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In chemical kinetics, the activation energy (abbreviated E a) is the energy barrier which must be overcome for a sufficient number of reactant molecules to acquire enough kinetic energy for a reaction to occur appreciably. The activation energy can generally be achieved by supplying energy, for example, in the form of heat, to the system or through the intervention of a catalyst. The Arrhenius equation gives the temperature dependence of the rate constant k: E a is obtained from the slope of a plot of ln k versus 1/T, where T is the absolute temperature in Kelvin. The activation energy is usually measured in kJ/mol.
E a is related to the rate (k) via the equation
where A is a constant called the frequency or pre-exponential factor, usually given in units of s−1, and R is the universal gas constant.
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© 2014 Springer-Verlag Berlin Heidelberg
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Cleaves, H.J.(. (2014). Activation Energy. In: Amils, R., et al. Encyclopedia of Astrobiology. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-27833-4_25-3
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DOI: https://doi.org/10.1007/978-3-642-27833-4_25-3
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Publisher Name: Springer, Berlin, Heidelberg
Online ISBN: 978-3-642-27833-4
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Activation Energy- Published:
- 25 December 2022
DOI: https://doi.org/10.1007/978-3-642-27833-4_25-4
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Activation Energy- Published:
- 15 April 2015
DOI: https://doi.org/10.1007/978-3-642-27833-4_25-3