254 HYDROGENATED COMPOUNDS OF NITROGEN. 



Second Section Ethylamine. 



1. This alkali is gaseous in summer ; it boils at + 18'1, it is 

 extremely soluble in water, and forms well-defined salts. 



2. Analysis. Its purity was proved by eudiometric analysis, 

 a more reliable process than analysis by weight for such com- 

 pounds. These are the results in volume : 



ETHYLAMINE. 



3. Heat of combustion of ethylamine. Four detonations made 

 with weights of this base ranging between '11 and '12 of a grm. 

 gave, at about 20 '5 with gaseous ethylamine (C 2 H 7 N = 45 

 grms.), the volume being constant 



2C 2 H 7 N gas + As = 4C0 2 gas + 7H 2 liquid + N a . 



According to the initial 

 weight of the alkali. 



416-3 Cal. 

 409-3 

 400-7 

 402-7 



Mean 407-2 , 



According to the final 

 weight of the carbonic acid. 



413-0 Cal. 

 403-3 

 406-4 

 416-4 



Mean 409-3 , 



The general mean 4- 408*5 must be increased by 1*2 to pass 

 to the ordinary heat of combustion under constant pressure, 

 which makes 4- 409*7 Cal. This number entails a limit of 

 error of about 4 Cal., an uncertainty that also occurs in the 

 following deductions. 



4. Heat of formation. The heat of combustion of the 

 elements being + 42 9 '5, we get for the heat of formation 



From the elements 



C 2 (diamond) -f H 7 + N = C 2 H 7 N gas + 19-8 



C 2 (charcoal) +25-8 



From ammonia 



C 2 (diamond) + H 4 + NH 3 = C 2 H 7 N gas +7-6 



C 2 (charcoal) + 13-6 



From ethylene 



C 2 H 4 + NH S = C 2 H 7 N +23-0 



From alcohol 



C 2 H 5 (HO) gas + NH 3 gas = C 2 H 7 N + H 2 +6-1 



5. Solution in water. Two experiments made at 190 on 



