Volumetric properties of aqueous solutions of malonic acid

• Densities of aqueous solutions of malonic acid were measured in wide m and T ranges.
• Determined densities permitted to evaluate the cubic expansion coefficients.
• And the apparent molar volumes and the second derivatives of volume with respect to T.
• The structure of water when malonic acid is dissolved in it, is discussed.

Densities of aqueous solutions of malonic acid in the (0.01–1.0) mole·kg−1 concentration range were measured at 5 K intervals, from 278.15 K to 343.15 K. These densities served to determine the apparent molar volumes. Changes of densities with temperature permitted evaluation of the cubic expansion coefficients and the derivatives of isobaric heat capacities with respect to pressure which are interrelated with the second derivatives of volume with respect to temperature. Thermal dependence of volumetric properties of aqueous solutions of malonic acid is examined in terms of changes in the structure of water.