The Haber process

Ammonia is produced in the Haber process.

The word equation for the reaction to produce ammonia is:

Draw one line from each element to a source of that element.

Ammonia is a gas at room temperature.

Figure 3 shows how ammonia is produced from nitrogen and hydrogen.

Which process takes place at X in Figure 3 ?

Tick () one box.

Complete the sentence.

Use Figure 3.

Table 1 shows the world production of ammonia between 1990 and 2020.

How did the world production of ammonia change between 1990 and 2020?

Use Table 1.

Determine the mean change in mass of ammonia produced per year between 2000 and 2020.

Use Table 1 and the equation:

Most of the ammonia produced in the Haber process is used to make fertilisers.

Which is a reason for the change in the world production of ammonia shown in Table 1 ?

Tick () one box.

Fertilisers produced using ammonia contain nitrogen.

Which two compounds used in fertilisers contain nitrogen?

Use the periodic table.

Tick () two boxes.

This question is about ammonia.

Ammonia is produced from nitrogen and hydrogen in the Haber process.

Hydrogen is produced from methane and steam.

The equation for one of the reactions in the production of hydrogen is:

The forward reaction absorbs energy from the surroundings.

Explain why a high temperature is used in this reaction.

Explain why as low a pressure as possible is used in this reaction.

A nickel catalyst is used in this reaction.

What is the effect of the nickel catalyst on the position of equilibrium?

Tick (✓) one box.

The nitrogen needed in the Haber process is obtained from air.

Calculate the approximate volume of air required to obtain 50 dm³ of nitrogen.

Figure 9 shows how ammonia is produced from nitrogen and hydrogen.

Explain how the mixture of ammonia, nitrogen and hydrogen is separated at X.

Ammonia is used to produce fertilisers.

Nitrogen is released into the air when bacteria break down fertilisers and dead plant matter.

One of the reactions during the production of hydrogen from methane (natural gas) releases carbon dioxide into the air.

The use of nitrogen to produce ammonia is more sustainable than the use of hydrogen to produce ammonia.

Give three reasons why.

This question is about ammonia and nitric acid.

In the Haber process ammonia is produced from nitrogen and hydrogen.

Figure 10 represents the Haber process.

Pipe P links the condenser to the reactor.

Why is the condenser linked to the reactor?

Use Figure 10.

Which metal is used as a catalyst in this reaction?

Nitric acid is produced by reacting ammonia with oxygen.

The word equation for the production of nitric acid is:

ammonia + oxygen → water + nitric acid

Platinum is a catalyst in this reaction.

Describe the test for oxygen gas.

Give the result if oxygen gas is present.

Figure 11 represents the reaction profile of the catalysed reaction between ammonia and oxygen.

Complete the reaction profile for the catalysed reaction in Figure 11.

You should:

label the activation energy

label the reactants and products, using the names of the reactants and products.

How would Figure 11 be different if no catalyst was used?

Tick (✓) one box.

Ammonia and nitric acid react to produce the salt, ammonium nitrate.

Ammonium ions and nitrate ions both contain nitrogen.

Suggest one use of ammonium nitrate.

This question is about ammonia and nitric acid.

In the Haber process ammonia is produced from nitrogen and hydrogen.

Figure 1 represents the Haber process.

Pipe P links the condenser to the reactor.

Why is the condenser linked to the reactor?

Use Figure 1.

Which metal is used as a catalyst in this reaction?

Nitric acid is produced by reacting ammonia with oxygen.

The word equation for the production of nitric acid is:

ammonia + oxygen → water + nitric acid

Platinum is a catalyst in this reaction.

Describe the test for oxygen gas.

Give the result if oxygen gas is present.

Figure 2 represents the reaction profile of the catalysed reaction between ammonia and oxygen.

Complete the reaction profile for the catalysed reaction in Figure 2.

You should:

label the activation energy

label the reactants and products, using the names of the reactants and products.

