The graph shows how the percentage of ammonia at equilibrium varies with temperature at two different pressures for the reaction:

N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

Line X shows data at 200 atm. Line Y shows data at 100 atm.

Which statement explains the difference between lines X and Y?

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Question

The graph shows how the percentage of ammonia at equilibrium varies with temperature at two different pressures for the reaction:

N₂(g) + 3H₂(g) ⇌ 2NH₃(g)

Line X shows data at 200 atm. Line Y shows data at 100 atm.

Which statement explains the difference between lines X and Y?

Accepted Answer

Higher pressure shifts equilibrium towards the side with fewer moles of gas — Award 1 mark for identifying that higher pressure favours the side with fewer moles of gas (products: 2 moles vs reactants: 4 moles), giving a higher percentage of ammonia. A is incorrect because pressure affects both reaction rates. B is incorrect as it describes the opposite effect. D is incorrect because pressure does not change Kc.

Answer

Higher pressure shifts equilibrium towards the side with fewer moles of gas

Answer

Higher pressure increases the equilibrium constant

Answer

Higher pressure increases the rate of the forward reaction only

Answer

Higher pressure shifts equilibrium towards the side with more moles of gas

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