首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 203 毫秒
1.
2.
3.
4.
5.
In this paper, the first, second and mean (N?O) bond dissociation enthalpies (BDEs) were derived from the standard (p° = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, ΔfHm°(g), at T = 298.15 K, of 2,2′-dipyridil N-oxide and 2,2′-dipyridil N,N′-dioxide. These values were calculated from experimental thermodynamic parameters, namely from the standard (p° = 0.1 MPa) molar enthalpies of formation, in the crystalline phase, ΔfHm°(cr), at T = 298.15 K, obtained from the standard molar enthalpies of combustion, ΔcHm°, measured by static bomb combustion calorimetry, and from the standard molar enthalpies of sublimation, at T = 298.15 K, determined from Knudsen mass-loss effusion method.  相似文献   

6.
Density data for dilute aqueous solutions of two amino acids (glycine, l-alanine) obtained using a flow vibrating-tube densimeter are presented together with partial molar volumes at infinite dilution (standard molar volumes, Vm,2°) calculated from the measured data. The experiments were performed at temperatures from (298 up to 443) K at pressures close to the saturation line of water, at pressures in the range from (15 to 17) MPa, and at 30 MPa. Values of an analogue of isothermal compressibility, κT,2°=-(1/Vm,2°)(?Vm,2°/?p)T, are also evaluated. Maxima on the curves Vm,2°(T) and κT,2°(T) are observed and discussed. The new data along with literature values of standard molar volumes and heat capacities are used for generating the recommended parameterization of an equation of state for standard molar thermodynamic properties of the aqueous amino acids.  相似文献   

7.
8.
9.
10.
11.
12.
13.
Standard state thermodynamic properties for aqueous sodium perrhenate at temperature in the range of (298.15 to 598.15) K and at psat were determined by high dilution solution calorimetry down to 10?4 m. Standard state partial molar heat capacities, Cp,2°, of aqueous sodium perrhenate calculated from present study are compared to literature values up to T = 398.15 K. The differences between Cp,2° of ReO4-(aq) and Cl?(aq) at lower temperature is much greater than that due to their internal molecular motions. Consequently, the perrhenate ion appears to have an ionic incomplete primary hydration shell as compared to the chloride ion. The ReO4-/Cl- difference in thermodynamic functions has now been well defined up to T = 598.15 K for other important high temperature calculations.  相似文献   

14.
15.
16.
17.
The standard (p° = 0.1 MPa) molar enthalpies of combustion, ΔcHm°, for crystalline 2-furanacrylic acid, 3-furanacrylic acid, and 3-(2-furyl)-2-propenal and for the liquid 2-furanacrylonitrile were determined, at the temperature 298.15 K, using a static bomb combustion calorimeter. For these compounds, the standard molar enthalpies of phase transition, Δcr,lgHm°, at T = 298.15 K, were determined by Calvet microcalorimetry. For the two crystalline furanacrylic acids the vapour pressures as function of temperature were measured by the Knudsen effusion technique and the standard molar enthalpies of sublimation, ΔcrgHm°, at T = 298.15 K were derived by the Clausius–Clapeyron equation. The results are as follows:  相似文献   

18.
19.
20.
Calcium titanofluoride CaTiF5(s) was prepared by solid-state reaction of CaF2(s) with TiF3(s) and characterized by X-ray diffraction method. The standard molar isobaric heat capacity (Cp,m) of CaTiF5(s) was determined by a power compensated differential scanning calorimeter in the temperature from 230 K to 710 K. A solid-state galvanic cell with CaF2 as electrolyte was used to determine the standard molar Gibbs energy of formation (ΔfGm) of CaTiF5 in the temperature range from 803 K to 1005 K. The galvanic cell can be depicted as:(-)Pt,O2(g,101.325kPa)/{CaO(s)+CaF2(s)}//CaF2//{CaTiF5(s)+CaTiO3(s)}/O2(g,101.325kPa),Pt(+)The second law analysis of present data were carried out to derive the standard entropy Sm(298.15K) and the enthalpy of formation ΔfHm(298.15K) and the values derived are 68.7 J · K−1 · mol−1 and −2848.4 kJ · mol−1, respectively.  相似文献   

Empty Cell-ΔcHm°(cr,l)/(kJ·mol-1)Δcr,lgHm°/(kJ·mol-1)
CalvetKnudsen
2-Furanacrylic acid (cr)3149.8 ± 0.5103.0 ± 0.7103.3 ± 0.5
3-Furanacrylic acid (cr)3151.5 ± 0.7104.9 ± 1.1106.8 ± 0.5
3-(2-Furyl)-2-propenal (cr)3425.7 ± 1.282.3 ± 0.4
2-Furanacrylonitrile (l)3562.5 ± 1.365.2 ± 0.6
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号