Final answer:
In balancing a chemical equation, the coefficients are altered to achieve atom balance on both sides, without changing the substances' molecular formula. This practice adheres to the law of conservation of mass and accurately reflects the ratios of reactants and products in a reaction.
Step-by-step explanation:
In balancing a chemical equation, we change the coefficients of the reactants and products to make the number of atoms on each side of the equation balance. It's important to remember that only the coefficients can be altered to balance the equation, as changing the formula subscripts would change the identity of the substance. For example, the reactant formula H₂O should not be changed to H₂O2, as this would result in hydrogen peroxide instead of water. Instead, one would adjust the coefficient for H₂O to '2' if needed to balance the oxygen atoms. In essence, you are modifying the number of molecules represented in the equation, but not the molecular formula itself.
When counting the number of atoms of each element in the equation, ensure that they are equal on both sides to satisfy the law of conservation of mass. Balancing equations is crucial as it reflects that matter is neither created nor destroyed in a chemical reaction. For instance, if you have a reaction like C(s) + 2H₂(g) → CH₄(g), the '2' in front of H₂ indicates that there are a total of four atoms of hydrogen as reactants, achieving balance with the product side.