VOLUME PROPERTIES AND STRUCTURE OF AQUEOUS SOLUTIONS OF UREA AT 263-348 K
The apparent molar volume of urea φ in aqueous solution in the range <i>Т</i> = 273-323 K and <i>m</i> = 1-10 (molality) depends linearly on <i>m</i><sup><i></i>1/2</sup>. An equation for φ(<i>m</i>, <i>T</i>) was derived. The partial molar characteristics of urea and water (volume, dilatability, and temperature coefficients of volumes) were calculated. The dependences have characteristic points (extrema, inflection points), shifted to the region of lower temperatures for dilute solutions. The dependences for 2<i>m</i> and 4<i>m</i> of the urea solution retain the characteristics of the <i>Y</i><sub><i></i>1</sub>(<i>T</i>) of pure water. In these solutions, the proper structure of water is preserved.