Calorimetric measurements show that the heats of mixing two n-alkanes (of similar chainlength) in the liquid phase, are very small, and may often be neglected. Also, calculation of the entropy of n-alkane binary mixtures in the liquid and in the high temperature solid alpha-RII Rotator phase, by integration of experimentally obtained enthalpies, show that the excess entropies are negligible for all practical purposes. n-Alkane liquid mixtures between neighbouring homologs may therefore be considered as ideal solutions.