Chapter 12.2, Problem 21LC

Interpretation Introduction

Interpretation: The use of mole ratios in chemical calculations needs to be explained.

Concept introduction: A mole ratio can be defined as the ratio between the amounts in moles of any two substances involved in a balanced chemical equation.

Answer to Problem 21LC

Mole ratios are used in chemical calculations to convert moles of reactant or product to different moles of reactant or product.

Explanation of Solution

Consider a balanced chemical equation:

  ${\text{2H}}_{\text{2}}{\text{+O}}_{\text{2}}\to {\text{2H}}_{\text{2}}\text{O}$

In this reaction, two moles of hydrogen react with one mole of oxygen to give two moles of water.

A mole ratio conversion for the balanced chemical equation can be written as:

  $\frac{1{\text{ mole of H}}_2}{\frac{1}{2}{\text{ mole of O}}_2}\frac{1{\text{ mole of O}}_2}{2{\text{ mole of H}}_2}\frac{1{\text{ mole of H}}_2\text{O}}{1{\text{ mole of H}}_2}$

So, this is how mole ratio conversion can be done in calculations.