1. 4. Balancing Reactions How are coefficients different from subscripts? 2H 2 + O 2  2H 2 O subscripts = # of atoms

2. 4. Balancing Reactions How are coefficients different from subscripts? 2H 2 + O 2  2H 2 O coefficients = how many

3. 4. Balancing Reactions 2H 2 + O 2  2H 2 O subscripts = # of atoms coefficients = how many

4. 4. Balancing Reactions H 2 + O 2  H 2 O 2 subscripts = # of atoms coefficients = how many

5. New Unit: Stoichiometry OBJECTIVE: Balancing Reactions + Grams  Moles + Moles  Grams

6. Topics to be Covered 1. What is Stoichiometry? 2. 1 Step Conversions 3. 2 Step Conversions 4. 3 Step Conversions 5. Limiting Reactants 6. Percentage Yield

7. What is Stoichiometry? ▪ It is: – The QUANTITATIVE relationships between reactants and products – Using MATH and NUMBERS to calculate reactants and products 1. What is Stoichiometry?

8. 1. What is Stoichiometry Balanced Reactions are like recipes

9. 1. What is Stoichiometry What information is missing?? butter brown sugar egg flour baking soda salt + chocolate chips cookies

10. 1. What is Stoichiometry What information Is missing?? 3/4 butter 1/2 brown sugar 1 egg 1 1/2 flour 1 baking soda 1/4 salt + 1 chocolate chips 30 cookies

11. 1. What is Stoichiometry Balanced Reactions are like recipes 3/4 cup butter 1/2 cup brown sugar 1 egg 1 1/2 cups flour 1 teaspoon baking soda 1/4 teaspoon salt + 1 cup chocolate chips 30 cookies

13. Fundamental Measurements What we measure UNIT ▪ Distance ▪ Mass ▪ Time ▪ Electric current ▪ Temperature ▪ Amount ▪ Intensity of light ▪ Meter ▪ Gram ▪ Seconds ▪ Amps ▪ Kelvin ▪ Mole ▪ Candela

14. Fundamental Measurements What we measure UNIT ▪ Distance ▪ Mass ▪ Time ▪ Electric current ▪ Temperature ▪ Amount ▪ Intensity of light ▪ Meter ▪ Gram ▪ Seconds ▪ Amps ▪ Kelvin ▪ Mole ▪ Candela

15. 1. What is Stoichiometry? KI + Pb(NO 3 ) 2  PbI 2 + KNO 3

16. 1. What is Stoichiometry? 2KI + Pb(NO 3 ) 2  PbI 2 + 2KNO 3 COEFFICIENTS = amount of MOLES KI = 2 moles Pb(NO 3 ) 2 = 1 mole PbI 2 = 1 mole KNO 3 = 2 moles

17. 1. What is Stoichiometry? 2KI + Pb(NO 3 ) 2  PbI 2 + 2KNO 3 Stoichiometry = using coefficients from balanced reactions to convert grams  moles and much more.

18. 2. 1 Step Conversions OBJECTIVE: Use stoichiometry to solve calculation problems

19. 2. 1 Step Conversions 2H 2 + O 2  2H 2 O You have 3 moles of O 2 How many moles of H 2 O can you produce? How do you solve something like this?

20. 2. 1 Step Conversions 2H 2 + O 2  2H 2 O How do you solve something like this? 1.Balance Reaction first!!! 2.Sideways T and MOLE RATIO

21. 1. 2Na + Cl 2  2NaCl 5 moles of Na = ? moles NaCl? 2. CH 4 + 2O 2  CO 2 + 2H 2 O 2 moles of CH 4 = ? moles CO 2 ? 3. Cu + 2AgNO 3  2Ag + Cu(NO 3 ) 2 4 moles of AgNO 3 = ? moles Ag? 4. 2KI + Pb(NO 3 ) 2  PbI 2 + 2KNO 3 43 moles of KI = ? moles KNO 3 ? 2. 1 Step Conversions

22. 3.2-Step Conversions OBJECTIVE: Grams  Moles  Mole Ratio

23. 3. 2-Step Conversions 2H 2 + O 2  2H 2 O You have 64 grams of O 2 How many moles of H 2 O can you produce? How do you solve something like this?

24. 3. 2-Step Conversions 2H 2 + O 2  2H 2 O You have 64 grams of O 2 How many moles of H 2 O can you produce? How do you solve something like this? 1. Balance2. Grams -> Moles3. Mole Ratio

27. 4. 3-Step Conversions & Alternate Routes OBJECTIVE: Add more routes to Stoichiometry Highway

28. 4. 3-Step Conversions

29. Avogadro Avenue 2H 2 + O 2  2H 2 O 12.04 x 10 23 particles of H 2 How many moles of H 2 O?

30. 4. 3-Step Conversions

31. Liter Lane 2H 2 + O 2  2H 2 O 44.8 L of H 2 How many moles of H 2 O?

32. 4. 3 Step Conversions and Alternate Routes 1.C 5 H 12  C 5 H 8 + 2H 2 1.89 x 10 24 molecules of C 5 H 12. How many molecules of C 5 H 8 ? 2.Br 2 + 5F 2  2BrF 5 2.89 x 10 24 molecules of Br 2. How many molecules of BrF 5 ? 1.11 x 10 20 molecules of F 2. How many molecules of BrF 5 ? 3.C 5 H 12  C 5 H 8 + 2H 2 1.366 L of C 5 H 12. How many liters of C 5 H 8 ? 2.0.0973 L of C 5 H 12. How many liters of C 5 H 8 ? 3.1.98 L of C 5 H 12. How many liters of H 2 ?

