Can any one tell me the the difference between the two?
I was doing this problem:
2H2(g) + O2(g) -> 2H2O
What is the standard Gibbs free energy of formation of water vapor at 25oC, if for the reaction shown below, deltaH = -484 kJ/mol and deltaS = -89 J/mol K?
Now I did the calculation as: deltaG = (-484000)-([273+25]*-89] = -457 kJ/mol
But the answer came to be: -457/2 = -229kJ/mol
My Questions are:
A) Why do you divide by 2? Isn't Gibbs free energy an extensive property?
B) If the question had said "What is the standard free energy.." then the answer would be -457kJ/mol?