34 ELECTROCHEMICAL INVESTIGATION OF LIQUID AMALGAMS 



Then 



n n vF = 3272.1 joules 



ATT 

 Fv T - = 2844.4 joules 



Difference U = + 427.7 joules 



Thus upon the dilution with mercury of an amalgam containing nearly 

 two per cent (1.846 per cent) by weight of thallium to about treble its 

 volume (more exactly, 3.5 fold) we should obtain 428 joules or 102 small 

 calories for every 204 grams of thallium. 



Again, in cell C2-C3, ^ = 0.020485, A?r = 0.002 125, AT = 30.00, 

 7 = 273.09, v i, and F = 96,530. Then 



tr vF = 1978 joules 



FvT KT ~ J ^ 9 Joules 

 Difference U = 109 joules 



Turning now to the indium amalgams, we may consider for example 

 the cell Ei-E2, in which TT O = 0.014455, A?r = -OOi33i, AT = 30.00, 

 7=273.09, v = 3, ^ = 96,530. 



Then 



;r vF= 4186 joules 



vFT = 3509 joules 



Difference U 677 



This difference, the heat of dilution, is here much larger even than in the 

 concentrated thallium cell, because the electrochemical equivalent of 

 indium is only about one-sixth as great as that of thallium. In the case of 

 a cell with very dilute amalgams, on the other hand, the heat of dilution is 

 almost negligible, as is shown by the following calculation of cell Gi-G2, 

 about a hundred times as dilute as the previous example. There 



= 1858 joules 



= 1862 joules 



Difference U = 4 joules 



The agreement here is very satisfactory, being about 0.25 per cent. 

 The minus sign can hardly be significant, as the probable error of the 

 measurements is as great as 4 joules. 



There now remains to be considered only the tin amalgam cells. For 

 example, we have in one cell, H2-H3 : 7r = o.oio6i4, A7r = o.ooi2o6, 

 Ar=3O.oo, 7=273.09, v = 2, ^ = 96,530. Then 



TT vF = 2284 joules 



ATT 



joules 



Difference /= 69 joules 



