Heat capacities and isentropic compressibilities of electrolytes in propylene carbonate at 25 °C

1987 ◽  
Vol 65 (6) ◽  
pp. 1402-1406 ◽  
Author(s):  
Gérald Perron ◽  
Guylaine Trudeau ◽  
Jacques E. Desnoyers
Keyword(s):  
Propylene Carbonate ◽  
Infinite Dilution ◽  
Alkali Halides ◽  
Heat Capacities ◽  
Apparent Molar Heat Capacities ◽  
Solvent Interactions ◽  
Isentropic Compressibilities ◽  
Ionic Size ◽  
Tetraalkylammonium Halides ◽  
Heat Capacities Of Electrolytes

The heat capacities per unit volume and sound velocities of many solutions of 1:1 electrolytes in propylene carbonate (PC) were measured at 25 °C. Combining these data with previously published densities, apparent molar heat capacities and isentropic compressibilities were calculated. By extrapolation to infinite dilution, the corresponding standard partial molar quantities were obtained. The heat capacities and compressibilities of water in PC were also calculated. Through ionic additivity, it was possible to calculate these functions for all alkali and tetraalkylammonium halides. The magnitude and trends with ionic size of the heat capacities of electrolytes in PC are similar to those in other aprotic solvents such as acetonitrile (ACN) and dimethylformamide (DMF) and significantly different from those in water. On the other hand, with compressibilities, the magnitudes sssssssare the same in PC and in water for alkali halides but significantly different for tetraalkylammonium halides. The trends with ionic size are similar to those in ACN. These effects can be interpreted through ion–solvent interactions. The separation of these thermodynamic functions into their ionic contributions is also discussed.

Isentropic compressibilities of electrolytes in acetonitrile at 25 °C

1981 ◽  
Vol 59 (14) ◽  
pp. 2212-2217 ◽  
Author(s):  
Isobel Davidson ◽  
Gérald Perron ◽  
Jacques E. Desnoyers
Keyword(s):  
General Formula ◽  
Free Space ◽  
Infinite Dilution ◽  
Inorganic Ions ◽  
The Other ◽  
Square Root ◽  
Isentropic Compressibilities ◽  
Ionic Size ◽  
Acetonitrile Solutions ◽  
Solvent Molecules

The sound velocities of some 1:1 electrolytes in acetonitrile were measured by the "sing around" method. Apparent molal isentropic compressibilities [Formula: see text] of the electrolytes were derived from these data and from previously determined densities. Infinite dilution partial molal compressibilities [Formula: see text] were obtained by extrapolation from the plot [Formula: see text] against the square-root of the molality. Approximate ionic values are obtained on the assumption that [Formula: see text] In general, [Formula: see text] of inorganic ions are much more negative in acetonitrile than in water and, except for Li+, show little dependence on ionic size. On the other hand, [Formula: see text] of tetraalkylammonium bromides become increasingly positive as the size of the cations increases. This is again in contrast with [Formula: see text] of these electrolytes in water which remain negative. These large positive values arise from the free space between the ions and the solvent molecules, which is large in acetonitrile solutions.

Apparent molar heat capacities and volumes of unsaturated heterocyclic solutes in aqueous solution at 25 °C

1980 ◽  
Vol 58 (7) ◽  
pp. 704-707 ◽  
Author(s):  
Octavian Enea ◽  
Carmel Jolicoeur ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Heterocyclic Compounds ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Group Additivity ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Partial Molar Heat Capacities

Measurements at 25 °C with flow calorimeters and densimeters have led to heat capacities and densities of aqueous solutions of 15 unsaturated heterocyclic compounds containing nitrogen. From the results of these measurements we have obtained apparent molar heat capacities and volumes of the solutes. Extrapolations to infinite dilution have led to corresponding standard state apparent and partial molar heat capacities and volumes, which have been analyzed in terms of atomic and group additivity relationships.

Thermodynamics of aqueous carbon dioxide and sulfur dioxide: heat capacities, volumes, and the temperature dependence of ionization

1983 ◽  
Vol 61 (11) ◽  
pp. 2509-2519 ◽  
Author(s):  
José A. Barbero ◽  
Loren G. Hepler ◽  
Keith G. McCurdy ◽  
Peter R. Tremaine
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Experimental Heat ◽  
Chemical Relaxation ◽  
Vibrating Tube Densimeter ◽  
New Equation

