Standard molar entropy

About: Standard molar entropy is a research topic. Over the lifetime, 1586 publications have been published within this topic receiving 29886 citations.

Adsorption of rhodamine b from an aqueous solution: kinetic and thermodynamic studies

Abstract: The Acid Activated Vitex Negundo Stem was used as a potential low cost and available adsorbent for the removal of dyes from waste water. Adsorption studies were carried out in a batch process with initial dye concentration, contact time, adsorbent dose and effect of temperature. The equilibrium data satisfied both Langmuir and Freundlich isotherm models. The experimental data were analyzed using the pseudo –second order kinetic model. The changes in standard free energy(∆G o ), standard entropy(∆S o ), standard enthalpy (∆H o ) were calculated. The thermodynamic study has showed that the dye adsorption phenomenon onto AAVNS was favourable, endothermic and spontaneous.

Thermodynamic properties of second generation poly(phenylene-pyridyl) dendrimer

Abstract: The temperature dependence of heat capacity Cpo = f (T) of second generation hard poly(phenylene-pyridyl) dendrimer (G2-24Py) was measured by a adiabatic vacuum calorimeter over the temperature range 6–320 K for the first time. The experimental results were used to calculate the standard thermodynamic functions: heat capacity Cpo (T), enthalpy Ho(T)–Ho(0), entropy So(T)–So(0) and Gibbs function Go(T)–Ho(0) over the range from T → 0 K to 320 K. The standard entropy of formation at T = 298.15 K of G2-24Py was calculated. The low-temperature heat capacity was analyzed based on Debye’s heat capacity theory of solids. Fractal treatment of the heat capacity was performed and the values of the temperature characteristics and fractal dimension D were determined. Some conclusions regarding structure topology are given.

Thermodynamic study of oxygen dissolved in liquid InSn alloys

Abstract: A modified coulometric titration method with the electrochemical cell O in liquid InSn alloys¦ZrO2 (+ CaO)¦air, Pt was used to measure the activity coefficient γo of oxygen in liquid InSn alloys at 1073 and 1273 K over the entire composition range. The molar enthalpy ΔHO° and the molar entropy ΔSO° of oxygen dissolution for 1 2 O 2 (101325 Pa) → O(1 mol .% ) were evaluated from the results. The In γO values and the ΔHO° and ΔSoO° values plotted in terms of alloy composition lie approximately on the line corresponding to the additive equation.

Vapour Pressures of Some Disperse Dyes

Abstract: THE vapour pressure, heat and standard entropy of sublimation of two disperse dyes, 1-methylamino-anthraquinone and 1-(β-hydroxyethyl)aminoanthraquinone, have been determined.

A Thermodynamic Study of the Interaction between Urease and Copper Ions

Abstract: A thermodynamic study of copper ions by jack bean urease (JBU) was carried out at two temperatures of 27 and 37?C in Tris buffer (30 mM; pH=7.0) using an isothermal titration calorimetry. There is a set of twelve identical and non-interacting binding sites for copper ions. The intrinsic dissociation equilibrium constant and the molar enthalpy of binding are 285 µM and ?15.2 kJ/mol at 27?C and 346 µM and ?14.6 kJ/mol at 37?C, respectively. The molar entropy of binding is ?17.2 J K-1 mol-1at 27?C and +19.1 J K-1 mol-1 at 37?C. Hence, the binding process of copper ion to JBU is not only enthalpy driven but also it is entropy driven, which the role of entropy driven should be more effective by increasing the temperature.