Mech 3. From a thermodynamic point of view, the step represented by i) reaches the final state through an exothermic process that releases about 100 to 117 kJ/mol (see Table ), although the decreasing entropy change leads to a much less favorable product at higher temperatures, for instance ΔrG= -33 kJ/mol at T= 535 °C. The resulting Keq is then expected to decrease significantly from about 10 +13 to 10 +2 at T= 25 and 535 °C, respectively.