Sulfuric acid equilibrium calculations

That the photoreactive species is the carbonium ion and not the corresponding alcohol is clearly indicated by the relative concentrations of the two species present. The calculated equilibrium constant for 5% aqueous sulfuric acid implies an alcohol content of 2 7 x 10 %, much too low to account for any detectable photoreaction from this covalent species. In addition, when the tropylium salt is irradiated in the absence of acid, neither 3 nor 4 is detected as a product, but rather ditropyl (5) and its photoisomer (6) are observed. 

Exercise 18-9 Use bond energies and the stabilization energy of ethanoic acid (18 kcal mole-1, Section 18-2A) to calculate AH° for the addition of water to ethanoic acid to give 1,1,1-trihydroxyethane. Compare the value you obtain with a calculated AH° for the hydration of ethanal in the vapor phase. Would you expect the rate, the equilibrium constant, or both, for hydration of ethanoic acid in water solution to be increased in the presence of a strong acid such as sulfuric acid Explain. 

The parameters of the Michaelis-Menten type kinetics were calculated for the reactions and are summarized in Table II. The apparent Michaelis constant values (Km) are rather large, indicating that the concentration of the complex at the equilibrium state is not high, unlike ordinary enzymatic reactions. The ratio of kJKm against the second-order rate constant with sulfuric acid (k2) can be considered to be an indication of the rate enhancement. The ratio increased with increasing mole fraction of the vinyl alcohol repeating unit in the copolymer and with... 

Adequate description of both the equilibrium geometry and vibrational spectra is critically important for the free energy calculations. Table 21.1 presents a comparison of equilibrium geometries of sulfuric acid monohydrate obtained at different levels of theory with experimental data of Leopold with co-authors [118]. As maybe seen from Table 21.1, both ab initio and DFT methods reproduce the hydrate structure with sufficient accuracy. The PW91PW91 and MP2 in combination 6-311-1—l-G(3df,3pd) basis set provide the best overall agreement with experimental data. 

Indirect determinations of the formal oxidation potential of Bk(IV)-Bk(III) couple in sulfuric and nitric acids have been made by tracer measurement. From the Bk(IV)/Bk(III) ratios and the corresponding Ce(IV)/Ce(III) ratios at equilibrium conditions one can calculate the oxidation potential of the Bk(IV)-Bk(III) couple. The Bk(IV)/Bk(III) ratio can be determined by extracting Bk(IV) by an appropriate organic solvent. The formal oxidation potentials of the Bk(IV)-Bk(III) couple in IN and 0.5N sulfuric acid were found to be 1.42 and 1.44 volts using trilaurylmethylammonium sulfate in carbon tetrachloride as a solvent. In 6N nitric acid the oxidation potential of the couple was found to be 1.56 volts by using 0.18M tributylphosphate. Whereas, in IN to 2N nitric acid berkelium was not oxidized by cerium(IV). 

One mole of 1-butanol theoretically requires one mole each of sodium bromide and sulfuric acid, but the procedure calls for use of a slight excess of bromide and twice the theoretical amount of acid. Excess acid is used to shift the equilibrium in favor of a high concentration of hydrobromic acid. The amount of sodium bromide taken, arbitrarily set at 1.2 times the theory as an insurtmce measure, is calculated as follows ... 

The air pollutant sulfur dioxide can be partially removed from stack gases in industrial processes and converted to sulfur trioxide, the acid anhydride of commercially important sulfuric acid. Write the equation for the reaction, using the smallest whole-number coefficients. Calculate the value of the equilibrium constant for this reaction at 25°C, from values of AGf in Appendix K. 

Ionic systems, such as water solutions of NaCl, CuS04, K2Cr04, and Ca(NOs)2 and solutions of sulfuric acid in ethyl alcohol, were among the objects of Johnson s experiments (I) that led him to conclude that there exists equilibrium electrical noise of a universal nature that manifests thermal motion of charged particles in conductors on a macroscopic level. Independently of a particular conductivity mechanism, the voltage spectral density, Sv(/), of this noise can be calculated from the real part of the system... 

The gravimetric, the bithermal, and the method based on the interpolation of weight changes are the best known, but of these the gravimetric method is the most widespread. This method is described here in detail references are provided for the others [8-10,29]. Constant vapor pressure is maintained by means of an acid or salt solution of a specified concentration. It is known that the moisture content of wet air, in equilibrium with an add or salt solution of known concentration, is constant at a given temperature. Partial pressures of water vapor developed with the use of solutions of sulfuric acid can be determined, as shown in Figure 2.1. The relative vapor pressure above an aqueous solution of sulfuric acid as a function of concentration and temperature can be calculated by the correlation [2]... 

The mechanism of sulfuric acid formation and scavenging in the Pasadena precipitation samples is also poorly understood. Aerosol sulfate measurements were too few for comparison with the excess sulfate concentrations, the sulfate in excess of that expected from sea salt. Sulfur dioxide concentrations during the storm were consistently 10 or 20 ppb with an uncertainty of 5 ppb. Gas scavenging of sulfur dioxide to form sulfite species and oxidation to sulfate before analysis of the sample could account for a large fraction of the excess sulfate. Equilibrium total sulfite was calculated from PSO2 i s sured at ground level and measured pH,by equations 17-20. 

Values for K in Tables II, III, and IV were derived by calculation of all uncombined sulfite as free sulfurous acid. This approach lacks validity to a certain extent since it assumes only HSOj", free sugar, and bisulfite addition compound in the equilibrium. Obviously, this is hardly possible in systems the pH values of which are so high or so low that little or no HSOa ion is present. In fact, the addition compounds obtained at the upper ranges might actually be some type of aldehyde-sulfite rather than aldehyde-bisulfite. There is an almost complete lack of quantitative application of the concept of variant HSOa ion content in sugar work however, Sundman did extend some of his data (Table II) by computing K on the basis of HSO rather than total sulfur dioxide calculated as bisulfite. The results are shown in Table V. 

It has long been held that a separation of carboxylic acids by I EC requires the use of an acidic eluent to repress ionization of the analytes and thereby give sharp peaks. However, equilibrium constant calculations indicate that alkane carboxylic acids are extensively ionized (60 - 97%) in predominately aqueous solution at the low concentrations generally used in liquid chromatography. It is questionable that added sulfuric acid is really effective in converting the solute acids to their molecular form. 

Venimadhavan et. al. (1999) developed batch reactive distillation model for production of butyl acetate in presence of sulfuric acid catalyst. They also studied the kinetics of esterification of acetic acid with butanol and calculated the thermodynamic equilibrium constant in a temperature range of 373 K- 393 K. They found that the equilibrium constant did not vary strongly with temperature. 

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