Two structural isomers of C6H14 are shown below.
• n-hexane: CH3CH2CH2CH2CH2CH3
• 2,2-dimethylbutane (neopentane): (CH3)3CCH3
Both substances have the same molar mass (86 g mol−1), yet their macroscopic properties differ markedly.
(1) Describe how the three–dimensional shapes of the two isomers differ and identify which isomer has the larger surface area available for intermolecular contact.
(2) Predict which isomer has the higher melting point. Support your prediction with a discussion of the types and relative strengths of the intermolecular forces operating in the solids.
(3) At 25 °C, which isomer would you expect to exhibit the higher vapor pressure? Explain how your answer is consistent with the analysis in part (b).