DECOMPOSITION OF AMMONIUM NITRATE. 411 



The permanent pressure at 0, taking into account the volume 

 of the liquid water (450 c.c. for 1 kgm.), will be, for a density 



of charge 

 n 



4187 atm. Qr 432 kgm. 



n - 0-450 n - 0450 



For n = 1, we should have in theory 787 kgm. per square 

 centimetre. The salt being decomposed in its own volume, 

 that is, 1 grm. occupying 0'585 c.c., the permanent pressure 

 becomes 3200 kgm. 



At the temperature developed by decomposition, the water 

 being gaseous, the theoretical pressure would be 



976 V + 273~/ 6344 atm. 6555 kgm. 



=? - - or 



n n n 



The salt being decomposed in the same volume which it 

 occupies in the solid state, 11,200 kgm, 



These values represent the maximum of the effects which can 

 be produced by the decomposition of ammonium nitrate, all the 

 following reactions producing less heat and a less volume of gas. 



10. (4th) The formation of nitrogen monoxide is the pre- 

 ponderating reaction when we proceed by progressive heating. 

 This reaction, 



N0 3 HNH 3 (solid) N 2 + 2H 2 0, 



would liberate 



Liquid water, -f 29*5 Cal. at constant pressure, 4- 301 at con- 

 stant volume. 



Gaseous water, 4- 10'2 Cal. at constant pressure, -f 121 at con- 

 stant volume. 



The volume of the gases produced at the temperature t will 

 be 



22-3 litres (l 4- ^), the water being liquid, 



66-9 litres (l + ^r ), the water being gaseous ; 

 \ Zio/ 



or for 1 kgm. 



278-7 litres ( 1 + 7=r\ the water being liquid, 

 > 2 to/ 



836'2 litres (l + 7 - \ the water being gaseous. 

 \ 27o/ 



The theoretical temperature at constant volume is 



