Catalysts

This question is about methanol.

Methanol is used in screenwash.

Screenwash is used to keep car windscreens clean.

Screenwash is a formulation.

Define the term ‘formulation’.

Carbon monoxide and hydrogen are used to produce methanol.

The conditions used in the production of methanol are:

• high temperature

• high pressure

• a catalyst.

The equation for the reaction is:

91 kJ/mol of energy is transferred during the exothermic forward reaction.

How much energy is transferred when methanol is decomposed into carbon monoxide and hydrogen?

Tick () one box.

A scientist developed a principle to predict the effect of changing conditions on a system at equilibrium.

What was the name of the scientist?

What is the effect of increasing the temperature on the proportion of methanol in the equilibrium mixture?

Tick () one box.

What is the effect of using a catalyst on the proportion of methanol in the equilibrium mixture?

Tick () one box.

Explain the effect of increasing the pressure on the proportion of methanol in the equilibrium mixture.

Explain the effect of using a catalyst on the rate of production of methanol.

The catalyst allows the reaction to take place at a lower temperature.

Explain one advantage of using a lower temperature in the production of methanol.

Do not refer to the position of equilibrium in your answer.

Methanol (CH₃OH) can also be produced by reacting carbon dioxide with hydrogen.

Water is the other product of the reaction.

Write a balanced equation for the reaction.

Some factors affect the rates of chemical reactions.

A student investigated the effect of changing the particle size of calcium carbonate on the rate of reaction with hydrochloric acid.

Figure 6 shows the apparatus.

Describe a method the student could use to produce valid results.

The student investigated the effect of increasing the temperature on the rate of a reaction.

Explain the effect of increasing the temperature on the rate of a reaction.

Refer to particles and collisions in your answer.

Catalysts affect the rate of reactions.

What is meant by a ‘catalyst’?

What are catalysts in biological systems called?

Some factors affect the rates of chemical reactions.

A student investigated the effect of changing the particle size of calcium carbonate on the rate of reaction with hydrochloric acid.

Figure 3 shows the apparatus.

Describe a method the student could use to produce valid results.

The student investigated the effect of increasing the temperature on the rate of a reaction.

Explain the effect of increasing the temperature on the rate of a reaction.

Refer to particles and collisions in your answer.

Catalysts affect the rate of reactions.

What is meant by a ‘catalyst’?

What are catalysts in biological systems called?

Sulfuric acid is produced by an industrial process.

In the process, sulfur dioxide (SO₂) reacts with oxygen (O₂) to produce

The equation for the reversible reaction is:

The forward reaction releases 198 kJ/mol of energy.

What is the amount of energy transferred during the reverse reaction?

Tick () one box.

The concentration of oxygen is increased.

What is the effect on the position of the equilibrium?

Tick () one box.

The pressure is decreased.

What is the effect on the position of the equilibrium?

Tick () one box.

The temperature is increased.

What is the effect on the position of the equilibrium?

Tick () one box.

A catalyst is used in the reaction.

Suggest what effect the catalyst has on the position of the equilibrium.

Give one reason for your answer.

A scientist measured how the number of moles of sulfur dioxide, oxygen and

sulfur trioxide varied with time during the reaction.

Figure 5 shows the results.

Determine the time taken for the reaction to reach equilibrium.

Explain your answer.

Use Figure 5.

Figure 6 shows the results for sulfur trioxide.

Determine the rate of reaction at 60 seconds.

A catalyst is used to increase the rate of decomposition of hydrogen peroxide.

Hydrogen peroxide decomposes to produce water and oxygen. Write a word equation for the reaction.

A student investigated the rate of decomposition of hydrogen peroxide using three different catalysts:

• manganese dioxide

• copper oxide

• zinc oxide.

Figure 7 shows the apparatus.

This is the method used.

1. Measure 25 cm³ of hydrogen peroxide solution into a flask.

2. Add 0.5 g of manganese dioxide catalyst to the flask.

3. Attach a gas syringe to the flask.

4. Measure the volume of oxygen produced every 20 seconds for 120 seconds.

5. Repeat steps 1 to 4 two more times.

6. Repeat steps 1 to 5 using copper oxide catalyst.

7. Repeat steps 1 to 5 using zinc oxide catalyst.

Which two control variables are used in the investigation? Tick (✓) two boxes.

Table 3 shows the results with manganese dioxide catalyst.

Figure 8 shows a graph of the results with copper oxide catalyst and with zinc oxide catalyst.

Complete Figure 8. You should:

• plot the data for the manganese dioxide catalyst from Table 3

• draw a line of best fit.

The first two points have been plotted for you.

Which is the best catalyst? Give one reason for your answer. Use the completed Figure 8. Tick (✓) one box.

The student repeated the investigation with manganese dioxide catalyst. The results were all close to the true value. Complete the sentence. Choose the answer from the box.

Results that are close to the true value are

The student repeated the investigation using manganese dioxide catalyst at a higher temperature. Complete the sentence. Choose the answer from the box.

A student investigated the rate of decomposition of hydrogen peroxide using three different catalysts:

• manganese dioxide

• copper oxide

• zinc oxide.

Figure 2 shows the apparatus.

This is the method used.

