What was the free energy change?

The reaction represented by the equation C(s) + H2O(l) → CO(s) + H2(s) was carried out at 27°C if the enthalpy change was + 4500 J and the entropy change was + 12J, what was the free energy change? (∆G = ∆H – T∆S)

A. – 4176 J
B. +4176 J
C. – 900 J
D. + 900 J
E. +8100 J

Correct Answer:

Option D = + 900 J