According to the law of conservation of mass, matter:

• A. can be converted entirely into energy during a chemical reaction
• B. can disappear if the reaction is exothermic
• C. cannot be created or destroyed in a chemical reaction
• D. is always lost as heat in every chemical reaction

Answer: (C)

Verified step by step guidance

1. Understand the law of conservation of mass: it states that in a chemical reaction, matter cannot be created or destroyed; it only changes forms.
2. Recognize that this law implies the total mass of reactants equals the total mass of products in a chemical reaction.
3. Evaluate the given options by comparing them to the law: matter cannot be converted entirely into energy in a chemical reaction, nor can it disappear, even if the reaction releases heat (exothermic).
4. Note that energy changes (like heat release) do not affect the total mass of matter involved in the reaction.
5. Conclude that the correct interpretation is that matter cannot be created or destroyed in a chemical reaction, consistent with the law of conservation of mass.