Exercise 4 | Chemical Thermodynamics

Calculate ΔG0rxn for the following reaction at 25°C:

SBr4 (g) → S (g) + 2 Br2 (l)

Is the reaction spontaneous?


Data: ΔH0rxn = 115.0 kJ

ΔS0rxn = 125.0 J.K-1

ΔG0rxn = ΔH0rxn - T ΔS0rxn and 25°C = 298K

ΔG0rxn = 115.0 x 103 – 298 x 125.0

ΔG0rxn = 77.75 kJ


ΔG0rxn > 0: the reaction is not spontaneous.

Input of energy from an external source is necessary to form additional products.