Alright, This is a followup to my previous post: thanks for the advice on the two questions. I got the HH one. That was quite easy. However, I'm not getting this one correctly: N2O4 --> 2NO2 Delta G is 2.8kJ (under standard conditions). At what temp will it become spontaneous? So. I know Gibb's is: Delta G = Delta H - T(delta S) The delta H for N2O4 is 9.66 and NO2 is 33.85 The delta S for N2O4 is 304.3 and NO2 is 240.46 This is per my book I plug those into the Delta H and Delta S equations: 2(33.85) - 9.66 = 58 2(240.46) - 304.3 = 176.9 T = Delta H / Delta S This comes out to 0.328 K That can't be right! What did I do wrong?