[KellyLittle]

I have the reaction K(s) + O2 (g) --> KO2 (s) and I need to find ΔS°.

Here is my given information:
S°(KO2) = 122.5 J/K*mol
S° (O2) = 205.0 J/K*mol
S° (K) = 64.67 J/K*mol
ΔH° fusion (KO2) = -284.5 kJ/mol
ΔH° fusion (O2) = 0 kJ/mol
ΔH° fusion (K) = 0 kJ/mol

Here are my calculations:
ΔS° of the system = (122.5 J/K*mol) - (64.67 J/K*mol + 205.0 J/K*mol) = -147.17 J/K*mol
ΔH° = (-284.5 kJ/mol) - (0 + 0) = -284.5 kJ/mol = -284500 J/mol
ΔS° of the surroundings = -ΔH°/T = -(-284500 J/mol)/298K = 954.70 J/K*mol
ΔS° = ΔS° of the surroundings + ΔS° of the system = 954.70 J/K*mol + -147.17 J/K*mol = 807.52 J/K*mol

But this is the wrong answer.  I feel like I did all of my calculations right and I double checked the math.  What am I missing?