• # question_answer 76)   If the combustion of 1 g of graphite produces 20.7 kJ of heat, what will be the molar enthalpy change? Give the significance of sign also.

Heat of combustion $\Delta H$ = - Heat released by 1 mole or 12 g of carbon $=-20.7\times 12$ $=-248.4kJ\,mo{{l}^{-1}}$