Question

Why is there no change in the temperature when the process of melting takes place?

Answer 1

The answer is C - Because the supplied heat is used to increase the kinetic energy of the molecules. The process of melting is the change of state from solid to liquid. Molecules in a solid are closely packed together, thus the molecules cannot move, they only vibrate and a solid consists of strong forces of attraction between them. To change from solid state to liquid state these forces of attraction should be broken, by using heat. Note that : first the kinetic energy of molecules increases then the forces of attraction become weak upon vibrating molecules, then the forces of attraction are broken.

Answer 2

Answer: A. Because the supplied heat is used to overcome the force of attraction between the molecules.

Explanation: During melting, the added heat does not make the molecules to move faster, but rather, it makes them to fall apart. The heat energy added during the phase change is used to overcome some of the forces that hold the molecules together, allowing them to move further away from each other.