State whether the following reactions are spontaneous or non spontaneous at low temperature, high temperature or all temperatures?
a) PCl3 (g) + Cl2(g)---PCl5(g) delta H = -87.9 KJ
b) CO2 (g) + H2 (g)-----CO (g) + H2O (g) delta H = +41.2KJ
c) NH4CO2NH2 (s)-----2NH3 (g) +CO2 (g) delta H = +159.2 KJ