Partition nondimensional

Usually evaporation of water is formulated as a function of relative humidity. Explain how this formalism is linked to the usual two-phase air-water model in which the nondimensional Henry s law constant (i.e., the air-water partition constant) of the exchanged chemical appears. 

Table 24.5 Characteristic Data of Chemical Tracers Used for the Gas Exchange Experiment Nondimensional Henry s Law Constant, Ki3/vi, Molecular Diffusion Coefficient in Air, Dia, and Water, Diw, Octanol-Water Partition Coefficient, Kiow, All valid for 4°C (Data from Cirpka et al., 1993)...

Much more rarely is used Kuenen gas-solubility coefficient, which describes volume of component i solved in unit weight of water at partial pressiue 1 bar. Even rarer is encoimtered Ostvald solubility coefficient, which describes the ratio of component i concentrations in water and gas phase in conditions of equilibriimi at low pressure. This nondimensional coefficient in its content is similar to the partition coefficient expressed not in molar fractions and this is why it is not equal to it. 

Then, by analogy with equation (2.167), we get nondimensional value of the partition coefficient... 

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