What happens to the mass during a chemical reaction?

During a chemical reaction, the principle of conservation of mass states that the total mass of the reactants (the substances that undergo the reaction) must equal the total mass of the products (the substances formed as a result of the reaction). This means that no matter how the atoms are rearranged or how new substances are formed, the overall quantity of matter remains constant. As a result, the total mass before the reaction occurs is the same as the total mass after the reaction has taken place. This fundamental concept is a cornerstone of chemistry, illustrating that matter cannot be created or destroyed during a chemical reaction, only transformed.

Understanding this principle helps clarify why other options do not accurately reflect the behavior of mass in chemical reactions. For instance, suggesting that mass is lost or increased contradicts established scientific principles, as does the idea that mass varies based on specific reactants, since the conservation of mass applies universally across all chemical reactions.