GCSE AQA Chemistry Reversibility & Equilibrium: This question is about reversibl

Question

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:

CH₄(g) + H₂O(g) ⇌ CO(g) + 3H₂(g)

10.1 Calculate the atom economy for the formation of hydrogen in stage 1.

Relative atomic masses (Ar):
H = 1  C = 12  O = 16

10.2 Explain why a low pressure is used in stage 1.

Give your answer in terms of equilibrium.

10.3 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:

CO(g) + H₂O(g) ⇌ CO₂(g) + H₂(g)

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.

Figure 10

A temperature of 450 °C and a pressure of 200 atmospheres are used in the Haber process.

10.4 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.

This question is about reversible reactions and equilibrium - AQA - GCSE Chemistry - Question 10 - 2019 - Paper 2