AQA GCSE Trilogy Chemistry Paper 2 Foundation November 2020 question paper 8464/C/2F

Crude oil is a mixture of hydrocarbons.

Complete the sentences. Choose answers from the box.

There are three stages, A, B and C, in separating hydrocarbons from crude oil. Stage A Hydrocarbons evaporate Stage B Crude oil is heated Stage C Vapours condense

Give the correct order for stages A, B and C.

What is the name of the process used in separating hydrocarbons from crude oil? Tick (✓) one box.

Alkanes are hydrocarbons. Figure 1 represents an alkane.

What is the formula of the alkane in Figure 1 ?

What does X represent in Figure 1 ? Tick (✓) one box.

What is the general formula for alkanes? Tick (✓) one box.

Hydrocarbons are used to make polymers. Polymers are used to make plastic bags. In one year 8.0 billion plastic bags were used. The next year there was a charge for plastic bags and only 1.3 billion plastic bags were used. Calculate the decrease in the number of plastic bags used.

This question is about carbon dioxide in the Earth’s atmosphere. Figure 2 shows how the percentage of carbon dioxide in the Earth’s atmosphere has changed over 4.6 billion years.

What was the highest percentage of carbon dioxide in the Earth’s atmosphere? Use Figure 2.

The percentage of carbon dioxide in the atmosphere has decreased since Earth’s early atmosphere. Which two processes have decreased the percentage of carbon dioxide in the Earth’s atmosphere? Tick (✓) two boxes.

The total amount of carbon dioxide emitted over the life cycle of a product can be measured. What name is given to the total amount of carbon dioxide emitted during the life cycle of a product? Tick (✓) one box.

Carbon dioxide dissolves in water. Figure 3 shows the mass of carbon dioxide dissolved in water at different temperatures.

Complete Table 1. Use Figure 3.

Calculate the difference in the mass of carbon dioxide dissolved in 1 dm³ of water at 5 °C and at 15 °C Use Table 1.

Carbon dioxide is a greenhouse gas. The greenhouse effect happens in four stages. The four stages are: Stage A Carbon dioxide stops longer wavelength radiation escaping Stage B Radiation is absorbed by the Earth Stage C Longer wavelength radiation is emitted Stage D Shorter wavelength radiation enters the atmosphere. What is the correct order of stages A, B, C and D ? Tick (✓) one box.

Changes in the percentage of carbon dioxide in the Earth’s atmosphere cause climate change. Give two effects of climate change.

A student investigated the mass of dissolved solids in water samples. Figure 4 shows the apparatus used.

This is the method used.

1. Record the mass of a dry evaporating basin.

2. Pour 25 cm³ of the water sample into the evaporating basin.

3. Place the evaporating basin on the beaker for 10 minutes.

4. Record the mass of the evaporating basin and contents.

What is used to find the mass of the evaporating basin? Tick (✓) one box.

One error is that droplets of water collect on the bottom of the evaporating basin.

Suggest how this error affects the mass of the evaporating basin and contents.

How can this error be corrected?

Another error in the method is that not all the water was removed from the water sample. How can this error be corrected? Tick (✓) one box.

The water in the water sample turns into steam. What is the name of this process?

Another student did the experiment correctly with three water samples A, B and C. Table 2 shows the results.

The range is the difference between the largest value and the smallest value. Which water sample has the greatest range of results? Tick (✓) one box.

Calculate the mean mass X for water sample A. Use Table 2.

What is the dependent variable in this experiment? Tick (✓) one box.

A different water sample contains 3.6 g of dissolved solids in 150 cm³ Calculate the mass of dissolved solids in 25 cm³ of this sample.

This question is about hydrogen peroxide.

The symbol equation for the decomposition of hydrogen peroxide (H₂O₂) is:

Complete the word equation for the decomposition of hydrogen peroxide.

A student investigated the effect of different catalysts on the decomposition of hydrogen peroxide. The student measured the volume of gas collected every 30 seconds for 5 minutes. Figure 5 shows the apparatus used.

Which two variables should the student keep the same to make the investigation a fair test? Tick (✓) two boxes.

Figure 6 shows a gas syringe.

What is the volume of gas in the syringe?

Table 3 shows the student’s results for one catalyst.

Six of the other results have been plotted on Figure 7.

Complete the graph in Figure 7. You should:

• plot the results from Table 3

• draw a line of best fit for all of the results.

The student repeated the experiment with other catalysts and plotted a graph for each of the catalysts used.

Suggest how the student could use these graphs to identify the best catalyst.

All the graphs level off at the same volume of gas. Suggest why.

In another investigation, a student increased the temperature of the hydrogen peroxide. Why is the rate of reaction faster when the temperature of the hydrogen peroxide is increased? Tick (✓) two boxes.

This question is about mixtures.

Which substance is a mixture? Tick (✓) one box.

Food colourings are often mixtures of dyes. What name is given to mixtures that are designed as useful products?

A student investigated a purple food colouring, Y, using chromatography. The student compares Y with dyes A, B and C.

Figure 8 shows the apparatus used.

Chromatography involves a stationary phase and a mobile phase.

Draw one line from each phase to what is used for that phase. Use Figure 8. Phase What is used

Figure 9 shows the student’s results.

What three conclusions can you make about the dyes in food colouring Y ?

In a different experiment a student recorded these results: Distance moved by dye G = 60 mm Distance moved by solvent = 80 mm Calculate the R_f value of dye G.

This question is about the Earth’s resources.

When most fuels burn carbon dioxide is produced.

Balance the equation for the combustion of propane.

Describe the test for carbon dioxide. Give the result of the test.

Propane can be cracked to produce propene and hydrogen. Complete the symbol equation for the reaction.

Describe the test for hydrogen. Give the result of the test.

Propene is an alkene. Describe the test for alkenes. Give the colour change in the test.

Some students investigated the effect of temperature on the rate of reaction.

The students reacted sodium thiosulfate solution with hydrochloric acid. This is the method used.

1. Use a beaker to measure 50 cm³ of heated sodium thiosulfate solution into a

conical flask.

2. Measure the temperature of the room.

3. Put the conical flask on a black cross drawn on a piece of paper.

4. Start a timer.

5. Use the same beaker to measure 10 cm³ of hydrochloric acid into the conical flask.

6. Stop the timer when the cross is no longer visible.

The students repeated the experiment at a different room temperature. Figure 10 shows the apparatus.

The method contains errors and does not produce accurate results.

Describe a method the students should use to produce accurate results. You do not need to write about safety precautions.

Some students investigated the effect of temperature on the rate of a

different reaction. They recorded the loss of mass from their apparatus at 40 °C Figure 11 shows the results.

Calculate the mean rate of reaction between 1 minute and 3 minutes at 40 °C Use Figure 11 and the equation:

Draw a curve on Figure 11 for the results you would expect at a temperature of