1. How much does a reaction really produce?
Limiting Reactants

2. Reactants combine in specific whole-number ratios
Limiting Reactant: reactant that is used up first limiting the amount of the other reactants that can participate in the reaction
Excess Reactant: any reactant that is not completely used up in the chemical reaction

3. Determining Limiting Reactant How many sandwiches can be made?

4. Analogy for Limiting Reactants Pizza Time
Analogy for Limiting Reactants Pizza Time!! The following ingredients are required to make one pizza:
400 g flour
50 mL water
10 g yeast
120 g sauce
250 g cheese
5 g oregano
5 g basil

5. You are given the following supplies…
500 pizza pans
60 kg sauce
100 kg cheese
2.5 kg oregano
2.5 kg basil
5 kg yeast
25 L water
200 kg flour

6. Answer the following questions:
Which ingredient is the limiting reactant?
How many pizzas can be made?
If you sold each pizza for $3.50, how much money can be made from the sale of this many pizzas?
If you were able to get twice as much cheese, how many pizzas would you be able to make?

7. Determining the Limiting Reactant for Reactions
Change all of the reactants to moles
Select one of the reactants (Reactant #1)
Use the mole ratio to determine how much of the other reactant (Reactant #2) would be needed to complete the reaction.
Evaluate your answer to determine the limiting reactant

8. Evaluating the Results of the Previous Calculation
If the amount of reactant #2 necessary (determined from mole ratio) is less than the amount present, reactant #1 is the limiting reactant
If the amount of reactant #2 necessary is greater than the amount present, reactant #2 is the limiting reactant

9. Determining the Limiting Reactant for Reactions
Change all of the reactants to moles
Select one of the reactants (Reactant #1)
Use the mole ratio to determine how much of the other reactant (Reactant #2) would be needed to complete the reaction.
Evaluate your answer to determine the limiting reactant
Perform calculations based on the limiting reactant

10. Why is determining the limiting reactant important?
Chemicals cost money
If the most expensive chemical is the limiting reactant, money can be saved