1. Measure 20 cm³ of hydrogen peroxide solution into a flask.

2. Add 0.5 g of manganese dioxide catalyst to the flask.

3. Attach a gas syringe to the flask.

4. Measure the volume of oxygen produced every 30 seconds for 180 seconds.

5. Repeat steps 1 to 4 two more times.

6. Repeat steps 1 to 5 using copper oxide catalyst.

7. Repeat steps 1 to 5 using zinc oxide catalyst.

The equation for the decomposition of hydrogen peroxide is:

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

Using 10 cm³ of hydrogen peroxide solution gives less accurate results than using 20 cm³ of hydrogen peroxide solution of the same concentration. Explain why.

Suggest one possible source of systematic error in the investigation.

Table 3 shows the results for manganese dioxide catalyst.

Figure 3 shows a graph of the results with copper oxide catalyst and with zinc oxide catalyst.

Complete Figure 3. You should:

• plot the data from Table 3

• draw a line of best fit.

The first point has been plotted for you.

Which catalyst gives the fastest rate of reaction? Give one reason for your answer. Use the completed Figure 3.

The rate of reaction is not dependent on the volume of hydrogen peroxide solution. Explain why.

Figure 4 shows the results from a different investigation.

Determine the rate of reaction at 20 seconds. Show your working on Figure 4. Give your answer to 3 significant figures.

This question is about ammonia and its compounds.

A student heated a sample of ammonium chloride.

The equation for the reaction is:

One product is ammonia.

What is the name of the product with the formula HC l ?

Ammonia is a gas.

What is the state symbol for ammonia?

Tick (✓) one box.

How does the equation show that the reaction is reversible?

The industrial process to produce ammonia uses a catalyst.

Figure 5 shows the reaction profile for the reaction with and without a catalyst.

Which letter represents the activation energy for the reaction with a catalyst?

Tick (✓) one box.

Give one reason why using a catalyst reduces costs.

Do not answer in terms of activation energy.

Ammonia is in a mixture that is used as a household cleaner.

What is a mixture that has been designed as a useful product called?

This question is about catalysts and equilibrium.

What type of substance is a catalyst in biological systems? Tick (✓) one box.

Explain how a catalyst increases the rate of a reaction.

The reversible reaction for the production of ammonia is:

What can scientists predict using Le Chatelier’s Principle?

Describe how a reversible chemical reaction is able to reach equilibrium.

Explain the effect of increasing the pressure on the yield of ammonia.

The forward reaction to produce ammonia is exothermic. Explain the effect of increasing the temperature on the yield of ammonia.

Cars cause atmospheric pollution.

Figure 2 shows the percentage of cars in the UK using different energy sources.

The percentage of cars using petrol is 54%. Draw the bar for petrol on Figure 2.

Some car emissions contain nitrogen dioxide.

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

Which column of data has the greatest range? Tick (✓) one box.

Explain why the concentration of nitrogen dioxide in the air is lower on Sunday.

Calculate the mean value for the concentration of nitrogen dioxide in the air in the city centre for the days from Monday to Friday. Use Table 1.

Nitrogen dioxide is removed from car emissions by catalytic converters.

Which two of the following are correct statements about catalysts? Tick (✓) two boxes.

The catalyst in catalytic converters contains platinum. Platinum is an unreactive metal obtained from the Earth’s crust. Complete the sentence. Choose the answer from the box.

Platinum is a.

Emissions from cars that burn fossil fuels contain carbon dioxide. What is used to test for carbon dioxide? Tick (✓) one box.

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.

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.

Figure 6 shows the percentage by mass of some metals in the Earth’s crust.

What is the percentage by mass of calcium in the Earth’s crust?

Tick (✓) one box.

The percentage by mass of magnesium in the Earth’s crust is 2.1%

Draw the bar for magnesium on Figure 6.

Copper sulfate is produced during the extraction of copper from the Earth’s crust.

Copper is produced from copper sulfate solution using iron.

The word equation for the reaction is:

copper sulfate + iron → iron sulfate + copper

From the equation a company calculated that 648 kg of copper sulfate are needed to produce 617 kg of iron sulfate and 258 kg of copper.

Calculate the mass of iron needed to make 258 kg of copper.

Copper is used as a catalyst.

Figure 7 shows the reaction profile for a reaction without a catalyst.

Draw an arrow on Figure 7 to show the activation energy.

The reaction profile for the reaction without a catalyst is shown again in Figure 8.

Draw a reaction profile on Figure 8 for the same reaction with a catalyst.

What are catalysts in biological systems called?

Tick (✓) one box.

This question is about copper and fuels.

Copper is extracted from low-grade ores by phytomining. Describe how copper metal is produced by phytomining.

Another method of extracting copper from low-grade ores is bioleaching. A solution of copper sulfate (CuSO₄) produced by bioleaching has a

Relative atomic masses (A_r): Cu = 63.5 O = 16 S = 32 Calculate the number of moles of copper that can be produced from 1 dm³ of this solution.

Copper is used as a catalyst. Figure 1 shows reaction profiles for a reaction with and without a catalyst.

How do the reaction profiles show that using a catalyst does not affect the overall energy change for the reaction?

Tick (✓) one box.

Copper is a catalyst in a reaction to produce ethanol from carbon dioxide. Ethanol (C₂H₅OH) is used as a fuel. Suggest why producing ethanol from carbon dioxide is sustainable.

Chemistry plays an important role in sustainable development. What is sustainable development?