What does the Law of Conservation of Mass state? (1 point)
A. Matter cannot be rearranged during a chemical reaction.
B. The total mass of all of the reactants prior to a chemical reaction must equal the total mass of all the products after the reaction.
C. Matter is neither created or destroyed in a chemical reaction, only rearranged.
D. The total mass of reactants prior to a chemical reaction is greater than the mass of the product due to the release of energy
The Correct Answer and Explanation is:
The correct answer is B. The total mass of all of the reactants prior to a chemical reaction must equal the total mass of all the products after the reaction.
Explanation:
The Law of Conservation of Mass, formulated by Antoine Lavoisier in the late 18th century, is one of the foundational principles of chemistry. This law states that mass cannot be created or destroyed in a chemical reaction; it can only be rearranged. Therefore, the mass of the reactants in a chemical reaction is always equal to the mass of the products, provided that the system is closed and no mass enters or leaves the reaction environment. This principle holds true for all chemical reactions, whether they involve simple combinations or complex transformations.
Let’s break down the answer choices:
- A. Matter cannot be rearranged during a chemical reaction: This is incorrect. In fact, during a chemical reaction, atoms are rearranged to form new substances. What the law actually says is that the total amount of mass remains the same before and after the reaction, even though the arrangement of atoms may change.
- B. The total mass of all of the reactants prior to a chemical reaction must equal the total mass of all the products after the reaction: This is the correct interpretation of the Law of Conservation of Mass. It emphasizes that while atoms may be rearranged, no atoms are lost or gained in the process. For example, in a combustion reaction, the mass of the fuel and oxygen before burning equals the mass of the resulting carbon dioxide and water vapor produced.
- C. Matter is neither created nor destroyed in a chemical reaction, only rearranged: While this statement is true and closely related to the law, it is not as precise in context as option B, which directly addresses the balance of mass before and after the reaction.
- D. The total mass of reactants prior to a chemical reaction is greater than the mass of the product due to the release of energy: This is incorrect. The release of energy (in the form of heat, light, or sound) during a chemical reaction does not affect the mass of the system. Energy and mass are related (via Einstein’s equation, (E = mc^2)), but in chemical reactions at the scale of ordinary conditions, the energy released is negligible compared to the mass involved.
In conclusion, the Law of Conservation of Mass tells us that in any chemical reaction, the mass of the reactants is always equal to the mass of the products, reinforcing that mass is conserved throughout the reaction process.