Sulfur trioxide is formed by the catalytic oxidation of sulfur dioxide:

Question

2SO2(g)+O2(g)→2SO3(g)
If ΔH∘= -197.8kJ/mol and ΔS∘= -188.0J/K , what is ΔStotal for this reaction?
Is the reaction spontaneous under standard-state conditions at 25 ∘C?

Answer 1

dH surroundings = -dH/T
dStotal = dH surroundings + dH system (in the problem)

Answer 2

Awesome thank you!
How would I determine when the reaction goes nonspontaneous?

Answer 3

If dStotal is +, the reaction is spontaneous.