NITROGEN: AMMONIA §5 



XXI. NITROGEN: AMMONIA 



Previous experiments have shown that the gaseous element 

 nitrogen is neither combustible nor a supporter of combustion. 

 The German and French names for nitrogen — sticksioff and 

 azote — express its inability to support life when respired. It 

 was found that atmospheric air consists mainly of a mixture of 

 oxygen and nitrogen in the proportion of about i to 4, or 

 more exactly 20.9 and 79.1 per cent, by volume. This 

 atmospheric nitrogen contains, how^ever, about i per cent, of 

 argon, a gaseous element of still greater inactivity. 



In the combined state, nitrogen is an essential constituent 

 of all animal and vegetable organisms. When nitrogenous 

 organic matter decays, or when it is destructively distilled, the 

 hydrogen compound of nitrogen, ammonia, is produced, just 

 as sulphuretted hydrogen is produced from organic matter 

 containing sulphur. Heat some horn shavings in a test-tube. 

 Note the pungent smell of the escaping ammonia gas (" spirit 

 of hartshorn "). Test the gas with litmus paper. Has it an 

 acid reaction like the hydrogen compounds of sulphur and 

 chlorine, or has it an alkaline reaction ? If the latter, it is a 

 base, and able to unite with acids forming salts. Hold a glass 

 rod moistened with hydrochloric acid to the mouth of the 

 tube. Is there any evidence of a salt, the hydrochloride of 

 ammonia, being formed ? Analysis shows that ammonia 

 contains 82.35 per cent, of nitrogen and 17.65 per cent, of 

 hydrogen. What is the simplest formula that would represent 

 its composition ? 



Procure some commercial sal-ammoniac, the hydrochloride 

 of ammonia. Note its fibrous crystalline structure, its solu- 

 bility in water, its neutrality to litmus. Ammonia being a 

 volatile base, it may be prepared from this salt by taking 

 advantage of the facts stated on p. 77. Mix a little sal- 

 ammoniac with any fixed base, e.g. lime, potash, soda, etc. 



