ABSTRACT
This chapter investigates the transport of water across the interfacial region which begins with the kinetic theory of gases. It must be emphasized that the kinetic theory of gases deals with molecules striking an idealized surface in a gas, not a physical interface such as an air-water interface. The theory of absolute reaction rates provides physical justification for the existence of the evaporation coefficient for water and permits the calculation of values which are in reasonable agreement with experimentally determined values. Experimentally determined values of the evaporation coefficient would therefore be expected to reflect the nonideality of the experimental situation. In the literature on the experimental determination of evaporation and condensation coefficients, the concept of the diffusional resistance to the transport of water is encountered. The diffusional resistance concept provides a convenient separation of the study of the evaporation of water into investigations of three regions: the gas phase, the liquid-gas interfacial region, and the liquid phase.
