Which of the following best explains how the appearance of a substance can change without it becoming a different substance?

• A. A chemical change only affects the physical state of a substance, not its composition.
• B. A physical change involves breaking chemical bonds and forming new substances.
• C. A physical change alters the form or appearance of a substance but does not change its chemical identity.
• D. A chemical change always results in a new substance with different properties.

Answer: (C)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: A physical change affects the form or appearance of a substance without altering its chemical composition, while a chemical change results in the formation of one or more new substances with different chemical properties.
2. Recognize that physical changes include changes in state (such as melting, freezing, or boiling), shape, or size, but the molecules themselves remain the same.
3. Note that chemical changes involve breaking and forming chemical bonds, which changes the substance's chemical identity and produces new substances.
4. Analyze the given options to identify which statement correctly describes a change in appearance without a change in chemical identity.
5. Conclude that the best explanation is that a physical change alters the form or appearance of a substance but does not change its chemical identity.