What would happen if enough thermal energy is added to a liquid?

• A. The liquid will undergo a phase change and become a gas.
• B. The liquid will freeze and become a solid.
• C. The liquid will decompose into its constituent elements.
• D. The liquid will remain unchanged.

Answer: (A)

Verified step by step guidance

1. Understand that adding thermal energy to a substance increases the kinetic energy of its molecules.
2. Recognize that when enough thermal energy is added to a liquid, its molecules move faster and overcome intermolecular forces holding them together in the liquid phase.
3. Recall that the phase change from liquid to gas is called vaporization or boiling, which occurs at the liquid's boiling point.
4. Note that freezing (liquid to solid) happens when thermal energy is removed, not added, so it is not the correct outcome here.
5. Conclude that with sufficient thermal energy, the liquid undergoes a phase change and becomes a gas.