (X) for the concentration of nitrogen dioxide in the air in the city centre on Sunday.

Each value in Table 3 has an uncertainty of ± 2 micrograms per m³.

Explain why this uncertainty is most significant for countryside data.

Nitrogen dioxide is removed from car emissions by catalytic converters.

In a catalytic converter nitrogen dioxide (NO₂) reacts to produce nitrogen and oxygen.

Complete the equation for the reaction.

You should balance the equation.

The catalyst in a catalytic converter contains platinum.

Platinum is a finite resource.

What is meant by a ‘finite resource’?

Emissions from cars contain carbon dioxide.

Explain why carbon dioxide emissions during use and operation are not the total carbon footprint for a car.

Refer to the stages of the life cycle assessment of a car in your answer.

Ammonia is produced when a mixture of nitrogen and hydrogen reacts.

The equation for the reaction is:

Nitrogen is obtained from the air.

The mixture of nitrogen and hydrogen must not contain carbon dioxide and oxygen.

Explain how a sample can be tested to show that carbon dioxide is not present in the mixture.

A catalyst is used in the reaction.

Explain how a catalyst increases the rate of a reaction.

The equation for the reaction to produce ammonia is repeated here.

The reaction reaches equilibrium.

Explain how an equilibrium is reached.

Suggest how the catalyst affects the equilibrium position.

Give one reason for your answer.

What is the effect of increasing the pressure on the reaction to produce ammonia?

Tick (✓) one box.

The forward reaction is exothermic.

Explain the effect of increasing the temperature on the yield of ammonia gas produced at equilibrium.