How would Figure 2 be different if no catalyst was used?

Tick (✓) one box.

Ammonia and nitric acid react to produce the salt, ammonium nitrate.

Ammonium ions and nitrate ions both contain nitrogen.

Suggest one use of ammonium nitrate.

This question is about sulfuric acid.

Sulfuric acid contains sulfate ions.

Describe the test for the presence of sulfate ions in sulfuric acid.

Give the result of the test.

One stage in the industrial production of sulfuric acid is the reaction of sulfur dioxide with oxygen to produce sulfur trioxide.

This reversible reaction reaches dynamic equilibrium.

Figure 7 shows the percentage yield of sulfur trioxide in this reaction at different temperatures.

Which statement about the forward reaction is correct?

Use Figure 7.

Tick (✓) one box.

The equation for the reaction is:

Explain why the percentage yield of sulfur trioxide in this reaction is greater if the pressure is higher.

In industry, the reaction is done at 450 °C and atmospheric pressure.

Under these conditions the yield of sulfur trioxide is 86%.

Suggest two reasons why a higher pressure is not used.

This reaction uses a catalyst to increase the rate of the reaction.

The catalyst is a metal oxide.

Which is the most likely metal in the metal oxide catalyst?

Use the periodic table.

Tick (✓) one box.

Ammonia is produced in the Haber process. The raw materials for the Haber process are nitrogen and hydrogen.

Draw one line from each raw material to the source of that raw material.

What are the states of nitrogen and of hydrogen when used in the Haber process? Tick (✓) one box. State of nitrogen State of hydrogen

The word equation for the production of ammonia is: nitrogen + hydrogen ⇌ ammonia The atom economy of the reaction is 100%.

How does the word equation show that the atom economy is 100%? Tick (✓) one box.

Figure 5 represents the Haber process.

A mixture of nitrogen, hydrogen and ammonia enters X.

Complete the sentences. Choose answers from the box.

In X, the mixture is cooled. The ammonia can be removed from X because the ammonia is

The unreacted nitrogen and hydrogen are

Table 8 shows the percentage yield of ammonia at different pressures.

Plot the data from Table 8 on Figure 6. Draw a line of best fit.

What is the effect of increasing the pressure on the percentage yield of ammonia? Use Table 8.

This question is about fertilisers. Ammonium nitrate is a fertiliser containing nitrogen.

Complete the sentence. Choose the answer from the box.

Ammonium nitrate is produced by reacting ammonia with

Ammonium nitrate fertiliser is sold in 600 kg bags. A farmer spreads 40 bags of ammonium nitrate fertiliser on land with an area

Calculate the mass of ammonium nitrate fertiliser spread per m² of land.

A scientist works for a company which makes ammonium nitrate fertiliser. The scientist investigates the effect of different fertilisers on crop growth. The scientist concludes that the ammonium nitrate fertiliser improves crop growth more than other fertilisers. Suggest one reason why this conclusion might not be valid.

A different fertiliser containing nitrogen has the formula K₂NH₄PO₄

How many atoms of nitrogen are in the formula K₂NH₄PO₄?

Nitrogen and potassium in the fertiliser K₂NH₄PO₄ are important for good crop growth. Which other element in the fertiliser K₂NH₄PO₄ is important for good crop growth? Tick (✓) one box.

Some fertilisers are mixtures of different compounds in fixed proportions. What name is given to a mixture of different compounds in fixed proportions?

Ammonia is produced in the Haber process. The raw materials for the Haber process are nitrogen and hydrogen. The equation for the reaction is:

Give the sources of the nitrogen and of the hydrogen used in the Haber process.

How does the equation for the reaction show that the atom economy of the forward reaction is 100%?

Figure 4 represents the Haber process.

Explain how the ammonia produced is separated from the unreacted nitrogen and hydrogen in X.

The Haber process uses a temperature of 450 °C and a pressure of 200 atmospheres. Table 6 shows the percentage yield of ammonia produced at 450 °C using different pressures.

