Molecular Formulas of Alkanes

A series of compounds, like the n-alkanes, that differ only by the number of —CH2— groups, is called a homologous series, and the individual members of the series are called homolt For example, butane is a homolog of propane, and both of these are homologs of hexane and decane. 

Although we have derived the C H2 +2 formula using the unbranched u-alkanes, it applies to branched alkanes as well Any isomer of one of these n-alkanes has the same molecular formula. Just as butane and pentane follow the C H2 +2 l eir branched isomers isobutane, isopentane, and neopentane also follow the rule. 

1 TABLE 3-2 Formulas and Physical Properties of the Unbranched Alkanes, Called the n-Alkanes  

Alkane Number of Carbons Structure Formula Boiling Point (°C) Melting Point (°C) Density  

---

Classification of Hydrocarbons (Review) 87 3-2 Molecular Formulas of Alkanes 88 3-3 Nomenclature of Alkanes 89... 

---