1. Stoichiometry
“Cookbook Chemistry”

2. There are many similarities between baking and chemistry
Starting point
Raw ingredients
Reactants
Ending Point
Delicious dish
Products
How much
Recipe
Mole Ratio

3. S’more Stoichiometry

4. C3H8(g) + O2(g)  CO2(g) + H2O(g)
The combustion of propane (C3H8(g)):
C3H8(g) + O2(g)  CO2(g) + H2O(g)
Balance the equation to determine the mole ratio.
Mole ratio =

5. The synthesis of ammonia (NH3(g)):
N2(g) + H2(g)  NH3(g)
Mole ratio =
If 2 mol of N2 react in an excess of H2, how many moles of NH3 will be produced?

6. CH3OH(l) + O2(g)  CO2(g) + H2O(g)
The combustion of methanol (CH3OH(l)):
CH3OH(l) + O2(g)  CO2(g) + H2O(g)
Mole ratio =
If 3.5 mol of methanol are present,
How many moles of O2 are reacted?
How many moles of H2O are produced?

7. Stoichiometry Races! CH4 + 2 O2 → CO2 + 2 H2O
How many moles of CO2 will be produced from 2 mol of CH4 and 4 mol of O2 ?
How many moles of H2O will be produced from 1 mol of CH4 and 18 mol of O2 ?

8. Calculating Unknown Masses
We already know how to convert from mole to mass
Now we can use our balanced equation to calculate masses of reactants and products
We use a stoichiometry table

9.  72.0 g of O2 will be produced from 1.50 mol KClO3
What mass of O2 will be produced through the decomposition of 1.50 mol KClO3?
2 KClO3
 2 KCl
+ 3 O2 MM
32.00 g/mol n
1.50 mol
= 3 molO2 X molKClO3
2 molKClO3
= molO2 m
= mol X g
1 mol
= g
 72.0 g of O2 will be produced from 1.50 mol KClO3

10. What mass of Cu2S will be produced if 2.00 g of Cu are reacted?
 8 Cu2S(s) MM
63.55 g/mol
g/mol n
= 2.00 g X 1 mol
63.55 g
= mol
= 8 molCu2S X molCu
16 molCu
= mol m
2.00 g
= mol X g
1 mol
= 2.50 g
 2.50 g of Cu2S will be produced from 2.00 g Cu

11. Practice Makes Perfect 
Worksheet A
Worksheet B