Equilibria

The total pressure = 150 kPa and the mole fraction of ammonia was 0.80:

partial pressure of the ammonia is 150 x 0.80 = 120 kPa

The other partial pressures are 150 – 120 = 30 kPa

Since there is a 1:3 mole ratio for nitrogen: hydrogen, the mole fraction for nitrogen is 0.25 and for hydrogen it's 0.75 (3 x 0.25)

pp nitrogen = 0.25 x 30 = 7.5 kPa

pp hydrogen = 0.75 x 30 = 22.5 or 23 kPa

pp of ammonia = 0.8 x 150 = 120 kPa

Straightforward, but the mark will be lost if square brackets are used

Enthalpy change is negative so reaction is exothermic in the forward direction.

Increasing temperature will cause a decrease in the value of the equilibrium constant

Equilibrium will move left in the endothermic direction

to reduce the temperature