caa a22 4500 477139566 CHVBK 20180405111728.0 cr unu---uuuuu 170330e19970201xx s 000 0 eng 10.1007/BF02767923 doi (NATIONALLICENCE)springer-10.1007/BF02767923 Potentiometric measurements of the first hydrolysis quotient of magnesium(II) to 250°C and 5 molal ionic strength (NaCl) [Elektronische Daten] [Donald Palmer, David Wesolowski] The first molal hydrolysis quotient, Q1.1, of Mg2+ was measured potentiometrically from 1 to 250°C at ionic strengths of 0.11, 0.31, 1.01, and 5.0 mol-kg-1 in an aqueous NaCl medium using a hydrogen-electrode, concentration cell. Only hydrolysis of the first four percent of the magnesium in solution could be followed before precipitation of brucite, Mg(OH)2(cr), occurred. The log Q1.1 values were fitted as a function of temperature and ionic strength using four adjustable parameters. The resulting constants are compared with the limited existing low temperature data. At infinite dilution and 25°C the following quantities are reported: logK 1.1 = -11.68±0.05, †Hso = 70.1±1.2 kJ-mol-1, †So = 11±4 J-K-1-mol-1, and †C p o = 0 J-K-1-mor-1. At each ionic strength, including the values extrapolated to infinite dilution, the heat capacity change for the hydrolysis reaction was zero,i.e., logQ 1.1 was found to be a linear function of the reciprocal temperature in Kelvin, at least over the measured range of l-250°C. The hydrolysis constants at infinite dilution were modeled to 550°C and two kbar pressure with a function incorporating solvent density using published results obtained at these extreme conditions. Plenum Publishing Corporation, 1997 Magnesium nationallicence hydrolysis nationallicence potentiometry nationallicence thermodynamics nationallicence aqueous nationallicence temperature nationallicence ionic strength nationallicence Palmer Donald Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Building 4500S, P.O. Box 2008, 37831-6110, Oak Ridge, Tennessee aut Wesolowski David Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Building 4500S, P.O. Box 2008, 37831-6110, Oak Ridge, Tennessee aut Journal of Solution Chemistry Springer-Verlag 26/2(1997-02-01), 217-232 0095-9782 26:2<217 1997 26 10953 https://doi.org/10.1007/BF02767923 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02767923 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Palmer Donald Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Building 4500S, P.O. Box 2008, 37831-6110, Oak Ridge, Tennessee aut NATIONALLICENCE 700 1- Wesolowski David Chemical and Analytical Sciences Division, Oak Ridge National Laboratory, Building 4500S, P.O. Box 2008, 37831-6110, Oak Ridge, Tennessee aut NATIONALLICENCE 773 0- Journal of Solution Chemistry Springer-Verlag 26/2(1997-02-01), 217-232 0095-9782 26:2<217 1997 26 10953 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer