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## Bell Ringer

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**Bell Ringer**Aluminum + Sulfuric Acid Aluminum Sulfate + Hydrogen Gas Which of the following is the balanced chemical equation for the reaction shown above? A Al + H2SO4Al2(SO4)3 +H2 B 2Al +3H2SO4Al2(SO4)3 +3H2 C 2Al +3H2SO4Al2(SO4)3 +H2 D 2Al +H2SO4Al2(SO4)3 +H2 2004 SOL**2.25 cups flour**8 Tbsp butter 0.5 cups shortening 0.75 cups sugar 0.75 cups brown sugar 1 tsp salt 1 tsp baking soda 1 tsp vanilla 0.5 cups Egg Beaters Chocolate Chip Cookies**2.25cupsflour**8Tbspbutter 0.5cupsshortening 0.75cupssugar 0.75cupsbrown sugar 1tspsalt 1tspbaking soda 1tspvanilla 0.5cupsEgg Beaters How much? Of what? What units? Chocolate Chip Cookies**How much?**Of what? Chocolate Chip Cookies • 2.25flour • 8butter • 0.5shortening • 0.75sugar • 0.75brown sugar • 1salt • 1baking soda • 1vanilla • 0.5Egg Beaters**How much?**What units? Chocolate Chip Cookies • 2.25cups • 8Tbsp • 0.5cups • 0.75cups • 0.75cups • 1tsp • 1tsp • 1tsp • 0.5cups**How much?**Of what? What units? Chocolate Chip Cookies • 2.25cupsflour • 8Tbspbutter • 0.5cupsshortening • 0.75cupssugar • 0.75cupsbrown sugar • 1tspsalt • 1tspbaking soda • 1tspvanilla • 0.5cupsEgg Beaters**Get on with it!**What does this have to do with CHEMISTRY?**(177ºC)**1 batch of chocolate chip cookies! 2.25 cups flour + 8 Tbsp butter + 0.5 cups shortening + 0.75 cups sugar + 0.75 cups brown sugar + 1 tsp salt + 1 tsp baking soda + 1 tsp vanilla + 0.5 cups Egg Beaters unit substance coefficient (a synthesis reaction)**Welcome to STOICHIOMETRY**Ms. Besal 2/23/2006**What is Stoichiometry?**• The study of quantitative relationships within chemical reactions • A balanced equation is the key to stoichiometry! • Tools you’ll need for this chapter: • Writing proper formulas and balanced reactions • Converting from mass to moles and vice versa**Let’s Revisit the Cookies…**For 1 batch: The Egg Beaters I have are close to expiring! I’d like to use the rest of them in this recipe. I have 1.5 cups of Egg Beaters. • 2.25 cups flour • 8 Tbsp butter • 0.5 cups shortening • 0.75 cups sugar • 0.75 cups brown sugar • 1 tsp salt • 1 tsp baking soda • 1 tsp vanilla • 0.5 cups Egg Beaters How many batches of cookies can I make with that many Egg Beaters?**Let’s Revisit the Cookies…**For 1 batch: I have 1.5 cups of Egg Beaters. • 2.25 cups flour • 8 Tbsp butter • 0.5 cups shortening • 0.75 cups sugar • 0.75 cups brown sugar • 1 tsp salt • 1 tsp baking soda • 1 tsp vanilla • 0.5 cups Egg Beaters How many batches of cookies can I make with that many Egg Beaters? 1 batch cookies 1.5 cups E.B. x = 0.5 cups E.B. 3.0 batches of cookies**Let’s Revisit the Cookies…**For 1 batch: I have 1.5 cups of Egg Beaters. • 2.25 cups flour • 8 Tbsp butter • 0.5 cups shortening • 0.75 cups sugar • 0.75 cups brown sugar • 1 tsp salt • 1 tsp baking soda • 1 tsp vanilla • 0.5 cups Egg Beaters How much butter do I need to deplete (use up) the Egg Beaters? 