Answer to Question #175158 in General Chemistry for Johnson Precious Mayokun

Question

Nitrogen gas reacts with hydrogen gas to form ammonia gas. Given that the standard entropies of nitrogen, hydrogen and ammonia gases are 192, 131 and 193 JK-¹mol-¹ respectively, calculate the standard entropy change for the reaction

Answer 1

1/2 N2 + 3/2 H2 > NH3

∆ S ° = ∆S° (product) - ∆S° (Reactant)

∆S° = 192- (1/2 ×191.5 + 3/2 × 130.5)

∆S° = 192.6 - (95.75 + 195.75)

∆S° = 192.6 - 291.5 = -98.9 J/mol -k

Therefore ∆S° of the formation of Ammonia is -98.9 J/mol -k