The heat of sublimation for a substance is the amount of energy required to convert one mole of the substance from its solid state to its gaseous state at standard-state conditions without passing through the liquid state.In this case, we are given that it requires 25.2 kJ of energy to sublime 1 mole of dry ice solid carbon dioxide at its standard-state conditions. Therefore, the heat of sublimation for dry ice is 25.2 kJ/mol.