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### Delta G at Boiling Point

Posted: Sun Mar 11, 2018 10:35 am
why is gibbs free energy zero at 100 boiling point (number 9.91)

### Re: Delta G at Boiling Point

Posted: Sun Mar 11, 2018 11:13 am
At boiling point, the change in temperature is zero so change in enthalpy is also zero (infer that pressure is constant so W=0). Since change in enthalpy is zero, we also want change in entropy to be zero. This happens when W=0.

### Re: Delta G at Boiling Point

Posted: Sun Mar 11, 2018 1:40 pm
At boiling point, temperature and pressure are constant. Therefore, the change in enthalpy would be zero.

### Re: Delta G at Boiling Point

Posted: Fri Mar 16, 2018 12:44 am
If you remember the graph of phase transitions, as a phase transition is about to occur, energy is still supplied to the system but temperature doesn't change immediately. Thus, at the point of a phase transition, such as the boiling point, there is no change in temperature. As delta G is a factor of change in temperature, delta G = 0 at the boiling point.