I've looked at this problem for the last few days you've posted it and I still don't like any of the answers. A isn't right and I knew B wasn't right which makes the choice between C and D. I don't like either of those answers and here is why.
If you look at the equation, you would guess that delta S is positive for the reaction as shown. Plug this into delta G for dG = dH - TdS
If dH is - and dS is +, then dG MUST be - at all temperatures so it CAN'T (at least in my opinion) depend on T. I would pick D EXCEPT I don't think T has anything to do with it. I think it's an open and shut case for the reaction to be spontaneous. The only way C can be correct is for delta S to be negative in which case it certainly would depend on T. However, I looked up the S values and calculated delta S for the reaction and it is indeed positive as we would guess. So I think the only choice is D and I don't like that because it does NOT, in my opinion, depend on T. I think it is spontaneous at any T. I would be interested in knowing exactly how this question is answered correctly. Technically I don't think the correct answer is listed.
The ?H of the reaction below is -575.13 kJ. Is this reaction spontaneous?
2ZnS + 3O2 + C ? 2SO2 + 2Zn + CO2
A. It is not because the ?H of the reaction is negative.
C. It depends on the temperature because the ?H of the reaction is negative and the ?S is negative.
D. It depends on the temperature because the ?H of the reaction is negative and the ?S is positive.
I guessed b which was wrong. You to tell me the correct answer.
2 answers
The correct answer is C.
1 answer