﻿492 Mr. S. A. Shorter : Application of the Theory 



Approximate Expressions connecting the Freezing-Point with 



the Solvent Potential Lowering^ Osmotic Pressure, and 



Vapou r- P ress 1 1 re . 



If we regard all the specific heats involved in equation (17) 



as independent, of the temperature, the equation reduces to 



the simpler form 



A„ (,,p, i) = IV g - ,1) - '— /„ («, p, e v ) - yi t (^- T - log ^) 



For the purpose of practical calculation, the equation may 

 he written in the form 



where - t 4- T 



The relation between the osmotic pressure and the freezing- 

 point may be simplified in the following manner. Let us 

 suppose that the pure solvent in the case of the osmotic 

 pressure measurements, and the solution in the case of the 

 freezing-point determinations, are both under atmospheric 

 pressure. We may express the mean value of P in terms of 

 its value at atmospheric pressure by means of equation (2) 

 of Part I. Simplifying equation (15) in this manner and 

 combining it with equation (1 ( J) we obtain the following 

 relation * : — 



n (,, *r, f) P (s, w, f)(l-*Xfi) = Ut (j - J-) 



-'-- I ,, < ,,.,«- w {i(i=iy-^)' + ...} 

 +^W + Kt) - --}- • • • <«- 



* It is quite justifiable to take account of the compressibility and at 

 tbe same time neglect the variation with temperature of the specific 

 heats. 



