The equation CaCO3(s) Right arrow. CaO(s) CO2(g) shows the decomposition of calcium carbonate. Delta. H = 178. 3 kJ/mol, and Delta. S = 160. 5 J/(molmc019-4. JpgK). The free energy change for the reaction is 130. 5 kJ/mol. Which correctly states the temperature at which the reaction took place and whether the reaction is spontaneous or nonspontaneous? Use Delta. G = Delta. H – TDelta. S. 0. 30 K, spontaneous 1. 92 K, spontaneous 297. 8 K, nonspontaneous 1,924 K, nonspontaneous.