Which of the following best describes a physical change?

• A. A reaction that involves the breaking and forming of chemical bonds.
• B. A process in which energy is always absorbed and a new compound is formed.
• C. A change that alters the form of an object without changing its chemical identity.
• D. A change that produces a new substance with different chemical 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 but does not alter its chemical composition, while a chemical change results in the formation of one or more new substances with different chemical properties.
2. Analyze the options given: Identify which options describe changes involving chemical bonds or formation of new substances, as these indicate chemical changes.
3. Recognize that a physical change involves changes such as changes in state (solid, liquid, gas), shape, or size without changing the substance's chemical identity.
4. Match the description that states 'a change that alters the form of an object without changing its chemical identity' to the concept of a physical change.
5. Conclude that the correct description of a physical change is the one that emphasizes alteration in form without chemical composition change, distinguishing it from chemical changes that involve bond breaking or new substances.