1. Stoichiometry Chapter 9 Limiting reagents

2. In Stoichiometry: We work in moles. We cannot calculate grams of product from grams of reactant

3. Step 1: Grams of reactant to moles of reactant Step 2: Moles of reactant to moles of product Step 3: Moles of product to grams of product

4. Review  Converting mass to moles: divide grams by molar mass  Converting moles to mass: multiply moles by molar mass  Converting moles to particles: multiply moles by 6.02 x 10 23  Can you go from mass to particles?

5. Limiting Reagents

8. Limiting Reagents: a video  http://wps.prenhall.com/wps/media/objects /439/449969/Media_Portfolio/Chapter_11/ Limiting_Reagent.MOV http://wps.prenhall.com/wps/media/objects /439/449969/Media_Portfolio/Chapter_11/ Limiting_Reagent.MOV http://wps.prenhall.com/wps/media/objects /439/449969/Media_Portfolio/Chapter_11/ Limiting_Reagent.MOV

10. Theoretical Yield  This is the amount of product expected in a perfect world with the amount of reactant given.  In Limiting reagent problems, you find the amount each reactant would produce with no other constraints. That is two or more calculations depending on the number of reactants.  The reactant that forms the least amount of product in its theoretical yield is the limiting reagent.

11. How to do these problems:  First write a balanced chemical equation.  Find the molar mass of each “player” be it product or reactant. (coefficients are not used to calculate molar mass)  Convert the mass of each reactant given to moles. Grams divided by grams/mol.

12. How to continued:  Find the molar ratio to convert moles of reactant to moles of product. (This is where you use coefficients)  Convert moles of product to grams of product.  If this is a limiting reagent problem, repeat for the other reactant and compare results.  If you can add, subtract, divide, and multiply, you can do this!!

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