What is the law of conservation of mass?

The law of conservation of mass states that mass cannot be created or destroyed in a chemical reaction. This fundamental principle dictates that the total mass of reactants must equal the total mass of products in a closed system. It emphasizes that during any chemical change, the atoms involved are merely rearranged to form new substances while the total mass remains constant.

This concept is critical because it forms the basis for stoichiometry and other calculations in chemistry, allowing scientists to predict the outcomes of reactions accurately. It underpins various chemical principles and experiments, confirming that the number of atoms before and after a reaction remains the same, thus reflecting the conservation of mass.

The other answer choices suggest inaccuracies regarding the nature of mass in chemical reactions, which is why they do not hold true in the context of the law of conservation of mass.