Bell Ringer Aluminum Sulfuric Acid Aluminum Sulfate Hydrogen
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 + H 2 SO 4 Al 2(SO 4)3 + H 2 B 2 Al + 3 H 2 SO 4 Al 2(SO 4)3 + 3 H 2 C 2 Al + 3 H 2 SO 4 Al 2(SO 4)3 + H 2 D 2 Al + H 2 SO 4 Al 2(SO 4)3 + H 2 2004 SOL
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
Chocolate Chip Cookies • • • How much? • • • 2. 25 8 0. 5 0. 75 1 1 1 0. 5 cups Tbsp cups tsp tsp cups flour butter shortening sugar brown sugar salt baking soda vanilla Egg Beaters What units? Of what?
Chocolate Chip Cookies • • • How much? • • • 2. 25 8 0. 5 0. 75 1 1 1 0. 5 flour butter shortening sugar brown sugar salt baking soda vanilla Egg Beaters Of what?
Chocolate Chip Cookies • • • How much? • • • 2. 25 8 0. 5 0. 75 1 1 1 0. 5 cups Tbsp cups tsp tsp cups What units?
Chocolate Chip Cookies • • • How much? • • • 2. 25 8 0. 5 0. 75 1 1 1 0. 5 cups Tbsp cups tsp tsp cups flour butter shortening sugar brown sugar salt baking soda vanilla Egg Beaters What units? Of what?
Get on with it! What does this have to do with CHEMISTRY?
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 coefficient substance (177ºC) 1 batch of chocolate chip cookies! (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: • • • 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 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. How many batches of cookies can I make with that many Egg Beaters?
Let’s Revisit the Cookies… For 1 batch: • • • 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 I have 1. 5 cups of Egg Beaters. How many batches of cookies can I make with that many Egg Beaters? 1. 5 cups E. B. x 1 batch cookies = 0. 5 cups E. B. 3. 0 batches of cookies
Let’s Revisit the Cookies… For 1 batch: • • • 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 I have 1. 5 cups of Egg Beaters. How much butter do I need to deplete (use up) the Egg Beaters? 1. 5 cups E. B. x 8 Tbsp butter 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!
Example: Mole-Mole Problems 2 H 2 + O 2 2 H 2 O How many moles of water can be formed from 0. 5 mol H 2? 0. 5 mol H 2 x 2 mol H 2 O = 0. 5 mol H 2 O 2 mol H 2
Mole-Mole Practice 3 Cu. SO 4 + 2 Al 1. a. 0. 5 mol Al x Al 2(SO 4)3 + 3 Cu Mole ratio 3 mol Cu. SO 4 2 mol Al = 0. 8 mol Cu. SO 4 b. 0. 5 mol Al x 1 mol Al 2(SO 4)3= 0. 3 mol Al 2(SO 4)3 2 mol Al c. 0. 5 mol Al x 3 mol Cu 2 mol Al = 0. 8 mol Cu
Mole-Mole Practice 3 Ca + 2 Al. Cl 3 2. a. b. c. 3 Ca. Cl 2 + 2 Al 2. 5 mol Ca x 2 mol Al. Cl 3 2. 5 mol Ca x 3 mol Ca. Cl 2 2. 5 mol Ca x 3 mol Ca 2 mol Al 3 mol Ca = 1. 7 mol Al. Cl 3 = 2. 5 mol Ca. Cl 2 = 1. 7 mol Al
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 H 2 + O 2 2 H 2 O How many moles of water can be formed from 48. 0 g O 2? 48. 0 g O 2 x 1 mol O 2 x 2 mol H 2 O = 3. 00 mol H 2 O 32. 00 g O 2 1 mol O 2
Mass-Mole Practice 3 Cu. SO 4 + 2 Al 1. a. 13. 5 g Al x 1 mol Al 26. 98 g Al b. 13. 5 g Al x 1 mol Al 26. 98 g Al c. 13. 5 g Al x 1 mol Al 26. 98 g Al Al 2(SO 4)3 + 3 Cu Mole ratio 3 mol Cu. SO 4 x 2 mol Al = x 1 mol Al 2(SO 4)3 = 2 mol Al x 3 mol Cu 2 mol Al 0. 751 mol Cu. SO 4 0. 250 mol Al 2(SO 4)3 = 0. 751 mol Cu
Mass-Mole Practice 3 Ca + 2 Al. Cl 3 2. a. 5. 7 g Ca x 1 mol Ca 3 Ca. Cl 2 + 2 Al x 40. 08 g Ca 2 mol Al. Cl 3 3 mol Ca b. 5. 7 g Ca x 1 mol Ca 40. 08 g Ca x c. 5. 7 g Ca x 1 mol Ca 40. 08 g Ca x 3 mol Ca. Cl 2 3 mol Ca 2 mol Al 3 mol Ca = 0. 095 mol Al. Cl 3 = 0. 14 mol Ca. Cl 2 = 0. 095 mol Al
Mass-Mass Problems Example: 2 H 2 + O 2 2 H 2 O How many grams of water can be formed from 48. 0 g O 2? 48. 0 g O 2 x 1 mol O 2 x 2 mol H 2 O x 18. 02 g H 2 O = 54. 1 g H 2 O 32. 00 g O 2 1 mol H 2 O
Mass-Mass Practice 3 Cu. SO 4 + 2 Al Al 2(SO 4)3 + 3 Cu Mole ratio 3 mol Cu. SO 4 1. a. 8. 5 g Al x 1 mol Al x 26. 98 g Al 2 mol Al 159. 61 g Cu. SO 4 = x 1 mol Cu. SO 4 75 g Cu. SO 4 b. 8. 5 g Al x 1 mol Al 2(SO 4)3 x 342. 14 g Al 2(SO 4)3 = 26. 98 g Al 2 mol Al 1 mol Al 2(SO 4)3 54 g Al 2(SO 4)3
Mass-Mass Practice c. 8. 5 g Al x 1 mol Al 26. 98 g Al x 3 mol Cu 2 mol Al x 63. 55 g Cu 1 mol Cu 30. g Cu =
Mass-Mass Practice 3 Ca + 2 Al. Cl 3 2. a. 1. 9 g Ca x 1 mol Ca 3 Ca. Cl 2 + 2 Al x 40. 08 g Ca 2 mol Al. Cl 3 3 mol Ca x 133. 33 g Al. Cl 3 = 1 mol Al. Cl 3 4. 2 g Al. Cl 3 b. 1. 9 g Ca x 1 mol Ca 40. 08 g Ca x 3 mol Ca. Cl 2 3 mol Ca x 110. 98 g Ca. Cl 2 = 1 mol Ca. Cl 2 5. 3 g Ca. Cl 2
Mass-Mass Practice 3 Ca + 2 Al. Cl 3 3 points c. 1. 9 g Ca x 1 mol Ca x 40. 08 g Ca 3 Ca. Cl 2 + 2 Al 2 mol Al 2 points 3 mol Ca 3 points For Monday’s Quiz: • 2 Mass-Mass problems, 10 points each • Watch for Significant Figures! • Label EVERYTHING! x 26. 98 g Al 1 mol Al 2 points = 0. 85 g Al
- Slides: 27
