Question

Is the following reaction spontaneous at 25*C?
delta s reaction = -217 J/K*mol
delta H rxn = -1202 KJ

2Mg (s) + O2 (g) -> 2MgO (s)

delta suniverse = delta s system - delta H system / T

i got positive (+) 3.81 x 10 ^ 3 J/K

and my notes says it is spontaneous but i feel like it is non spontaneous

because when delta g is negative and delta h is < tdeltas it should be spontaneous & the opposite of that makes it non spon for an endothermic reaction....i hope this makes sense


my question is why is it spontaneous? thank you in advance

Answer 1

I'm having trouble making sense of it. If DS for the reaction = -217 J/K then why do you have it listed as -217 J/K*mol? So is DS rxn = -217 J or 2*-217 J?
Same kind of question for DH.

Answer 2

DS = -217 J/(K)mol
DH = -1202 KJ -> -1202 x 10^3 J

does this make any sense?