# Homework Help: Coexistance Curve

1. Apr 9, 2010

### subtletuna

1. The problem statement, all variables and given/known data
Consider the liquid-gas coexistence curve. Show that C$$_{(g)}$$ − C$$_{(l)}$$ = T($$\stackrel{d}{dT}$$ $$\Delta$$$$_{(vap)}$$S) for T, P along the coexistence curve. Now use the fact that
$$\Delta$$(vap)S = $$\Delta$$(vap)H/T along the coexistence curve, and the fact that $$\Delta$$(vap)H is positive and decreases with increasing T, to show that C(g) < C(l) . Note that this inequality applies only at Tvap.

2. Relevant equations

3. The attempt at a solution

2. Apr 10, 2010

### Gokul43201

Staff Emeritus
Please show us what you have tried. We can not help you unless you first put in some effort.