Q48P - Chemistry: Molecular Nature Of Matter And Change

Question

How does a balanced chemical equation apply the law of conservation of mass?

Step-by-Step Solution

Answer

In a balanced equation, the same number of atoms are present on both sides of the arrow, therefore, the mass on the both sides of the arrow are same. Hence, the law of conservation of mass applied on the balanced chemical equation.

Step 1: Considering the following chemical equation

${\mathbf{CH}}_{\mathbf{4}}\mathbf{+}\mathbf{2}{\mathbf{O}}^{\mathbf{2}}\mathbf{\to }{\mathbf{CO}}_{\mathbf{2}}\mathbf{+}\mathbf{2}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}$

Considering this balanced chemical equation for the combustion of methane.

Step 2: Relation between chemical equation and law of conservation of mass

All the balanced chemical equation tells that there must have the same number of each atom on both sides of the arrow.

In the above chemical equation, there are 1C atom, 4 H atoms, and 4 O atoms on both sides of the arrow.

The number of atoms will not change, therefore the total mass of all the atoms will be the same before and after the reaction. This states that the overall mass of the reaction is conserved. Hence, the law of conservation of mass applied to the balanced chemical equation