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5.1 Exothermic and endothermic reactions

Syllabus
0620–2026–2027
Topic
5.1
Level
—

5.1.1—An exothermic reaction transfers

  • State: an exothermic reaction transfers thermal energy to the surroundings leading to an increase in the temperature of the surroundings

5.1.2—An endothermic reaction takes in

  • State: an endothermic reaction takes in thermal energy from the surroundings leading to a decrease in the temperature of the surroundings

5.1.3—Interpret reaction pathway diagrams

  • Interpret reaction pathway diagrams showing exothermic and endothermic reactions

5.1.4—Transfer of thermal energy during a

  • State: the transfer of thermal energy during a reaction is called the enthalpy change, ∆H, of the reaction. ∆H is negative for exothermic reactions and positive for endothermic reactions

5.1.5—Activation energy, Ea, as the minimum

  • Define activation energy, Ea, as the minimum energy that colliding particles must have to react

5.1.6—And label reaction pathway diagrams

  • Draw and label reaction pathway diagrams for exothermic and endothermic reactions using information provided, to include: (a) reactants (b) products (c) enthalpy change of the reaction, ∆H (d) activation energy, Ea

5.1.7—Bond breaking is an endothermic

  • State: bond breaking is an endothermic process and bond making is an exothermic process and explain the enthalpy change of a reaction in terms of bond breaking and bond making

5.1.8—Enthalpy change of a reaction using

  • Calculate the enthalpy change of a reaction using bond energies

Objective notes

8 learning objectives
ConceptIGCSE Chemistry