Chapter 7, Problem 7.20CP

Interpretation Introduction

Interpretation: The condition for the total pressure in a mixture of gases to be equal to the sum of the partial pressure for real gases needs to be determined.

Concept Introduction: The ideal gas equation is the equation which gives the relations between P, V, n and T of gases. It can be written as:

  $\text{P}\times \text{V = n}\times \text{R}\times \text{T}$

Usually gases do not follow ideal behavior under all conditions of pressure, temperature and volumes. The relation of P, V, n and T of real gases can be given by Vander Waals equation:

  $\left(\text{P + }\frac{{\text{n}}^{\text{2}}\text{a}}{{\text{V}}^{\text{2}}}\right)\left(\text{V- n b}\right)\text{ = nRT}$

Hence $\text{P = }\frac{\text{nRT}}{\text{ V-nb}}\text{ - }\frac{{\text{n}}^{\text{2}}\text{a}}{{\text{V}}^{\text{2}}}$