Densities of aqueous sodium chloride, potassium chloride, magnesium chloride, and calcium chloride binary solutions in the concentration range 0.5-6.1 m at 25, 30, 35, 40, and 45.degree.C

Abstract

The densities of the binary solutions Nad-H20, KCI-H20, MgClj-HjO, and CaCI2-H20 were measured at 1 atm, from 25 to 45 °C and from 0.5 to 6.1 m, by using a commercially available oscillating tube-type densitometer. The data sets were described by using least-squares polynomial regression analysis. Statistical evaluation of the experimental data Indicates that uncertainties In the concentrations of the solutions due to adsorption of water by the salts during weighing Is the major source of error In the density measurements. The magnitude of this error Is greater for MgCI2 and CaCI2 solutions because of the hygroscopic nature of these salts. The measured densities of NaCI and KCI solutions have a standard deviation of 5.515 X 10~3 g/cm3. Standard deviations for MgCI2 and CaCI2 solutions range from 2.329 X 10~4 to 2.334 X 10"4 g/cm3 and from 2.796 X 10'4 to 2.839 X 1CT4 g/cm3, respectively. The experimental density data compare well with published values.

Effective solvent mediated potentials of Na+ and Cl− ions in aqueous solution: temperature dependence

“…1 Temperature dependence of the density of Na + -Cl À aqueous solution. Green squares-explicit water MD simulations (this work), red circles-experimental data for Na + -Cl À aqueous solution, 37 blue triangles-experimental data for pure water. 39 Fig .…”

Volumetric properties of water, and solutions of sodium chloride and potassium chloride at temperatures fromT= 277.15 K toT= 343.15 K at molalities of (0.1, 0.5, and 1.0)mol·kg−1

“…At constant temperature, a typical behaviour of α(T, m) with respect to molality is shown in figure 7 where the present and literature cubic expansion coefficients of sodium chloride solutions and potassium chloride solutions are plotted for T = 298.15 K. Cubic expansion coefficients based on 5 K or 10 K intervals were reported explicitly by Gibson and Loeffler, (8,20) Jones et al, (9) and Rogers and Pitzer, (18) the additional values were calculated here from the available literature densities ρ(T, m). (66,67,69,71,73) Although the α(T, m) values were derived from different sources their scatter is reasonable. Since we are more interested in the temperature dependence, the α(T, m) are limited only to three molalities at each temperature, and all the available cubic expansion coefficients were fitted only for T = 298.…”

“…(24,61,70,77) The usual reasons were large temperature gaps and different molalities. In only a few investigations were measurements of density performed at closely spaced temperature intervals and at fixed molalities {1 K intervals, m(NaCl) = 0.11425 mol·kg −1 and m(KCl) = 0.11528 mol·kg −1 from T = 293.15 K to T = 313.15 K by Millero and Drost-Hansen; (61) 5 K intervals, m(KCl) = 0.1355 mol·kg −1 from T = 278.15 K to T = 318.15 K by Bull and Breese; (62) m(NaCl, or KCl) = (0.05, 0.1, 0.5, 1.0, 2.0, 3.0, 4.0, and 5.0) mol·kg −1 from T = 288.15 K to T = 328.15 K by Isono; (69) m(NaCl) = 1.0 mol·kg −1 and m(KCl) = (0.5 and 1.0) mol·kg −1 from T = 298.15 K to T = 318.15 K by Romankiw and Chou (71) }. The studies devoted to the evaluation of molar volumes at constant temperature are much more numerous than those dealing with the volume against temperature relations at constant molality and pressure.…”

Volumes of MgCl2(aq) at temperatures from 298 K to 623 K and pressures up to 30 MPa

“…The fairly extensive volumetric data for MgCl 2 (aq) at atmospheric pressure and near-ambient temperatures have been reviewed on several occasions (8)(9)(10) and need not be discussed here except to note that one useful reference (11) has often been overlooked in these otherwise comprehensive accounts. At elevated pressures, Chen et al (12) used a magnetic float densimeter to measure densities between the temperatures 273 K and 323 K, pressures up to 100 MPa, and molalities below 0.32 mol·kg −1 .…”