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4. Balancing Reactions

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

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4. Balancing Reactions

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  1. 4. Balancing Reactions How are coefficients different from subscripts? 2H2+ O2 2H2O subscripts= # of atoms

  2. 4. Balancing Reactions How are coefficients different from subscripts? 2H2+ O2 2H2O coefficients = how many

  3. 4. Balancing Reactions 2H2+ O2 2H2O subscripts= # of atoms coefficients = how many

  4. 4. Balancing Reactions H2+ O2 H2O2 subscripts= # of atoms coefficients = how many

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

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

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

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

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

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

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

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

  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. 1. What is Stoichiometry? KI + Pb(NO3)2 PbI2 + KNO3

  15. 1. What is Stoichiometry? 2KI + Pb(NO3)2 PbI2 + 2KNO3 COEFFICIENTS=amount of MOLES KI = 2 moles Pb(NO3)2 = 1 mole PbI2 = 1 mole KNO3 = 2 moles

  16. 1. What is Stoichiometry? 2KI + Pb(NO3)2 PbI2 + 2KNO3 Stoichiometry = using coefficients from balanced reactions to convert grams  moles and much more.

  17. 2. 1 Step Conversions OBJECTIVE: Use stoichiometry to solve calculation problems

  18. 2. 1 Step Conversions 2H2+ O2 2H2O You have 3 moles of O2 How many moles of H2O can you produce? How do you solve something like this?

  19. 2. 1 Step Conversions 2H2+ O2 2H2O How do you solve something like this? • Balance Reaction first!!! • Sideways T and MOLE RATIO

  20. 2. 1 Step Conversions • 2Na + Cl2 2NaCl 5 moles of Na = ? moles NaCl? • CH4+ 2O2 CO2 + 2H2O 2 moles of CH4= ? moles CO2? • Cu + 2AgNO3 2Ag + Cu(NO3)2 4moles of AgNO3= ? moles Ag? • 2KI + Pb(NO3)2 PbI2 + 2KNO3 43 moles of KI = ? moles KNO3?

  21. 3. 2-Step Conversions OBJECTIVE: Grams  Moles  Mole Ratio

  22. 3. 2-Step Conversions 2H2+ O2 2H2O You have 64 grams of O2 How many moles of H2O can you produce? How do you solve something like this?

  23. 3. 2-Step Conversions 2H2+ O2 2H2O You have 64 grams of O2 How many moles of H2O can you produce? How do you solve something like this? 1. Balance 2. Grams -> Moles 3. Mole Ratio

  24. 4. 3-Step Conversions & Alternate Routes OBJECTIVE: Add more routes to Stoichiometry Highway

  25. 4. 3-Step Conversions Avogadro Avenue

  26. 4. 3-Step Conversions Avogadro Avenue 2H2 + O2 2H2O 12.04 x 1023 particles of H2 How many moles of H2O?

  27. 4. 3-Step Conversions Liter Lane

  28. 4. 3-Step Conversions Liter Lane 2H2 + O2 2H2O 44.8 Lof H2 How many moles of H2O?

  29. 4. 3 Step Conversions and Alternate Routes • C5H12 C5H8 + 2H2 1.89 x 1024 molecules of C5H12. How many molecules of C5H8? • Br2 + 5F2  2BrF5 2.89 x 1024 molecules of Br2. How many molecules of BrF5? 1.11 x 1020 molecules of F2. How many molecules of BrF5? • C5H12  C5H8 + 2H2 • 366 L of C5H12. How many liters of C5H8? • 0.0973 L of C5H12. How many liters of C5H8? • 1.98 L of C5H12. How many liters of H2?

  30. C5H12 C5H8 + 2H2 1.89 x 1024 molecules of C5H12. How many molecules of C5H8? • Br2 + 5F2  2BrF5 2.89 x 1024 molecules of Br2. How many molecules of BrF5? 1.11 x 1020 molecules of F2. How many molecules of BrF5? • C5H12  C5H8 + 2H2 • 366 L of C5H12. How many liters of C5H8? • 0.0973 L of C5H12. How many liters of C5H8? • 1.98 L of C5H12. How many liters of H2?

  31. 4. 3 Step Conversions and Alternate Routes • C5H12 C5H8 + 2H2 1.89 x 1024 molecules of C5H12. How many molecules of C5H8? • Br2 + 5F  2BrF5 2.89 x 1024 molecules of Br2. How many molecules of BrF5? 1.11 x 1020 molecules of F2. How many molecules of BrF5?

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

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

  34. 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

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

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

  37. 5. Limiting Reactants 2H2+ O22H2O • 10 moles of H2 • 10 moles of O2. • How many moles of H2O? How to Solve? Identify limiting reactant. Limiting Reactant = Smaller Number

  38. 5. Limiting Reactants Fe + S  Fe2S3 2Fe + 3S  Fe2S3 • 12 moles of Fe • 12 moles of S • How many moles of Fe2S3? (Identify limiting reactant) WHAT IS FIRST STEP? BALANCE

  39. 5. Limiting Reactants NO +Cl2NOCl • 4 molof NO • 4 molof Cl2 • How many molof NOCl? BALANCE FIRST!!

  40. 5. Limiting Reactants NO +Cl2NOCl • 100g of NO • 100g of Cl2 • How many molof NOCl?

  41. 5. Limiting Reactants Fe + S Fe2S3 • 10 moles of Fe • 12 moles of S. • How many moles of Fe2S3? Identify limiting reactant. • 150 g of Fe • 120g of S. • How many grams of Fe2S3? • Go to Word Document

  42. 5. Limiting Reactants H2+N2NH3 • 12L of H2 • 10L of N2 • How many grams of NH3? • 25g of H2, 35g of N2. How many liters of NH3?

  43. 6. Percentage Yield OBJECTIVE: Measuring Efficiency

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