Activation Energy

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The rate constant is a function of the temperature and can be calculated from the Arrhenius equation:


The same formula can be used to calculate the activation energy Ea from a set of experimentally determined rate constants at different temperatures.
For example, in the hydrolysis of 2-chloro-2-methylpropane, the following data was obtained:
T/K303 298293288283
k*10^29.413.593.082.44 1.82
The exponential equations can be converted to the linear form by taking the logarithm of both sides, which in our case would give: Plotting lnk against 1/T should give an approximately straight line relationship with a slope, Ea/R and an intercept, lnA. In this case the calculations involve the lnk values instead of the plain k values, and the reciprocal values of the temperature.

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