1. Reaction Rates What affects the rate of reaction?

2. Reaction Rates Collision Theory – in order for molecules to react, they must collide with sufficient kinetic energy.

3. Reaction Rates Energy Diagram shows how energy (y axis) changes throughout the course of a chemical reaction (x axis).

4. Reaction Rates Endothermic Reaction – the energy of the product is greater than that of reactants Exothermic Reaction – the energy of the reactants is greater than that of the products

5. Reaction Rates Activated complex – transitional structure that is neither reactant nor product, but some characteristics of both

6. Reaction Rates Temperature – reactions occur faster at higher temperature (more kinetic energy) Concentration – higher concentration causes higher rate (more likely to collide) Catalyst – a substance that speeds up the reaction by lowering the activation energy Surface area – smaller pieces react faster