Which of the following changes occurs as a solid is heated?

• A. The solid undergoes deposition to form a gas.
• B. The solid melts to form a liquid at its melting point.
• C. The solid freezes to form a liquid.
• D. The solid condenses to form a gas.

Answer: (B)

Verified step by step guidance

1. Understand the phase changes of matter: solids, liquids, and gases can transform from one state to another through processes such as melting, freezing, condensation, vaporization, sublimation, and deposition.
2. Identify what happens when a solid is heated: heating a solid increases its temperature until it reaches its melting point, where it changes from a solid to a liquid. This process is called melting.
3. Recognize that deposition is the reverse of sublimation, where a gas turns directly into a solid without becoming a liquid, so deposition does not occur when heating a solid.
4. Note that freezing is the process where a liquid turns into a solid, which happens when cooling, not heating.
5. Understand that condensation is the process where a gas turns into a liquid, which also occurs upon cooling, not heating a solid.