33. 1. C 5 H 12  C 5 H 8 + 2H 2 1.89 x 10 24 molecules of C 5 H 12. How many molecules of C 5 H 8 ? 2. Br 2 + 5F 2  2BrF 5 2.89 x 10 24 molecules of Br 2. How many molecules of BrF 5 ? 1.11 x 10 20 molecules of F 2. How many molecules of BrF 5 ? 3. C 5 H 12  C 5 H 8 + 2H 2 1. 366 L of C 5 H 12. How many liters of C 5 H 8 ? 2. 0.0973 L of C 5 H 12. How many liters of C 5 H 8 ? 3. 1.98 L of C 5 H 12. How many liters of H 2 ?

34. 4. 3 Step Conversions and Alternate Routes 1.C 5 H 12  C 5 H 8 + 2H 2 1.89 x 10 24 molecules of C 5 H 12. How many molecules of C 5 H 8 ? 2.Br 2 + 5F  2BrF 5 2.89 x 10 24 molecules of Br 2. How many molecules of BrF 5 ? 1.11 x 10 20 molecules of F 2. How many molecules of BrF 5 ?

35. 5. Limiting Reactants OBJECTIVE: Running out of “ingredients”

36. 5. Limiting Reactants 8 buns + 12 patties Which will run out first?

37. Limiting Reactant Excess Reactant ▪ The reactant that controls the quantity of product that can form in a chemical reaction ▪ Stuff that runs out first ▪ The reactant that is not completely used up in a chemical reaction ▪ Stuff left over

38. 5. Limiting Reactants 8 buns + 12 patties Which is limiting?

39. 5. Limiting Reactants 4 franks + 12 buns Which is limiting?

40. 2 H 2 + O 2  2 H 2 O – 10 moles of H2 – 10 moles of O2. – How many moles of H 2 O? How to Solve? Identify limiting reactant. Limiting Reactant = Smaller Number 5. Limiting Reactants

41. Fe + S  Fe 2 S 3 2 Fe + 3 S  Fe 2 S 3 – 12 moles of Fe – 12 moles of S – How many moles of Fe 2 S 3 ? (Identify limiting reactant) WHAT IS FIRST STEP? BALANCE 5. Limiting Reactants

42. NO +Cl 2  NOCl – 4 mol of NO – 4 mol of Cl 2 – How many mol of NOCl? BALANCE FIRST!! 5. Limiting Reactants

43. NO +Cl 2  NOCl – 100g of NO – 100g of Cl 2 – How many mol of NOCl? 5. Limiting Reactants

44. Fe + S  Fe 2 S 3 – 10 moles of Fe – 12 moles of S. – How many moles of Fe 2 S 3 ? Identify limiting reactant. – 150 g of Fe – 120g of S. – How many grams of Fe 2 S 3 ? ▪ Go to Word Document 5. Limiting Reactants

45. H 2 +N 2  NH 3 – 12L of H 2 – 10L of N 2 – How many grams of NH 3 ? – 25g of H 2, 35g of N 2. How many liters of NH 3 ? 5. Limiting Reactants

46. 6. Percentage Yield OBJECTIVE: Measuring Efficiency

51. 6. Percentage Yield Efficiency of a reaction = Percentage Yield

52. Formula for Percentage Yield 6. Percentage Yield

53. Actual Yield Theoretical Yield ▪ What is actually produced. ▪ What you have been calculating so far ▪ If reaction occurs with 100% efficiency

54. 2Al + 6HCl -> 2AlCl 3 + 3H 2 You calculated a theoretical yield of 8.77 grams for AlCl 3. But only 5.66 grams of AlCl 3 is actually produced. What is the percentage yield? You calculated a theoretical yield of 9.79 grams for H 2. The actual yield for H 2 is 4.04. What is the percentage yield?

55. 6. Percentage Yield 2Al + 6HCl -> 2AlCl 3 + 3H 2 The theoretical yield is 98.5 grams for AlCl3. This reaction has 77 percentage yield. What is the actual yield?

56. 2H 2 O 2 -> 2H 2 O +O 2 1.How many L of O 2 is produced from 250g of H 2 O 2 ? 2.If reaction has 68% yield, how many L of O 2 is actually produced?

57. 2P +Cl 2 -> 2PCL 3 1.500L (actual yield) of PCl3 needs to be produced. 2.The reaction as a 75% yield. How many grams of Cl2 is needed?

58. 2P +Cl 2 -> 2PCL 3 1.450g of P, 448L Cl 2, ?g of PCl 3 2.Actual Yield is 148g, what is % yield? 3.If % Yield is 48%, how much PCl 3 would actually be produced 4.Suppose P is in excess, and 300g of PCl 3 needed to be produced. The % Yield is 72%. How many L of Cl 2 is needed?

59. 3H 2 + N 2 -> 2NH 3 1.40L of H 2, 15L of N 2, ?g of NH 3 2.Actual Yield is 17.9L of NH 3, what is % Yield? 3.If reaction has % Yield of 82%, how many molecules of NH 3 would be produced? 4.N2 is in excess, reaction has 62% Yield. 500L of NH 3 need to produced. How many g of H 2 is needed?