Apparent molar volumes and apparent molar heat capacities of aqueous potassium hydrogen phthalate (KHP) and potassium sodium phthalate (KNaP) at temperatures fromT = 278.15 K toT = 393.15 K at the pressure 0.35 MPa |
| |
| Affiliation: | 1. Volgograd State Technical University, Prospect Lenin 28, Volgograd 400131, Russia;2. JSC Federal Scientific and Production Centre «Titan – Barricady», Prospect Lenin b/n, Volgograd 400071, Russia;3. Branch of LUKOIL-Engineering VolgogradNIPImorneft, Prospect Lenin 96, Volgograd 400078, Russia;1. Department of Physical Chemistry, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock, Germany;2. Department “Science and Technology of Life, Light and Matter, University of Rostock, Dr-Lorenz-Weg 1, D-18059 Rostock, Germany;3. Department BCI, Laboratory of Thermodynamics, Technische Universität Dortmund, Emil-Figge-Str 70, D-44227 Dortmund, Germany;1. Graduate School of Agriculture, Hokkaido University, Sapporo 060-8589, Japan;2. Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan;1. Dept .of Physics, Kuvempu University, Shankaraghatta, Karnataka 577451, India;2. Dept. of physics, Mangalore University, Mangalore, Karnataka 574199, India;1. Faculty of Mechanics and Mathematics of Lomonosov Moscow State University, Russia;2. Institute of Mechanics of Lomonosov Moscow State University, Russia;3. Mechanical Engineering Research Institute of the Russian Academy of Sciences, Russia |
| |
| Abstract: | A vibrating-tube densimeter (DMA 512P, Anton Paar, Austria) was used to investigate the densities and volumetric properties of aqueous potassium hydrogen phthalate (KHP) and potassium sodium phthalate (KNaP). Measurements were made at molalities m from (0.006 to 0.66)mol · kg − 1, at temperatures from 278.15 K to 368.15 K and at the pressure 0.35 MPa. The densimeter was calibrated through measurements on pure water and on 1.0 mol · kg − 1NaCl(aq). We also used a twin fixed-cell, power-compensation, differential-output, temperature-scanning calorimeter (NanoDSC 6100, Calorimetry Sciences Corporation, Spanish Fork, UT, U.S.A.) to measure solution heat capacities. This was accomplished by scanning temperature and comparing the heat capacities of the unknown solutions to the heat capacity of water. Apparent molar volumes Vφand apparent molar heat capacities Cp, φof the solutions were calculated and fit by regression to equations that describe the surfaces (Vφ, T, m) and (Cp, φ, T, m). Standard state partial molar volumesV2o and heat capacities Cp,2owere estimated by extrapolation to the m = 0 plane of the fitted surfaces. Previously determinedCp, φ for HCl(aq) and NaCl(aq) were used to obtain (ΔrCp, m, T, m) for the proton dissociation reaction of aqueous hydrogen phthalate. This (ΔrCp,m, T, m) surface was created by subtracting Cp,φfor KHP(aq) and for NaCl(aq) from the sum of Cp,φfor KNaP(aq) and for HCl(aq). Surfaces representing (ΔrHm, T, m) and (pQa, T, m), where pQadenotes the molality equilibrium quotient, were created by integration of our (ΔrCp,m, T, m) surface using values for (ΔrHm, m) and (pKa, m) at T = 308.15 K from the literature as integration constants. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
