Rate constant second order

The use of both Eyring and Arrhenius equations requires the use of appropriate rate constants. For a second-order reaction, for example, second-order rate constants should be used. Fitting conditional pseudo-first-order rate constants, as is sometimes incorrectly done, introduces an additional temperature-independent term. As a result, what may be reported as AS is in fact the sum (AS + ln[excess reagent]), as can be easily shown by substituting /c excess reagent] for k in Equation 8.117. The calculated A// term, on the other hand, is the same regardless of which rate constant, second order or pseudo-first order, is used. 

N,M L moF s Rate constant (second order) of reaction between molecules N and M... 

Cu-C bond formation has also been studied. Rate constants (second order at 25°C) have been measured for the reaction of copper(II) tetraglycine, [Cu(II)G4], with various radicals generated by pulse radiolysis ... 

Third-order rate constant (second-order term in reductant). HjA = ascorbic acid, r = 0 °C, initial reaction assuming rate first-order in oxidant and reductant. l.OM-NaCl, T = 14.9 °C. l.OM-NaCl. T = 30 °C. T = 40 °C. T = 22 °C,... 

Assuming complete binding of the dienophile to the micelle and making use of the pseudophase model, an expression can be derived relating the observed pseudo-first-order rate constant koi . to the concentration of surfactant, [S]. Assumirg a negligible contribution of the reaction in the aqueous phase to the overall rate, the second-order rate constant in the micellar pseudophase lq is given by ... 

Since the second reaction rate constant is orders of magnitude greater than the first at temperatures near room temperature, the first reaction may be regarded as the rate controlling step. Since ethanol is used as the solvent, the reaction will follow pseudo first-order kinetics. The rate of this liquid phase reaction can be expressed as... 

The little k s are rate constants (numbers) that tell you how fast the individual steps are. You will see two kinds of little k s, rate constants— first-order and second-order (Fig. 8-3). 

The rate of SECOND-ORDER REACTIONS depends on the concentration of both substrates. If the concentration of B is constant. A disappears in a first-order fashion, but the rate constant for A disappearance depends on the concentration of B. 

Despite the sometimes impressive reaction rate enhancements, second-order rate constants for most bimolecular reactions involving counterions actually decrease,with just a few remaining virtually constant or increas-ing. As discussed (vide supra), micellar rate constants for (pseudo) unimole-cular reactions are frequently lower than rate constants in water. Many of the... 

The reduction of platinum(IV) complexes involves two one-equivalent changes PtIV- Ptni— Ptn the first step is rate-determining. Second-order rate constants with vanadium(II) (kv) and with hexaammineruthenium(II) (A Ru) show linear correlation (equation 6).171... 

The rate of polymer synthesis in co-dodecalactam polymerization is proportional to the first power of the catalyst concentration (in contrast to e-caprolactam, where the rate is second-order in the catalyst concentration when the concentrations of an activator and the catalyst are equal). If the system Na-caprolactam/Na-acetyl e-caprolactam is used in equimolar ratio as the catalyst/activator mixture and the range of concentrations is [C] = 0.35 -1.5 mol% (or 0.0175 - 0.075 mol/1), the dependence of the constant ko on [C] is as follows ... 

The ET rates obeyed second-order kinetics, showing a first-order dependence on the concentration of each reactant [O2 and (TPP)Co] (69). The observed second-order rate constant (/robs) for the M" promoted ET increases finearly with increasing metal ion concentration (69). This indicates that the binding of M"" " to O2 is coupled with ET when M " " promoted ET occurs in a concerted manner (MCET) rather than a stepwise manner. If the rate-determining step were a uphill ET from (TPP)Co to O2, followed by rapid binding of M" to 02 , the ET rate would be independent of metal ion concentration. 

From the initial concentrations, benzoquinone is the limiting reactant. Additionally, since the reaction is conducted in a dilute liquid-phase, density changes can be neglected. The reaction rate is second-order from the units provided for the reaction rate constant. Thus,... 

Turnover Number. The rate constant (First order) for the breakdown of the [ES] complex, kcat (ks), is also known as the turnover number, that is the maximum number of substrate molecules processed/active site (moles substrate/mole active site) kcat=V max /[E] total- Note that this is best determined under saturating conditions. At very low concentrations of [S] can find the second-order rate constant for the conversion of E + S-j>E + P Vo = (kcat / Km)([E][S]. 

It is relatively nonabsorbing in the spectral region where (CpMo(CO)3)2 strongly absorbs due to the 0(Mo-Mo) -> o (Mo-Mo) transition. (ii) The intermediate s decay follows second-order kinetics at essentially diffusion controlled rates. The second order rate constants at 20° are k = (2 1) x 10 (THF), (3 1)... 

Char combustion kinetics have been previously reported for Antrim shale by Rostam-Abadi and Mickelson (9). In that study the authors reported that the rate was second order with respect to the char remaining and that there was noticeable chemisorption of (>2 Attempts to fit our data for the Antrim shale to a second order rate expression were unsuccessful and, in all cases, the data appeared to follow first order kinetics. Although we did not have the precision to measure O2 chemisorption, this phenomenon is consistent with our previous observations (6 ) of catalytic activity in those shales containing decomposed mineral carbonates. That is, the catalytic activity of CaO was attributed to its ability to chemisorb 02 As will be discussed in more detail below, the Antrim shale sample did not contain such carbonates and no catalytic behavior was observed. However, the magnitude of the rate constants reported by Rostam-Abadi and Mickelson (9) are very similar to those measured here. 

This is the desired result, giving the rate as second order in chlorine and first order in light intensity. By choosing different termination steps to be controlling, we can obtain different expressions for —d[C 2 ldt, some involving [Pr], [CI2], and [7] to other powers. Comparison of the various results with experimentally determined rates allows us to choose the best form of the rate equation and to evaluate the ratio of rate constants for example, k tp-Jk-, in Eq. (E). From measurements only on stable species, individual values of k cannot, in general, be established. 

The model equation which shows a better fitting to the experimental data presents two parameters ki (the constant rate of toluene oxidation) and k2 (the constant rate of catalyst oxidation). The reaction rate is second order dependent on toluene partial pressure (Pt) and first order dependent on oxygen partial pressure (Po), leading to the following equation... 

We are investigating the kinetics of aqueous reactions between Fe(II)(NTA)NO and sodium sulfite under well-controlled conditions. Our preliminary results indicate that the reaction rate is second order with respect to the concentration of Fe(II)(NTA)NO and first order with respect to the concentration of SO32-. The major nitrogen product is N2O. The rate constant is about 2.15 x 10 M 2 sec-l at 20°C. Work is in progress to determine the temperature and ionic strength dependence of the reaction and to identify all products for mass balance. We are also studying the kinetics of the reaction between Fe(II)(NTA)(SO3-2) and NO. 

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