Which of the following best describes the difference between a physical change and a chemical change?

• A. A physical change involves breaking chemical bonds, while a chemical change does not.
• B. A physical change can only occur at high temperatures, while a chemical change can occur at any temperature.
• C. A physical change always produces energy, while a chemical change does not.
• D. A physical change alters the appearance or state of a substance without changing its chemical composition, while a chemical change results in the formation of new substances with different chemical properties.

Answer: (D)

Verified step by step guidance

1. Understand the definitions of physical and chemical changes: A physical change affects the form or appearance of a substance but does not alter its chemical identity, while a chemical change results in the formation of one or more new substances with different chemical compositions.
2. Recognize that physical changes include changes in state (such as melting, freezing, or boiling) or shape, where no new substances are formed and chemical bonds remain intact.
3. Identify that chemical changes involve breaking and forming chemical bonds, leading to new substances with different properties, such as rusting, combustion, or digestion.
4. Evaluate the given options by comparing them to these definitions, noting that only the option describing the alteration of appearance or state without changing chemical composition for physical changes, and formation of new substances for chemical changes, is accurate.
5. Conclude that the best description distinguishes physical changes as changes in appearance or state without chemical composition change, and chemical changes as those producing new substances with different chemical properties.