According to the Law of Conservation of Mass, why does the mass of a substance remain the same after a chemical reaction?

• A. Because chemical reactions only involve changes in physical state, not mass.
• B. Because energy is converted into mass during the reaction.
• C. Because atoms are neither created nor destroyed during a chemical reaction.
• D. Because the products always have less mass than the reactants.

Answer: (C)

Verified step by step guidance

1. Understand the Law of Conservation of Mass, which states that in a chemical reaction, matter is neither created nor destroyed.
2. Recognize that chemical reactions involve rearrangement of atoms to form new substances, but the total number of atoms remains constant.
3. Since atoms are the fundamental units of matter, and their number does not change, the total mass of the system remains the same before and after the reaction.
4. Note that changes in physical state (like solid to liquid) do not affect the mass, but chemical reactions involve breaking and forming bonds without loss or gain of atoms.
5. Therefore, the mass of the substances involved in a chemical reaction remains constant because atoms are conserved throughout the process.