Quick review

Demonstrations

Begin discussion of progression curve

Homework

Lycopodium powder

Elephant’s toothpaste

Luminol mixture when cold

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 determinesthe rate of this reaction?

6. What represents the intermediates?

A

B

D

C E

F

G

Reaction mechanism

S2O82- + I- SO4

2- + SO4I- (slow)SO4I- + I- SO4

2- + I2 (fast)

Use Hess’s law to determine the overall reaction for these 2 steps.

Sketch a graph of this reaction mechanismWhich compound / ion is the

intermediate?Which step will determine the rate of this

reaction?

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

Read and take notes over Section 19.5Start on pg 568 with Reaction Mechanisms

Concept Quiz on Friday dealing with rates and progression curves