Which energy changes are associated with a liquid boiling?

• A. Release of heat and increase in kinetic energy of molecules
• B. Absorption of heat and decrease in kinetic energy of molecules
• C. Absorption of heat and increase in potential energy of molecules
• D. Release of heat and decrease in potential energy of molecules

Answer: (C)

Verified step by step guidance

1. Understand that boiling is a phase change from liquid to gas, which requires energy input to overcome intermolecular forces.
2. Recall that during boiling, the temperature remains constant, so the kinetic energy of the molecules does not increase or decrease significantly.
3. Recognize that the energy absorbed during boiling is used to increase the potential energy of the molecules by breaking intermolecular attractions, not to increase kinetic energy.
4. Identify that this energy absorption without temperature change is called the enthalpy of vaporization or heat of vaporization.
5. Conclude that the correct energy changes during boiling are absorption of heat and increase in potential energy of molecules.