The Haber process and the idea of optimum condition

Question 1

What is the equation for the Haber process?

Answer 1

N2(g) + 3H2(g) ⇋ 2NH3 (g)
ΔH = -93kJmol-1

Question 2

Use Le Chatelier’s principle to predict the conditions of temperature best suited to obtain the maximum yield of ammonia
(forward reaction is exothermic)

Answer 2

Decreasing the temperature causes equilibrium to shift in the direction of the exothermic reaction which releases heat
Equilibrium shifts to the right hand
side
The yield of products increases

Question 3

Use Le Chatelier’s principle to predict the conditions of pressure best suited to obtain the maximum yield of ammonia
(forward reaction is exothermic)

Answer 3

Increasing the pressure causes equilibrium to shift to the side with the fewest gas moles
Equilibrium shifts to the right hand side
The yield of products increases

Question 4

If the optimum theoretical conditions are low, what does this mean for pressure and temperature?

Answer 4

Slow rate of reaction

Question 5

If the optimum theoretical conditions are high, what does this mean for pressure?

Answer 5

Uses a large amount of energy/fuel
Provides a safety risk

Question 6

If the optimum theoretical conditions are high, what does this mean for temperature?

Answer 6

Uses a large amount of energy/fuel

Question 7

What reaction rate will high temperatures and pressures produce?

Answer 7

Fast rate of reaction

Question 8

How do catalysts affect optimum theoretical conditions?

Answer 8

Allow equilibrium to be established more quickly
Allow the reaction to be carried out at a lower operating temperature (less energy used)