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** Coefficients effect of temperature **

** Reaction effect of temperature **

** Reaction rate effect of temperature **

** Reaction rate, temperature coefficient **

Effective encounter distances for reaction of solvated electrons with electron scavengers at room temperature compared with crystallographic encounter distances Unless otherwise noted, the solvent is water (containing an inert electrolyte in some cases). Corrections for ionic interactions according to eqn. (106) were applied and reaction rate coefficient were extrapolated to zero ionic strength (Chap. 3, Sect. 1.6 and 1.7). Many of these studies have been mentioned in Chap. 3, Sect. 2 [Pg.102]

The effect of temperature on the rate of reactions is frequently expressed in terms of a temperature coefficient, Qio, which is the factor by which the rate increases by raising the temperature 0 C. [Pg.279]

Partly for historical reasons the effect of temperature changes on the rate coefficient, k, of chemical reactions frequently continues to be discussed in terms of the experimental activation energy, given by [Pg.121]

The effect of temperature is unusual as cool flame combustion reactions show a region of temperatures and pressures in which the rate shows anomalous behaviour the rate decreases as the temperature increases - the negative temperature coefficient effect. [Pg.254]

It is interesting to consider the temperature dependence of the reaction rates predicted by these limiting expressions, which are contained in the effective rate coefficients. The true surface reaction rate coefficient has the temperature dependence [Pg.290]

For diffusion controlled corrosion reactions e.g. dissolved oxygen reduction, and the effect of temperature which increases diffusion rates, then by substituting viscosity and the diffusion coefficients at appropriate temperatures into the Reynolds No. and Schmidt No., changes in corrosion rate can be calculated. [Pg.319]

Thermal effects constitute a significant portion of the study devoted to catalysis. This is true of electrochemical reactions as well. In general the reaction rate constants, diffusion coefficients, and conductivities all exhibit Arrhenius-type dependence on temperature, and as a rule of the thumb, for every 10°C rise in temperature, most reaction rates are doubled. Hence, temperature effects must be incorporated into the parameter values. Fourier s law governs the distribution of temperature. For the example with the cylindrical catalyst pellet described in the previous section, the equation corresponding to the energy balance can be written in the dimensionless form as follows [Pg.431]

The rapidity of the reaction can be seen by the large effect low pressures ( 1 torr) of oxygen can have on the free radical polymerization of a reactive olefin such as styrene [22]. The reaction rate coefficients are expected to be typical for exothermic radical—radical reactions with essentially no activation energy. Thus, if R is alkyl, log(feQ/l mole-1 s-1) would be 9.0 0.5, and be independent of temperature. For simple resonance-stabilized radicals, log(feD/l mole-1 s-1) would be 8.5 0.5. [Pg.25]

The rate at which oxygen is absorbed is markedly accelerated by heat and by exposure to light, particularly in the ultraviolet and near-ultraviolet range (7, 8). The effect of temperature on the rate of oxidative deterioration is shown graphically in Figure 4 (9). The coefficient of reaction increased markedly above 60 °C (140 °F). [Pg.2606]

Boltzmann constant. The effective path length of the collision cell is X, while T and p are the temperature and the pressure of the reactant gas, respectively. Pressure dependent cross section data were plotted and then extrapolated to zero pressure using the method of Armentrout and coworkers [44]. The reaction rate coefficients, which are dependent on the lifetime of the ion molecule complex, were calculated and converted to an expression for the phenomenological rate coefficient [44] by (14.2). [Pg.298]

From the slope of plots of lc2i versus pressure Kircher and Sander determined the termolecular rate coefficients and their temperature dependence for M = Ar and N2. The values of these are k(Ar) = 8.4 X 10- exp (1100 K) and k(N2) = 1.9 X lO " exp(980/T) in cm molecule" s . Thus the termolecular rate coefficient in N2 is about 5.1 X 10 at 298 K. The effect of one atmosphere of N2 is to increase the effective bimolecular rate coefficient from about 1.6X10 to about 2.9 X10 cm molecule s . If water vapor is present, a further enhancement about 70% is found with 10 torr H2O at 298 K. The recommended expression for modelling the HO2 + HO2 reaction in air at high pressures and in the presence of water vapor is given by the expression [Pg.212]

** Coefficients effect of temperature **

** Reaction effect of temperature **

** Reaction rate effect of temperature **

** Reaction rate, temperature coefficient **

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