Final answer:
Matter is neither created nor destroyed during a chemical reaction, following the Law of Conservation of Mass. The mass of the products always equals the mass of the reactants, with a mere rearrangement of atoms occurring.
Step-by-step explanation:
During a chemical reaction, matter cannot be destroyed or created. This concept is known as the Law of Conservation of Mass, which states that in a chemical reaction, the mass of the products equals the mass of the reactants. Matter and mass may change forms into other substances like liquids, gases, and solids, but the total amount remains constant. Reactants, which are elements or compounds that enter into a chemical reaction, interact to form new substances called products. However, the rearrangement of atoms that occurs does not affect the actual mass of the atoms involved.
The arrangement of particles might change, as well as the energy within the system, but the principle that matter is conserved remains valid. For example, when hydrogen peroxide (H₂O2) decomposes, it breaks down into water (H₂O) and oxygen (O2), changing the structure but not the mass of the particles involved. Each molecule of hydrogen peroxide yields two molecules of water and one molecule of oxygen, but the total mass and number of atoms remain the same before and after the reaction.