Final answer:
In a balanced chemical equation, it is necessary for the number of atoms of each element to be equal on both sides, reflecting the law of conservation of matter. Coefficients are used to balance the equation, and the chemical formulas of substances cannot be altered in this process.
Step-by-step explanation:
In the context of a balanced chemical equation, it is essential that there is the same number of atoms of each individual element in the reactants and the products. This reflects the law of conservation of matter, stating that matter cannot be created or destroyed in a chemical reaction. Hence, the sum of the individual atoms of all elements must be equal on both sides of the reaction.
To achieve a balanced equation, one must insert coefficients in front of the chemical formulas in the equation. These coefficients represent the relative amounts of molecules or formula units necessary to balance the number of atoms. The coefficients should be in the simplest whole number ratios. For example, H₂(g) + O₂(g) → 2 H₂O(l) illustrates a balanced equation with four hydrogen atoms and two oxygen atoms on each side.
An important point to remember is that while balancing, the chemical formulas of the individual substances cannot be altered because they represent fixed combinations of atoms. If an element appears multiple times on one side of a chemical equation, the total number of atoms for that element is the sum of all those instances, taking into account the appropriate coefficients and subscripts within the chemical formulas.