8 Tbsp butter 1.5 cups E.B. x = 0.5 cups E.B. 24 Tablespoons of butter**… Back to Chemistry**• There are three types of stoichiometry problems we will deal with today: • Mole-Mole problems (1 conversion) • Mass-Mole problems (2 conversions) • Mass-Mass problems (3 conversions) given required**Baby Steps… Mole-Mole Problems**• Step 1: Write a BALANCED EQUATION • Step 2: Determine the mole ratio from the coefficients in the equation. • Mole ratio = moles of required substance moles of given substance • Step 3: Set up the problem like a unit conversion and solve!**Mole-Mole Problems**Example: 2 H2O 2 H2 + O2 How many moles of water can be formed from 0.5 mol H2? 2 mol H2O 0.5 mol H2 0.5 mol H2O x = 2 mol H2**3**2 3 Mole-Mole Practice CuSO4 + Al Al2(SO4)3 + Cu Mole ratio 3 mol CuSO4 1. a. 0.5 mol Al 0.8 mol CuSO4 x = 2 mol Al 1 mol Al2(SO4)3 b. 0.5 mol Al 0.3 mol Al2(SO4)3 x = 2 mol Al 3 mol Cu c. 0.5 mol Al 0.8 mol Cu x = 2 mol Al**3**2 2 Mole-Mole Practice Ca + AlCl3 3 CaCl2 + Al 2 mol AlCl3 2. a. 2.5 mol Ca 1.7 mol AlCl3 x = 3 mol Ca 3 mol CaCl2 b. 2.5 mol Ca 2.5 mol CaCl2 x = 3 mol Ca 2 mol Al c. 2.5 mol Ca 1.7 mol Al x = 3 mol Ca**Mass-Mole Problems**• Step 1: Write a BALANCED EQUATION • Step 2: Calculate the molar mass of your given substance and convert from mass to moles • Step 3: Determine the mole ratio from the coefficients in the equation • Step 4: Set up the conversion and solve!**Mass-Mole Problems**Example: 2 H2O 2 H2 + O2 How many moles of water can be formed from 48.0 g O2? 1 mol O2 2 mol H2O 48.0 g O2 3.00 mol H2O x x = 32.00 g O2 1 mol O2**3**2 3 Mass-Mole Practice CuSO4 + Al Al2(SO4)3 + Cu Mole ratio 1 mol Al 3 mol CuSO4 1. a. 13.5 g Al 0.751 mol CuSO4 x x = 26.98 g Al 2 mol Al 1 mol Al 1 mol Al2(SO4)3 b. 13.5 g Al x x 0.250 mol Al2(SO4)3 = 26.98 g Al 2 mol Al 1 mol Al 3 mol Cu c. 13.5 g Al x 0.751 mol Cu x = 26.98 g Al 2 mol Al**3**2 2 Mass-Mole Practice Ca + AlCl3 3 CaCl2 + Al 1 mol Ca 2 mol AlCl3 2. a. 5.7 g Ca x x 0.095 mol AlCl3 = 40.08 g Ca 3 mol Ca 1 mol Ca 3 mol CaCl2 b. 5.7 g Ca x x 0.14 mol CaCl2 = 40.08 g Ca 3 mol Ca 1 mol Ca 2 mol Al c. 5.7 g Ca x x 0.095 mol Al = 40.08 g Ca 3 mol Ca**Mass-Mass Problems**Example: 2 H2O 2 H2 + O2 How many grams of water can be formed from 48.0 g O2? 1 mol O2 2 mol H2O 18.02 g H2O 48.0 g O2 54.1 g H2O x x x = 32.00 g O2 1 mol O2 1 mol H2O**3**2 3 Mass-Mass Practice CuSO4 + Al Al2(SO4)3 + Cu Mole ratio 1 mol Al 3 mol CuSO4 159.61 g CuSO4 1. a. 8.5 g Al = x x x 26.98 g Al 2 mol Al 1 mol CuSO4 75 g CuSO4 1 mol Al 1 mol Al2(SO4)3 342.14 g Al2(SO4)3 b. 8.5 g Al x x x = 26.98 g Al 2 mol Al 1 mol Al2(SO4)3 54 g Al2(SO4)3**Mass-Mass Practice**1 mol Al 3 mol Cu 63.55 g Cu c. 8.5 g Al x x x = 26.98 g Al 2 mol Al 1 mol Cu 30. g Cu**3**2 2 Mass-Mass Practice Ca + AlCl3 3 CaCl2 + Al 1 mol Ca 2 mol AlCl3 133.33 g AlCl3 2. a. 1.9 g Ca x x x = 40.08 g Ca 3 mol Ca 1 mol AlCl3 4.2 g AlCl3 1 mol Ca 3 mol CaCl2 110.98 g CaCl2 b. 1.9 g Ca x x x = 40.08 g Ca 3 mol Ca 1 mol CaCl2 5.3 g CaCl2**3**2 2 3 points 2 points 2 points 3 points Mass-Mass Practice Ca + AlCl3 3 CaCl2 + Al 1 mol Ca 2 mol Al 26.98 g Al c. 1.9 g Ca x x x = 40.08 g Ca 3 mol Ca 1 mol Al 0.85 g Al • For Monday’s Quiz: • 2 Mass-Mass problems, 10 points each • Watch for Significant Figures! • Label EVERYTHING!