Chapter 3, Problem 129AP

Interpretation Introduction

Interpretation:

The molar mass of air is to be calculated with given percent of nitrogen, oxygen, and argon.

Concept introduction:

Stoichiometry involves the calculation of number of atoms of reactants and products in a balanced chemical equation.

Number of moles of a compound is the ratio of given mass and the molar mass.

$\text{Number}\text{of}\text{moles =}\frac{\text{Given mass}}{\text{Atomic mass}}$

Mass of compound can be calculated as

$\text{mass}\text{=}\frac{\text{given}\text{percent}}{\text{100}}\text{×}\text{molecular}\text{mass}$

$\text{molar mass of air =}\text{mass of nitrogen +}\text{mass of oxygen}\text{+}\text{mass of argon}$