C 73 Conductivity, thermal measurements, and phase diagram of the Na2S2O7-NaHSO4 system [Text] / G. Hatem [et al.] // The Journal of Physical Chemistry B. - 1999. - V. 103, N 6. - P1027-1030. - Bibliogr.: 14 ref. . - ISSN 1089-5647 Рубрики: ХИМИЧЕСКИЕ НАУКИ Кл.слова (ненормированные): ДИАГРАММЫ ФАЗОВЫЕ -- ФАЗОВЫЕ ДИАГРАММЫ -- ПРОВОДИМОСТЬ -- ИЗМЕРЕНИЯ ТЕРМИЧЕСКИЕ -- ТЕРМИЧЕСКИЕ ИЗМЕРЕНИЯ -- БИНАРНЫЕ СИСТЕМЫ -- СИСТЕМЫ БИНАРНЫЕ -- ЗАВИСИМОСТИ ТЕМПЕРАТУРНЫЕ -- ТЕМПЕРАТУРНЫЕ ЗАВИСИМОСТИ -- Na2S2O7-NaHSO4 -- K2S2O7-KHSO4 -- Na2S2O7 -- Na -- K -- НАТРИЙ -- КАЛИЙ -- NaHSO4 -- K2S2O7 -- KHSO4 -- ХИМИЯ Аннотация: The conductivity of the Na2S2O7-NaHSO4 binary system has been measured for 15 different compositions in the full composition range, and in the temperature range 400-700 K. Phase transition temperatures were obtained, and the phase diagram was constructed. It is of the simple eutectic type, where the eutectic is found to have the composition X(NaHSO4)=0.97, as calculated from the measured thermodynamic properties, and to melt at 179 C. The partial enthalpy and entropy of mixing have been obtained, and the negative entropy points to a structural order of the melt, presumably due to hydrogen bonding, as found earlier for the K2S2O7-KHSO4 system. For each composition measured of the Na2S2O7-NaHSO4 system in the molten state, the conductivity has been expressed by equations of the form k=A(X)+B(X)(T-Tm)+C(X)(T-Tm)(2), where Tm is the intermediate temperature of the measured temperature range |