Excess Thermal Expansion Factors of Polar Mixtures and Aqueous Solutions

Excess thermal expansion factor of non-polar mixtures is the order of 10−6 K−1 and within an experimental error. On the other hand, those of polar mixtures and aqueous solutions are very large and the order of 10–5 K−1, up to the order of 10−4 K−1 in an extreme case. The excess thermal expansion factors express well the excesses of entropy volume cross fluctuation and enthalpy volume cross fluctuation estimated from thermal expansion factor and molar volume. Those of aqueous solutions are, however, reduced by small molar volume of water.