Question

What is the ∆G for the following reaction between O3 and O2? 3O2(g) 2O3(g) Given: O3: ∆H = 285.4 kJ ∆S = -137.14 J/K)

Answer 1

We’ll be using the equation:
dG = dH - TdS (replace ‘d’ with triangle)

I’m going to assume 0 degrees Celsius.
At 0 C (273 K):

dG = dH - TdS
dG = (285,400 J) - (273 K)(-137.14 J/K)
dG = 285,400 J + 37,439.2 J
dG = 322,839.2 J or 322.84 kJ

The dG of this reaction is +322.84 kJ. This reaction is not considered spontaneous.

This answer, in this instance, would be D. If the temperature used in the question is not 0 degrees C, replace the temperature that I used for calculation with the Kelvin temperature given in the problem (K = C + 273), and simplify to find the answer.