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1.
The kinetics of the reactions of ClO3 with HSO3 and H2SO3 was studied by measuring the concentration of [Cl] and [H+] both in chlorate-bisulfite and chlorate-sulfite/bisulfite solutions. A reaction mechanism was applied for simulation of the experimental observations. Rate constants k1 = (1±0.5)·10−4 M−1 s−1 and k2 = (0.23±0.01) M−1 s−1 were determined for the following reactions:
((1))
((2))
Rate constant k1 was obtained directly from the experimental results of chloratesulfite/ bisulfite reactions, where reaction (1) is predominant. Rate constant k2 was obtained by computer fitting of [Cl] and [H+] to the experimental values both in chlorate-bisulfite and chlorate-sulfite/bisulfite reactions.  相似文献   

2.
In the search of a useful method for determining excess enthalpies as a function of temperature Calvet calorimetry was employed. To this end, excess molar enthalpies
at 298.15 and 333.15 K and excess molar heat capacities
within 283.15–333.15 K were determined for the 1-decanol+n-decane system over the whole composition range. An isothermal flow Calvet-type calorimeter was used for
measurements, whereas
were determined by means of a Setaram Micro DSC calorimeter. Excess enthalpies within 283.15–333.15 K were indirectly obtained through the integration of
(T) data using
at 298.15 K. The results obtained at 333.15 K agreed with those determined directly, implying the thermodynamic consistency of the measured data and, therefore, the reliability of the indirect method.  相似文献   

3.
The state of the water-soluble salt iron(III) chloride in AOT reverse micelles dispersed in carbon tetrachloride has been investigated by FT-IR spectroscopy. Interestingly, while the entrapment of a lot of water-soluble inorganic salts in AOT reverse micelles requires preliminarily the presence of significant amounts of water within the micellar core, solubilization of FeCl3 occurs without the need to add water in the micellar solution reaching the very high solubility value, expressed as the maximum salt-to-surfactant molar ratio, of 1.30. The analysis of the spectral features of the investigated samples leads to hypothesize that iron(III) chloride is confined within the reverse micellar core as small size melted clusters of ionic species arising from the reactions
accompanied by a marked structural rearrangement of the AOT head group domain surrounding the micellar core and a shift of the sodium counterion from the micellar core surface to its interior. This picture has been further corroborated by conductivity measurements of FeCl3/AOT/CCl4 solutions as a function of the salt-to-surfactant molar ratio.  相似文献   

4.
The solubility of rhodochrosite (MnCO3) at 25°C under constant carbon dioxide partial pressure p(CO2) was determined in NaCl solutions as a function of ionic strength I. The dissolution of MnCO3(s) for the reaction
has been determined as a function of pH. From these values, we have determined the equilibrium constant for the stoichiometric solubility of MnCO3(s) in NaCl solutions
These values have been fitted to the equation
with a standard error of = 0.1 with Iand concentrations in molalities. The extrapolated value of log K o sp(–10.3) in water is in good agreement with literature data (–10.1 to 10.8) determined in solutions of different composition and ionic strength. The measured values of the activity coefficient, T(Mn2+) and T(CO3 2–), have been used to estimate the stability constant for the formation of the MnCO3ion pair, K *(MnCO3 0). The value of K 0(MnCO3 0) calculated from the values of K *(MnCO3) by the Pitzer equation ( = 0.1) in this study (4.8 ± 0.1) is in reasonable agreement with literature data.  相似文献   

5.
The solubility of siderite (FeCO3) at 25°C under constant CO2 partial pressure [p(CO2)] was determined in NaCl solutions as a function of ionic strength. The dissolution of FeCO3(s) for the reaction
has been determined as a function of pH = – log[H+]. From these values we have determined the equilibrium constant for the stoichiometric solubility to FeCO3(s) in NaCl
These values have been fitted to the equation
with a standard error of s = 0.15. The extrapolated value of log(K o sp) – 10.9 in water is in good agreement with data in the literature (– 10.8 to – 11.2) determined in solutions of different composition and ionic strength.The measured values of the activity coefficient, T(Fe2+) T(CO3 2–), have been used to estimate the stability constant for the formation of the FeCO3 ion pair, K*(FeCO3). The values of K*(FeCO3) have been fitted to the equation (s = 0.09)
The value of log[K o(FeCO3)] in water found in this study (6.3 ± 0.2) is slightly higher than the value found from extrapolations in 1.0 m NaClO4 solutions (5.9 ± 0.2). These differences are related to the model used to determine the activity coefficients of the Fe(II) and carbonate species in the two solutions.  相似文献   

6.
From stopped-flow spectrophotometric studies on the kinetics of dissociation of [M(trien)]2+ (M=CuII, NiII) to M aq 2+ and trien H 4 4+ in aqueous acid medium, it has been established that the reaction occurs in a complex manner conforming to the relation
  相似文献   

7.
The Gibbs free energies of formation of Eu3RuO7(s) and Eu2Ru2O7(s) have been determined using solid-state electrochemical technique employing oxide ion conducting electrolyte. The reversible electromotive force (e.m.f.) of the following solid-state electrochemical cells have been measured:
The Gibbs free energies of formation of Eu3RuO7(s) and Eu2Ru2O7(s) from elements in their standard state, calculated by the least squares regression analysis of the data obtained in the present study, can be given, respectively, by:
The uncertainty estimates for Δf G o(T) include the standard deviation in e.m.f. and uncertainty in the data taken from the literature.  相似文献   

