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Stoichiometry

Stoichiometry. Limiting Reactants, Percent Yield, Theoretical Yield. Review. Learning Targets. I can determine mole ratios from a balanced chemical equation . I can calculate quantitative relationships using mole ratios and a balanced chemical equation. What is Stoichiometry?.

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Stoichiometry

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  1. Stoichiometry Limiting Reactants, Percent Yield, Theoretical Yield

  2. Review

  3. Learning Targets • I can determine mole ratios from a balanced chemical equation. • I can calculate quantitative relationships using mole ratios and a balanced chemical equation.

  4. What is Stoichiometry? Stoichiometry: The study of quantitative relationships between amounts of reactants used and products formed. -Based on the Law of Conservation of Mass -What you start with, you must end with. -Massreactants = Massproducts

  5. Mole Ratios • Mole Ratio: A ratio between the number of moles of any two substances in a balanced equation. Fe(s) + O2(g) Fe2O3(s) Write all the possible mole ratios:

  6. Practice Problems: Write the mole ratios 1. Al(s) + ___Br2(l) AlBr3(s) 2. KClO3(s) KCl(s) + O2(g)

  7. Mole Map Update

  8. Step-by-Step (identify the specific path and use steps needed to get there) 1. Write a balanced chemical equation. • Interpret the equation in terms of moles. 2. Determine the moles of the given substance using a mass-to-mole conversion. • Use the inverse (mol/g) of the molar mass as the conversion factor. 3. Determine the moles of the unknown substance from the moles of the given substance. • Use the appropriate mole ratio from the balanced chemical equation as the conversion factor. 4. From the moles of the unknown substance, determine the mass of the unknown substance using a mole-to-mass conversion. • Use the molar mass as the conversion factor.

  9. Moles-to-Moles Model ____Al + ____O2 ____ Al2O3 If given 3.0 moles of aluminum metal how many moles of aluminum oxide can be produced? How many moles of oxygen gas are needed to produce 3.5 mol of aluminum oxide?

  10. Moles-to-Grams Model ____ C6H6 + ____O2 ____ CO2 + ____ H2O If there are 7.653 moles of C6H6, how many grams of CO2 are produced? If you start out with 40.992 grams of C6H6, how many moles of H2O would form?

  11. Your Turn! • Unit Packet Part 1 • Independent Practice 4, 6, 7, 8, 11, 12, 13 Support: FLOW CHART!, Previous Examples, Blog, Book (pgs 299- 311)

  12. Grams-to-Grams Model ____ C6H6 + ____O2 ____ CO2 + ____ H2O If there are 7.6653 grams of C6H6, how many grams of CO2 are produced? If you have 72.33 grams of CO2 that was produced, how many grams of O2 were needed?

  13. Your Turn! • Unit Packet Part 1 • Independent Practice 16-21 • Mixed Review #1-12 Support: Previous Examples, Blog, Book (pgs 299- 311) Formative Assessment over Part 1 and 2 Tomorrow!

  14. QUESTIONS!?

  15. Stoichiometry Practice (See Packet) • Partner-Practice • “Speed Dating with Stoichiometry” • Date Preparation: • Paper • Periodic Table • Calculator • Pen/pencil • Polyatomic Ion Chart • 4 Minutes/ Date

  16. #1 • If 20.0 g of magnesium react with excess hydrochloric acid, how many grams of magnesium chloride are produced (hydrogen is the other product)? • (78.4 g MgCl2)

  17. #2 • Calculate the mass of hydrochloric acid needed to react with 10.0 g zinc (single displacement—what are the products?). • (11.2 g HCl)

  18. #3 • How much silver phosphate is produced if 10.0 g of silver acetate react with excess sodium phosphate (double displacement –what is the other product?)? • (8.36 g Ag3PO4)

  19. Unit 9 Formative Assessment #1 • When finished continue practice on MIXED REVIEW in packet!

  20. What Do You Think? A standard s’moreis made from 2 graham crackers, 1 marshmallow, and 1 square of chocolate. • How could you determine how many complete s’mores could be made from 1 box of crackers, 1 bag of marshmallows and 1 bar of chocolate? “To figure out how many s’mores could be made, I would…”

  21. POGIL Limiting Reactant • Complete in groups! • Complete in your notes! • “Check-points”

  22. POGIL Check-up • Describe a limiting reactant and how you find it. • What is the purpose of determining the limiting reactant?

  23. Limiting Reactant In-class Example #1 • Given 2.5 moles of Na2CO3 and 2 moles of Ca(OH)2. What is the limiting reactant?

  24. Limiting Reactant In-class Example #2 • If you have 80 grams of zinc and 90 grams of hydrochloric acid, which is the limiting reactant? • How many grams of zinc chloride can be produced?

  25. Limiting Reactant Example If 3.4 moles of lithium nitride react with 2.9 moles of calcium chloride, which reactant is the limiting reactant? How many moles of each product can be produced? What amount of the excess reactant is left over? 2Li3N + 3CaCl2 6LiCl + Ca3N2 Answers: CaCl2 is limiting, 5.8 molLiCl, 0.97 mol Ca3N2 1.5 mol Li3N

  26. Your Turn! • Unit Packet Part 3 • Independent Practice 6-13 Support: Previous Examples, Blog, Book (pgs 312-315)

  27. Practice(Limiting Reactants) • If 0.75 g of magnesium is reacted with 2.4 g of oxygen, how many grams of magnesium oxide can be produced? • (answer: 1.2 g MgO)

  28. Unit 9 Formative Assessment #2 • When finished continue practice on Limiting Reactants AND/OR review pages 317-318 in textbook and questions 1-4 Part 4. • Additional Practice Available!! • See Mrs. Bechtum for copies

  29. Percent Yield

  30. Cookies (Percent Yield) I followed a recipe to make a dozen cookies and I had all of the ingredients required, but it only made 10 cookies.

  31. Actual Yield: When you do a chemical reaction, this is the amount of chemical that you actually make (i.e. The amount of stuff you can weigh) • Theoretical Yield: the amount of product we predict that we should get using the balanced chemical equation. • Percent Yield=

  32. Percent Yield and Cooking We need to make cookies and the recipe is as follows: 2 eggs + 1 cup sugar + 2 cups flour  2 dozen cookies Only have 1.5 cups of flour How many cookies can we make, and why?

  33. HCl(aq) + NaOH(aq) NaCl(s) + H2O(l) Start with 5.0 grams of NaOH and after the reaction I have 6.3 grams of NaCl. What is the percent yield of the reaction?

  34. With A Partner • A student runs a reaction to prepare 40.0g of aspirin and yet recovers only 15.5g. What is the percent yield (please show/be able to explain your work)?

  35. I2O5+ CO  CO2 + I2 If you are given 80g of I2O5 to react with 28g of CO, what mass of I2could be produced? If 40.64 g of I2 were actually produced what would the percent yield be?

  36. Your Turn! • Unit Packet Part 4 • Independent Practice 3-10 Support: Previous Examples, Blog, Book (pgs 317-318)

  37. Exit Slip • On a half sheet of paper please put your name and the following... • One thing you learned today (briefly explain it) and one or two questions you have after today’s lesson. Thank you for your attention!

  38. Unit 9 Formative Assessment #3 • When finished continue practice! • Additional Practice Available!! • See Mrs. Bechtum for copies

  39. Lab and Review Day • See Lab Handout • Review Packet • Test tomorrow!! (25pts) • Review FAs, Notes, Readings…

  40. Unit 9 Test-Stoichiometry • Complete Individually • Submit when finished on front table. • Begin reading pages 361-367

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