The heat of sublimation is the amount of energy required to convert a substance from its solid phase directly to its gas phase without passing through the liquid phase. In the case of dry ice solid carbon dioxide , we can calculate the heat of sublimation by adding the enthalpy of fusion and the enthalpy of vaporization.Heat of Sublimation = Enthalpy of Fusion + Enthalpy of VaporizationGiven:Enthalpy of Fusion = 9.2 kJ/molEnthalpy of Vaporization = 25.1 kJ/molHeat of Sublimation = 9.2 kJ/mol + 25.1 kJ/mol = 34.3 kJ/molTherefore, the heat of sublimation for dry ice is 34.3 kJ/mol.