1. Percent Yield

2. Percent Yield
“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 % of Mg3N2 was produced in a chemical reaction. What happened to the rest? (purity, other reactions, remaining product, etc.)

4. Limiting Reactant

5. Stoichiometry Refresher
____ Mg + _____ Cl2  MgCl2
10.0 grams of magnesium metal reacts with chlorine. How many grams of magnesium chloride are produced?

6. 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

7. 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.

8. Example 1
_____ Mg + ______ O2  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?
Limiting reactant– O2
16.67g MgO

9. Example 2
Aspirin synthesis: 2C7H6O3 + C4H6O3 2C9H8O4 + H2O When 20.0g of C7H6O3 and 20.0g of C4H6O3 react, which is the limiting reactant? What is the mass (in grams) of aspirin produced? What is the limiting reactant?
C7H6O3 – limiting reactant
26.1g of aspirin produced

10. Example 3 _____ I2O5 + _____ CO  _____ CO2 + ____ I2
80.0 grams of I2O5 reacts with 28.0 grams of CO. What is the mass of I2 that can be produced from this reaction?
What is the limiting reagent?

11. Example 4 __C3H6 + ___NO  __C3H3N + ____H2O + ____ N2
If I have 21.6 grams of C3H6 and 21.6 grams of NO, how much (in grams) C3H3N will I produce?
What is the limiting reagent?