The heat of vaporization for ethanol is 0.826 kJ/g. Calculate the heat energy in joules required to boil 76.55 g of ethanol. heat energy: J rThe heat of vaporization of water is 40.66 kJ/mol. How much heat is absorbed when 1.89 g of water boils at atmospheric pressure? heat: kJ rHow many grams of benzene, C6H6, can be melted with 77.6 kJ of heat energy? The molar heat of fusion of benzene is 9.95 kJ/mol. bun rA certain substance has a heat of vaporization of 41.05 kJ/mol. At what Kelvin temperature will the vapor pressure be 3.50 times higher than it was at 339 K? T = K