Ok, so if you have 3.12 moles and the enthalpy change is 3.16 kJ PER mole, then the energy change needed for solid to liquid transformation is? It is a similar process for finding the energy needed to go from liquid to gas, but you'll be using a different enthalpy value obviously. Then you need to add these energy values onto your calculation of (100.0g)(0.424ca/gc)(337.2k-175.5k) but you will need to convert to the same units.