When a gas condenses, what happens to the molecules within the gas?

• A. The molecules move closer together and their kinetic energy increases.
• B. The molecules move farther apart and their kinetic energy increases.
• C. The molecules remain at the same distance but their kinetic energy increases.
• D. The molecules move closer together and their kinetic energy decreases.

Answer: (D)

Verified step by step guidance

1. Understand the process of condensation: it is the phase change from gas to liquid.
2. Recall that in a gas, molecules are far apart and move rapidly with high kinetic energy.
3. During condensation, molecules lose energy, causing them to slow down and come closer together.
4. Recognize that as molecules move closer, their kinetic energy decreases because temperature typically drops during condensation.
5. Conclude that when a gas condenses, the molecules move closer together and their kinetic energy decreases.