Table 268. 

 LATENT AND TOTAL HEATS OF VAPORIZATION OF THE ELEMENTS. 



233 



The following table of theoretical values is taken from J. W. Richards, Tr. Amer. Electr ch. 

 Soc. 13, p. 447, 1908. They are computed as follows: STm (8 = mean value atomic specific 

 heat, Dulong-Petit constant, 0° to T° K, Tm = melting point, Kelvin scale) plus 2Tm (latent 

 heat of fusion is approximately zTm, J. Franklin Inst. 1897) plus io{Tb - Tm) (specific heat 

 of liquid metals is nearly constant and equal to that of the solid at Tm, Tb = boiling point, Kelvin 

 scale) plus 2^Ti) (23 = Trouton constant; latent heat of vaporization of molecular weight 

 in grams is approximately 23 times Tb) = 33^6. Total heat of vapor when raised from 273° K 

 (0° C) equals 33r6 - 1700 (mean value of Dulong-Petit constant between 0° and 273° K is 

 1700). Heats given in small calories per gram. 



Smithsonian Tables- 



I 



