Chapter 11, Problem 11.102CP

Interpretation Introduction

Interpretation:

The normal boiling point of ${\text{CCl}}_{\text{2}}{\text{F}}_{\text{2}}$in ⁰C should be determined.

Concept introduction:

The vaporization curves of major liquids have same shapes. The vapor pressure consistently increments as the temperature increments. A better method is to discover the mathematical approach for the increment in pressure as a function of temperature. experiments appeared that the temperature T and vapor pressure P are connected,


${\text{P α e}}^{{\text{-ΔH}}_{\text{vap}}\text{/RT}}$

Here,

  $\Delta {\text{H}}_{\text{vap}}$ = Enthalpy
   R = constant

So, if we assume that, P₁ as well as P₂are the vapor pressures at two temperatures T₁ and T₂, then we can find a below simple connection

  $\text{ln}\left(\frac{{\text{P}}_1}{{\text{P}}_2}\right)\text{ = }\frac{\Delta {\text{H}}_{\text{vap}}}{\text{R}}\left(\frac{1}{{\text{T}}_2}\text{ -}\frac{1}{{\text{T}}_1}\right)$

This is recognized as the Clausius-Clapeyron Equation and permits us to assess the vapor pressure at a different temperature, if the vapor pressure is identified at certain temperature, and if an enthalpy of vaporization is identified.