20 VETERINARY STATE BOARD 



pared by neutralizing hydrochloric acid with ammonia water. The 

 solution is evaporated and the crystalline mass remaining is am- 

 monium chloride. HCl + NH^OH = NH^Cl + H^O. 

 Give the chemical name and formula of two compounds of ammonia. 

 Ammonium chloride, NH^Cl, ammonium nitrate, NH^NOj. 



Am 



Name the important constituents of air and give the approximate per- 

 centages of each constituent. 



By weight By volume 



Nitrogen 76, 77 



Oxygen 23 21 



C02, ammonia, argon, etc 1 2 



State three facts tending to show that air is a mixture and not a 

 compound. 



1. By artificially mixing oxygen and nitrogen in the proportions 

 found in the air, no energy change (heat) that indicates chemical 

 union takes place. 



2. Analysis shows air taken from different heights to be slightly 

 variable. 



3. By passing air through water it is changed, oxygen being more 

 soluble than nitrogen. 



Mention the injurious substances added to the air in breathing. What 

 per cent, of carbon dioxide is fatal to the animal breathing it? 

 Carbon dioxide and disease germs are added to the air in 

 breathing. 



It is not advisable to allow animals to breathe for any length 

 of time air containing more than 1 per cent. CO2 ; 5 per cent, pro- 

 duces insensibility, and 8 per cent, causes death in a few minutes. 



What element constitutes four-fifths of the air? 



Nitrogen. 



CARBON 



Give (a) the symbol, (b) specific gravity, (c) the physical and chemical 

 properties of carbon. 

 (a) C. (b) In its purest form, 3.5; graphite, 2.15; amorphous 

 forms, 1.5 to 2. (c) One of the most common elements, tasteless, 

 odorless, non-volatile, infusible and insoluble in all its forms; 

 black in color, except in the form of the diamond, and is combustible^ 

 yielding CO^. It unites readily with a great many elements, forming 

 important compounds. 



