Need help understanding entropy please..studying for a final.. Can someone help me understand how come C(s)+O2 (g)--CO2(g) in not favored by entropy but 2CO2(s)+O2(g)--2CO(g) is.

Question

Need help understanding entropy please..studying for a final.. Can someone help me understand how come C(s)+O2 (g)-->CO2(g) in not favored by entropy but 2CO2(s)+O2(g)-->2CO(g) is.

aaronq · Answer

in the first reaction there is not $net$ gain because you're not increasing the amount of gas molecules, in contrast in the second, there are 2 gas molecules on the right side. SO you're taking one gas molecule (and a solid) and making 2 gas molecules.

anonymous · Answer

Ohhh!! That makes much more sense when you put it that way. We were taught to look at the moles and the state but I never understood the correlation. Thank you so much!