A balanced chemical equation represents a chemical reaction where the number of atoms for each element is the same on both the reactant and product sides. This ensures the law of conservation of mass is upheld. For example, the balanced equation for the combustion of methane is:
CH4+2O2→CO2+2H2O\text{CH}_4 + 2\text{O}_2 \rightarrow \text{CO}_2 + 2\text{H}_2\text{O}
Here, one molecule of methane (CH4\text{CH}_4) reacts with two molecules of oxygen (O2\text{O}_2) to produce one molecule of carbon dioxide (CO2\text{CO}_2) and two molecules of water (H2O\text{H}_2\text{O}). Each side of the equation has one carbon atom, four hydrogen atoms, and four oxygen atoms, illustrating a balanced equation.
