How much heat (in J) is required to convert 30.0g of dry ice (CO2(s)) at -80C to gas at -78C? At 1 atm, solid dry ice undergoes a phase transition directly to gas. This sublimation point of dry ice is at -78C, and the enthalpy of publimation of dry ice is 0.57J/g. The heat capacity of dry ice is 7.9 J/(g K). less than 250 between 250 and 400 J between 400 and 500 J more than 500