IGCSEChemistryOxford AQARevision NotesEnergy ChangesCalculating & Explaining Energy ChangeCatalysts

Catalysts (Oxford AQA IGCSE Chemistry)

Revision Note

Alexandra Brennan

Expertise

Chemistry

Catalysts

  • Catalysts provide the reactants with a different pathway for a chemical reaction that has a lower activation energy

  • By lowering the activation energy, Ea, a greater proportion of molecules in the reaction mixture have sufficient energy for an effective collision

  • As a result of this, the rate of the catalysed reaction is increased compared to the uncatalysed reaction

Energy level diagram for an exothermic reaction with and without a catalyst

exo-reaction-profile-with-catalyst

A catalyst lowers the activation energy

Exam Tip

You are expected to be able to draw a curve for the activation energy with a catalyst on a provided energy level diagram.

Make sure that the curve starts and finishes in the same place as the original curve but is lower.

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    Alexandra Brennan

    Author: Alexandra Brennan

    Alex studied Biochemistry at Newcastle University before embarking upon a career in teaching. With nearly 10 years of teaching experience, Alex has had several roles including Chemistry/Science Teacher, Head of Science and Examiner for AQA and Edexcel. Alex’s passion for creating engaging content that enables students to succeed in exams drove her to pursue a career outside of the classroom at SME.