Question

Predict the sign of ΔG for an endothermic reaction with an increase in entropy.

Answer 1

The Gibbs free energy of the system is a state function because it is defined in terms of thermodynamic properties that are state functions. The change in the Gibbs free energy of the system that occurs during a reaction is therefore equal to the change in the enthalpy of the system minus the change in the product of the temperature times the entropy of the system.

G = H - (TS)

If the reaction is run at a constant temperature, this equation can be written as follows.

G = H - TS ......(1)

for exothermic reaction H = -ve for exothermic reaction and S is +ve for an increase in entropy

so sign of G is -ve according to equation (1)