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In physical chemistry, the Arrhenius equation is a formula for the temperature dependence of reaction rates.The equation was proposed by Svante Arrhenius in 1889, based on the work of Dutch chemist Jacobus Henricus van 't Hoff who had noted in 1884 that the van 't Hoff equation for the temperature dependence of equilibrium constants suggests such a formula for the rates of both forward and ...
In the Arrhenius equation, the term activation energy (Ea) is used to describe the energy required to reach the transition state, and the exponential relationship k = A exp (−Ea/RT) holds. In transition state theory, a more sophisticated model of the relationship between reaction rates and the transition state, a superficially similar ...
F.R. Larson and J. Miller proposed that creep rate could adequately be described by the Arrhenius type equation: = / Where r is the creep process rate, A is a constant, R is the universal gas constant, T is the absolute temperature, and is the activation energy for the creep process.
Arrhenius plot. In chemical kinetics, an Arrhenius plot displays the logarithm of a reaction rate constant, ( , ordinate axis) plotted against reciprocal of the temperature ( , abscissa). [1] Arrhenius plots are often used to analyze the effect of temperature on the rates of chemical reactions. For a single rate-limited thermally activated ...
Pre-exponential factor. In chemical kinetics, the pre-exponential factor or A factor is the pre-exponential constant in the Arrhenius equation (equation shown below), an empirical relationship between temperature and rate coefficient. It is usually designated by A when determined from experiment, while Z is usually left for collision frequency.
Viscosity models for mixtures. The shear viscosity (or viscosity, in short) of a fluid is a material property that describes the friction between internal neighboring fluid surfaces (or sheets) flowing with different fluid velocities. This friction is the effect of (linear) momentum exchange caused by molecules with sufficient energy to move ...
Different checkpoints for different temperatures can be calculated by using the Arrhenius equation. For example, with an activation energy of 0.7e V, T j of 135 °C and T use of 55 °C the equivalent checkpoints will be at 29, 102, 303 and 606 hours. Electrical testing should be completed as soon as possible after the samples are removed.
The equation for the rate constant is similar in functional form to both the Arrhenius and Eyring equations: k ( T ) = P Z e − Δ E / R T , {\displaystyle k(T)=PZe^{-\Delta E/RT},} where P is the steric (or probability) factor and Z is the collision frequency, and Δ E is energy input required to overcome the activation barrier.