Complete Figure 5. The first two points have been plotted. You should:

• use a suitable scale for the x-axis

• plot the remaining data from Table 6

• draw a line of best fit.

Determine the percentage yield of ammonia at 450 °C and 500 atmospheres. Show your working on Figure 5.

The equation for the production of ammonia in the Haber process is:

The forward reaction is exothermic. The conditions used are:

• a temperature of 450 °C

• a pressure of 200 atmospheres

• the presence of an iron catalyst.

Explain why these conditions are chosen for economical production of ammonia in the Haber process. You should include references to the rate of reaction and the position of equilibrium.

This question is about ammonia and fertilisers.

Ammonia is produced from nitrogen and hydrogen.

A catalyst is used to speed up the reaction.

The word equation for the reaction is:

nitrogen + hydrogen ammonia

What does the symbol show about the reaction?

Which catalyst is used when ammonia is produced from nitrogen and hydrogen?

Tick (✓) one box.

Figure 1 shows the reaction profile for the production of ammonia both with a catalyst and without a catalyst.

What is represented by label X ?

Tick (✓) one box.

Ammonia is used to produce fertilisers.

NPK fertilisers contain the elements nitrogen, phosphorus and potassium.

A fertiliser contains:

• 22% phosphorus

• 25% potassium.

Draw a bar chart on Figure 2 to show the percentages of phosphorus and of potassium in this fertiliser.

Why do the percentages of phosphorus and of potassium in this fertiliser not add up to 100%?

Fertilisers help plants grow by adding essential elements to soil.

Table 1 shows the percentages of nitrogen, phosphorus and potassium in four fertilisers, A, B, C and D.

Plants lacking essential elements do not grow well because:

• too little phosphorus can cause slow plant growth

• too little potassium can cause leaves to have brown edges.

Which fertiliser helps prevent slow plant growth and brown leaf edges?

Use Table 1.

Tick (✓) one box.

Which fertiliser has the greatest total percentage of essential elements?

Use Table 1.

Tick (✓) one box.

Hydrogen is a raw material in the Haber process.

Hydrogen is produced from methane.

The word equation for the reaction is:

methane + steam carbon monoxide + hydrogen

How can you tell that the reaction is reversible?

The forward reaction is endothermic.

Name the type of energy change in the reverse reaction.

A nickel catalyst is used in this reaction.

Why is a catalyst used in this reaction?

Tick (✓) two boxes.

The Haber process also uses nitrogen to produce ammonia.

Figure 1 shows how the world production of ammonia changed between 1950 and 2010.

Describe how the world production of ammonia changed between 1950 and 2010.

Most of the ammonia produced is used to make fertilisers.

Why did the world production of ammonia change between 1950 and 2010?

Tick (✓) two boxes.

Table 1 shows data about four fertilisers, A, B, C and D.

Which combination of fertilisers A, B, C and D provides all of the elements needed for an NPK fertiliser?

Use Table 1.

Tick (✓) one box.

Which fertiliser is not made using ammonia?

Use Table 1.

Tick (✓) one box.

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.

This question is about gases. Figure 3 shows how nitrogen is used in the Haber Process to produce ammonia.

Gas X in Figure 3 is obtained from methane. Name gas X.

Give the approximate temperature and pressure used in the reactor.

The mixture of gases from the reactor cools in the condenser. Suggest why ammonia condenses but the other gases do not.

The Earth’s early atmosphere was different to Earth’s atmosphere today. Scientists think that the Earth’s early atmosphere was like the atmosphere found on Venus today. Table 2 shows the amounts of carbon dioxide and oxygen in the atmospheres of Venus and Earth today.

The percentages of carbon dioxide and oxygen have changed from Earth’s early atmosphere to Earth’s atmosphere today. Explain the processes that led to these changes.

Why are scientists not certain about the percentage of each gas in the Earth’s early atmosphere?