Autoprotolysis constants of ethylene glycol–water mixtures at different temperatures and related thermodynamic quantities

1967 ◽  
Vol 0 (0) ◽  
pp. 166-169 ◽  
Author(s):  
Surath Kumar Banerjee ◽  
Kiron Kumar Kundu ◽  
Mihir Nath Das
2019 ◽  
Vol 7 (1) ◽  
pp. 18-26
Author(s):  
Soleen S. Ahmed ◽  
Lazgin A. Jamil

The first and second dissociation constants of malonic acid in different composition of (ethylene glycol-water)%, (10, 20 and 30)% mixed solvent determined using the electromotive force measurements of galvanic cells without liquid junction at nine different temperatures,  at  interval, including the body temperature. The value of the first and second thermodynamic dissociation constants have been used to determine the thermodynamic quantities of two dissociation processes. These quantities involved the standard free energy,  standard enthalpy change,  standard entropy change,  and standard heat capacity change.


Author(s):  
Mohammad Hemmat Esfe

In the present article, the effects of temperature and nanoparticles volume fraction on the viscosity of copper oxide-ethylene glycol nanofluid have been investigated experimentally. The experiments have been conducted in volume fractions of 0 to 1.5 % and temperatures from 27.5 to 50 °C. The shear stress computed by experimental values of viscosity and shear rate for volume fraction of 1% and in different temperatures show that this nanofluid has Newtonian behaviour. The experimental results reveal that in a given volume fraction when temperature increases, viscosity decreases, but relative viscosity varies. Also, in a specific temperature, nanofluid viscosity and relative viscosity increase when volume fraction increases. The maximum amount of increase in relative viscosity is 82.46% that occurs in volume fraction of 1.5% and temperature of 50 °C. Some models of computing nanofluid viscosity have been suggested. The greatest difference between the results obtained from these models and experimental results was down of 4 percent that shows that there is a very good agreement between experimental results and the results obtained from these models.


2009 ◽  
Vol 7 (4) ◽  
pp. 929-937 ◽  
Author(s):  
Nagaraj Shetti ◽  
Rajesh Hegde ◽  
Sharanappa. Nandibewoor

AbstractOxidation of an amino acid, L-tyrosine (L-Tyr) by diperiodatocuprate(III) (DPC) in alkaline medium at a constant ionic strength of 0.1 mol dm−3 was studied spectrophotometrically at different temperatures (288.1–313.1 K). The reaction between DPC and L-Tyr in alkaline medium exhibits 1:4 stoichiometry (L-Tyr:DPC). Intervention of free radicals was observed in the reaction. Based on the observed orders and experimental evidence, a mechanism involving monoperiodatocuprate(III) (MPC) as the reactive oxidant species has been proposed. A suitable mechanism is proposed through the formation of a complex and free radical intermediate. The products were identified by spot test and characterized by spectral studies. The reaction constants involved in the different steps of the mechanism were calculated. The activation parameters with respect to slow step of the mechanism were computed and are discussed. The thermodynamic quantities were determined for different equilibrium steps. Isokinetic temperature was also calculated and found to be 252.3 K.


1977 ◽  
Vol 30 (12) ◽  
pp. 2621 ◽  
Author(s):  
UN Dash

With the cell Ag-AgCl|KCl(m3), K2A(m2), KHA(m1), QH2-Q|Pt, where A stands for SO42- or CO32-, the ionization constants of the HSO4- and HCO3- ions in formamide have been determined at different temperatures. The standard thermodynamic quantities, ΔG�, ΔH� and ΔS�, have been calculated.


1980 ◽  
Vol 58 (4) ◽  
pp. 323-327 ◽  
Author(s):  
Upendra Nath Dash ◽  
Uttam Kumar Nayak

The ionization constant, K, of trans-crotonic acid, and the first and second ionization constants, K1 and K2, of adipic acid have been determined in water at seven different temperatures ranging from 15 to 45 °C with the help of the cells without liquid junction using silver – silver chloride and quinhydrone electrodes. The variations of pK, pK1, and pK2 with temperature have been expressed by the equations[Formula: see text]and[Formula: see text]From the temperature coefficient of the ionization constants, the standard enthalpy, entropy, Gibbs energy, and heat capacity changes of the corresponding dissociation processes have been calculated. Using the values of ionization constants of adipic acid, the standard potential of the Ag(s)/Ag2Ad(s)/Ad2− electrode, and the related standard thermodynamic quantities for the electrode process[Formula: see text]have been calculated in water at those temperatures.


2020 ◽  
Vol 299 ◽  
pp. 112127 ◽  
Author(s):  
Ayda Hatefi ◽  
Elaheh Rahimpour ◽  
Taravat Ghafourian ◽  
Fleming Martinez ◽  
Mohammad Barzegar-Jalali ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document