Structural and Physical Properties of Alkanes

The common structural feature of all alkanes is the carbon chain. This chain influences the physical properties of not only alkanes but also any organic molecules possessing such a backbone. This section will address the properties and physical appearance of such structures. 

Alkanes exhibit regular molecular structures and properties 

Draw zigzag hashed-wedged line structures for 2-methylbutane and 2,3-dimethylbutane. 

The longest man-made linear alkane is C39oH782 synthesized as a molecular model for polyethene (polyethylene). It crystallizes as an extended chain, but starts folding readily (picture) at its melting point of 132°C, in part due to attractive intramolecular London forces. 

Attractive forces between molecules govern the physical properties of alkanes 

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