1. Limiting Reactants& Percent Yield

2. Limiting Reactants • How many grams of water can you make if you start with 2.0g of H2 and 0g of O2? • Zero! You must have Oxygen to bond with Hydrogen to make water.

3. Limiting Reactant • controls quantity of product formed in reaction • completely used up - no left overs

4. Excess Reactants • all is not used - there are excess or left overs

5. According to Brownie Recipe, what would be the limiting reactant if you have the following ingredients: 2cup butter bottle full of vanilla 6 cups flour 16 oz’s chocolate 1/2 cup sugar bottle of baking pdr dozen eggs bottle of salt

6. Brownies: Yields 24 • 1 tsp vanilla • 2/3 c flour • ½ tsp baking powder • ¼ tsp salt • ½ c butter • 2 sq. unsweetened chocolate • 1 c sugar • 2 eggs

7. How to Find Limiting Reactant • find how much product each reactant can make • reactant that makes least is limiting reactant

8. What is the limiting reactant when 79.1g of Zn react with 1.05 L of 2.00M HCl to produce ZnCl2 and H2? • Zn + 2HCl --> ZnCl2 + H2

9. If 15.5g Al reacts with 46.7g Cl2 gas, then AlCl3 is formed. • Which reactant is limiting? • Which reactant is in excess? • How much excess reactant is there? • What is the mass of AlCl3 produced? • What is the percent yield if 55.0g AlCl3 is actually produced?

10. Find the percent yield if the actual yield was 0.95 mol H2

11. Percent Yield • Theoretical yield - calculated product - could have been formed • Actual yield - product from an experiment - actually formed

12. Percent Yield = Actual yield . times 100 theoretical yield