1. Double Cheeseburgers and Stoichiometry
1 Double Cheeseburger needs 1 bun, 2 patties, 2 slices of cheese, 4 strips of bacon
For 5 Double Cheeseburgers how many units of each ingredient do I need?
Fill in the final column below with how many complete burgers I can make:
Buns
Patties
Cheese Slices
Bacon Strips
How Many Burgers? 2 4 8 16 30 32 48

2. Objectives
To understand the concept of limiting reactants
To learn to recognize the limiting reactant in a reaction
To learn to use the limiting reactant to do stoichiometric calculations
To learn to calculate percent yield

3. A. The Concept of Limiting Reactants
Stoichiometric mixture
N2(g) + 3H2(g)  2NH3(g)

4. A. The Concept of Limiting Reactants
Limiting reactant mixture
N2(g) + 3H2(g)  2NH3(g)

5. A. The Concept of Limiting Reactants
For a Limiting reactant mixture the number of moles are not balanced to match the reaction equation
N2(g) + 3H2(g)  2NH3(g)
Limiting reactant is the reactant that runs out first
When the limiting reactant is exhausted, then the reaction stops

6. B. Calculations Involving a Limiting Reactant

7. B. Calculations Involving a Limiting Reactant

8. C. Percent Yield
Theoretical Yield
The maximum amount of a given product that can be formed when the limiting reactant is completely consumed.
The actual yield (amount produced) of a reaction is usually less than the maximum expected (theoretical yield).
Percent Yield
The actual amount of a given product as the percentage of the theoretical yield.

9. According to his pre-lab theoretical yield calculations a student’s experiment should have produced 1.44g of magnesium oxide. When he weighed his product after reaction, only 1.23g of magnesium oxide was present. What is the student’s percent yield?