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Mole Review

Mole Review. 1.) Calculate the number of moles in 60.4L of O 2 . 2.) How many moles are there in 63.2g of Cl 2 ?. 1 mol O 2. 60.4L O 2. = 2.7 mol O 2. 22.4L O 2. 1mol Cl 2. 63.2g Cl 2. = 0.903mol Cl 2. 70g Cl 2. Unit 08 . Math In Chemistry Stoichiometry. Proportional Relationships.

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Mole Review

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  1. Mole Review 1.) Calculate the number of moles in 60.4L of O2. 2.) How many moles are there in 63.2g of Cl2? 1 mol O2 60.4L O2 = 2.7 mol O2 22.4L O2 1mol Cl2 63.2g Cl2 = 0.903mol Cl2 70g Cl2

  2. Unit 08 Math In Chemistry Stoichiometry

  3. Proportional Relationships Tiny Tyke Tricycle Company F + S + 3W + H + 2P → FSW3HP2 Scheduled to make 640 tricycles. How many wheels should they order?

  4. Proportional Relationships 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. I have 5 eggs. How many cookies can I make? Ratio of eggs to cookies 5 eggs 5 doz. 2 eggs = 12.5 dozen cookies

  5. Proportional Relationships Stoichiometry mass relationships between substances in a chemical reaction for example: you can determine the amount of a compound required to make another compound based on the mole ratio Mole Ratio indicated by coefficients in a balanced equation 2 Mg + O2 2 MgO 2 Moles of magnesium react with 1 mole of oxygen to form 2 moles of magnesium oxide.

  6. 2 Mg + O2 2 MgO What would be the mole ratio of magnesium to magnesium oxide? 2 : 2 Conversion factor = 2 mol Mg 2 mol MgO What would be the mole ratio of oxygen to magnesium? 1 : 2 Conversion factor = 1 mol O2 (Mole Ratio) 2 mol Mg

  7. Practice 5 F2 + 2NH3 N2F4 + 6HF 1. What is the mole ratio of NH3 to F2? Write the mole ratio as a conversion factor. 2. What is the mole ratio of HF to N2F4? Write the mole ratio as a conversion factor. 2:5 2mol NH3 5mol F2 6:1 6mol HF 1mol N2F4

  8. Stoichiometry Steps 1. Identify known & unknown. 2. Convert known to mole. (if necessary) 3. Use Mole Ratio. 4. Convert moles to unknown unit. (if necessary) Mole ratio- get from equation Units of unknown known Mol of unknown Mol of known Mol of unknown

  9. mol unknown Molar mass unknown 1 mol Known Known g Molar mass Known mol known 1 mol unknown Mol ratio- get from equation Mass-Mass Stoichiometry • Mass of reactants equals the products • Law of Conservation of Mass • ONLY mass and atoms are conserved in every chemical reaction

  10. Mass-Mass Stoichiometry #1 The reaction of fluorine with ammonia produces dinitrogen tetrafluoride and hydrogen fluoride. 5F2 + 2 NH3→ N2F4 + 6HF How many grams of NH3 are required to produce 7.38g HF?

  11. Mass-Mass Stoichiometry #2 5F2 + 2 NH3→ N2F4 + 6HF How many grams of N2F4 can be produced from 265g F2?

  12. Mass-Mass Stoichiometry #3 2C2H2 + 5O2→ 4CO2 + 2H2O How many grams of oxygen are required to burn 52.0g C2H2?

  13. C. Stoichiometry Problems • Calculate the number of grams of NH3 produced by the reaction of 5.40 g of hydrogen with an excess of nitrogen. N2 + 3H2→ 2NH3

  14. __S + __O2→ __SO3 Mole-Mole Examples #1 • Write the equation. • Balance the equation. • How many moles of SO3 are produced when there are 4.5 moles of S? • Known = • Unknown =

  15. 2C3H7OH + 9O2→ 6CO2 + 8H2O Mole-Mole Examples #2 Isopropyl alcohol (C3H7OH) burns in the air to this equation: • Write the equation. • Calculate the moles of oxygen needed to react with 3.40 moles of isopropyl alcohol.

  16. 2C3H7OH + 9O2→ 6CO2 + 8H2O Mole-Mole Examples #3 • Find the moles of water when 6.20 mol O2 reacts with C3H7OH.

  17. Volume-Volume Stoichiometry • Formula to use: Known (L) 1 mol known mol unknown 22.44 L unknown 1 22.4 L known mol known 1 mol unknown

  18. C3H8 + 5O2→ 3CO2 + 4H2O Volume Example #4 If 20 liters of oxygen are consumed in the above reaction, how many liters of carbon dioxide are produced?

  19. Limiting Reactants/Reagents • Available Ingredients • 4 slices of bread • 1 jar of peanut butter • 1/2 jar of jelly • Limiting Reactant/Reagents • bread • Excess Reactants/Reagents • peanut butter and jelly

  20. Limiting Reactants/Reagents • Limiting Reactant/Reagent • used up in a reaction • determines the amount of product • Excess Reactant/Reagent • added to ensure that the other reactant is completely used up • cheaper & easier to recycle

  21. Limiting Reagents 1. Write a balanced equation. 2. For each reactant, calculate the amount of product formed. 3. Smaller answer indicates: • limiting reactant • amount of product

  22. Limiting Reagents 79.1 g of zinc react with 0.90 L of HCl. Identify the limiting and excess reactants. How many liters of hydrogen are formed at STP? Zn + 2HCl  ZnCl2 + H2 79.1 g 0.90 L ? L

  23. Limiting Reagents Zn + 2HCl  ZnCl2 + H2 79.1 g 0.90 L ? L 79.1 g Zn 1 mol Zn 65 g Zn 1 mol H2 1 mol Zn 22.4 L H2 1 mol H2 = 27.3 L H2

  24. Limiting Reagents Zn + 2HCl  ZnCl2 + H2 79.1 g 0.90 L ? L 0.90 L HCl 1 mol HCl 22.4 L HCl 1 mol H2 2 mol HCL 22.4 L H2 1 mol H2 = 0.45 L H2

  25. Limiting Reagents Zn: 27.3 L H2HCl: 0.45 L H2 Limiting reagent: HCl Excess reagent: Zn

  26. Percent Yield Percent yield- the ratio of the actual yield to the theoretical yield Actual yield- the amount of product formed when a reaction is carried out in the laboratory Theoretical yield- the calculated amount of product formed during a reaction

  27. Percent Yield measured in lab calculated on paper

  28. Percent Yield • When 45.8 g of K2CO3 react with excess HCl, 46.3 g of KCl are formed. Calculate the theoretical and % yields of KCl. K2CO3 + 2HCl  2KCl + H2O + CO2 45.8 g ? g actual: 46.3 g

  29. Formulas to Use Mole - Mole Known mol of unknown mol of known Mol Ratio – from equation Mass - Mass mol of unknown Known g 1 mol known molar mass unknown mol of known 1 mol unknown molar mass known OR OR Other 6.02 × 1023 particles mol of unknown Known L 1 mol known 22.4 L unknown OR mol of known 1 mol unknown particles 22.4 L known 6.02 × 1023 particles

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