Estimation models for Henry's law constant (H), water solubility (S_w), vapor pressure (P_v), and octanol/water partition coefficient (K_ow) of nonelectrolytes are derived from basic thermodynamic equations. The resultant regression equations require only two molecular descriptors, which are available from chemical structure through semiempirical quantum chemical calculations: free energy of solvation (δG_s), and molecular contact surface area (CSA). Results are presented for a set of 17 benzenes with experimental data taken from literature, yielding squared correlation coefficients r²_adj (adjusted for degrees of freedom) between 0.83 and 0.95. The discussion includes limitations from currently available continuum solvation models to calculate δG_s, aspects of potential error compensation, and the suitability of this approach to understand macroscopic compound properties in terms of calculated quantities that represent distinct types of intermolecular interactions.