Question

Calculate the internal energy at 298 K for the formation of one mole of ammonia, if the enthalpy change at constant pressure is – 42.0 kJ mol^–1. (Given : R = 8.314 J K^–1 mol^–1)

Answer 1

Formation of 1 mole of ammonia.

1/2 N₂ (g) + 3/2 H₂ (g) → 2NH₃ (g)

Δn = Number of moles of gaseous product – number of moles of gaseous reactant