DECOMPOSITION OP AMMONIUM NITRATE. 413 



solid state, 4860 kgm. ; values nearly the same as those corre- 

 sponding to nitrogen monoxide. 



12. (6th) The formation of nitrogen trioxide 



3N0 3 H, NH 3 (solid) = 4N + N 2 3 + 6H 2 0. 



Liquid water, + 42*5 Cal. at constant pressure, 4- 43*1 at constant 



volume. 

 Gaseous water, 4- 23'3 Cal. at constant pressure, 4- 251 at constant 



volume. 



The volume of the gases at the temperature t is the same as 

 for nitrogen monoxide, viz. 



4- 22*3 litres (1 4- T^A the water supposed liquid ; 

 \ 273/ 



4- 66'9 litres (\ -J -- \ the water supposed gaseous. 

 \ 273/ 



In all cases this reaction can only be developed upon a 

 fraction of matter ; nitrogen trioxide existing only in the dis- 

 sociated state in presence of nitric oxide and nitric peroxide, 

 which are in excess. Hence it appears useless to give the 

 calculations relative to the pressures and temperatures, a remark 

 which is equally applicable to the following reactions. 



(7th) The formation of nitric peroxide, 



2N0 3 HNH 3 (solid) = N 3 4- NO a 4- 4H 2 O, 

 would liberate 



Liquid water, 4- 48 Cal. at constant pressure, 4- 49*5 at constant 



volume. 

 Gaseous water, 4- 29*5 Cal. at constant pressure, 4- 31*4 at constant 



volume. 



The volume of the gases, at the temperature t, is the same as 

 for nitrogen monoxide and for nitrogen trioxide. 

 (8th) The formation of gaseous nitric acid, 



5N0 3 HNH 3 (solid) = 2HN0 3 4- 8N 4- 9H 2 0, 



would liberate, the acid and the water being gaseous, and not 

 combined, + 33'4 Cal. at constant pressure, 4- 351 Cal. at con- 

 stant volume. 



The volume of the gases at the temperature t y the water and 



the acid assuming the gaseous state, would be 67 litres (1 4- ^\ 



( t 

 That of the permanent gases, 17 '8 litres (l -f ;~A being the 



least of all. On the contrary, the heat liberated is the greatest. 

 But this mode of decomposition is accessory. 



13. We have deemed it useful to develop the study of the 

 manifold and simultaneous modes of decomposition of am- 



