Which of the following best describes what happens during evaporation?

• A. A liquid changes into a solid as it loses heat.
• B. A liquid changes into a gas at the surface without boiling.
• C. A gas changes into a liquid as it cools.
• D. A solid changes directly into a gas without passing through the liquid phase.

Answer: (B)

Verified step by step guidance

1. Understand the process of evaporation as a phase change involving a liquid turning into a gas.
2. Recognize that evaporation occurs only at the surface of the liquid, unlike boiling which happens throughout the liquid.
3. Note that evaporation does not require the liquid to reach its boiling point; it can happen at temperatures below boiling.
4. Identify that during evaporation, molecules at the surface gain enough energy to overcome intermolecular forces and escape into the gas phase.
5. Conclude that evaporation is best described as a liquid changing into a gas at the surface without boiling.