A flow microcalorimeter and vibrating tube densimeter were used at 25 °C to obtain apparent molar heat capacities and volumes of aqueous NaHCO3, KHCO3, NaHSO3, and KHSO3, from 0.1 to 1.0 mol kg−1, aqueous CO2 from 0.01 to 0.10 mol kg−1 and aqueous SO2 from 0.045 to 2.0 mol kg−1. The contribution of "chemical relaxation" (changes in equilibrium state and enthalpy due to change in temperature) to the experimental heat capacities of aqueous SO2 required special attention, leading to the derivation of a new equation for calculating this effect. Standard state values for the heat capacities and volumes of aqueous CO2, SO2, HCO3−, and HSO3− were obtained from the apparent molar properties by extrapolation to infinite dilution. Combining these results with other thermodynamic data from the literature gave estimates of log K1b the equilibrium constant for the first neutralization of CO2 and SO2, at high temperatures. The results for CO2 reproduce very accurate literature values to within 0.2 at 200 °C. The expression for the reaction [Formula: see text] log K1b = 22.771 + 2776.0/T–8.058 log T, is consistent with the sparse and limited experimental data.

Enthalpies and heat capacities of solution for tert-butyl chloride and bromide in alcohols. Application of SPT, SRMR, and MS

1987 ◽  
Vol 65 (7) ◽  
pp. 1474-1478 ◽  
Author(s):  
R. M. C. Gonçalves ◽  
A. M. N. Simões
Keyword(s):  
Infinite Dilution ◽  
Heat Capacities ◽  
Scaled Particle Theory ◽  
Butyl Chloride ◽  
Particle Theory ◽  
Solvent Interactions ◽  
Tert Butyl ◽  
Tert Butyl Chloride ◽  
Solvent Solvent ◽  
Enthalpies Of Solvation

Enthalpies and heat capacities of solution at infinite dilution for tert-butyl chloride and bromide in several alcohols are reported at 30, 35, and 40 °C.The Scaled Particle Theory (SPT), the Sinanoglu, Reiss, and Moura Ramos (SRMR) and the Model Solute (MS) methods were applied to the enthalpies of solvation. Significant differences in the results calculated from these theories were analysed and data discussed in terms of solute–solvent–solvent interactions.

Apparent molar heat capacities and volumes of aqueous electrolytes at 25 °C: Cr(NO3)3, LaCl3, K3Fe(CN)6, and K4Fe(CN)6

1979 ◽  
Vol 57 (21) ◽  
pp. 2798-2803 ◽  
Author(s):  
Jan J. Spitzer ◽  
Inger V. Olofsson ◽  
Prem Paul Singh ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solutions ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Aqueous Electrolytes ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes ◽  
High Charge ◽  
Flow Calorimeter ◽  
Partial Molar Properties

We have used a flow calorimeter and a flow densimeter for measurements at 25 °C of heat capacities and densities of aqueous solutions of four electrolytes of high charge type: LaCl3, Cr(NO3)3, K3Fe(CN)6, and K4Fe(CN)6. Results of these measurements have been used for calculating corresponding apparent molar heat capacities and apparent molar volumes, which have been extrapolated to infinite dilution to obtain the corresponding standard state apparent molar and partial molar properties. Uncertainties resulting from extrapolations of heat capacities are discussed. Results of our measurements are compared with those of earlier related investigations.

Apparent molar heat capacities and volumes of aqueous electrolytes at 25 °C: Na2SO4, K2SO4, Na2S2O3, Na2S2O8, K2S2O8, K2CrO4, Na2MoO4, and Na2WO4

1978 ◽  
Vol 56 (14) ◽  
pp. 1871-1873 ◽  
Author(s):  
Inger V. Olofsson ◽  
Jan J. Spitzer ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solutions ◽  
Infinite Dilution ◽  
Heat Capacities ◽  
Aqueous Electrolytes ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Density Measurements ◽  
Dilute Aqueous Solutions

We have made beat capacity and density measurements leading to apparent molar beat capacities and volumes for dilute aqueous solutions of Na2SO4, K2SO4, Na2S2O3, Na2S2O8, K2S2O8, K2CrO4, Na2MoO4, and Na2WO4. We have used these apparent molar quantifies to extrapolate to infinite dilution to obtain the corresponding standard state apparent and partial molar quantities. These latter values have been used in calculation of conventional ionic beat capacities and volumes.

Apparent molar heat capacities and volumes of aqueous electrolytes at 25°C: NaIO3, KMnO4, and MnCl2

1979 ◽  
Vol 28 (1) ◽  
pp. 155-160 ◽  
Author(s):  
Jan J. Spitzer ◽  
Inger V. Olofsson ◽  
Prem Paul Singh ◽  
Loren G. Hepler
Keyword(s):  
Heat Capacities ◽  
Aqueous Electrolytes ◽  
Apparent Molar Heat Capacities
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