Home / IB DP Chemistry: AHL 16.2 Activation energy : Study Notes

IB DP Chemistry: AHL 16.2 Activation energy : Study Notes

16.2 Activation energy

Essential Idea:
The activation energy of a reaction can be determined from the effect of temperature on reaction rate.

Understandings:

  • The Arrhenius equation uses the temperature dependence of the rate constant to determine the activation energy.
  • A graph of 1/T against ln k is a linear plot with gradient – Ea / R and intercept, lnA.
  • The frequency factor (or pre-exponential factor) (A) takes into account the frequency of collisions with proper orientations.

Applications and Skills:

  • Analysing graphical representation of the Arrhenius equation in its linear form \(ln\;k = \frac{-E_a}{RT}+ln \;A\)
  • Using the Arrhenius equation  \(k=Ae^{\frac{-E_a}{RT}}\)
  • Describing the relationships between temperature and rate constant; frequency factor and complexity of molecules colliding.
  • Determining and evaluating values of activation energy and frequency factors from data.

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