The commercial production of water gas utilizes the reaction under standard conditions : C+H2O(g)→H2+CO . The heat required for this endothermic reaction may be supplied by adding a limited amount of air and burning some carbon to CO2 . How many g of carbon must be burnt to CO2 to provide enough heat for the water gas conversion of 100 g carbon? Neglect all heat losses to the environment. Also ΔHf∘ of CO, H2O(g) and CO2 are -110.53, -241.81 and -393.51 kJ/mol respectively.