Why does a liquid's rate of evaporation increase when the liquid is heated?

• A. Heating decreases the intermolecular forces in the liquid, causing the liquid to freeze.
• B. Heating increases the pressure above the liquid, which forces more molecules to evaporate.
• C. Heating causes the liquid molecules to become heavier, making them evaporate faster.
• D. Heating increases the average kinetic energy of the liquid's molecules, allowing more molecules to escape into the vapor phase.

Answer: (D)

Verified step by step guidance

1. Understand that evaporation is the process where molecules at the surface of a liquid gain enough energy to overcome intermolecular forces and enter the gas phase.
2. Recognize that heating a liquid increases the average kinetic energy of its molecules, which means more molecules have sufficient energy to escape from the liquid surface.
3. Recall that intermolecular forces are not decreased by heating; rather, the energy of molecules increases, allowing them to overcome these forces temporarily.
4. Note that heating does not increase the pressure above the liquid in a way that forces evaporation; instead, evaporation itself can increase vapor pressure.
5. Conclude that the key reason evaporation rate increases with heating is because more molecules have enough kinetic energy to break free from the liquid and become vapor.