# Homework Help: Clausius-Clapeyron equation and water

1. Jul 13, 2012

### genericusrnme

1. The problem statement, all variables and given/known data

Using the Clausius-Clapeyron equation, determine the slope of dp/dT for water-ice I equilibrium and explain why you can skate on ice but not on solid argon.

2. Relevant equations

Clausius-Clapeyron equation

3. The attempt at a solution

I know what the clausius-clapeyron equation is but I have no idea how I'm supposed to determine the slope for water - there is no information in the book so far on water so I really have no idea how I could write the change in entropy and volume as functions of temperature..

I'm completely at a loss here (and most likely overlooking something simple)

(I wasn't sure if this should be in introductory or advanced physics, the textbook I'm using doesn't really mention what level it's geared at)

2. Jul 13, 2012

### TSny

Consider the melting of 1 gram of H2O.

Note ΔS= Q/T where Q is the heat required to melt 1 gram of ice (79.7 cal = 333 J) and T is the temperature corresponding to equilibrium between ice and water.

ΔV = Vf-Vi where Vi is the volume of 1 gram of ice and Vf is the volume of 1 gram of water. You can calculate these volumes from the known densities of ice and water at the melting point temperature (ice: 0.917 g/cm3, water: 1.000 g/cm3).