1. The problem statement, all variables and given/known data Hvap = 22.6E5 J/Kg. R=8.315E3 Jkmol^-1K^-1. 1kmol water = 18kg Keeping in mind that latent heats are enthalpies, what is the change in internal energy when 1kg water is converted to steam at pressure of 1atm and temperature of 100C. 2. Relevant equations dU = dQ - PdV. 3. The attempt at a solution dQ = mHvap PdV = 1atm (Vfinal - Vinitial) Vfinal >>Vinitial -> PdV = 1atm(Vfinal). Assume ideal gas-> V = nRT/P =18kilomoles * R*373 / 1atm?