Which statement 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 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.
• C. A physical change always produces heat, while a chemical change does not.
• D. A physical change can only occur at high temperatures, while a chemical change can occur at any temperature.

Answer: (B)

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 properties.
2. Recognize that physical changes include changes in state (such as melting, freezing, or boiling) or shape, where the molecular structure remains the same.
3. Know that chemical changes involve breaking and forming chemical bonds, leading to new substances (e.g., rusting, combustion, or digestion).
4. Evaluate the given statements by comparing them to these definitions: For example, the statement that a physical change involves breaking chemical bonds is incorrect because bond breaking is characteristic of chemical changes.
5. Conclude that the correct description is the one stating that a physical change alters appearance or state without changing chemical composition, whereas a chemical change produces new substances with different chemical properties.