Equilibrium in the formation of barium carbonate from barium sulphate

1976 ◽  
Vol 54 (24) ◽  
pp. 3872-3875
Author(s):  
Harry Horlings ◽  
Donald S. Scott ◽  
John R. Wynnyckyj
Keyword(s):  
Free Energy ◽  
Barium Carbonate ◽  
Equilibrium Constants ◽  
Barium Sulphate ◽  
Heat Of Reaction ◽  
Temperature Range ◽  
Free Energy Of Formation ◽  
Energy Of Formation

Heat of reaction and free energy of formation at 25 °C were determined from experimental equilibrium yields for the reaction[Formula: see text]in an aqueous solution.The values are 5045 and 1927 cal/mol respectively. Equilibrium constants for the reaction were determined over a temperature range from 20 to 193 °C.

Tautomeric equilibria and pKa values for 'sulfurous acid' in aqueous solution: a thermodynamic analysis

1979 ◽  
Vol 57 (4) ◽  
pp. 454-457 ◽  
Author(s):  
J. Peter Guthrie
Keyword(s):  
Aqueous Solution ◽  
Free Energy ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Acid Solutions ◽  
Sulfurous Acid ◽  
Free Energy Of Formation ◽  
Dilute Aqueous Solutions ◽  
Sulfite Ion ◽  
Energy Of Formation

The free energy of formation of dimethyl sulfite in aqueous solution can be calculated as −91.45 ± 0.79 kcal/mol; this calculation required measurement of the solubility of dimethyl sulfite. From this value and the pKa of SO(OH)2, using previously reported methods, the free energy of formation of SO(OH)2 can be calculated to be −129.26 ± 0.89 kcal/mol. Comparison of this value with the value obtained from the free energy of formation of 'sulfurous acid' solutions, calculated from the free energy of formation of sulfite ion and the apparent pKa, values, permits evaluation of the free energy of covalent hydration of SO2 as 1.6 + 1.0 kcal/mol, in agreement with earlier qualitative spectroscopic observations. From the apparent pKa and the anticipated pKa values for the tautomers (SO(OH)2, pK1 = 2.3; HSO2(OH), pK1 = −2.6) it is possible to calculate the free energy change for tautomerization of SO(OH)2 to H—SO2(OH) as +4.5 ± 1.2 kcal/mol. All equilibrium constants required for Scheme 1, describing the species present in dilute aqueous solutions of SO2, have been calculated. In agreement with previous Raman studies the major tautomer of 'bisulfite ion' is calculated to be H—SO3−.

The Solubility of Metallic Selenium under Anoxic Conditions

2000 ◽  
Vol 663 ◽  
Author(s):  
Yoshihisa Iida ◽  
Tetsuji Yamaguchi ◽  
Shinichi Nakayama ◽  
Tomoko Nakajima ◽  
Yoshiaki Sakamoto
Keyword(s):  
Free Energy ◽  
Solid Phase ◽  
Equilibrium Constants ◽  
Absorption Spectrometry ◽  
X Ray Diffraction ◽  
Molar Free Energy ◽  
Anoxic Conditions ◽  
X Ray ◽  
Free Energy Of Formation ◽  
Energy Of Formation

ABSTRACTThe solubility of metallic selenium was measured in a mixture of 0.1M-NaCl and 0.05M-N2H4under anoxic conditions (O2 < 1 ppm) by both oversaturation and undersaturation methods. Equilibrium was attained in 40 days. The aqueous selenium species identified were HSe at pH between 5 and 8, and Se42at pH between 10 and 13, by UV-Vis absorption spectrometry. The solid phase was identified as Se (cr) by X-ray diffraction. The equilibrium constants ofSe(cr) + H+ + 2e- = HSe- logK0 = -6.5±0.5 and4Se(cr) + 2e- = Se42- logK0 = -16.8±0.5were determined. The standard molar free energy of formation of HSe- and Se42-was determined to be (37.1±2.9) and (95.9±2.9) kJ/mol, respectively.

Standard Gibbs free energy of formation of ZrOS

1990 ◽  
Vol 163 (1) ◽  
pp. 109-113 ◽  
Author(s):  
Zhi-Tong Sui ◽  
Xing-Yi Xiao ◽  
Ke-Qin Huang ◽  
Chang-Zhen Wang
Keyword(s):  
Free Energy ◽  
Gibbs Free Energy ◽  
Standard Gibbs Free Energy ◽  
Free Energy Of Formation ◽  
Energy Of Formation

Thermodynamical study of (CaGa2S4)x(BaGa2S4)1−x solid solutions

2021 ◽  
pp. 2150469
Author(s):  
T. G. Naghiyev ◽  
R. M. Rzayev
Keyword(s):  
Free Energy ◽  
Solid Solutions ◽  
Calculation Method ◽  
Solid Phase ◽  
Ternary Compounds ◽  
Free Energy Of Formation ◽  
Concentration Dependences ◽  
Solid Phase Reactions ◽  
Two Phases ◽  
Energy Of Formation

The solid solutions of [Formula: see text] were synthesized by solid-phase reactions from powder components of CaS, BaS, and Ga2S3. The temperature-concentration dependences of the Gibbs free energy of formation of [Formula: see text] solid solutions from ternary compounds and phase diagrams of the CaGa2S4–BaGa2S4 were determined by a calculation method. It was revealed that continuous solid solutions are formed in these systems. The spinodal decomposition of [Formula: see text] solid solutions into two phases is predicted at ordinary temperatures.

Sign in / Sign up

Export Citation Format

Share Document