Chapter 5, Problem 5.99PAE

Interpretation Introduction

Interpretation:

A mixture of CH₄(g) and C₃H₈(g) with a total pressure of 425 torr is prepared in a reaction vessel. Just enough O₂ (g) is added to allow complete combustion of the two hydrocarbons. The gas mixture is ignited, and the resulting mixture of CO₂(g) and H₂O(g) is cooled back to the original temperature. If the total pressure of the products is 2.38 atm, the mole fraction of the C₃H₈ in the original mixture should be calculated.

Concept introduction:

For a mixture of two gases, the sum of mole fraction is 1. Thus, if the value of mole fraction of 1st gas is x then, mole fraction of 2^nd gas will be 1-x.

Also, mole fraction is related to partial pressure and total pressure as follows:

${\text{P}}_{\text{A}}={\mathrm{X}}_A{P}_T$

Here, ${\text{P}}_{\text{A}}$ is partial pressure of gas A, ${\mathrm{X}}_A$ is mole fraction of gas A and $P_T$ is total pressure of the mixture of gas.