EFFECT OF A CATALYST ON A CHEMICAL REACTION Objective: to observe the effect of a catalyst during a decomposition reaction. Page 48 of IAN

FACTORS THAT AFFECT CHEMICAL REACTIONS 1. Concentration of reactants 2. Temperature of reactants 3. Surface area contact between reactant molecules 4. Use of catalysts or inhibitors

EFFECT OF A CATALYST ON A CHEMICAL REACTION Catalyst: any chemical which increases the speed of a reaction – NOT a part of the reaction (not a reactant or a product). Inhibitor: any chemical which decreases the speed of a reaction

USING A CATALYST Hydrogen Peroxide (H 2 O 2 ) decomposes into water (H 2 O) and oxygen (O 2 ) naturally (on its own) and slowly. Manganese Dioxide (MnO 2 ) Catalyst: (H 2 O 2 ) in the presence of decomposes very quickly MnO 2

SPLINT TEST Tests for: O 2 supports burning: The presence of excess oxygen (O 2 ) being produced. A glowing splint will flame up in the presence of O 2. So, the “ember” turns into a flame again.

LAB ACTIVITY 1.Put a small amount of salt into the left test tube. 2.Put a small amount of baking soda into the right test tube. 3.Manganese Dioxide (MnO 2 ) is already in the middle test tube. 4.Pour one inch of hydrogen peroxide (H 2 O 2 ) into each of the test tubes. 5.Test for the presence of excess oxygen (O 2 ) with the splint test. 6.Record your observations in your IAN.

OBSERVATIONS Test tube with salt: Test tube with MnO 2 : Test tube with b. soda: Page 47 of IAN (Make this data table on pg 47 of your IAN) (Save room for conclusions below it)

CONCLUSIONS 1.Is there any MnO 2 left in the test tube? Why was it not used up in the reaction? 2.What is the purpose of the catalyst in this reaction? 3.Balance the equation: MnO 2 4H 2 O  ? H 2 O + 2O 2 Also on page 47 of IAN

CONCLUSIONS 1.Is there any MnO 2 left in the test tube? yes Why was it not used up in the reaction? Because it is a catalyst 1.What is the purpose of the catalyst in this reaction? To speed up the reaction 2.Balance the equation: MnO 2 4H 2 O  _4_H 2 O + 2O 2