IGCSEChemistryOxford AQARevision NotesEnergy ChangesCalculating & Explaining Energy ChangeCatalysts

Catalysts (Oxford AQA IGCSE Chemistry): Revision Note

Exam code: 9202

Alexandra Brennan

Written by: Alexandra Brennan

Reviewed by: Stewart Hird

Updated on

Oxford AQA ChemistryOxford AQA Combined Science Double Award: 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

Examiner Tips and Tricks

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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    Author
    Reviewer
    Alexandra Brennan

    Author: Alexandra Brennan

    Expertise: Chemistry Content Creator / Senior Marketing Executive

    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.

    Stewart Hird

    Reviewer: Stewart Hird

    Expertise: Chemistry Content Creator

    Stewart has been an enthusiastic GCSE, IGCSE, A Level and IB teacher for more than 30 years in the UK as well as overseas, and has also been an examiner for IB and A Level. As a long-standing Head of Science, Stewart brings a wealth of experience to creating Topic Questions and revision materials for Save My Exams. Stewart specialises in Chemistry, but has also taught Physics and Environmental Systems and Societies.