1. Stoichiometry
Comes from the Greek words stoicheion, meaning “element,” and metron, meaning “measure.”

2. Stoichiometry Calculations
Theoretical yield
Compare grams and moles of 2 substances
Review of Stoichiometry - using grams – YouTube
(mole ratio activity???)

3. STEPS: Balance equation
Write given and unknown above substance in the reaction
Use coefficient for the number of moles and periodic table for amount in grams
Set up a proportion
Cross multiply and divide

4. Example #1
How many grams of Aluminum oxide will be produced from 10.0 grams of Aluminum? 4 Al + 3 O2 → 2 Al2O3

5. Example #2
What is the mass (in grams) of magnesium oxide produced from mol of magnesium? __Mg + ___O2 → ___MgO

6. Example #3
How many moles of lithium hydroxide are required to react with 2.38 moles of carbon dioxide?
___LiOH + __CO2  __Li2CO3 + __H2O

7. Limiting Reactant – reactant that is completely used up first
Excess Reactant – reactant that is left over

8. To determine limiting reactant:
Use given amount of only ONE reactant to determine how much you need of the other reactant. Use logic to determine which one will be used up first

9. For example: If you have 12 pieces of bread and 8 patties, which one is the limiting reactant?

10. Example #1
If 2.0 mol of HF are exposed to 4.5 mol of SiO2, which is the limiting reactant?
__HF + __ SiO2 → __SiF4 + __H2O

11. Example #2
What is the limiting reagent if 36.0 g of H2O is mixed with 167 g Fe in the following reaction:
3 Fe H2O  Fe3O H2

12. Percent Yield
Ratio of actual yield to the theoretical yield, multiplied by 100.
Actual Yield = measured amount of product obtained (in lab)
Theoretical Yield = (expected yield) maximum amount of product that can be produced (calculated on paper)

13. Example
In an experiment, Bob reacted 75.0 g of CO and produced 68.4 g CH3OH. What is the percent yield of CH3OH? (calculate theoretical yield first)
CO H2  CH3OH