Chocolate Chip Cookies

1. 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 • 1 bag chocolate chips

2. 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 • 1bag chocolate chips

3. How much? Of what? Chocolate Chip Cookies • 2.25flour • 8butter • 0.5shortening • 0.75sugar • 0.75brown sugar • 1salt • 1baking soda • 1vanilla • 0.5Egg Beaters • 1 chocolate chips

4. 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 • 1 bag chocolate chips

5. Get on with it! What does this have to do with CHEMISTRY?

6. (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 + chips unit substance coefficient (a synthesis reaction)

7. Welcome to STOICHIOMETRY

8. What is stoichiometry? • Compositionstoichiometry deals with the mass relationships of elements in compounds. • Reaction stoichiometry involves the mass relationships between reactants and products in a chemical reaction. • All reaction stoichiometry calculations start with a balanced chemical equation.

9. 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?

10. 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

11. 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

12. … Back to Chemistry • There are three types of stoichiometry problems: • Mole-Mole problems (1 conversion) • Mass-Mole problems (2 conversions) • Mass-Mass problems (3 conversions) given required

13. Stoichiometry Problems • Stoichiometric problems are solved by using ratios from balanced chemical equations to convert the given quantity. • A mole ratio is a conversion factor that relates the amount in moles of any two substances involved in a chemical reaction. • This information is obtained from the balanced chemical equation.

14. Mole Ratios • Example: • The relationships between product and reactants or reactants can be expressed in the following mole ratios: 2 H2O 2 H2 + O2

15. Mole Ratios 2 H2 + O2 2 H2O

16. Practice • For each reaction, write all possible mole ratios.

17. 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

18. Mole-Mole Practice 3 CuSO4 + 2 Al Al2(SO4)3 + 3 Cu 1. Convert 0.5 mol CuSO4 to mol Cu 0.5 mol CuSO4 x 3 mol Cu 0.5 mol Cu = 3 mol CuSO4 2. Convert 0.5 mol Al to mol CuSO4 3 mol CuSO4 0.5 mol Al x 0.8 mol CuSO4 = 2 mol Al

19. 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 balanced equation. • Step 4: Set up the conversion and solve.

20. 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

21. 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

22. Mole – Mass Practice 3 Ca + AlCl3 2 3 CaCl2 + Al 2 3 mol Ca 40.08 g Ca 0.095 mol AlCl3 x x = 5.7 g Ca 2 mol AlCl3 1 mol Ca

23. 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

24. 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

25. 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