Heat capacities and volumes of dissociation of phosphoric acid (1st, 2nd, and 3rd), bicarbonate ion, and bisulfate ion in aqueous solution

1982 ◽  
Vol 60 (16) ◽  
pp. 2141-2150 ◽  
Author(s):  
John W. Larson ◽  
Kevin G. Zeeb ◽  
Loren G. Hepler
Keyword(s):  
Text Analysis ◽  
Heat Capacities ◽  
Acid Dissociation ◽  
Apparent Molar Heat Capacities ◽  
Flow Calorimeter ◽  
Buffer Solutions ◽  
Calorimetric Measurements ◽  
State Formula ◽  
Effects Of Temperature ◽  
Temperature And Pressure

Measurements at 25 °C with a flow calorimeter and a flow densimeter have led to heat capacities and densities of aqueous solutions of H3PO4, NaH2PO4, Na2HPO4, Na3PO, NaHCO3, Na2CO3, H2SO4, and various buffer solutions. Results are presented in terms of apparent molar heat capacities [Formula: see text] and apparent molar volumes [Formula: see text]. Analysis of the experimental [Formula: see text] values to obtain the desired standard state [Formula: see text] values for single electrolytes requires that allowance be made for hydrolysis and dissociation reactions of certain solutes, along with extrapolation to zero concentration. Analysis of [Formula: see text] values requires similar considerations of hydrolysis and dissociation reactions, allowance for enthalpy and equilibrium changes ("relaxation") during calorimetric measurements, and extrapolation to zero concentration. Procedures for these calculations are presented. The [Formula: see text] and [Formula: see text] values that result from all of these measurements and calculations are used to obtain ΔCp0 and ΔV0 values for acid dissociation reactions, which are then related to effects of temperature and pressure on other thermodynamic properties.

Thermodynamics of acid dissociation of aqueous bisulfite ion: ΔH0, ΔCP0, and ΔV0 at 298.15 K

1981 ◽  
Vol 59 (7) ◽  
pp. 1068-1073 ◽  
Author(s):  
Gregory C. Allred ◽  
John W. Larson ◽  
Loren G. Hepler
Keyword(s):  
Pressure Dependence ◽  
Acid Dissociation ◽  
Dissociation Reaction ◽  
Density Measurements ◽  
Carbonate Ion ◽  
Calorimetric Measurements ◽  
Enthalpy Of Proton Transfer ◽  
Temperature And Pressure ◽  
Enthalpy Of Protonation ◽  
Sulfite Ion

Calorimetric measurements of the enthalpy of protonation of sulfite ion and the enthalpy of proton transfer from bisulfite ion to carbonate ion have led to two independent values for the standard enthalpy of the acid dissociation reaction represented by HSO3−(aq) = H+(aq) + SO32− (aq). Further calorimetric and density measurements have led to apparent and partial molar heat capacities and volumes for sulfite and bisulfite ions. Results of all of these measurements are summarized by ΔH0 = −3.59 ± 0.10 kJ mol−1, ΔCP0 = −262 ± 7 J K−1 mol−1, and ΔV0 = −28.7 ± 1.0cm3 mol−1 for the acid dissociation of HSO3− (aq) at 298.15 K. These results are used for thermodynamic calculations of the temperature and pressure dependence of the equilibrium constant for acid dissociation of HSO3− (aq).

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.

Palladium-catalyzed carbonylation of 1,5-cyclooctadiene. Effects of temperature and pressure

1991 ◽  
Vol 56 (3) ◽  
pp. 663-672 ◽  
Author(s):  
Curtis B. Anderson ◽  
Rade Marković
Keyword(s):  
Carbon Monoxide ◽  
Oxidative Carbonylation ◽  
Influence Of Temperature ◽  
Carbonylation Reaction ◽  
Palladium Catalyzed ◽  
Effects Of Temperature ◽  
Temperature And Pressure

The influence of temperature and carbon monoxide pressure on the course of oxidative carbonylation reaction of 1,5-cyclooctadiene in the presence of the palladium(II) salts as a catalyst, was investigated.

scholarly journals Effects of temperature and pressure on the glass transitions of plastic bonded explosives

2000 ◽  
Vol 357-358 ◽  
pp. 89-95 ◽  
Author(s):  
Mary Stinecipher Campbell ◽  
Danielle Garcia ◽  
Deanne Idar
Keyword(s):  
Glass Transitions ◽  
Effects Of Temperature ◽  
Temperature And Pressure

scholarly journals Effects of Temperature and Pressure on Sulfate Reduction and Anaerobic Oxidation of Methane in Hydrothermal Sediments of Guaymas Basin

2004 ◽  
Vol 70 (2) ◽  
pp. 1231-1233 ◽  
Author(s):  
Jens Kallmeyer ◽  
Antje Boetius
Keyword(s):  
Sulfate Reduction ◽  
Deep Sea ◽  
Anaerobic Oxidation Of Methane ◽  
Anaerobic Oxidation ◽  
Guaymas Basin ◽  
Oxidation Of Methane ◽  
Hydrothermal Sediments ◽  
Deep Sea Sediments ◽  
Effects Of Temperature ◽  
Temperature And Pressure

ABSTRACT Rates of sulfate reduction (SR) and anaerobic oxidation of methane (AOM) in hydrothermal deep-sea sediments from Guaymas Basin were measured at temperatures of 5 to 200°C and pressures of 1 × 105, 2.2 × 107, and 4.5 × 107 Pa. A maximum SR of several micromoles per cubic centimeter per day was found at between 60 and 95°C and 2.2 × 107 and 4.5 × 107 Pa. Maximal AOM was observed at 35 to 90°C but generally accounted for less than 5% of SR.

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