What does the principle of conservation of mass state regarding chemical reactions?

• A. Mass can be created or destroyed
• B. Mass is transformed into energy
• C. Mass is neither created nor destroyed
• D. Mass decreases in closed systems

Answer: (C)

The principle of conservation of mass asserts that in a closed system, the total mass of reactants must equal the total mass of products in a chemical reaction. This means that during a chemical reaction, atoms are rearranged to form new substances, but the overall quantity of matter remains constant.

In practical terms, if you start with a specific amount of reactants, you will end up with an equivalent amount of products, although the matter may exist in different forms. This fundamental concept is crucial for understanding stoichiometry in chemical reactions and forms the basis for many chemical calculations.

The other options do not align with this principle. Claiming that mass can be created or destroyed contradicts the conservation principle, as it implies that the amount of matter can change during reactions. The idea that mass is transformed into energy is a reference to Einstein's equation E=mc², which suggests matter can convert into energy, but it doesn't apply to typical chemical reactions where mass remains constant. Lastly, the notion that mass decreases in closed systems is inconsistent with the conservation of mass, as it implies loss of matter, which doesn't occur in a properly closed system through a reaction.