Chapter 8, Problem 8.37NP

Interpretation Introduction

Interpretation:

The temperature and pressure at the triple point needs to be calculated based on the given thermodynamic equations depicting the variation in the vapor pressure of the solid and liquid phases at the triple point.

Concept Introduction:

The relationship between pressure (P), temperature (T) and the enthalpy change (ΔH) associated with a phase transition reaction is given via the Clausius-Clapeyron equation:

  $\text{lnP = }\frac{-\text{ΔH}}{\text{R}}\left(\frac{\text{1}}{\text{T}}\right)\text{ + C -----(1)}$

Where R = 8.314 J/mol-K and C is a constant

Triple point is a thermodynamic space in which solid, liquid and gaseous phases of a substance coexist

At the triple point:

Vapor pressure of the solid = Vapor pressure of the liquid