Chemistry Matter and Change Chapter 11 Stoichiometry Chemistry Matter and Change Chapter 11

Chapter 11 Big Idea Mass relationships in chemical reactions confirm the law of conservation of mass

11.1 Defining Stoichiometry Chemistry Matter and Change 11.1 Defining Stoichiometry

11.1 Main Idea The amount of each reactant present at the start of a chemical reaction determines how much product can form.

11.1 Objectives Describe the types of relationships indicated by a balanced chemical reaction. State the mole ratios from a balanced chemical reaction.

11.1 Review Vocabulary Chemical reaction Reactant Product Q: Why was the mole of oxygen molecules excited when he walked out of the singles bar?  A: He got Avogadro's number!

11.1 New Vocabulary Stoichiometry Mole ratio Composition stoichiometry Reaction stoichiometry

Cookies Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies If you have only one egg, how many cookies can you make? What information do you need?

Cookies 2 large eggs Yield: 5 dozen cookies Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies If you have only one egg, how many cookies can you make? 1 egg 60 cookies = 30 cookies 2 egg

Cookies Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies If you need to make 100 cookies, how much flour do you need? What information do you need?

Cookies Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies If you need to make 100 cookies, how much flour do you need? What information do you need? 100 cookies 2.25 Cups flour = 3.75 C flour 60 cookies

Cookies Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies If you have 3 teaspoons of salt and 5 eggs, how many cookies can you make?

Cookies If you have 3 teaspoons of salt and 5 eggs, how many cookies can you make? Ingredients 2 1/4 cups all-purpose flour 1 teaspoon baking soda 1 teaspoon salt 1 cup butter, softened 3/4 cup granulated sugar 3/4 cup packed brown sugar 1 teaspoon vanilla extract 2 large eggs 2 cups (12-oz. pkg.) NESTLÉ® TOLL HOUSE® Semi-Sweet Chocolate Morsels 1 cup chopped nuts Yield: 5 dozen cookies So, how many cookies can you make? Which ingredient limited the number of cookies? 3 t salt 60 cookies = 180 cookies 1 t salt 5 eggs 60 cookies = 150 cookies 2 eggs

Reactions are Recipes Peanut butter and jelly sandwich 2 T peanut butter 2 T jelly 2 slices bread 2T PB+ 2 T jelly + 2 slices bread  1 PB &J Water 2 moles H2 1 mole O2 2H2 + O2  2H2O

Stoichiometry Two types Composition stoichiometry: deals with mass relationships of elements in a compound Reaction stoichiometry: deals with the mass relationships between products and reactants in a chemical reaction

The Key is MOLE RATIOS All chemical reactions are described in moles You can convert moles of one substance to moles of another substance given a BALANCED EQUATION

Recall Periodic Table Grams Moles

Practice For the equation = 1 = 1 = 1 N2+3H22NH3 What is the mole ratio for nitrogen to hydrogen? What is the mole ratio for hydrogen to ammonia? What is the mole ratio for nitrogen to ammonia? 1 mole N2 = 1 3 mole H2 3 mole H2 = 1 2 mole NH3 1 mole N2 = 1 2 mole NH3

C6H12O6 + 6 O2  6 H2O + 6 CO2 reaction type:______________________ If 12 moles of oxygen was consumed, how many moles of CO2 were produced? reaction type:______________________ If 12 moles of oxygen was consumed, how many moles of C6H12O6 were consumed?

2H2O2  2H2O + O2 reaction type:______________________ If 3 moles of oxygen are produced, what is the mass of water that was produced? reaction type:______________________ If 3 moles H2O2 are consumed, what is the mass of oxygen that is produced?

Can you… Describe the types of relationships indicated by a balanced chemical reaction. State the mole ratios from a balanced chemical reaction.

11.2 Stoichiometric Calculations Chemistry Matter and Change 11.2 Stoichiometric Calculations

11.2 Main Idea The solution to every stoichiometry problem requires a balanced chemical reaction.

11.2 Objectives List the sequence of steps used in solving stoichiometric problems. Solve stoichiometric problems.

Are you part of the solution or part of the precipitate? 11.2 Review Vocabulary Chemical reaction Diatomic element Are you part of the solution or part of the precipitate?

