Thermochemistry question...?

Question

The heat of vaporization for 1.0 mol of water at 100 degreesC and 1.0atm is 40.6 kJ/mol. Calculate delta S for the process H2O(l) --> H2O(g) at 100 degrees C.

Answer 1

OK...You can start with the equation of DG (I'm using D instead of writing "delta").

DG = DH -TDS You've seen that equation, right? OK..Since the boiling point of water is 100 degreed C at 1 atm pressure, we are really talking about an equilibrium situation. So, DG= 0.

Consequently, DH = TDS.

Since you know DH and you know T (in Kelvin), you can calculate DS. Make sure that you convert DH into Joules (instead of kilojoules) before you finish the problem.