Arrhenius plot of rate constants

Figure 4. Arrhenius plot of rate constants determined for 600K MW polystyrene samples.

The apparent activation energy for the absorption/desorption process is usually evaluated from the Arrhenius plot of rate constant k values with temperature [166] by simply plotting a straight line InA vs. IRT. 

Arrhenius plot of rate constants for monomer five solvents of different polar- (30),... 

Figure 47. Arrhenius plots of rate constants (kx and k2) for the epimerization of moxalactam in frozen solution, calculated according to a reversible reaction model. (Reproduced from Ref. 350 with permission.)...

Figure 3. Arrhenius plot of rate constants, given as log k versus 10 /T (K) for select examples of isotopic reactions in gaseous systems (dashed lines) and aqueous systems (solid lines). Numbers refer to rate data for individual reactions summarized in Table 1 (see Appendix). Consult Table 1 for the proper rate units used for these examples because they are not all the same. Also note that rate constants for reactions (7) and (8) have been scaled by 10 ° for convenience of plotting.

Arrhenius plot of rate constants extracted from TS-CSTR data as temperature was ramped during a single run. The number of points available is such that the experimental data produces the almost-continuous line shown. The fitted Arrhenius line is shown as a solid line. 

Rate constants at different temperatures were determined for both sample sets. The slope of an Arrhenius plot of rate constant versus 1/T gives an activation energy of 35 kj/mol for CuO formation. Without PAni, an activation energy of 50 kJ/mol was calculated. 

Fig. 5.5 Arrhenius plots of rate constants for the reactions of OH + toluene and 1,2,3 trimethylbenzene (Adapted from Perry et al. 1977)...

FIGURE 4.24. Arrhenius plot of rate constants corresponding with the discharging kinetics (kj,) and oxygen consumption (k ). (Adapted from Nowotny, J., J. Mater. Sci., 1977, 12, 1143-1160.)... 

Figure 5.4-36. Fit of first-order kinetics for three Figure 5.4-37. Arrhenius plot for rate constants isothermal reaction periods (reprinted with obtained from the isothermal reaction periods permission from Landau et al. (1994). Copyright (reprinted with permission from Landau et al. (1994) American Chemical Society). (1994). Copyright (1994) American Chemical...

Figure 13 shows the increase of U with decreasing temperature, because the equilibrium is shifted in the direction of the solvent-separated ion pair no free anion is present. The rate constants k8C and kC8, respectively, can be calculated from these effects using Equations 20 and 15a. Figure 14 shows an Arrhenius plot of these constants. 

Degradation rate constants were obtained by linear regression least squares analysis of plots of log % EDB remaining vs time. Pseudo-first order rate constants were used to generate Arrhenius plots (log rate constant vs 1/T °K) to estimate activation energies (E ) and to make extrapolated estimates of rate constants and half-life values at ambient temperature. 

Three sets of data, sieved to yield constant-temperature triplets, were used to obtain the initial estimates of the parameters (kinetic constants) in these rate expressions. Arrhenius plots of these constants yielded the initial estimates of the activation energy and frequency factor of each of the temperature-dependent parameters. The initial values of the Arrhenius parameters were then inserted into the all-up rate expressions, including all the Arrhenius parameters. 

First-order reaction kinetics fit satisfactorily the rate of DAO decomposition as shown in Figure 6. This fact was confirmed also by considering a wide range of DAO concentrations in ethylene at 450 C, as illustrated in Figure 7. From Arrhenius plots, the rate constant of DAO decomposition was obtained as below,... 

Figure A3.10.25 Arrhenius plots of CO oxidation by O2 over Rli single crystals and supported Rli/Al203 at PCO = PO2 = 0.01 atm [43]. The dashed line in the figure is the predicted behaviour based on the rate constants for CO and O2 adsorption and desorption on Rli under UHV conditions.

As an illustration of these considerations, the Arrhenius plot of the electron-transfer rate constant, observed by DeVault and Chance [1966] (see also DeVault [1984]), is shown in fig. 13. 

Fig. 15. Arrhenius plot of the rate constant for the transfer of H and D atoms in the CH-O fragment for the reaction (6.17).

An Arrhenius plot of the rate constant, consisting of the three domains above, is schematically shown in fig. 45. Although the two-dimensional instanton at Tci < < for this particular model has not been calculated, having established the behavior of fc(r) at 7 > Tci and 7 <7 2, one is able to suggest a small apparent activation energy (shown by the dashed line) in this intermediate region. This consideration can be extended to more complex PES having a number of equivalent transition states, such as those of porphyrines. 

Usually the Arrhenius plot of In k vs. IIT is linear, or at any rate there is usually no sound basis for coneluding that it is not linear. This behavior is consistent with the conclusion that the activation parameters are constants, independent of temperature, over the experimental temperature range. For some reactions, however, definite curvature is detectable in Arrhenius plots. There seem to be three possible reasons for this curvature. 

Prepare the solutions and measure the pH at one temperature of the kinetic study. Of course, the pH meter and electrodes must be properly calibrated against standard buffers, all solutions being thermostated at the single temperature of measurement. Carry out the rate constant determinations at three or more tempertures do not measure the pH or change the solution composition at the additional temperatures. Determine from an Arrhenius plot of log against l/T. Then calculate Eqh using Eq. (6-37) or (6-39) and the appropriate values of AH and AH as discussed above. 

Fig. 7.35 Arrhenius plot of the parabolic rate constant for the oxidation of Ni to NiO (after...

The temperature dependence of a reaction rate lies in the rate constant and, as we shall see in Section 13.12, that temperature dependence gives valuable insight into the origins of rate constants. In the late nineteenth century, the Swedish chemist Svante Arrhenius found that the plot of the logarithm of the rate constant (In k) against the inverse of the absolute temperature (1 IT) is a straight line. In other words,... 

An Arrhenius plot of In k against 1/T is used to determine the Arrhenius parameters of a reaction a large activation energy signifies a high sensitivity of the rate constant to changes in temperature. 

Fig. 2. Arrhenius plots of the rate constants of the anionic polymerization of methyl methacrylate in THF as the solvent and with Na+ orCs+ as the counterion. (R. Kraft, A. H. E. Muller, V. Warzelhan, H. Hocker, G. V. Schulz, Ref.35>)...

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