32 



ENERGY CHANGES INVOLVED IN DILUTION OF AMALGAMS. 



The " parent " amalgam, 0.91 per cent, had density 13.465, at 20.00 C. 



The new diluted amalgam, 1^2 X 0.91 per cent, had density 13.527. 



57-6 

 Then follows the calculation of the concentration ratio of the two amal- 

 gams, No. 3 and No. 4: 



T =TT^X 5 X 1.001 = 3.908; log ^-0.59198. 

 c 4 14 698 13.527 J * ' & c i * * 



In the same way the concentration ratios of other diluted amalgams made 

 from No. 3 was calculated. These are recorded in the following table. 

 The few necessary corrections for weights are included without comment, 

 and the factors correcting for dissolved zinc are given without details. 



Concentration Ratios of Zinc Amalgams. Preliminary Series {Cell I). 



Having been thus prepared, the four amalgams, No. 3, No. 4, No. 5, and 

 No. 6, were admitted into the four cups of the cell with all precautions, and 

 the potentials were measured under the following conditions : 



Temperature of thermostat (corrected) 23.09 C. = 296.17 abs. 



Temperature of i-volt cell = 21 ; its potential was therefore 0.9925. 



The formula for the calculation of v will be 



8.316 X TX 2.3026 ^ . c x 



*=-- w * o X log. 



2 X 96580 s c 2 



Log -A- for the pair of amalgams No. 4 and No. 6 is found by subtracting 

 log ^ from log -^ ; because A -f- -- = ^-. 



C i C 6 C 6 C i C 6 



61 Of this zinc 0.006 gram was dissolved in ammonia during the amalgamation. 

 Hence the weight of zinc dissolved in the mercury was 1.110 or 0.909 per cent. 



