1. Limiting Reactants
The Limiting Reactant is the reactant that is completely consumed in the reaction.
This reactant produces the least amount of product in stoic calculations.
That is the amount of product that can be made since you run out of a reactant.
All other reactants are in excess (some left over).
Calculating Limiting Reactant
Perform stoic calculations with all given reactant amounts to the same product.
Limiting reactant makes the least amount of product.

2. 2 bread + 1 cheese + 1 lettuce + 1 meat  1 sandwich
YUMMY!!!!!!
2 bread + 1 cheese + 1 lettuce + 1 meat  1 sandwich
What if you had 40 slices of bread, 15 slices of cheese, 25 leaves of lettuce, and 20 slices of meat, which would limit the amount of sandwiches you can make?
40 slices of bread can make 20 sandwiches
15 slices of cheese can make 15 sandwiches
25 leaves of lettuce can make 25 sandwiches
20 slices of meat can make 20 sandwiches
15 slices of cheese is the limiting reactant because it can only make 15 sandwiches (the least amount of product).

3. 2 bread + 1 cheese + 1 lettuce + 1 meat  1 sandwich
40 slices of bread can make 20 sandwiches
15 slices of cheese can make 15 sandwiches
25 leaves of lettuce can make 25 sandwiches
20 slices of meat can make 20 sandwiches
If you made the 15 sandwiches that you could make, how much bread, lettuce, and meat would be left?
There is enough bread left to make 5 sandwiches, so 10 slices of bread.
There is enough lettuce left to make 10 sandwiches, so 10 leaves of lettuce.
There is enough meat left to make 5 sandwiches, so 5 slices of meat.

4. C O2 → CO2
5 mol mol
According to the equation, 1 mole of carbon reacts with 1 mole of oxygen gas to produce 1 mole of carbon dioxide.
Suppose you mixed 5 moles of carbon with 10 moles of oxygen and the reaction occurred.
Which reactant would be the limiting reactant?
5 mol of C only make 5 mol of CO2
Which reactant would be the excess reactant?
10 mol of O2 makes 10 mol of CO2

5. Limiting Reactant Problem
Silicon dioxide is usually quite unreactive but reacts readily with hydrogen fluoride according to the following equation.
SiO HF → SiF H2O
25.0 g g ? ?
If 30.0 g of HF are exposed to 25.0 g SiO2, which is the limiting reactant?

6. SiO2 + 4HF → SiF4 + 2H2O 25.0 g 30.0 g 0.375 mol 0.750 mol
How many grams of SiO2 is left from the reaction on the previous slide?
SiO HF → SiF H2O
25.0 g g mol mol
(HF is the limiting reactant producing mol SiF4 or mol H2O)
To determine the amount of excess reactant left, you will need to perform a stoichiometric calculation to determine the amount used from the limiting reactant or amount of product produced.
Once you have calculated the amount of the excess that was used, subtract it from the original amount to find what is left over.