Homologous Series The 1-Substituted Alkanes

We now turn to our first homologous series of organic compounds, 1- 

Members of this series are composed of tetracoordinate, almost tetrahedral, and putatively sp3 hybridized carbon atoms. Their structures differ by a constant CH2, or methylene group. The difference between the gas phase enthalpies of formation of successive members of this series, i.e. 

If the principle of bond additivity were completely valid and experiments were without flaws or glitches , the quantity 5i(n, X) would be a constant independent of the value of n and of the substituent X. This is simply shown if we recast enthalpies of formation in terms of bond energies where the sum of bond energies for a molecule may be thermodynamically equated to the energy of atomization. Assuming both the enthalpies of formation and atomization energies refer to the molecule at the same temperature, a simple correction for 

A practicable approach to studying the enthalpy-of-formation differences in eq. 1 recognizes that the gaseous and liquid enthalpies of formation for compounds in a homologous series are linearly correlated with the number of carbon (nc) atoms in the molecules. For compounds in the gaseous state 

Constants from the linear regression analysis of equation 3 for several homologous series (kJ mol1) 

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