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Chemical Engineering vocabulary · Reactions and Reactors

Activation energy

Meaning in chemical engineering, with examples

nounCommon term

In chemical engineering, activation energy means: The minimum energy that reacting molecules need for a reaction to happen. A high value means the rate is very sensitive to temperature; a catalyst lowers it.

In Turkish: aktivasyon enerjisi, etkinleşme enerjisi

How it is used

Used in kinetics and safety studies. Engineers find it from lab data with the Arrhenius equation, k = A·exp(−Ea/RT), and give it in kJ/mol. It explains why a small temperature rise can speed up a reaction a lot.

Example sentences

  1. The activation energy is about 90 kJ/mol, so around 80 °C a 10 °C rise more than doubles the rate.

  2. The new catalyst lowers the activation energy, so we can run the reactor 30 °C cooler.

Common collocations

  • apparent activation energy
  • Arrhenius equation
  • lower the activation energy
  • activation energy barrier
  • reaction rateHow fast reactants are used up or products are formed, usually given as moles per unit volume per unit time. It depends on temperature, concentration and catalyst.
  • catalystA substance that makes a reaction go faster, or more selectively, without being used up itself. In industry it is often a solid in pellets placed in a reactor bed.
  • rate-limiting stepThe slowest step in a series of steps, such as reaction, diffusion or heat removal, which controls how fast the whole process can go.
  • exothermicDescribes a reaction or process that releases heat to its surroundings, such as combustion, neutralization or most polymerizations.

This word in other fields

The same English word can have a different meaning in another field:

More terms: Reactions and Reactors

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