Energy Transfer in Chemical Reactions

• Heat Transfer: Most chemical reactions involve either heat loss or heat gain.
• There are two types: exothermic; endothermic;

1. Collision Theory and Activation Energy

Effective Collisions: For a new product to form, particles must collide effectively.

• Effective Collision: One that results in the formation of products.

2. Exothermic and Endothermic Reactions

• Bonds: Bonds are formed.
• Energy Change (△H): Negative △H indicates energy is given out.

• In an endothermic reaction, bonds are broken.
• This type of reaction takes in heat
• Energy Change (△H): Positive △H indicates energy is taken in.

3. Activation Energy (EA)

4. The effect of a Catalyst on Activation Energy

• Function: A catalyst lowers the activation energy required.
• Result: Reactants need less energy for a successful collision, increasing the reaction rate.