The amount of heat energy needed to convert unit mass of a liquid into a gas at the same temperature is called its heat of vaporization.
(heat energy; needed; to convert unit mass of a liquid into a gas at the same temperature) (The amount of heat energy; is called; its heat of vaporization)
heat energy The amount of heat energy
needed is called
to convert unit mass of a liquid into a gas at the same temperature
its heat of vaporization