What is a product?

• A. A starting substance in a chemical reaction.
• B. A substance formed as a result of a chemical reaction.
• C. A substance that is never changed.
• D. A reactant used as a catalyst.

Answer: (B)

In a chemical reaction, the starting materials are changed into new substances. A product is the substance formed as a result of that change—the new material that appears after the reaction occurs. This happens as atoms rearrange and bonds break and form to make something different from the original substances. The other ideas describe the starting materials (reactants) or something that isn’t consumed in the reaction (like a catalyst), which isn’t what a product is. So the correct understanding is that a product is the substance formed as a result of a chemical reaction.