1. CHAPTER 9 STOICHIOMETRY
STOICHIOMETRY IS THE BRANCH OF CHEMISTRY THAT DEALS WITH:
A) MASS RELATIONSHIPS OF ELEMENTS IN COMPOUNDS
B) MASS RELATIONSHIPS BETWEEN REACTANTS AND PRODUCTS IN CHEMICAL REACTIONS.
1) COMPOSITION STOICHIOMETRY- DEALS WITH MASS RELATIONSHIP OF ELEMENTS IN COMPOUNDS. (Uses subscripts & Oxidation #’s)
(LAW OF DEFINITE COMPOSITION & MULTIPLE PROPORTIONS) (Chap3)
2) REACTION STOICHIOMETRY- DEALS WITH MASS RELATIONSHIPS
AMONG REACTANTS AND PRODUCTS IN A CHEMICAL REACTION
(BALANCED EQUATIONS & CONSERVATION OF MASS)

2. 4 TYPES OF REACTION-STOICHIOMETRY PROBLEMS
1) MOLE - MOLE, MOLES OF A -> MOLES OF B
2H2 + O2  2H2O
2 mols mol  mols
6 mols +__mols ____mols
2) MOLE - MASS, MOLES OF A -> MOLES OF B -> MASS OF B
2 mols + 1 mol  2 mols
6 mols + 3 mols __6__mols
Mass of O2 ____and mass of water____
Mols of O2 x 32g = mass of O2 96g)
1 MOL
Mols of water x 18g = mass of water (108g)

3. 2 mols + 1 mol  2 mols 3) MASS-MOLE,
MASS OF A -> MOLS OF A -> MOLS OF B
2H O2  2H2O
2 mols + 1 mol  2 mols
28g OF Hydrogen produces _______mols of water
28g x 1mol x 2mol H20 = mols of water
2g mols H2
4) MASS-MASS,
MASS A -> MOLES A -> MOLES B -> MASS OF B
28g of Hydrogen produces _______grams of water
28g x 1mol x 2mol H20 = mols of water x 18g
2g mols H mol water

4. CONVERSION FACTORS MOLAR MASS AND MOLE RATIO
MOLE RATIO - CONVERSION FACTOR THAT RELATES # OF MOLES OF ANY 2 SUBSTANCES IN A REACTION *COEFFICIENTS
Molar Mass – Mass of a mole,
- Formula mass in grams

5. Solving Problems TO SOLVE REACTION STOICHIOMETRY PROBLEMS:
1. BALANCE EQUATION
DETERMINE WHAT IS GIVEN AND WHAT IS REQUIRED. (Read Problem)
(GIVEN MOLES OR MASS - REQUIRED MOLES OR MASS)
IF GIVEN MASS, # OF MOLES OF GIVEN MUST BE CALCULATED BY THE EQUATION:
MASS
# OF MOLS = MOLAR MASS
3. FROM EQUATION CALCULATE MOLE RATIOS
4. USE MOLE RATIOS TO FIND THE # OF MOLS REQUIRED.(Use Coefficients)
5. IF MASS OF REQUIRED CALCULATE USING THE SAME EQUATION
# OF MOLS = MOLAR MASS OR MASS = # OF MOLS x MOLAR MASS

6. CONVERSION FACTORS MOLAR MASS AS CONVERSION FACTOR ARE:
A g B) I MOL Al2O3
1 MOL Al2O g
C) g D) 1 MOL Al
1 MOL Al g
E) ___32g__ F) 1 MOL OF O2
1 MOL OF O g

7. CONVERSION FACTORS 2Al2O3 -> 4Al + 3O2
A) 2 MOLES OF ALUMINUM OXIDE OR B) MOLES OF Al
4 MOLES OF ALUMINUM MOLES OF Al2O3
C) 4 MOLS OF Al OR D) 3 MOLS OF O2
3 MOLS OF O MOLS OF Al
E) 2 MOLS OF Al OR F) 3 MOLS OF O2
3 MOLS OF O MOLS OF Al2O
THEREFORE IF GIVEN 13 MOLES OF Al2O3, HOW MANY MOLS OF Al WILL BE PRODUCED.
13 MOLES OF Al2O3 X 4 MOLS OF Al = 26 MOLS OF Al
2 MOLS OF Al2O3

8. THEREFORE, IF YOU WANTED THE MASS OF THE ALUMINUM PRODUCED IN THE PREVIOUS PROBLEM, YOU CALCULATE THE FOLLOWING
26 MOLS OF Al x g Al = 702g OF Al
1 MOL OF Al

9. 9.2 IDEAL STOICHIOMETRY CALCULATIONS
ASSUME COMPLETE CONVERSION OF ALL REACTANTS
INTO PRODUCTS.
1) MOLE - MOLE CALCULATION -
MOLES OF SUBSTANCE A -> MOLS OF B
MOLES OF A x MOLE RATIO B -> MOLS OF B A
2) MOLE - MASS CALCULATION –
MOLES OF A -> MOLS OF B -> MASS OF B
MOLS OF A x MOLE RATIO B x MOLAR MASS OF B = MASS OF B

10. 3) MASS - MOLE CALCULATION – MASS OF A -> MOL OF A -> MOLS OF B
MASS OF A x MOLE RATIO OF B -> MOLS OF B
MOLAR MASS OF A A
4) MASS - MASS CALCULATION –
Mass A Mols A  Mols B  Mass B
MASS OF A X MOLE RATIO B -> MOLS B X Molar Mass B ->Mass B
MOLAR MASS OF A A