What does the law of conservation of mass state?

The law of conservation of mass is a fundamental principle in chemistry that states that the total mass of substances involved in a chemical reaction remains constant, regardless of the processes that occur during the reaction. This means that mass cannot be created or destroyed; it can only be transformed from one form to another. During a chemical reaction, the atoms that make up the reactants are rearranged to form the products, but the total number of atoms and their mass before and after the reaction remains unchanged.

This principle is critical for understanding chemical equations, as it allows us to balance reactions accurately. For example, if a reaction starts with a specific mass of reactants, the products formed must also have that same total mass, reinforcing that no mass has been lost or gained during the reaction.

In contrast, the other options present concepts that contradict this law. The idea that mass can be created during a chemical reaction does not align with the conservation principle, as does the notion that mass can be destroyed in a closed system. Additionally, while it is true that mass may change forms in physical changes (such as evaporation), the law of conservation specifically addresses mass in the context of chemical reactions, reinforcing that it remains conserved throughout the process.