78 NON-METALS AND THEIR COMBINATIONS. 



QUESTIONS. 



111. State the physical and chemical properties of nitrogen. 



112. Mention the principal constituents of atmospheric air and the 

 quantity in which they are present. 



113. By what processes can the four chief constituents of atmospheric 

 air be determined? 



114. Mention some decompositions by which ammonia is generated. 



115. Explain the process of making water of ammonia. 



116. State the physical and chemical properties of ammonia gas and 

 ammonia water. 



117. How is nitrogen monoxide obtained, and what are its properties ? 



118. Describe the process for making nitric acid, and give symbols for 

 decomposition. 



119. How does nitric acid act on animal matter, and what are its 

 properties generally? 



120. Give tests and antidote for nitric acid. 



13. CARBON. 



O = 12. 



Occurrence in nature. Carbon is a constituent of all organic 

 matter. In a pure state it is found crystallized as diamond and 

 graphite, amorphous in a more or less pure condition in the 

 various kinds of coal, charcoal, boneblack, lampblack, etc. As 

 carbon dioxide carbon is found in the air, as carbonic acid in 

 water, as carbonates (marble, limestone, etc.) in the solid portion 

 of our earth. 



Properties. The three different allotropic modifications of 

 carbon differ widely from each other in their physical properties. 



Diamond is the purest form of carbon; it crystallizes in 

 regular octahedrons, cubes, or in some figures geometrically 

 connected with these. Diamond is the hardest substance known ; 

 it is infusible, but burns when heated intensely, forming carbon 

 dioxide. 



Graphite, plumbago, or black-lead, is carbon crystallized in short 

 six-sided prisms; it is a somewhat rare, dark gray mineral, 

 chiefly used for lead-pencils. 



Amorphous carbon is a soft, black, solid substance. 



