Chemical reactions involve the breaking of chemical bonds in reactants and the formation of new chemical bonds in products. During these processes, atoms are neither created nor destroyed. They are simply rearranged into new combinations.
For example, consider the combustion of methane:
$$\text{CH}_4 + 2\text{O}_2 \rightarrow\text{CO}_2 + 2\text{H}_2\text{O}$$
In this reaction, one molecule of methane reacts with two molecules of oxygen to produce one molecule of carbon dioxide and two molecules of water. The number of carbon, hydrogen, and oxygen atoms is the same on both sides of the equation:
- Carbon: 1 atom on both sides
- Hydrogen: 4 atoms on both sides
- Oxygen: 2 atoms on both sides
The law of conservation of mass holds true for all chemical reactions. It is a fundamental principle that helps scientists to balance chemical equations and to track the flow of atoms through reactions.
