LESSONS IN CHEMISTRY 



15 



Properties of Nitrogen. On applying to nitrogen the 

 same tests that we used in studying oxygen, we find the 

 physical properties of the two gases are very similar. Both 

 are colorless, tasteless, and odorless gases. In chemical 

 properties, however, they differ widely. When we thrust 

 into a jar of nitrogen a glowing splinter of carbon, the spark 

 is at once extinguished. Burning sulphur is affected in the 

 same way, and even phosphorus ceases to burn as soon as it 

 comes in contact with nitrogen. All this means that phos- 

 phorus, sulphur, and carbon will not combine with nitrogen 

 as they do with oxygen. In fact, nitrogen may be character- 

 ized as the least active of all elements. It does not readily 

 unite with any other element, and the compounds in which 

 nitrogen is found are very unstable. Gunpowder and nitro- 

 glycerin owe their explosive power to the fact that the 

 nitrogen present easily loses its hold upon the other ingredi- 

 ents. The nitrogen in the air prevents oxidation from going 

 on at too rapid a rate. 



COMPOSITION OF THE AIR 



PROPORTION 

 -OF INGREDIENTS 

 PHYSICAL PROPERTIES 

 OF INGREDIENTS 



COLORLESS, ODORLESS, 

 TASTELESS GAS. 



COLORLESS, ODORLESS, 

 TASTELESS GAS. 



CHEMICAL PROPERTIES 

 OF INGREDIENTS 



WILL NOT BURN 



WILL NOT MAKE THINGS BURN, 



USED TO DILUTE THE OXYGEN. 



WILL NOT BURN 



MAKES THINGS BURN BY COMBIN- 

 ING WITH THEM TO FORM OXID8. 



FIG. 3. Composition of the Air. 



