Excess molar enthalpies (E)(m) and excess molar volumes V-m(E) have been determined for {xCH(3)(CH2)(2)CH3 + (1 - x)CH3CH2OH} at the temperatures (298.15, 323.15, and 348.15) K and at the pressures (5, 10, and 15) MPa. Large and positive H-m(E) and C-p,m(E), are explained in terms of chemical, physical, and structural effects. The small (partial derivative H-m(E)/partial derivative p)tau, which changes sign from positive to negative with increasing x, is explained by a small V-m(E), which changes from negative to positive as x increases.