Molar enthalpy increments for (0.5 H2O+0.5C2H5OH) at temperatures up to 573.2 K and pressures up to 11.3 MPa

2000 ◽  
Vol 32 (4) ◽  
pp. 439-449 ◽  
Author(s):  
C.J. Wormald ◽  
M.D. Vine
Keyword(s):  
Molar Enthalpy ◽  
Enthalpy Increments

Thermochemistry of uranium compounds. XVI. Calorimetric determination of the standard molar enthalpy of formation at 298.15 K, low-temperature heat capacity, and high-temperature enthalpy increments of UO2(OH2)•H2O (schoepite)

1988 ◽  
Vol 66 (4) ◽  
pp. 620-625 ◽  
Author(s):  
I.R. Tasker ◽  
P. A. G. O'Hare ◽  
Brett M. lewis ◽  
G. K. Johnson ◽  
E. H. P. Cordfunke
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Low Temperature ◽  
Thermodynamic Properties ◽  
Enthalpy Of Formation ◽  
Molar Heat Capacity ◽  
Temperature Drop ◽  
Molar Enthalpy ◽  
Standard Molar Enthalpy ◽  
Enthalpy Increments

Three precise calorimetric methods, viz., low-temperature adiabatic, high-temperature drop, and solution-reaction, have been used to determine as a function of temperature the key chemical thermodynamic properties of a pure sample of schoepite, UO2(OH)2•H2O. The following results have been obtained at the standard reference temperature T = 298.15 K: standard molar enthalpy of formation [Formula: see text] molar heat capacity [Formula: see text] and the standard molar entropy [Formula: see text] The molar enthalpy increments relative to 298.15 K and the molar heat capacity are given by the polynomials: [Formula: see text] and [Formula: see text], where 298.15 K < T < 400 K. The present result for [Formula: see text] at 298.15 K has been combined with three other closely-agreeing values from the literature to give a recommended weighted mean [Formula: see text] from which is calculated the standard Gibbs energy of formation [Formula: see text] at 298.15 K. Complete thermodynamic properties of schoepite are tabulated from 298.15 to 423.15 K.

Thermodynamic properties of multicomponent electrolyte solutions in mixed solvents. 5• HCl + NaCl + urea + water at 278.5–318.15 K

1988 ◽  
Vol 66 (4) ◽  
pp. 637-644 ◽  
Author(s):  
Dian-Yuan Men ◽  
Jia-Zhen Yang ◽  
Chun-Yu Liang ◽  
Li-Tian Zhang ◽  
Huan Gao ◽  
...  
Keyword(s):  
Mixed Solvents ◽  
Electrolyte Solutions ◽  
Absolute Temperature ◽  
Molar Enthalpy ◽  
Free Energies ◽  
Force Measurements ◽  
Solution Theory ◽  
Electrolytic Solution ◽  
Harned's Rule ◽  
Electromotive Force Measurements

This paper reports electromotive force measurements of the cells[Formula: see text]and[Formula: see text]in mixed solvents of urea, mole fraction x = 0.05, at five temperatures from 278.15 to 318.15 K. The standard potentials of Ag–AgCl electrode in mixed solvents were obtained from the emf of cell (A) for HCl of molality mA from 0.02 to 0.11 mol kg−1, both by extrapolation on the basis of an extended Debye–Hückel equation and by a polynomial approach proposed in this paper on the basis of Pitzer's electrolytic solution theory. The standard free energies of transfer for HCl are discussed. The activity coefficients of HClγA in HCl + NaCl + urea + water have also been obtained from the emf of cell (B) at constant total ionic strength I = 0.5, 1.0, 1.5, and 2.0 mol kg−1. The experimental results show that HCl obeys Harned's rule and log γA is a linear function of absolute temperature T. They also indicate that the relative partial molar enthalpy of HCl obeys a similar Harned's rule.

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