amount of heat to evaporate water
That is, water has a high heat of vaporization, the amount of energy needed to change one gram of a liquid substance to a gas at constant temperature. Waterâs heat of vaporization is around 540 cal/g at 100 Â°C, water's boiling point. Note that some molecules of water â ones that happen to have high kinetic energy â will escape from the surface of the water even at lower temperatures.