Volume change for the formation of magnesium sulfate ion pairs at various temperatures

1974 ◽  
Vol 78 (13) ◽  
pp. 1287-1294 ◽  
Author(s):  
Frank J. Millero ◽  
William L. Masterton
Keyword(s):  
Magnesium Sulfate ◽  
Volume Change ◽  
Ion Pairs ◽  
Sulfate Ion

scholarly journals Water-separated ion pairs cause the slow dielectric mode of magnesium sulfate solutions

2018 ◽  
Vol 148 (22) ◽  
pp. 222812 ◽  
Author(s):  
Shavkat I. Mamatkulov ◽  
Klaus F. Rinne ◽  
Richard Buchner ◽  
Roland R. Netz ◽  
Douwe Jan Bonthuis
Keyword(s):  
Magnesium Sulfate ◽  
Ion Pairs ◽  
Sulfate Solutions

Thermodynamics and mechanism of hydrophobic interaction

1977 ◽  
Vol 30 (4) ◽  
pp. 741 ◽  
Author(s):  
DG Oakenfull ◽  
DE Fenwick
Keyword(s):  
Free Energy ◽  
Volume Change ◽  
Hydrophobic Interaction ◽  
Ion Pairs ◽  
Hydrophobic Hydration ◽  
Partial Molar Volumes ◽  
Hydrocarbon Chain ◽  
Ion Pair ◽  
Pair Formation ◽  
Ion Pair Formation

.In the mixed solvent, 0.1 mole fraction ethanol-water, long-chain decyltrimethylammonium carboxylates form ion pairs. Ion-pair association constants (and hence the free energy of ion-pair formation) can be measured conductometrically. It is possible to separate the hydrophobic from the electrostatic contribution to the free energy of ion-pair formation by systematically varying the hydrocarbon chain length. We report measurements of the free energy of hydrophobic interaction (ΔG°HI) over the temperature range 278-328 K. The value of ΔG°HI becomes more negative (stronger hydrophobic interaction) with increasing temperature. The temperature coefficient of ΔG°HI was used to calculate the enthalpy (ΔH°HI) and entropy (ΔS°HI) of hydrophobic interaction. At low temperature the entropic contribution to the free energy is the larger but ΔH°HI, dominates at temperatures above c. 324 K. The volume change of hydrophobic interaction was similarly estimated from the volume change of ion-pair formation. We obtained values of apparent molar volume of the decyltrimethylammonium carboxylates (over a range of concentrations) from very precise density measurements. These could then be combined with the appropriate ion-pair association constant (from the conductance measurements) to give the partial molar volumes of the free ions and the ion pair. Hydrophobic interaction was found to be accompanied by a substantial increase in volume amounting to 10.2 ± 0.3 ml mol-1 for each pair of interacting methylene groups. Our results support the view that hydrophobic interaction occurs with a further ordering of water molecules over and above that which exists in the hydrophobic hydration layer surrounding an isolated hydrophobic molecule.

ION PAIRS IN A SOLONETZIC SOIL

1983 ◽  
Vol 63 (3) ◽  
pp. 479-484 ◽  
Author(s):  
A. ALZUBAIDI ◽  
G. R. WEBSTER
Keyword(s):  
Ion Pairs ◽  
Soil Samples ◽  
The Other ◽  
Sulfate Ion ◽  
Carbonate Ion ◽  
Low Concentrations ◽  
Solonetzic Soil ◽  
Ap Horizon ◽  
Ion Activities ◽  
High Concentrations

The kinds and concentrations of the major ion pairs were determined in saturation extracts of 141 soil samples collected from a Solonetzic soil treated with various kinds of tillage combined with surface-applied chemical amendments. The correlations between concentrations of ion pairs and EC and pH of saturation extracts were statistically tested. Sulfate ion pairs NaSO4−, MgSO40 and CaSO40 occurred in relatively high concentrations. The other ion pairs were of low concentrations. Of the total soluble Ca, ion pairs ranged from 20.8% in the Ap horizon to 50.5% in the Csk horizon and Mg was approximately the same. The comparable values for Na were 0.8% and 4.6%, respectively. Ion pairs NaSO4−, KSO4−, MgSO40 and CaSO40 were significantly correlated with EC. Only carbonate ion pairs were significantly correlated with pH. Correcting concentrations of Na, Ca and Mg for ion pairs and activities changed considerably the SAR values in the Bnt1 horizon. Key words: Ion pairs, Solonetzic soils, ion activities

scholarly journals SODIUM, MAGNESIUM, AND CALCIUM SULFATE ION-PAIRS IN SEAWATER AT 25C1

1969 ◽  
Vol 14 (5) ◽  
pp. 686-692 ◽  
Author(s):  
Dana R. Kester ◽  
Ricardo M. Pytkowicx
Keyword(s):  
Calcium Sulfate ◽  
Ion Pairs ◽  
Sulfate Ion ◽  
Sodium Magnesium

Ion-Pair Formation of Sodium Salts of Several Oxo Anions and Cadmium Halides in Water and the Distribution of Monovalent Sulfate Ion Pairs in Nitrobenzene

2010 ◽  
Vol 55 (7) ◽  
pp. 2463-2469 ◽  
Author(s):  
Yoshihiro Kudo ◽  
Daisuke Todoroki ◽  
Naoki Horiuchi ◽  
Shoichi Katsuta ◽  
Yasuyuki Takeda
Keyword(s):  
Ion Pairs ◽  
Ion Pair ◽  
Pair Formation ◽  
Sulfate Ion ◽  
Sodium Salts ◽  
Ion Pair Formation ◽  
Oxo Anions
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