386 



NOYES: NITROGEN PROBLEM IN RELATION TO WAR 



The nitrogen used in both of the processes just described is 

 obtained ordinarily from Uquid air by one of the famihar hque- 

 faction and distillation processes. 



It will be noted that the cyanide process accomplishes in a 

 ^ single operation a result which requires two operations in the 

 cyanamide process. By using soda instead of lime, we combine 

 the two steps (conversion of lime to carbide and of carbide to 

 cyanamide) into one. The final steaming is the same in both 

 processes. 



3. The synthetic process is an extremely simple one chemically, 

 involving the following reaction: 



No + 3H2 = 2NH3. 



There is a rather interesting history connected with this. The 

 proportion of ammonia which forms from the elements (hydrogen 

 and nitrogen) at atmospheric pressure at any temperature where 

 the rate is rapid enough so that it will form within a reasonable 

 time is extremely small. The proportions (by volume) of am- 

 monia at various temperatures and pressures that are present when 

 a mixture of three volumes of hydrogen and one of nitrogen 

 reaches equilibrium are shown in the table: 



Thus at 500° we find, from the laboratory investigations that have 

 been made on the equilibrium of this reaction, that there is only 

 0.13 per cent of the nitrogen converted into ammonia when the 

 mixed gases are at atmospheric pressure, whereas at 200 atmos- 

 pheres there is 18.1 per cent. As the temperature rises the 

 result is much less favorable. At 600° we get only 0.05 per cent, 

 and at 700° 0.02 per cent, at atmospheric pressure. These un- 

 favorable equilibrium conditions of the reaction, and the known 

 fact that its rate is very slight until the temperature gets high, 

 led to the belief that there was no hope of the development of 



