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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.


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TL;DR: In this article, the thermodynamic properties of β'-NiZn alloys with CsCl-type structure were investigated using the dew-point method and the integral quantities of NiZn were derived from the f.c. terminal solid solutions.
Abstract: The thermodynamic activity, partial molar entropy and partial molar enthalpy of zinc have been calculated based on the measurement of partial pressure of zinc above eleven β’-NiZn alloys exhibiting the CsCl-type of structure over the temperature interval 1042 to 1159 K, using the dew-point method. Good correlations are found between theory and experiment for all three partial quantities. Furthermore, from these results and the recently reported data on the f.c.c. terminal solid solutions, the corresponding partial quantities of nickel in β’-NiZn alloys are computed as well as the integral quantities. It is found that the thermal entropy of this phase remains constant with composition, an assumption used by Chang and co-workers in deriving the theoretical equations to account for the compositional variations of the thermodynamic properties for this type of ordered phase. A similar analysis is also made for the thermodynamic properties of the low-tempe rature form of the equi-atomic phase exhibiting the face-centered tetragonal superlattice structure.

19 citations

Journal ArticleDOI
TL;DR: In this paper, a nonisothermal galvanic cell comprising two interfaces between two immiscible electrolyte solutions has been employed to determine the standard entropy ( ) of ion transfer at the nitrobenzene (NB)|water (W) interface.
Abstract: A nonisothermal galvanic cell comprising two interfaces between two immiscible electrolyte solutions has been employed to determine the standard entropy ( ) of ion transfer at the nitrobenzene (NB)|water (W) interface. Under the conditions that only one ion (i) can partition between the NB|W interface, the nonisothermal emf has been measured. A nonequilibrium thermodynamic treatment has shown that the peak value (E0) of the nonisothermal emf, being usually observed within 1 min, is related to for ion i. However, E0 has also been shown, both experimentally and theoretically, to be influenced by thermal diffusion potentials arising in the bulk phases. Nevertheless, the contributions from the thermal diffusion potentials can be corrected for if the parameters for the ionic heats of transport are available, or they can be minimized by using adequate supporting electrolytes. Thus, accurate values of have been determined for various cations and anions. The determined values of for relatively hydrophobic cations...

19 citations

Journal ArticleDOI
TL;DR: In this article, the heat of formation of 1,1-dimethoxyethene, ΔHf(l) was determined from the boiling points at various pressures, and the free energy of transfer, 1.02
Abstract: We have determined the heat of formation of 1,1-dimethoxyethene, ΔHf(l) = −75.56 ± 0.87 kcal mol−1, by measuring the heat of hydrolysis. The heat of vaporization, 8.47 ± 0.10 kcal mol−1, was estimated from the boiling points at various pressures. The standard entropy of gaseous 1,1-dimethoxyethene, 82.02 ± 2. cal deg−1 mol−1, was calculated using frequencies obtained by MO calculations at the 6-31G** level. The free energy of transfer, 1.02 ± 1, was estimated by additivity with allowance for a distant polar interaction. Thus the free energy of formation in aqueous solution, ΔGf(aq) = −37.07 ± 1.48 kcal mol−1, could be calculated. The free energies of hydrolysis for enol ethers appear to be insensitive to structure; we used an average value and so calculated the values of the free energies of formation of the enols of acetic acid and methyl acetate, −67.90 ± 1.67 and −52.48 ± 1.53 kcal mol−1, respectively. These values are in good agreement with other recent evaluations. This method should be applicable to...

19 citations

Journal ArticleDOI
TL;DR: In this article, the authors investigated the hydrogen absorption properties of Pd-Ag-Ni alloys at temperatures between 273 and 433 K at hydrogen pressures up to 1000 Torr (133.32 kPa) by means of pressure-composition isotherm measurements and X-ray measurements of lattice parameters of hydrogen-free and hydrogenated alloys.

19 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of temperature variation on ion exchange equilibrium between an anion exchange membrane and solutions of electrolytes containing the most dominant anions of natural waters (CI−, NO− 3 and SO2minus; 4) was studied.
Abstract: The effect of the temperature variation on ion exchange equilibrium between an anion exchange membrane and solutions of electrolytes containing the most dominant anions of natural waters (CI−, NO− 3 and SO2minus; 4) was studied. All experiments were carried out at 0.3 mol l−1. AMX membrane experimented in this work is a commercial product provided by TOKUYAMA SODA. Humidity percentage and ion exchange capacity were determined. Ionic exchange isotherms for the binary systems (CI−/NO−)3,(CI−/SO2− 4) and (NO− 3 / SO2− 4) were established at different temperatures from 283 to 313 K. At 283 and 298 K, the affinity order was: CI− > NO− 3 > SO2− 4. This order was NO− 3 > CI− > SO2− 4 at 313 K. Selectivity coefficients Kj i and thermodynamic equilibrium constants K0j i calculated for uni-univalent and uni-bivalent ions exchange reaction system increase with increasing temperature. Thermodynamic parameters such as standard free enthalpy change, standard enthalpy change, and standard entropy change were calculated....

19 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202316
202229
202141
202055
201949
201857