How to do? Especially part b. Which equation should be used, U=QW L_vapU=QW OR U=Lvap? Because different answers will be calculated. Would you explain on that. Thank you

(a) The bubble point of water at one atmosphere is 100C. The enthalpy of evaporation at that condition is 2257kJ/kg. What is the entropy change of evaporation of one kilogram of water at 1atm and 100C. (b) Please estimate the internal energy change of evaporation of one kilogram of water at 1 atm and 100C. (c) The freezing point of water at one atmosphere is 0C. As we all know, freezing of water is an exothermic reaction at that condition. Does the entropy of water increase or decrease for the frozen process? Why? (d) A cup of water in the refrigerator is not frozen until -5 C due to the undercooling effect. Is the frozen process a reversible process (at 5C and 1atm )? Is it a spontaneous process