Question

I don't understand this one at all. Please help!

For the equation: MnO2 (s) + 2 CO (g) → Mn (s) + 2 CO2 (g)

1. Calculate ΔG° at 25°C

2. Calculate ΔG° at 125°C

Answer 1

#1.
dGo rxn = (n*dGo products) - (n*dGo reactants)

#2. Are you sure you don't mean dG rxn at 125 C. I was always under the impression that dGo is the standard at 25C. This T is not 25 C and I would call it dG rxn and not dGo rxn
For that calculate dHo rxn = (n*dHo products) - (n*dHo reactants).
Do the same with dSo rxn.
Then dG rxn = dHrxn - TdS reaction. Remember dH usually given in kJ and dS in J so convert one or the other.