In physical changes, substances might change in ________ but not in ________.

• A. mass; volume
• B. chemical composition; state
• C. color; atomic number
• D. state; chemical composition

Answer: (D)

Verified step by step guidance

1. Understand the difference between physical and chemical changes: Physical changes affect the form or appearance of a substance without altering its chemical identity, while chemical changes result in the formation of new substances with different chemical compositions.
2. Identify what properties can change during a physical change: Common physical changes include changes in state (solid, liquid, gas), shape, size, or volume, but the chemical composition remains the same.
3. Analyze the options given: 'mass; volume' is incorrect because mass typically remains constant in physical changes, and volume can change; 'chemical composition; state' is reversed because chemical composition does not change in physical changes, but state can; 'color; atomic number' is incorrect because atomic number never changes in physical or chemical changes.
4. Recognize that in physical changes, substances might change in state (such as melting or boiling) but not in chemical composition (the substance's molecular structure remains unchanged).
5. Conclude that the correct answer is 'state; chemical composition' because physical changes involve changes in physical state but not in the chemical makeup of the substance.