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Edexcel IGCSE Chemistry · Spec 3.5C-3.7C

Energy Level Diagrams & Bond Energies

Energy level diagrams and calculating energy changes from bond energies.

Chemistry revision video

Energy Level Diagrams & Bond Energies

Spec 3.5C-3.7C

What you need to know

  • Draw energy level diagrams for both types of reaction
  • Mark on the activation energy
  • Use bond energies to find the energy change

Active recall

Quick check

Answer each question before opening the answer.

How do you calculate the energy change using bond energies?

Energy change = energy to break bonds (bonds in reactants) − energy released making bonds (bonds in products).

On an energy profile, where are the products for an exothermic reaction?

Below the reactants (energy is released).

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