1. MOLAR MASS:

2. What is the Molar Mass of H2O?
REVIEW – MOLAR MASS
What is the Molar Mass of H2O?
What is the mass of H?
How many H are in the compound?
What is the mass of O?
How many are in the compound?
1.01g/mol 2
16.00 g/mol 1
2(1.01g) + 1(16.00g) = g/mol

3. What is the Molar Mass of CF4?
REVIEW – MOLAR MASS
What is the Molar Mass of CF4?
What is the mass of C?
How many are in the compound?
What is the mass of F?
12.01 g/mol 1
19.00 g/mol 4
1(12.01g) + 4(19.00g) = g/mol

4. What is the Molar Mass of MgSO4? What is the molar mass of CO2?
PRACTICE
What is the Molar Mass of MgSO4?
What is the molar mass of CO2?
What is the molar mass of CH3Cl?
g/mol
44.01 g/mol
50.49 g/mol

5. Percent Composition:

6. What is the definition of a percent???

7. PERCENT COMPOSITION OF COMPOUNDS
g of element ___________ X 100 = % Comp. g of compound

8. EXAMPLE ONE:
Calculate the percent composition of each of the elements when 9.03g of Magnesium reacts with 3.48g of Nitrogen
Step One: Calculate the total mass (in g)
Step Two: Calculate % of each element

9. EXAMPLE FOUR:
Calculate the percent composition of each element in the following compounds:
C2H6
Step One: Calculate the Molar Mass of the compound
Step Two: Calculate the total mass of each element in the compound (using the atomic mass and the subscript)
Step Three: Calculate the percent of each element

10. EXAMPLE NINE
Calculate the mass of the element in the given mass of the compound:
MASS OF HYDROGEN IN 350g OF C2H6
STEP ONE: Calculate the molar mass of the compound
STEP TWO: Calculate the total mass of HYDROGEN in the compound
STEP TWO: Calculate the percent composition of HYDROGEN in the compound
STEP THREE: Use the percent composition and the total mass given to calculate grams of Hydrogen in that specific sample
( TOTAL MASS X %COMP ) / 100 = g of element in sample