240 



EQUILIBRIUM BETWEEN CARBON DIOXIDE OF ATMOSPHERE 



Tables 2 and 3 correspond to table 1. 



Table 2. — Silver Valerate. 



Table 3. — Silver Butyrate. 



It is quite obvious from a consideration of the values in the last column 

 of each table that rather satisfactory constants are obtained in all cases for 

 the ion products of the silver salts in saturated solutions. It may be added 

 that of the two bracketed irregular values, the one in table 2 (last line) 

 corresponds to an experiment which shows the probability of some experi- 

 mental or other error in considering the seventh (next to the last) column, 

 where 0.6 remains unchanged, while it should grow smaller. And the 

 irregular value in table 3 (line 2) corresponds to an experiment the figures 

 for which, as given by Arrhenius, show a decided divergence from the prin- 

 ciple of isohydric solutions — so that it also is unreliable. 



Since, then, the results of Arrehnius's determinations, as thus calculated, 

 agree with the conception that for a difficultly soluble salt the solubility 

 product is a constant at a given temperature for saturated solutions, and 

 since this conclusion was also reached experimentally by A. A. Noyes^ 

 Findlay, and others, as explained above, we may accept this now as an 

 empirically-established fact. The values calculated below for the solu- 

 bility product of calcium carbonate on the basis of Schloesing's data also 

 show excellent agreement.^ 



The value of the " solubility product " for calcium carbonate is particu- 

 larly important for the study of the precipitation of calcium carbonate 

 under varying conditions, and its calculation is one of the first objects of 

 this investigation. Its significance lies in the fact that since in saturated 

 solutions of calcium carbonate in different mixtures the concentrations of 

 the calcium and the carbonate ions are variable, they need not and usually 



' Vide Stieglitz, Journal of the American Chemical Society, 30, 946 (1908), for a more 

 complete discussion of this question. 



