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 rate-limited thermally activated process, an Arrhenius plot gives a straight line, from which the activation energy and the pre-exponential factor can both be determined.

The Arrhenius equation given in the form:

:$k\; =\; A\; e^\{-E\_a/RT\}$

can be written equivalently as:

:$ln(k)\; =\; ln(A)\; -\; frac\{E\_a\}\{R\}left(frac\{1\}\{T\}\; ight)$

When plotted in the manner described above, the value of the extrapolated "y-intercept" will correspond to $ln(A)$, and the gradient of the line will be equal to $-E\_a/R$.

The pre-exponential factor, A, is a constant of proportionality that takes into account a number of factors such as the frequency of collision between and the orientation of the reacting particles.

The expression $-E\_a/RT$ represents the fraction of the molecules present in a gas which have energies equal to or in excess of activation energy at a particular temperature.

See also

* Arrhenius equation
* Eyring equation