In this paper convenient approximate expressions between saturation vapour and the size of a nucleus containing given amount of solute were derived. At first we assumed that saturation vapour pressure for plane surface of aqueous solution is given by where
P is saturation vapour pressure of aqueous solution,
Po that of pure water at the same temperature as the aqueous solution, θ mol concentration of solute, α, β, constants depending on the nature of solute. Then using (1) we derived approximate formulae of saturation vapour pressure for a condensation nucleus containing given amount of solute. They are as follows: where
P' is saturation vapour pressure for the drop of solution of radius
r,
P0 that for plane surface of pure water at the same temperature as the drop,
m the mass of solute in the drop,
A,
B, constants depending upon the nature of solute,
r0 the radius of the drop when the solution is saturated with solute,
r_??_, the radius of the final crystalline nucleus. Constants
A,
B were determined for NaCl-, MgCl
2-, MgSO
4-, K
2SO
4-, H
2SO
4-solution, and saturation vapour pressure
versus drop size relations for several given amounts of solute were obtained for the above solution.
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