Chapter 5, Problem 5.110PAE

Interpretation Introduction

Interpretation:

Average density of dry air should be identified.

Concept introduction:

Average density is the summation of all the gases divided by total numbre of gases available in it as follows:

$${\text{Average density = d}}_{\text{N2}}{\text{+ d}}_{\text{O2}}{\text{+ d}}_{\text{Ar}}{\text{+ d}}_{\text{CO2}}\text{/4}$$

From ideal gas equation

$$\text{PV = }\left(\text{m /M}\right)\text{ RT}$$

Density can be written as:

$$\text{d = m /V}$$

Hence,

$$\text{m /V = d = PM /RT}$$

Given:

Mole % N₂ = 31.929 %

Mole % O₂ = 8.567 %

Mole % Ar = 0.382 %

Mole % CO₂ = 0.013 %

Mole % other = 0.002 %