74 



WORK OF J. N. PEARCE. 



The total amount of water combined with the electrolyte passes through a mini- 

 mum at about 0.05 normal and then increases rapidly with increase in concentration. 

 This is seen in fig. 27, page 71. 



COPPER NITRATE. 



The mother-solution of the salt was diluted to convenient strength and the copper 

 determined electrolytically. 



Table 57. Copper Nitrate Data for Freezing-point and Conductivity Measurements, 



Specific Gravity, and Hydrates. 



Freezing-point. 



m 



0.01 



0.025 



0.05 



0.075 



0.25 



0.50 



0.75 



0.935 



1.50 



2.0 



A/m 



.05736 



. 13852 



. 25540 



.36979 



.221 



.589 



.190 



.512 



.284 



.89 



5.7365 

 5. 5401 [ 



5.108l| 



4.9306 



4.885 



5.178 



5.587 



5.895 



6.856 



8.44 



3.0841 

 2.9785 

 2.7463 

 2.6508 

 2.6264 

 2.7841 

 3.0039 

 3.1696 

 3.6861 

 4.5419 



a 



98.92 

 87.31 

 82.54 

 81.32 



Hydrates. 



/// 



0.025 



0.075 



0.075 



0.25 



0.50 



0.75 



0.935 



1.50 



2.0 



A/m 



L' 



M 



H 



75.76 

 81.10 

 77.85 

 67.29 

 59.15 

 52.54 

 48.21 

 37.29 

 28.36 



5.0502 



4.8769 



4.7560 



4.363 



4.060 



3.814 



3.653 



3.247 



2.914 



5.5401 

 5.1081 

 4.9306 



4.885 



5.5368 



5.1005 



4.9188 



4.852 



5.092 



5.441 



5.708 



6.447 



7.749 



4.882195.2 



2.435! 48.7 



1.839! 



5.607J 



11.26 22.5 

 16.612 22.15 

 19.953 

 27.575 



24.5 

 22.4 



24.651 



21.3 



18.38 



17.32 



Conductivity. p.Ji = llS. i 



Pv 



100 

 40 

 20 



13.34 

 4 



1.334 

 1.0695 

 0.0667 

 0.5 



108.84 

 101.2 

 95.7 

 91.86 

 79.4 

 69.8 

 62.0 

 56.89 

 44.0 

 33.47 



a 



92.24 

 85.76 

 81.10 

 77.85 

 57.29 



52.54 

 48.21 

 37.29 

 28.36 



Specific gravity. 



m 



Sp. gr. 





II 



sol 



1.00151 

 1.00408 

 1.00786 

 1.01171 

 1.04029 

 1.07723 

 1.11469 

 1 . 14262 

 1.22618 

 1.29262 



1001. 

 1004. 

 1007. 

 1011. 

 1040. 

 1077. 

 1114. 

 1142. 

 1226. 

 1292. 



sail 



Wiho 



Correction, 

 per cent. 



999.628 



999.384 



998.4759 



997.6395 



993.370 



983.390 



973.930 



968.140 



944.660 



917.260 



0.03 

 0.06 

 0.15 

 0.23 

 0.66 

 1.66 

 2.60 

 3.18 

 5.53 

 8.27 



Amer. Chem Journ., 33, 578 (1905). 



Copper nitrate crystallizes with 6 molecules of water and, therefore, should give 

 us hydration of the same order of magnitude as that found for the nitrate of cobalt 

 and nickel, which crystallize with the same amount of water. Reference to table 

 57 will show that this is the fact. The minimum for the total amount of combined 

 water is pronounced and lies between 0.075 and 0.25 normal. The hydration per 

 molecule decreases rapidly with increase in concentration to 0.05 normal, and then 

 becomes approximately constant. The curves representing the values of H and M 

 are given in figs. 28 and 29, respectively. 



NICKEL NITRATE. 



The nickel was determined electrolytically in diluted portions of the mother- 

 solution. 



The hydrating power of nickel nitrate is of the same order of magnitude as that 

 of cobalt and copper nitrates, which crystallize with the same amounts of water 



