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.

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.

Thermodynamic properties of aqueous diethanolamine (DEA), N,N-dimethylethanolamine (DMEA), and their chloride salts: apparent molar heat capacities and volumes at temperatures from 283.15 to 328.15 K

2000 ◽  
Vol 78 (1) ◽  
pp. 151-165 ◽  
Author(s):  
Christopher Collins ◽  
Joelle Tobin ◽  
Dmitri Shvedov ◽  
Rom Palepu ◽  
Peter R Tremaine
Keyword(s):  
Partial Molar Volumes ◽  
Heat Capacities ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes ◽  
Partial Molar Heat Capacities ◽  
Relaxation Effects ◽  
Chemical Relaxation ◽  
Young's Rule ◽  
Vibrating Tube Densimeter ◽  
Chloride Salts

Apparent molar heat capacities Cp,ϕ and apparent molar volumes Vϕ for aqueous diethanolamine (HOC2H4)2NH, diethanolammonium chloride (HOC2H4)2NH2Cl, N,N'-dimethylethanolamine (HOC2H4)(CH3)2N, and N,N'-dimethylethanolammonium chloride (HOC2H4)(CH3)2NHCl were determined from 283.15 to 328.15 K with a Picker flow microcalorimeter and vibrating tube densimeter. The experimental results have been analyzed in terms of Young's Rule with the Guggenheim form of the extended Debye-Hückel equation and appropriate corrections for chemical relaxation effects. These calculations lead to standard partial molar heat capacities and volumes for the neutral amines, (HOC2H4)2NH(aq) and (HOC2H4)(CH3)2N(aq), and the ions (HOC2H4)2NH2+(aq) and (HOC2H4)(CH3)2NH+(aq) over the experimental temperature range. Key words: standard partial molar volumes, standard partial molar heat capacities, diethanolamine, dimethyethanolamine, aqueous alkanolamine ionization.

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 some aqueous solutions of aliphatic amino acids at 288.15, 298.15, 313.15, and 328.15 K

1994 ◽  
Vol 72 (2) ◽  
pp. 362-368 ◽  
Author(s):  
Andrew W. Hakin ◽  
Michelle M. Duke ◽  
Sheri A. Klassen ◽  
Robert M. McKay ◽  
Kathryn E. Preuss
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Heat Capacities ◽  
Apparent Molar Volumes ◽  
Protein Chemistry ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes

The thermodynamics of amino acid systems are key to the understanding of protein chemistry. We have found that many previous studies of the apparent molar volumes and heat capacities of aqueous solutions of amino acids were conducted at the standard temperature of 298.15 K. This does not allow for the fact that most biological processes occur at temperatures removed from this standard condition.In an attempt to address this imbalance we have measured densities and heat capacities for aqueous solutions of glycine, L-alanine, L-serine, and L-threonine at 288.15, 298.15, 313.15, and 328.15 K using a Picker flow microcalorimeter. Apparent molar volumes and heat capacities, and the associated standard state partial molar properties have been calculated. Constant pressure variations of revised Helgeson, Kirkham, and Flowers equations have been fitted to calculated standard state volumes and heat capacities over the temperature range 288.15 to 328.15 K. These equations may be used to estimate standard state volumes and heat capacities, and hence equilibrium constants, for aqueous amino acid systems at higher temperatures.

The volumetric and thermochemical properties of aqueous solutions of L-valine, L-leucine, and L-isoleucine at 288.15, 298.15, 313.15, and 328.15 K

1994 ◽  
Vol 72 (6) ◽  
pp. 1489-1494 ◽  
Author(s):  
Michelle M. Duke ◽  
Andrew W. Hakin ◽  
Robert M. McKay ◽  
Kathryn E. Preuss
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aqueous Solutions ◽  
Constant Pressure ◽  
Heat Capacities ◽  
Thermochemical Properties ◽  
Acid System ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Fitting Procedures

