Simple predictive relationships for the estimation of pure normal alkanes' thermodynamic properties, like transition temperatures, phase change enthalpies, and heat capacities in the solid or liquid state, are established as a function of carbon atom number n(c), by combining our own calorimetric experimental results and a general review of literature data. This study underlines that total and melting enthalpies vary linearly with n(c) carbon atom number, whatever the parity of n(c), while order-disorder transition enthalpies show a quadratic variation and an alternating effect between odd- and even-numbered n-alkanes. Heat capacity variations versus temperature and the carbon chain length were represented by a model of group contributions for the liquid phase and by an expression derived from Einstein's model for the solid state.