Limiting Reactant
A.K.A. Stoichiometry
How do we determine which
reactant limits the product?
 One reactant remains while the other is
consumed in a reaction
 Mole ratio will help determine the
limiting reaction
 Need to create a conversion pathway
How Do Hot Fudge Sundaes and
Limiting Reactants Relate?
How Many Sundaes Can You Make?
Two!
The chocolate syrup limits the recipe!
Which reactant is the limiting
reactant?
 Which reactant remains when 6.70 mole
Na reacts with 3.2o moles of Cl2
 2 Na + Cl22 NaCl
Step 1
Moles of
reactant
Moles of
product
2 Na + Cl22 NaCl
Step 1
Step 1
Moles of Na
Mole Ratio
Moles of NaCl
6.70 moles of Na
2 mol NaCl
= 6.70 mol NaCl
2 mol Na
Moles of Cl2
Mole Ratio
Moles of Product
3.20 moles of Cl2
2 mol NaCl
= 6.40 mol NaCl
1 mol Cl2
Cl2 is the Limiting Reactant!
It’s Your Turn…
Limiting Reactant Worksheet
Limiting Reactant and Mass-Mass
Conversions
 Which reactant is the limiting reactant
when 3.5 g Cu reacts with 6.0 g AgNO3?
 Cu + AgNO3 Cu(NO3)2 + Ag;
balanced?
 Cu + 2 AgNO3 Cu(NO3)2 + 2 Ag
Create a Conversion Pathway
Cu + 2 AgNO3
Cu(NO3)2 + 2 Ag
 We have 3.5 g Cu and 6.0 g AgNO3
Step 1
Mass of
Reactant
Step 2
Moles of
Reactant
Step 3
Moles of
Product
Mass of
Product
Cu + 2 AgNO3
Cu(NO3)2 + 2 Ag
Mass of Cu
Molar Mass
of Cu
Mole Ratio
Molar Mass
of Ag
Mass of Ag
3.5 g Cu
1 mol Cu
2 mol Ag
108 g Ag
= 12 g Ag
63.5 g Cu
1 mol Cu
1 mol Ag
Mass of
AgNO3
Molar Mass
of AgNO3
Mole Ratio
Molar Mass
of Ag
Mass of Ag
6.0 g AgNO3
1 mol AgNO3
2 mol Ag
108 g Ag
= 3.8 g Ag
169.9 g
AgNO3
2 mol AgNO3
1 mol Ag
Silver nitrate is the limiting reactant!
Homework
 Read pp. 257-258
 Answer problems pg. 263: 45