CHEM 1211 Lecture 9 Outline of Last Lecture I Chemical Equilibria II Types of Reactions A Precipitation B Acid Base Neutralization C Gas Forming D Reduction Oxidation III Classifying RXNs Outline of Current Lecture I Example Reactions A Clicker Questions II Chemical Calculations A Mom s Pound Cake III Conceptual Understanding Current Lecture I Example Reactions 1 A student precipitates Ca OH 2 The precipitate is gelatinous and hard to manage What do we do to make it more manageable Heat Metal Oxide Solid Calcium Oxide reacts with water CaO s H2O l Ca OH 2 s 2 Barium Hydroxide Strong Base Sulfuric Acid Strong Acid 3 Silver Copper Demonstration Oxidized Cu s Cu2 aq 2e RXNs Produced acid base exchange precipitation Reduced 2 Ag aq e Ag s REDOX RXN 2 Ag aq Cu s Cu2 aq 2Ag s 4 H2O2 aq I aq O2 g H2O l I aq H2O2 Hydrogen Peroxide Total Charge of 0 I catalyst not spectator ions O2 Normal charge of 2 H oxidation state 1 Redox RXN or gas forming RXN H O Total Charge 0 2 1 2 x Finding the charge of ion in a compound X 1 when we know the total charge 1 1 0 1 2 H2O2 aq I aq O2 g H2O l I aq Ox Red H2O2 normally the oxidizing agent but here it is the ox and red agent A Clicker Questions 1 Acetic Acid reacts with Barium hydroxide The total ionic equation is 2CH3CO2 Ba2 2HO 2CH3CO2 Ba2 H2O Keep ions together don t break apart weak electrolytes 2 Which represents an oxidation process Fluoride ion converted into Fluorine Ox loss of e Charge is pos LEO goes GER Red Gain of e Oxidizing agent takes away eII Chemical Calculations Chemical arithmetic is like cooking A Mom s Pound Cake pound 2 sticks butter tsp fine salt cup veg shortening tsp baking powder 3 cups sugar 1 cup milk 5 eggs 1 tsp Vanilla extract 3 cups flour 9 cups of flour 3 cakes Clicker Q 3 How many cakes can we 6 cups of suger 2 cakes Make 2 20 eggs 4 cakes Reactants Products 2 tsp of vanilla 2 5 cakes III Conceptual Understanding 1 2H2 O2 2H2O Limiting Reagent O2 Still have some H2 left
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