1. Chapter 12: Stoichiometry
Table of Contents
Chapter 12: Stoichiometry
12.1: What is Stoichiometry?
12.2: Stoichiometric Calculations

2. DEMOS!  Combustion of Methane CH4 + O2 → CO2 + H2O
1 CH4 : 1 O2 8 ml CH4 : 8 ml O2
16 ml total
CH4 + 2O2 → CO2 + 2H2O
1 CH4 : 2 O2 8 ml CH4 : 16 ml O2
24 ml total
1st: FLAME: Add oxygen 1st – always have a little more fuel (methane) the 1st time around so that it doesn’t go off
2nd: BOOM: Add CH4 1st – mixes in better – more oxygen is best

3. DEMOS!  Combustion of Propane C3H5 + O2 → CO2 + H2O
1 C3H5 : 2 O2 3 ml C3H5 : 6 ml O2
9 ml total
C3H5 + 5O2 → 3CO2 + 4H2O
1 C3H5 : 5 O2 3 ml C3H5 : 15 ml O2
18 ml total
1st: FLAME: Add oxygen 1st – always have a little more fuel (methane) the 1st time around so that it doesn’t go off
2nd: BOOM: Add CH4 1st – mixes in better – more oxygen is best

4. DEMOS!  Combustion of Butane C4H10 + O2 → CO2 + H2O
2 C3H5 : 13 O2 2 ml C3H5 : 13 ml O2
15 ml total
1st: FLAME: Add oxygen 1st – always have a little more fuel (methane) the 1st time around so that it doesn’t go off
2nd: BOOM: Add CH4 1st – mixes in better – more oxygen is best

5. Chapter 12: Stoichiometry
Table of Contents
Chapter 12: Stoichiometry
Stoichiometry is the mathematical study of chemical reactions.
12.1: Mole-Mass
Stoichiometry ratios
The molar ratio of one reactant/product to another reactant/product
12.2: Stoichiometric Calculations
Used to calculate how much reactant (or product) will be consumed (or created) in a chemical reaction.
It shows quantitative relationship between the reactants and products.

6. 2 H2 molecules + 1 O2 molecule → 2 H2O molecules
Stoichiometry: Basic Concepts
Stoichiometry
The coefficients represent…
(Ionic compounds = formula units)
2H2 + O2 → 2H2O
2 H2 molecules + 1 O2 molecule → 2 H2O molecules
2 moles H2 + 1 mole O2 → 2 moles H2O
ratio: 2 mol H2 : 1 mol O2

7. Stoichiometry problems
Stoichiometry: Basic Concepts
Stoichiometry problems
1. Write balanced equation
a. Identify reactants and products
b. Write their chemical formulas (balance charges)
c. Balance the equation

8. Stoichiometry problems
Stoichiometry: Basic Concepts
Stoichiometry problems
2. Convert to moles
Just like we’ve been practicing
3. Convert from moles known to moles of unknown (from balanced equation)
4. Convert moles to needed units

9. Stoichiometry: Moles–Moles equations
Ex1) How many moles sodium hydroxide can be produced when 3.12 moles sodium sulfate are reacted with excess potassium hydroxide (double displacement)?
Na2SO KOH --> K2SO NaOH
3.12 mol Na2SO4
2 mol NaOH =
6.24
mol NaOH
1 mol Na2SO4

10. Stoichiometry: Moles–Moles equations
Na2SO KOH --> K2SO NaOH
Ex2) How many moles potassium sulfate can be produced from 7.36 moles potassium hydroxide?
7.36 mol KOH
1 mol K2SO4 =
3.68
mol K2SO4
2 mol KOH

11. Stoichiometry: Moles–Moles equations
Na2SO KOH --> K2SO NaOH
Ex 3) How many moles of potassium hydroxide are required to react with moles sodium sulfate?
11.47 mol Na2SO4
2 mol KOH =
22.94
mol Na2SO4
1 mol Na2SO4

12. Stoichiometry: Moles–Moles equations
Na2SO KOH --> K2SO NaOH
Ex 4) How many moles of potassium hydroxide did you use to create 7.12 moles NaOH?
7.12 mol NaOH
2 mol KOH =
7.12
mol KOH
2 mol NaOH

13. Just so you know… WA ch 12 + 11.4, 11.5 is ENORMOUS (200 points)
You can now do #11-18
Answers for #7-9 are given on the website
mmecall.weebly.com
You can also find…
Notes homework hints