Pre-exponential factor


Pre-exponential factor

In chemical kinetics, the preexponential factor or A factor is the pre-exponential constant in the Arrhenius equation, 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.

For a first order reaction it has units of s-1, for that reason it is often called frequency factor.

Values of A for some reactions can be found in here.

References

[http://www.iupac.org/goldbook/P04811.pdf IUPAC Goldbook definition of preexponential factor]

[http://goldbook.iupac.org/P04811.html IUPAC Gold Book definition of pre-exponential factor]


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Pre-charge — of the powerline voltages in a high voltage DC application is a preliminary mode which current limits the power source such that a controlled rise time of the system voltage during power up is achieved.When high voltage systems are designed… …   Wikipedia

  • Field electron emission — It is requested that a diagram or diagrams be included in this article to improve its quality. For more information, refer to discussion on this page and/or the listing at Wikipedia:Requested images. Field emission (FE) (also known as field… …   Wikipedia

  • Arrhenius equation — The Arrhenius equation is a simple, but remarkably accurate, formula for the temperature dependence of the rate constant, and therefore, rate of a chemical reaction. [http://www.iupac.org/goldbook/A00446.pdf Arrhenius equation] IUPAC Goldbook… …   Wikipedia

  • Marcus theory — is a theory originally developed by Rudolph A. Marcus, starting in 1956, to explain the rates of electron transfer reactions – the rate at which an electron can move or jump from one chemical species (called the electron donor) to another (called …   Wikipedia

  • Arrhenius plot — An Arrhenius plot displays the logarithm of a rate (ln(k), ordinate axis) plotted against inverse temperature (1/T, abscissa). Arrhenius plots are often used to analyze the effect of temperature on the rates of chemical reactions. For a single… …   Wikipedia

  • Reaction rate — Iron rusting a chemical reaction with a slow reaction rate. Wood …   Wikipedia

  • Reaction rate constant — In chemical kinetics a reaction rate constant k or λ quantifies the speed of a chemical reaction.[1] For a chemical reaction where substance A and B are reacting to produce C, the reaction rate has the form: Reaction: A + B → C k(T) is the… …   Wikipedia

  • Kinetic isotope effect — The kinetic isotope effect (KIE) is the ratio of reaction rates of two different isotopically labeled molecules in a chemical reaction. It is also called isotope fractionation, although this term is somewhat broader in meaning. A KIE involving… …   Wikipedia

  • river — river1 riverless, adj. riverlike, adj. /riv euhr/, n. 1. a natural stream of water of fairly large size flowing in a definite course or channel or series of diverging and converging channels. 2. a similar stream of something other than water: a… …   Universalium

  • Inflation (cosmology) — Inflation model and Inflation theory redirect here. For a general rise in the price level, see Inflation. For other uses, see Inflation (disambiguation). Physical cosmology …   Wikipedia


Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.