Which fundamental principle states that if matter is not being created or destroyed during a chemical reaction, the total mass of the reactants must equal the total mass of the products?

• A. Law of Multiple Proportions
• B. Dalton's Atomic Theory
• C. Law of Conservation of Mass
• D. Law of Definite Proportions

Answer: (C)

Verified step by step guidance

1. Understand that the question is asking about a fundamental principle related to mass during chemical reactions.
2. Recall that the Law of Conservation of Mass states that matter cannot be created or destroyed in a chemical reaction, so the total mass of reactants equals the total mass of products.
3. Differentiate this from other laws: the Law of Multiple Proportions deals with ratios of elements in compounds, Dalton's Atomic Theory explains atomic structure and behavior, and the Law of Definite Proportions states that a compound always contains the same elements in the same proportion by mass.
4. Identify that the principle describing the equality of mass before and after a chemical reaction is the Law of Conservation of Mass.
5. Conclude that the correct answer to the question is the Law of Conservation of Mass.