Standard state thermodynamic properties of aqueous sodium perrhenate using high dilution calorimetry up to 598.15K

High dilution calorimetric determination of the standard state thermodynamic differences between the properties of H+(aq) and Na+(aq) up to 598.15K

“…The Debye-Hückel limiting slope for enthalpy, A H , calculated from present study at temperature of 596.30 K is in good agreement with the best theoretical value in literature at that temperature. This agreement verifies that HReO 4 ðaqÞ obeys the simple limiting law for strong electrolytes and that extrapolations from low concentrations to infinite dilutions are justified up to temperature of 596.30 K. and (b): -, NaReO4ðaqÞ [24]; -, HReO4ðaqÞ, this study.…”

“…a Calculated from equation (11). b Djamali et al [24]. c Molar volume contribution calculated from unified theory of electrolytes [21].…”

“…The standard state partial molar heat capacities of HReO 4 ðaqÞ from present study and those of NaReO 4 ðaqÞ [24] are compared in figure 5. The results show the same general features as the other electrolytes at high temperatures and further confirms the dominance of electrostatic effects over chemical or structural effects as the critical temperature of water is approached [26].…”

“…The experimental heats of dilution for NaClðaqÞ [14], NaReO 4 ðaqÞ [24], and HReO 4 ðaqÞ were calculated from the integral heats of solution [12] at the highest temperature (596.30 K) and are summarized in figure 4. These heats of dilution were then used to calculate the Debye-Hückel limiting slope for enthalpy, A H , giving a value of (122 ± 6) kJ Á mol À3/2 Á kg 1/2 at temperature of 596.30 K (figure 4).…”