1. Give me
S’MORE Stoichiometry!
Today, we will use stoichiometric concepts – balancing reactions and mole/mass relationships – to identify and calculate for the limiting reagent of a reaction.

2. Gc + Ch + Mm  Sm Is this a balanced “reaction” for a typical s’more?
Let’s Make a S’More!
Gc + Ch + Mm  Sm Is this a balanced “reaction” for a typical s’more? 2

3. Perform Part A of the S’more Stoichiometry Handout.
Now You try:
Perform Part A of the S’more Stoichiometry Handout.

4. Today’s Topic: Limiting Reagents
The limiting reagent…
* Is the reactant that is the first to be completely consumed in the chemical reaction.
* Determines the maximum amount of product that can be formed from the reaction

5. Limiting Reagents Calculation Steps: * Balance the reaction.
* Start with the given number of moles OR mass for each reactant.
* Calculate how much of each product can be produced from each given reactant (Should be 2 separate mole to mole OR gram to gram calculations).
* Determine which reactant produces the SMALLEST number of moles/grams of the PRODUCT - that is the limiting reactant (and also the answer!).

6. Limiting Reagents Example: C3H8 + O2  CO2 + H2O 5 3 4
What mass of CO2 is produced with 250.0g C3H8 and 950.0g O2?
Step 1: Balance the equation –
C3H O2  CO H2O 5 3 4

7. Which reactant is the limiting reagent?
Limiting Reagents
Example, continued: What mass of CO2 is produced with 250.0g C3H8 and 950.0g O2?
Step 2: Use mass/mole stoichiometry to figure out how much CO2 is produced from each reactant -
Which reactant is the limiting reagent?
C3H8

8. Perform Part B of the S’more Stoichiometry Handout.
Now You try:
Perform Part B of the S’more Stoichiometry Handout.