Explain what happens to the molecular motion and energy of 1kg of water at 273K when it changes to the ice at the same temperature. How it is the latent heat of fusion related to the energy exchange that takes place during this change of state?

When water is converted to the ice at the same temperature, there are changes involved in internal potential energy. The molecular motion decreases as heat are released to the surroundings as the water get converted into ice.

Energy involved in the phase chnage = latent heat x Mass

= – 80cal/g x 1000 g

= – 80,000 cal

(-) sign indicates that thermal energy is decreased.