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Catalysts

Homogenous Catalysts are in the same physical state as the reactants.Heterogenous Catalysts are in a different physical phase to the reactants.
  • Reactants adsorb onto the active sites on the surface of the catalyst.
  • Bonds within the reactants break.
  • Bonds between the products form.
  • The products desorb from the surface of the catalyst.
Catalysts increase the rate of reaction by providing an alternative pathway with a lower activation energy, so catalysts increase the value of the rate constant, k.

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Specification: OCR Chemistry A (H432), A-level, 5.1.1 How fast?. Topic: Rate of Reaction.

Key terms in this lesson

rate equation
An equation that shows how the rate of a reaction depends on the concentration of each reactant, each raised to a power called its order.
activation energy
The minimum energy required for a collision between particles to result in a reaction.

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