1. Percent Yield

2. “yield—” the amount of product actually made through a chemical reaction. Why is this value important? Theoretical yield— calculated amount of product Actual/Experimental yield– the “true/actual” amount of product made in the chemical reaction, usually less than theoretical How is this value different than percent error?

3. Percent Yield = Actual yield x 100% Theoretical yield Ex. 98.80% of Mg 3 N 2 was produced in a chemical reaction. What happened to the rest? (purity, other reactions, remaining product, etc.)

5. Limiting Reactant

6. Stoichiometry Refresher ____ Mg + _____ Cl 2  MgCl 2 10.0 grams of magnesium metal reacts with chlorine. How many grams of magnesium chloride are produced?

7. Limiting Reactant Chemical compound that “limits” or determines how much product can be produced All of the compound is consumed in the reaction Excess reactant— chemical compound not consumed in the reaction plenty of the compound is available for the chemical reaction

8. Steps to find the limiting reactant Two stoichiometry problems in ONE !  Write a balanced equation  Find the amount of product (in grams) produced from each reactant amount.  The reactant producing the SMALLEST product is the limiting reactant.

9. Example 1 _____ Mg + ______ O 2  MgO 10.0 grams of magnesium metal reacts with 10.0 grams of oxygen. What is the mass of magnesium oxide produced in this reaction? What is the limiting reactant?

10. Example 2 Aspirin synthesis: 2C 7 H 6 O 3 + C 4 H 6 O 3 2C 9 H 8 O 4 + H 2 O When 20.0g of C 7 H 6 O 3 and 20.0g of C 4 H 6 O 3 react, which is the limiting reactant? What is the mass (in grams) of aspirin produced? What is the limiting reactant?

11. Example 3 _____ I 2 O 5 + _____ CO  _____ CO 2 + ____ I 2 80.0 grams of I 2 O 5 reacts with 28.0 grams of CO. What is the mass of I 2 that can be produced from this reaction? What is the limiting reagent?

12. Example 4 __C 3 H 6 + ___NO  __C 3 H 3 N + ____H 2 O + ____ N 2 If I have 21.6 grams of C 3 H 6 and 21.6 grams of NO, how much (in grams) C 3 H 3 N will I produce? What is the limiting reagent?

13. Homework p. 464 #2-3