Which of the following is not a chemical change?

• A. Cremation of remains.
• B. Decomposition of remains.
• C. Tearing of paper.
• D. Rusting of iron.

Answer: (C)

Understanding whether a change is chemical or physical helps identify what’s happening to the material. A chemical change means the substance actually changes composition and forms new substances; you often see new properties, like different odors, colors, bubbles, or a solid forming from a reaction.

Tearing paper is a physical change. You’re just breaking the paper into smaller pieces; the material on a molecular level (the cellulose) is the same substance, and no new chemical compounds are produced. The change is in shape and size, not in chemical identity.

Cremation involves burning, where the material reacts with oxygen and bonds are rearranged to form new substances such as carbon dioxide, water vapor, and ash—clear chemical change. Decomposition of remains is also chemical, as complex organic molecules are broken down into simpler substances. Rusting of iron is another chemical change, producing iron oxide, a substance with different properties from the original iron.