Chapter 6, Problem 1QC

Interpretation Introduction

Interpretation:

The role of coefficients in a balanced equation is to be determined.

Concept Introduction:

Balanced chemical reactions are reactions having equal number of atoms of each element before and after the chemical reaction. Coefficients are the numerical values added before the formula.

Explanation of Solution

The numerical coefficients in a chemical equation show the ratio of the molecules of each of the substances that are involved in the chemical reaction (both reactants and products).

For example, when hydrogen burns in oxygen, the equation for the reaction is,

$2{\text{H}}_2+{\text{O}}_2\to 2{\text{H}}_2\text{O}$

This shows that two molecules of hydrogen $\left({\text{H}}_2\right)$ will react with one molecule of oxygen $\left({\text{O}}_2\right)$ to give two molecules of water $\left({\text{H}}_2\text{O}\right)$ . In other words, the coefficients in the equation indicate the molar ratio of each substance in the reaction to every other substance.

This ratio is important when calculating the quantities of reactant(s) which will produce a certain quantity of product(s).

Without the coefficients in a chemical equation, one can only know that certain reactants will produce certain products, not the ratio in which they will react with each other.

Conclusion

The coefficients in a balanced chemical reaction represent the molar ratio of each substance in the reaction to every other substance.