3.6.1 Energy During Collision 3.6 Activation Energy 3.6.1 Energy During Collision LO: I understand how the chemical energy of a reaction mixture changes during the reaction.

collide break form A activated complex In order to react: collide the reactant molecules must . break the bonds in the reactants must . form the bonds in the products must . A The intermediate (A) is highly unstable and is known as an . activated complex LO: I understand how the chemical energy of a reaction mixture changes during the reaction.

The progress can be shown using a potential energy diagram: LO: I understand how the chemical energy of a reaction mixture changes during the reaction.

3.6.2 Potential Energy Diagrams LO: I understand what is meant by the activation energy.

The activation energy (Ea) is the additional energy needed by the reactant molecules to form the . activated complex activated complex PE Ea reactant PE Activation energy = 40 - 10 = 30 kJ mol-1 LO: I understand what is meant by the activation energy.

Ea = 80 kJ mol-1 Ea = 200 kJ mol-1 LO: I understand what is meant by the activation energy.

3.6.3 The Catalytic Effect LO: I understand the effect a catalyst has on the activation energy.

The catalyst , the activation energy. From the diagram: The catalyst makes no difference to the PE of the reactants or products. lowers The catalyst , the activation energy. less Using a catalyst, energy is needed to form an activated complex. LO: I understand the effect a catalyst has on the activation energy.