CHEMISTRY OF ORGANIC COMPOUNDS. 



INTRODUCTION. 



ORGANIC CHEMISTRY is the chemistry of the com- 

 pounds of carbon. It includes those compounds of 

 carbon which have had their origin in the organs of 

 plants and animals, as well as those which have been 

 produced exterior to the living organism. 



Most organic compounds are solid, partially crys- 

 talline, partially amorphous bodies; many are liquids; 

 only a few are gaseous at ordinary temperatures. All 

 of them are destroyed when heated above their melt- 

 ing or boiling point without access of air ; a very large 

 number cannot even be melted nor volatilized without 

 undergoing decomposition. The melting point and 

 boiling point are very characteristic properties for those 

 bodies, which are not readily decomposed at higher 

 temperatures. The difference in the boiling points of 

 organic compounds is very frequently made use of for 

 the purpose of separating them from each other, and 

 preparing them in a pure condition from a mixture 

 (partial distillation). 



Another very important property of those organic 

 bodies, which are volatile without decomposition, is 

 their specific gravity in the form of gas or vapor (vapor 

 density). Experience has shown, that the molecules 

 (the smallest quantity that can exist in a free condi- 

 tion) of the various chemical compounds in the form 

 of gas or vapor possess the same volume, and that this 

 volume is the same as that of two atoms (one molecule) 

 of hydrogen. 

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