Question

If a ice cube melts at 0⁰C but water also freezes at 0⁰C, what is the difference between melting and freezing in terms of:(please answer both questions)

A) The energy involved in the phase changes?

B) Particles of the substances during the phase change?

Answer 1

A. When ice melts at 0 degree, energy is added at a constant rate (heat of fusion). When water freezes at 0 degree, energy is subtracted at the same constant rate.

B. At 0 degree, particles of ice becomes less compact as it turns into water. As water freezes, the particles becomes more compact.