1. Stoichiometry

2. A. Proportional Relationships
2 1/4 c. flour
1 tsp. baking soda
1 tsp. salt
1 c. butter
3/4 c. sugar
3/4 c. brown sugar
1 tsp vanilla extract
2 eggs
2 c. chocolate chips
Makes 5 dozen cookies.
I have 5 eggs. How many cookies can I make?
Ratio of eggs to cookies
5 eggs
5 doz.
2 eggs
= 12.5 dozen cookies

3. A. Proportional Relationships
Stoichiometry
mass relationships between substances in a chemical reaction
based on the mole ratio
Mole Ratio
indicated by coefficients in a balanced equation
2 Mg + O2  2 MgO

4. B. Stoichiometry Steps 1. Write a balanced equation.
Use Mole Island and Stoich Cheat Sheet
B. Stoichiometry Steps
1. Write a balanced equation.
2. Identify the given and find.
3. Line up conversion factors.
Mole ratio - moles  moles
Molar mass - moles  grams
Molarity - moles  liters soln
Molar volume - moles  liters gas
Mole ratio - moles  moles
Core step in all stoichiometry problems!!
4. Check sig figs, units & circle your answer!

5. Conversion Factor # Moles A # Moles B
The #’s in front of A & B MUST come from the balanced chemical equation

6. Mole – Mole Relationship
Fe + O2  Fe2O3
1. Balance the reaction
2. Find the mole ratio of Iron to Oxygen
4 mol Fe / 3 mol O2
3. Find the mole ratio of Iron to Iron (III) oxide
4 mol Fe / 2 mol Fe2O3
4. Find the mole ratio it Oxygen to Iron (III) oxide
3mol O2 / 2 mol Fe2O3

7. Mole – Mole Relationship
How many moles of Fe2O3 will form from 5.0 mols of Fe?
5.0 mole Fe x 2 mol Fe2O3
4 mol Fe
2.5 mol Fe2O3

8. Mole - Mole Relationship
How many moles of KClO3 must decompose in order to produce 9 moles of oxygen gas?
2KClO3  2KCl + 3O2
? mol
9 mol
9 mol O2
2 mol KClO3
3 mol O2
= 6 mol
KClO3

9. Mole – Mass Relationship
How many grams of NaCl will be produced from 1.25 mol of chlorine gas reacting with sodium?
1. What type of reaction is this? Write the balanced equation.
2 Na + Cl2  2NaCl

10. Mole – Mass Relationship
2. Work the problem. Remember Mole Ratio and Sigfigs!
1.25 mol Cl2 x 2 mol NaCl x g NaCl
1 mol Cl mol NaCl
146 g NaCl

11. Mass to Mole Relationship
Fe3O4 + 4 CO  3 Fe + 4 CO2
How many moles of CO are needed to react with 16.5 g of Fe3O4

12. Mass – Mass Relationships
Ammonium nitrate decomposes into dinitrogen monoxide gas and water. Determine the amount of water produced if 25.0 g of ammonium nitrate decomposes.
1. Write the balanced reaction
NH4NO3  N2O + 2 H2O

13. Mass – Mass Relationships
25.0 g NH4NO3 x 1 mol NH4NO3 x 2 mol H2O x g H2O
g NH4NO mol NH4NO mol H2O
11.3 g H2O

14. Stoichiometry Problems
How many grams of silver will be formed from 12.0 g copper?
Cu + 2AgNO3  2Ag + Cu(NO3)2
12.0 g
? g
g Ag
1 mol Ag
12.0
g Cu
1 mol Cu
63.546
g Cu
2 mol Ag
1 mol Cu
= 40.7 g Ag