Densities and volumetric heat capacities have been measured for aqueous solutions of L-valine, L-leucine, and L-isoleucine at 288.15, 298.15, 313.15, and 328.15 K. These data have been used to calculate apparent molar volumes, [Formula: see text] and apparent molar heat capacities, [Formula: see text] which in turn have been used to obtain standard state volumes, [Formula: see text] and standard state heat capacities, [Formula: see text] for each aqueous amino acid system. Helgeson, Kirkham, and Flowers equations, for neutral organics in water, have been used to model the calculated standard state volumes and heat capacities of the amino acids as a function of temperature at constant pressure. The results of our fitting procedures may be used to predict the behaviour of [Formula: see text] and [Formula: see text] for the selected amino acid systems outside of the temperature range utilised in this investigation.

Densities and apparent molar volumes of aqueous aluminum chloride. Analysis of apparent molar volumes and heat capacities of aqueous aluminum salts in terms of the Pitzer and Helgeson theoretical models

1986 ◽  
Vol 64 (2) ◽  
pp. 353-359 ◽  
Author(s):  
Leslie Barta ◽  
Loren G. Hepler
Keyword(s):  
Aqueous Solutions ◽  
Interaction Model ◽  
Partial Molar Volumes ◽  
Theoretical Models ◽  
Heat Capacities ◽  
Apparent Molar Volumes ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Molar Volumes ◽  
Aqueous Aluminum

Densities of aqueous solutions of AlCl3 (containing dilute HCl) have been measured at 10, 25, 40, and 55 °C with results that have led to defined apparent molar volumes. We have used the Pitzer ion interaction model as the basis for analyzing these apparent molar volumes to obtain standard state (infinite dilution) partial molar volumes of AlCl3(aq) at each temperature. We have also made similar use of apparent molar heat capacities of aqueous solutions of AlCl3–HCl and Al(NO3)3–HNO3 from Hovey and Tremaine to obtain standard state partial molar heat capacities of AlCl3(aq) and Al(NO3)3(aq) at these same temperatures. Finally, the standard state partial molar volumes and heat capacities have been used with the Helgeson–Kirkham semi-theoretical equation of state for aqueous ions to provide a basis for estimating the thermodynamic properties of Al3+(aq) at high temperatures and pressures.

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.

Calorimetric investigations of aqueous amino acid and dipeptide systems from 288. 15 to 328. 15 K

1995 ◽  
Vol 73 (5) ◽  
pp. 725-734 ◽  
Author(s):  
Andrew W. Hakin ◽  
Michelle M. Duke ◽  
Lori L. Groft ◽  
Jocelyn L. Marty ◽  
Matthew L. Rushfeldt
Keyword(s):  
Amino Acid ◽  
Thermodynamic Properties ◽  
Heat Capacities ◽  
Group Additivity ◽  
Standard State ◽  
Apparent Molar Heat Capacities ◽  
Empirical Modelling ◽  
Temperature Dependences ◽  
Calorimetric Investigations ◽  
Capacity Data

Densities and heat capacities have been measured for aqueous solutions of L-asparagine, L-glutamine, glycylglycine, glycyl-L-valine, glycyl-L-asparagine, and glycyl-DL-leucine at 288.15, 298.15, 313.15, and 328.15 K. These data have been used to calculate apparent molar volumes, V2,ø, and apparent molar heat capacities, Cp,2,ø, which in turn have been used to obtain standard state volumes, [Formula: see text] and heat capacities, [Formula: see text] The semi-empirical modelling procedures of Helgeson, Kirkham, and Flowers have been used to subdivide the calculated standard state volume and heat capacity data into solvation and nonsolvation contributions. The nonsolvation components of the standard state properties are used in group additivity analyses. These analyses yield structural contributions to standard state volumes and heat capacities for the CH(NH2)CO2H, CH2, OH, COOH, CH, CONH2, and CONH groups. The temperature dependences of these contributions are discussed. Some comments are reported concerning the practicality of using the thermodynamic properties of aqueous amino acid and peptide systems as the basis for modelling standard state thermodynamic properties of aqueous protein systems. Keywords: heat capacities, densities, volumes, amino acids, peptides, group additivity.

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