The formula that always works: You may not always need the whole thing g “A” mol “A” mol “B” g “B” mol “B” g “A” mol “A” Given Periodic table Balanced equation Periodic table

2 NaOH + 1 CaBr2  2 NaBr + 1 Ca(OH)2 reaction type:______________________ If 27.3 g NaOH is consumed, how many moles of calcium hydroxide are produced? If 84.2 g of calcium bromide are consumed, how many moles of sodium hydroxide are consumed?

3 Pb + 2 H3PO4  3 H2 + 1 Pb3(PO4)2 reaction type:______________________ If 14.7 g of lead is consumed, what mass of hydrogen was produced? If 87.24 g of Lead phosphate needs to be produced, what mass of phosphoric acid is needed?

Can you… List the sequence of steps used in solving stoichiometric problems. Solve stoichiometric problems.

Chemistry Matter and Change 11.3 Limiting Reactants

A chemical reaction stops when one of the reactants is used up. 11.3 Main Idea A chemical reaction stops when one of the reactants is used up.

11.3 Objectives Identify the limiting reactant in a chemical equation. Identify the excess reactant and calculate the amount remaining after the reaction is complete. Calculate the mass of a product when the amounts of more than one reactant are given. Calculate the maximum yield and amount of excess reactant remaining.

Percent yield is a measure of the efficiency of a reaction. 11.3 Main Idea Percent yield is a measure of the efficiency of a reaction.

11.3 New Vocabulary Limiting reactant Excess reactant

11.3 Review Vocabulary Molar mass Q: What do you call a tooth in a glass of water?  A: One molar solution.

Limiting Reagent Peanut butter and jelly sandwich You have 16 T PB, 8 TB jelly and 4 slices of bread. Which one is the limiting reagent? Which are the excess reagents? Peanut butter and jelly sandwich 2 T peanut butter 2 T jelly 2 slices bread 2T PB+ 2 T jelly + 2 slices bread  1 PB &J

Limiting reagent problems Calculate the yield of any of the products (If you have to solve for one, use that one and save yourself some steps!) The one that gave you the least amount of product is the limiting reactant All others are excess reactants

If you have 8 car bodies and 36 tires, what will you have left over and how many complete cars will you have?

4 tires + 1 body  1 car Given 8 bodies and 36 tires 8 bodies 1 car limiting = 8 cars 1 body 36 tires 1 car = 9 cars 4 tires

What is left over? Calculate what you used then subtract 4 tires 8 cars 4 tires = 32 tires 1 car 36 tires - 32 tires 4 tires

4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) A 2.00 g sample of ammonia is mixed with 4.00 g of oxygen.  Which is the limiting reactant and how much excess reactant remains after the reaction has stopped? 4 NH3(g) + 5 O2(g) 4 NO(g) + 6 H2O(g) A

How much is left? Figure out how much was used and subtract from the initial amount

Can you… Identify the limiting reactant in a chemical equation. Identify the excess reactant and calculate the amount remaining after the reaction is complete. Calculate the mass of a product when the amounts of more than one reactant are given. Calculate the maximum yield and amount of excess reactant remaining.

Chemistry Matter and Change 11.4 Percent Yield

11.4 Objectives Calculate the theoretical yield of a chemical reaction from data. Determine the percent yield for a chemical reaction.

Q: What is the name of 007's Eskimo cousin? A: Polar Bond. 11.4 Review Vocabulary Process Yield Q: What is the name of 007's Eskimo cousin?  A: Polar Bond.

11.4 New Vocabulary Theoretical yield Actual yield Percent yield

Theoretical yield Calculated value If 120. g of propane, C3H8, is burned in excess oxygen, how many grams of water are formed?

Actual yield The amount measured (actual) If 120. g of propane, C3H8, is burned in excess oxygen and 140. g of water are formed, what is the percent yield?

Percent Yield Theoretical: 196 g water Actual: 140. g water

Can you… Calculate the theoretical yield of a chemical reaction from data. Determine the percent yield for a chemical reaction.