According to the Law of Conservation of Mass, how do the atoms present before a chemical reaction compare to the atoms present after the reaction?

• A. The number and type of atoms remain unchanged; they are simply rearranged.
• B. Atoms change into energy, so fewer atoms exist after the reaction.
• C. New atoms are created during the reaction, increasing the total number.
• D. Some atoms are destroyed during the reaction, reducing the total number.

Answer: (A)

Verified step by step guidance

1. Recall the Law of Conservation of Mass, which states that mass cannot be created or destroyed in a chemical reaction.
2. Understand that atoms are the fundamental units of matter and cannot be created or destroyed during ordinary chemical reactions.
3. Recognize that during a chemical reaction, atoms are rearranged to form new substances, but the total number and types of atoms remain the same.
4. Conclude that the mass and the number of atoms before and after the reaction must be equal, reflecting the conservation principle.
5. Therefore, the correct interpretation is that the number and type of atoms remain unchanged; they are simply rearranged during the reaction.