Molecules need energy to escape the hydrogen bonding that holds them in the liquid, and only the most energetic ones evaporate. The energy they carry away is drawn from the skin, lowering its temperature. Vaporization is endothermic, costing water about 40.7 kJ/mol near its boiling point. The same mechanism drives evaporative coolers and explains why damp skin feels cold in a breeze.
BThe departing water molecules absorb energy from the skin to break free of intermolecular attractions
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