Which term describes a change from one state to another without a chemical change?

• A. A chemical reaction
• B. An explosion
• C. Condensation
• D. Phase change

Answer: (D)

Phase change is the term for a substance changing from one state of matter to another (solid, liquid, gas) without changing its chemical identity. During these transitions, the molecules simply rearrange and energy is absorbed or released as latent heat, but no new substances are formed. That’s why this describes a physical change rather than a chemical one. Condensation is a specific example of a phase change (gas to liquid), but the general idea is phase change. An explosion and a chemical reaction involve making or breaking chemical bonds to form new substances, so they are not simply state changes. Examples of phase changes include melting, freezing, boiling, and sublimation.