Definitions  of Alkanes and Cycloalkanes
                          Hydrocarbons  contain only carbons and hydrogens.   Alkanes are noncyclic compounds that contain carbons and hydrogens.  Cycloalkanes are cyclic compounds that  contain carbons and hydrogens.  
                        Background  Information for Alkanes and Cycloalkanes
                          Alkanes  and cycloalkanes are nonpolar and do not have intermolecular hydrogen  bonding.  These compounds are  hydrophobic, do not dissolve in water, and are less dense than water.  The boiling points and melting points of  alkanes and cycloalkanes increase with increasing molecular weight.    The conformations of ethane are eclipsed  and staggered.  The conformations of  butane are totally eclipsed, gauche, eclipsed, and anti.  Smaller rings are more likely to undergo ring  opening reactions. The main conformations of cyclohexane are chair and boat.  Cyclopropane has a carbon-carbon bond angle  of 60o.  Cyclobutane has a  carbon-carbon bond angle of 90o.   Cyclopentane has a carbon-carbon bond angle of 108o.  Cyclohexane has a carbon-carbon bond angle of  109.5o.  The chair  conformation of cyclohexane is the most stable, with the hydrogens furthest  apart.  The boat conformation of  cyclohexane is the least stable, with the hydrogens the closest.  
                        Uses  of Alkanes and Cycloalkanes
                          The  uses of alkanes and cycloalkanes are defined by the carbon number:  C1 B C4 B  natural gas, petroleum gas, C5 B C12 B motor  fuel, C12 B C13 B  kerosene, C15 B C25 B  diesel, C16 - C30  -- heavy oil, >C25 B  petroleum jelly or paraffin wax, and residue B  asphalt.
                        IUPAC  Nomenclature for Alkanes and Cycloalkanes
                          The  longest continuous chain is the parent compound.  Number from whichever end that gives the  lowest possible combination of numbers for the alkyl groups. Number the  cycloalkane so that the lowest possible combination of numbers are used for the  substituents.  If the compound contains  an aliphatic ring and an aliphatic chain, the parent compound is the one with  the most carbons. 
                        Common  Nomenclature
                          Use n,  iso, sec, tert, and neo prefixes. 
                        Reactions  of Alkanes
                          Combustion  converts alkanes to carbon dioxide and water.   Cracking of hydrocarbons at high temperatures yield a mixture of smaller  alkanes and alkenes. Halogenation of alkanes occurs with halogen in the  presence of heat or light and through a radical mechanism. In the mechanism of  halogenation, radicals are formed in initiation.  In propagation, radicals are consumed and  radicals are formed.  In termination, the  radical are consumed.
                        Reactions  of Cycloalkanes
                          Halogenation of cycloalkanes occurs in the presence of  heat or light to form a halogenated cycloalkane. Ring opening of cyclopropane  occurs with hydrogen halide to form 1-halopropane. Ring opening of cyclopropane  occurs with halogen to give 1,3-dichloropropane. Ring opening of cyclopropane  occurs with hydrogen to produce propane.   Ring opening of cyclobutane occurs with hydrogen to produce butane.