Exothermic and endothermic reactions

1 State that an exothermic reaction transfers thermal energy to the surroundings leading to an increase in the temperature of the surroundings

4 State that the transfer of thermal energy during a reaction is called the enthalpy change, ΔH, of the reaction. ΔH is negative for exothermic reactions and positive for endothermic reactions

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

3 Interpret reaction pathway diagrams showing exothermic and endothermic reactions

5 Define activation energy, Eₐ, as the minimum energy that colliding particles must have to react 6 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, ΔH (d) activation energy, Eₐ 7 State that 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 8 Calculate the enthalpy change of a reaction using bond energies