According to the Law of Conservation of Mass, which of the following best explains why the mass of a closed system remains unchanged during a chemical reaction?

• A. New atoms are formed from nothing, increasing the mass.
• B. Energy is converted into mass, causing the total mass to increase.
• C. Atoms are neither created nor destroyed; they are simply rearranged into new substances.
• D. Some atoms disappear during the reaction, reducing the total mass.

Answer: (C)

Verified step by step guidance

1. Recall the Law of Conservation of Mass, which states that in a closed system, mass is neither created nor destroyed during a chemical reaction.
2. Understand that atoms are the fundamental units of matter and that chemical reactions involve breaking and forming bonds between atoms, but do not create or destroy atoms themselves.
3. Recognize that because the number and type of atoms remain constant, the total mass of the system remains unchanged even though the atoms may be rearranged into different molecules or compounds.
4. Eliminate options that suggest atoms are created from nothing or disappear, as these contradict the conservation principle.
5. Conclude that the best explanation is that atoms are neither created nor destroyed; they are simply rearranged into new substances, which maintains the total mass in a closed system.