GCEPhysicsHeat and Thermodynamics2020

During a change of state from liquid to gas at constant temperature, the heat energy supplied to the substance is used mainly to

Aincrease the kinetic energy of the molecules.
Bincrease the potential energy of the molecules by overcoming intermolecular forces.CORRECT
Cincrease both the kinetic and potential energies of the molecules equally.
Ddecrease the pressure of the surrounding atmosphere.
AI
Toaster Teacher
Why the answer is B, and why the others tempt you.
During a change of state (e.g., boiling), the temperature remains constant, which means the average kinetic energy of the molecules does not change. The latent heat supplied is used to overcome the intermolecular attractive forces, thereby increasing the potential energy of the molecules as they move further apart. This is why a thermometer placed in boiling water reads a constant temperature until all the liquid has vaporised.
Want this in Pidgin, Yoruba, Igbo or Hausa? Sign up free →

Practice more Physics questions

GCE Physics has thousands more questions like this — with Worked answers on every one.

Start practicing free →See all Physics questions