256 HYDROGENATED COMPOUNDS OP NITROGEN. 



The exact deductions that can be drawn from the heats of 

 combustion are really only valid for low heats of combustion or 

 for considerable differences, and attention must be called to the 

 limits of error involved in calculations of this kind, in order to 

 prevent any misapprehensions. 



5. Solution in water. Three experiments, made at about 20, 

 on weights of the base equal respectively to 4*753, 4*994, and 

 4-633 grms., and dissolved separately in 400 grms. of water, 

 gave for C 3 H 9 N (59 grms.) gaseous + 270 H 2 about + 12*82, 

 + 12-76, -f 13-2 ; on an average + 12-90 Cal. 



This figure is equal to the heat of solution of ethylamine, and 

 it shows in both bases a special affinity for water. 



6. Dilution. This affinity may be shown still more clearly 

 as regards trimethylamine, by experiments on dilution. 



A liquid saturated at about 19 contained 409*6 grms. of the 

 base per litre, or 478 grms. per kilog. Its density was *858 

 at 16. It corresponded to C 3 H 9 N + 7*17H 2 0. 



On being diluted with thirty times its volume of water, it 

 gave off + 3*89 Cal. at 19. 



Thus C 3 H 9 N, on combining with 7*17H 2 0, gives off only + 

 9 Cal., and that its subsequent dilution gives off about half as 

 much heat. 



For purposes of comparison we may repeat here some of the 

 figures obtained with ammonia. 



NH 3 + 7H 2 0, by its subsequent dilution, gives off + -32. 

 JSTH 3 -j- 19H 2 0, gives off only -f *02. 



These figures show that ammonia has much less tendency 

 than trimethylamine to form hydrates. 



The heat of dilution of the latter base when concentrated is 

 very considerable, and its value amounts to even double that of 

 potash and soda, taken at a corresponding degree of concentra- 

 tion. The heat of dilution of concentrated trimethylamine is 

 quite comparable to that of the hydracids. Now, such values 

 express the formation of certain successive hydrates, 1 a very 

 important circumstance in the study of the reactions of 

 hydracids, as well as those of trimethylamine. 



7. Formation of salts in solution. At 21 it was found 



C 3 H 9 N (1 eq. = 5 litres) + HC1 (1 eq. = 2 litres) ... + 8*9 



+ C 2 H 4 2 ... + 8-3 



+ H 2 S0 4 ... +10-9 



As a check to these results, we get by a double reciprocal 

 decomposition 



C 3 H 9 N (1 eq. = 2 litres) + KC1 (1 eq. = 2 litres) + 4-40\,,, , T 

 K 2 (1 eq. = 2 litres) + C 3 H 9 NHC1 (1 eq. = 2 litres) - O28/ M 



1 " Essai de Me'canique Chimique," torn. ii. pp. 151, 167. 



