25.2


 * INTRODUCTION TO HYDROCARBONS **
 * ===== Hydrocarbons can be divided into four general types: toc =====

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 * Alkanes ** are hydrocarbons that contain only single bonds. Because alkanes contain the largest possible number of hydrogen atoms per carbon atom, they are called saturated hydrocarbons. Ex: Ethen (CH3CH3)======

** Alkynes ** contain at least one C≡C triple bond. Ex: acetylene C2H2

 * In arotamic hydrocarbons the carbons atoms are connected in a planar ring structure, joint by both σ and π bonds between carbon atoms
 * Hydrocarbons molecules are relatively nonpolar. They are almost completely insoluble in water, but they dissolve readily in other nonpolar solvent
 * Their melting points and boiling point are determined London dispersion forces
 * Hydrocarbons of very low molecule weight are gases. Ex: C2H6
 * Those of moderate molecular weight are liquids. Ex: C6H14