In: Physics
Water standing in the open at 34.5°C evaporates because of the escape of some of the surface molecules. The heat of vaporization (553 cal/g) is approximately equal to εn, where ε is the average energy of the escaping molecules and n is the number of molecules per gram. (a) Find ε. (b) What is the ratio of ε to the average kinetic energy of H2O molecules, assuming the latter is related to temperature in the same way as it is for gases?