1. Identify the Representative Particle
Aluminum
hydrogen sulfide
Sodium chloride
Aluminum sulfate
Sulfur dioxide
sodium
Hydrogen

2. Identify the Representative Particles answers
Aluminum Al atoms
H2S molecules hydrogen sulfide
Sodium chloride NaCl fu’s
Al2(SO4)3 fu’s Aluminum sulfate
Sulfur dioxide SO2 molecules
sodium Na atoms
Hydrogen H2 molecules

3. Using Mole Calculations
Mass to Mol

4. Mass to Mole Use Molar Mass (g/mol) = MM (note: mol/g = 1/MM)
( substance g) X
mol g X 1 MM g
mol
Mass divided by Molar Mass = Moles

5. Mole to Mass Use Molar Mass (g/mol) = MM ( substance mol) X mol X MM g
Moles multiplied by Molar Mass = Grams

6. Summary Molar Mass = MM Mass to Mol: Divide by MM
Mol to Mass: Multiply by MM g MM
mol
X MM

7. Avogadro’s Principle
Equal volumes of different gases at the same T & P will contain the same number of particles
Same # of He atoms
as oxygen molecules He O2
Same temperature & pressure

8. Molar Volume He O2 32.0 g 4.0 g Avogadro 1811
One Mole of a gas at STP will occupy 22.4 L
STP = standard temp & pressure
0oC and 1 atm
22.4 L He O2
32.0 g
4.0 g

9. What is the volume of 38 g of fluorine gas at STP?
ANS
22.4 L

10. What is the volume of 10.09 g of neon at STP?
How many mol of Ne is this?
0.50 mol
If 1 mol would occupy 22.4 L what volume would this sample occupy?
ANS: L
(or ½ of what 1 mol occupies)

11. Summary mol to volume conversions for gases
X 22.4
mol
Vol (L)
22.4