8.
Activity coefficients for sodium chloride in the NaCl + Na2SO4 + H2O ternary system were determined from emf measurements of the cell
at 15, 25, 35, and 45°C and at total ionic strengths from 0.1 to 6 mol-kg–1. These activity coefficient were analyzed by using the Harned rule and the treatments of Scatchard–Rush–Johnson and Pitzer. The analysis of activity coefficients at trace concentration was also achieved and qualitatively interpreted by considering the ionic interactions that can take place in the mixed system. Finally, the excess Gibbs energy of the mixtures was calculated and qualitatively analyzed against the composition of the system.  相似文献   

9.
The osmium(VIII) catalysed IO4 oxidation of DMF in aqueous alkaline medium follows the rate law:
  相似文献   

10.
The equilibrium constant for the hydrolytic disproportionation of I2
has been determined at 25°C and at ionic strength 0.2 M(NaClO4) in buffered solution. The reaction was followed in the pH range where the equilibrium concentration of I2, I, and IO3 are commensurable, i.e., the fast equilibrium
is also established. The equilibrium concentrations of I2and I3 were determined spectrophotometrically, and the concentrations of all the other species participating in process (1) were calculated from the stoichiometric constraints. The constants determined are \log K_1 = -47.61\pm 0.07 and \log K_2 = 2.86 \pm 0.01.  相似文献   

11.
It was found that metastable equilibrium in the heterogeneous reaction
in H2PdCl4-hydrochloric acid solutions at 60°C depended on the dispersity of metallic palladium. It was shown experimentally that the dependence of the shift of the PdCl42−/Pd0 redox potential on the dispersity of palladium(0) was described by the Thomson equation. Original Russian Text ? O.V. Belousov, Yu.V. Saltykov, L.I. Dorokhova, L.A. Solov’ev, S.M. Zharkov, 2008, published in Zhurnal Fizicheskoi Khimii, 2008, Vol. 82, No. 4, pp. 749–753.  相似文献   

12.
The kinetics of substitution of aqua ligands fromcis-[Ru(bipy)2(H2O)2]2+ ion by salicylhydroxamic acid (L) in aqueous medium has been studied spectrophotometrically at different temperatures (50–65°C). The following rate law has been established in the pH range 4.0 to 5.8;
  相似文献   

13.
The kinetics of catalytic decomposition of NO over Cu/ZSM-5 catalyst has been studied in an integral flow reactor at atmospheric pressure. Kinetic analysis is based on the assumption that the surface reaction represents the rate-determining step. On the basis of theoretical considerations of different interactions between reactants and catalyst, and experimental evidences, three different mechanistic kinetic models were chosen. Also a power-law model was tested. The best agreement has been achieved with the model
  相似文献   

14.
The oxidation of H2NOH is first-order both in [NH3OH+] and [AuCl4 ]. The rate is increased by the increase in [Cl] and decreased with increase in [H+]. The stoichiometry ratio, [NH3OH+]/[AuCl4 ], is 1. The mechanism consists of the following reactions.
The rate law deduced from the reactions (i)–(iv) is given by Equation (v) considering that [H+] K a.
The reaction (iii) is a combination of the following reactions:
The activation parameters for the reactions (ii) and (iii) are consistent with an outer-sphere electron transfer mechanism.  相似文献   

15.
Based on the structure of characterization of Au/Fe2O3 catalysts, the mechanism of gold activation in supported gold catalysts was proposed as follow:
The possible catalytic active state is the partially oxidized gold (Au+) with unoccupied outer d orbitals, similar to the outer d orbital structure of Pt. Thus "inert" gold can become very active for CO oxidation.  相似文献   

16.
The energy E(G) of a graph G is defined as the sum of the absolute values of all the eigenvalues of the adjacency matrix of the graph G. This quantity is used in chemistry to approximate the total π-electron energy of molecules and in particular, in case G is bipartite, alternant hydrocarbons. In this paper, we show that if G = (V 1, V 2; E) is a bipartite graph with edges and , then
and
must hold.   相似文献   

17.
The determination of the second dissociation constant of carbonic acid K 2 in 5, 15, and 25 mass% ethanol—water mixed solvents has been made using cell of the type:
at 5 to 45°C. From these data, thermodynamic quantities, dissociation enthalpy, and dissociation entropy were determined. The dependence of pK 2 on dielectric constant of the mixed solvents is discussed in term of the Beveridge model.  相似文献   

18.
The narcissus constant, N = 2.3983843828..., is defined as a number that fulfills the narcissistic infinite nested radical equation
Incorporation of this constant, its square and its cube into the generalized version of the Lennard-Jones potential function gives the narcissus constant potential function
which (a) is suitable for modeling van der Waals interaction due to its agreement with the Lennard-Jones (12-6) potential energy curve over long range, and (b) forms simple generalized hybrid interatomic–intermolecular potential energy function due to its correlation with the averaged form of Lennard-Jones, Morse, Buckingham and Linnett potential energy curve near the minimum well-depth.   相似文献   

19.
The thermodynamic viability of the yttria-stabilized zirconia sensor (YSZS) [H2O, H+/ZrO2(Y2O3)/HgO/Hg] for the measurement of pH in high temperature aqueous solutions is evaluated by measuring potentials for this electrode and a conventional hydrogen electrode (HE) against a common reference electrode in a variety of solutions [0.01m H3PO4, 1m Na2SO4, 0.01m B(OH)3+0.01m KOH, and 0.01m KOH] at temperatures from 298.15K (25°C) to 573.115K (300°C). In order to compare theoretical and experimental potentials for the cell
  相似文献   

20.
The kinetics and mechanism of glutamic acid (GCO2H) oxidation by acid permanganate has been carried out in the absence and presence of sodium dodecyl sulphate (SDS). The surfactant enhances the reaction rate without changing the reaction mechanism. The overall rate expression for the reduction of MnVII may be written:
  相似文献   

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