Which statement best explains why the law of conservation of mass is more relevant to chemical changes than to physical changes?

• A. Chemical changes involve the rearrangement of atoms to form new substances, but the total mass of reactants and products remains constant.
• B. During chemical changes, mass is created or destroyed as new compounds form.
• C. Physical changes always result in a loss of mass because substances are separated.
• D. Physical changes involve the formation of new substances, so mass conservation does not apply.

Answer: (A)

Verified step by step guidance

1. Understand the law of conservation of mass: it states that mass cannot be created or destroyed in a closed system during any process.
2. Recognize that chemical changes involve the rearrangement of atoms to form new substances, but the total number of atoms—and thus the total mass—remains constant.
3. Note that physical changes involve changes in the state or appearance of a substance without altering its chemical identity, so the mass remains the same before and after the change.
4. Evaluate the given statements by comparing them to the law of conservation of mass and the nature of chemical and physical changes.
5. Conclude that the statement explaining chemical changes as rearrangements of atoms with constant total mass best aligns with the law of conservation of mass.