1. The problem statement, all variables and given/known data Background info: Evaporation of NH3(l) at its boiling point of -33.4degrees celcius and at a pressure of 100kPa requires heat absorption of 23.3x10^3 J mol-1. Question: NH3(g) is condensed at its boiling point at a pressure that is infinitesimally greater than 100kPa. Calculate.. a) w per mole (J mol-1) b) q per mole (J mol-1) c) change in molar internal energy U (J mol -1) d) change in molar enthalpy H (J mol-1) Thanks for your help. 2. Relevant equations ΔU = q + w ΔU = q - pextΔV ΔH = ΔU +p ΔV ΔH = ΔU + ΔngasRT PV=nRT Um(T)=3/2RT 3. The attempt at a solution P is also constant? because it's a condensation process? (a) irreversible work? (b) I would know when I figure out what w is.. (reverse) (c) zero because T stayed the same (d) isn't this already given in the question? (23.3 x 103)?