1. Quick review Demonstrations Begin discussion of progression curve Homework

2. Lycopodium powder Elephants toothpaste Luminol mixture when cold

3. Reaction mechanism graph- Sec 19.5 1. What does A and G represent? 2. How many steps does this reaction go though to get to completion? 3. Which is the slow step? 4. What represents the activated complexes? 5. Which step determines the rate of this reaction? 6. What represents the intermediates? A B D C E F G

4. Reaction mechanism S 2 O 8 2- + I - SO 4 2- + SO 4 I - (slow) SO 4 I - + I - SO 4 2- + I 2 (fast) a. Use Hesss law to determine the overall reaction for these 2 steps. b. Sketch a graph of this reaction mechanism c. Which compound / ion is the intermediate? d. Which step will determine the rate of this reaction?

5. Activation Energy –minimum amount of energy required for a reaction to occur. Activated Complex – a high energy temporary arrangement of reactant molecules. Rate-determining step – the slowest step in a reaction mechanism Intermediate – the product from one reaction that initiates a second reaction

6. Read and take notes over Section 19.5 Start on pg 568 with Reaction Mechanisms Concept Quiz on Friday dealing with rates and progression curves