220 



Conductivity of Aqueous Solutions. Part VII. 



83. EQUIVALENT -CONDUCTANCE VALUES AT ROUND TEMPERATURES. 



The next step in the further reduction of the data to comparable values 

 is their correction to round temperatures. Temperature-coefficients at 

 18, 218, and 306 were obtained by plotting against the temperature 

 the conductances given in the preceding tables after correcting them 

 approximately to round concentrations. Thus the correction to round 

 temperatures was made on the conductance alone, none being required 

 on the concentration. In the case of ammonium hydroxide, the data 

 obtained at 302, before the use of diphenylamine as a heating substance 

 was abandoned, permitted a more accurate calculation of the temperature- 

 coefficient than could be obtained for 306 by drawing the curve through 

 156, 218, and 306. Yet, since the correction to round temperatures 

 was seldom more than 2 per cent, the coefficient does not need to be 

 very accurately known. 



In table 79 are given the temperature-coefficients employed, expressed 

 in per cent of the equivalent conductance at the temperature in question 

 for the first four substances, and in per cent of the specific conductance 

 for ammonium acetate. 



Table 79. Temperature-coefficients of conductance. 



Substance. 



NH 4 C1 



NaC 2 H 3 2 



NH 4 OH . . . 



HCH 3 



NH 4 C 2 H 3 2 



1 NH 4 G,H 3 + \ 



1 NH 4 OH or 1 HC 2 H 3 2 / 



1 NH 4 CoH 3 0., -f \ 



3 NH 4 OH or 3 HC 2 H 3 2 J 



Milli- 



equivalents 



per liter. 



30 

 10 



2 

 30 

 10 



2 



300 



100 



10 



300 



100 



30 



10 



30 

 10 



30 

 10 



18. 



2.20 

 2.20 

 2.20 



2.38 

 2.15 



1.70 



2.75 



2.75 



2.75 



218. 



0.36 

 0.37 



-0.78 

 -0.66 



-<L77 



-0.85 



-0.82 



-0.77 



306 



0.16 

 0.21 

 0.26 

 0.20 

 0.25 

 0.32 



-2.65 

 -3.95 



-2.0 

 -3.0 

 -3.15 

 -3.35 



-2.8 

 -2.95 



-2.3 



-2.4 



In table 80 are given the conductance values for ammonium chloride. 

 The first column gives the number of the experiment, corresponding to 

 that in the table of Conductivity Data. The next three columns give the 

 concentration in milli-equivalents per liter of solution, calculated as 

 described in section 80. The fifth column shows the ratio, in equivalents, 



