The change in entropy, S, is related to the change in the number of moles of gas molecules, n_gas. Determine the change in the moles of gas for each of the reactions and decide if the entropy increases, decreases, or has little or no change.
A. The entropy, S, has little or no change.
B. The entropy, S, decreases.
Reaction A:
2Hg + O2 -> 2HO
n_gas = 1
Reaction B:
HO2 -> Hg + O2
n_gas = 1