When a refrigerant evaporates, which of the following best describes the process?

• A. Its temperature increases due to absorption of heat.
• B. It decomposes into its elemental components.
• C. It undergoes a chemical change and forms new substances.
• D. It undergoes a physical change by transitioning from liquid to gas.

Answer: (D)

Verified step by step guidance

1. Understand the nature of evaporation: Evaporation is the process where a liquid changes into a gas at a temperature below its boiling point, involving a phase change but not a chemical reaction.
2. Recall that during evaporation, the substance absorbs heat energy from the surroundings, which is used to overcome intermolecular forces, allowing molecules to escape into the gas phase without changing their chemical identity.
3. Recognize that because the refrigerant changes from liquid to gas without altering its molecular structure, this is a physical change, not a chemical change.
4. Note that the temperature of the refrigerant typically remains constant during evaporation because the absorbed heat is used for the phase transition (latent heat of vaporization), not for increasing temperature.
5. Conclude that the best description of the refrigerant evaporating is that it undergoes a physical change by transitioning from liquid to gas.