Question #dcdd2

1 Answer
Jan 16, 2016

Answer:

Phase changes go both ways, so the thermal energy of the system may increase or decrease.

Explanation:

DURING a phase change the temperature of the compound remains constant as the thermal energy is absorbed or released according to its unique heats of vaporization or fusion. Cooling and condensation are exothermic (Heat of Fusion ΔHf). Heating and vaporization are endothermic (Heat of Vaporization ΔHv).