What does the Law of Conservation of Mass state?

• A. Mass can be created in a chemical reaction
• B. Mass changes in physical states
• C. Mass remains constant during chemical reactions
• D. Mass can be destroyed

Answer: (C)

The Law of Conservation of Mass states that mass remains constant during chemical reactions. This principle was first articulated by Antoine Lavoisier in the late 18th century, asserting that in a closed system, the total mass of reactants must equal the total mass of products. In other words, when substances undergo a chemical change, no atoms are created or destroyed; they are simply rearranged.

This law is fundamental in chemistry because it underpins the calculation of reactants and products in various reactions and helps chemists balance chemical equations. Understanding that the mass stays the same allows scientists to predict how much of each substance will be involved in reactions, which is critical for both theoretical studies and practical applications in laboratory settings, manufacturing, and environmental science.