1. Reaction Theory: Collision, Activation and Potential Energy Diagrams (Chapter 16 Lesson 1&2)

2. Collision Theory In order for a reaction to occur, particles must collide with enough energy and in the proper orientation Potential Energy There must be enough energy to start breaking old bonds and making new bonds. This is called the activation energy. Activation Energy

3. Particle Orientation is Important

4. Sufficient Energy and Proper Orientation Are Both Needed for a Reaction to Occur

5. More Surface Area Increases the Speed (rate) of a Reaction In a reaction between magnesium metal and hydrochloric acid, magnesium atoms must collide with the hydrogen ions. When the magnesium atoms form one big lump...

6. Alka Seltzer Demo Effect of… Collisions: Dry vs. Solution Surface Area: Tablet vs. Powder

7. Higher Concentration Increases the Speed (rate) of a Reaction In terms of the collision theory, increasing the concentration of a reactant increases in the number of collisions between the reacting species per second and therefore increases the reaction rate.

8. Pressure Under higher pressure or at a higher concentration, gas molecules collide more frequently and react at a faster rate.

9. Temperature At higher temperatures, particles collide more frequently and with greater intensity.

10. Endothermic Reactions +ΔH Energy Absorbed “feels cold”

11. Exothermic Reactions -ΔH Energy Released “feels hot”