1. Mole Calculations 2

2. Molar Mass
The atomic mass of an element is the relative mass compared to Hydrogen. The unit is the atomic mass unit or amu.
The molar mass is the mass of one mole of particles
and the unit is grams/mole.

3. Formula Mass (amu) Molar Mass (g/mol)1H
1.0 amu
1.0 g/mole
4.0 amu
4.0 g/mole He
CO2

4. The molecular mass is the molar mass of a covalent
Compound.
CO2
1 ( 12.0 amu) + 2 (16.0 amu)
= 44.0 amu

5. Formula Mass (amu) Molar Mass (g/mol)1H
1.0 amu
1.0 g/mole
4.0 amu
4.0 g/mole He
44.0 amu
44.0 g/mole
CO2
Fe2O3

6. The formula mass is the molar mass of an ionic
compound.
Fe2O3
2 (55.8 amu) + 3 (16.0 amu)
= amu

7. Formula Mass (amu) Molar Mass (g/mol)1H
1.0 amu
1.0 g/mole
4.0 amu
4.0 g/mole He
44.0 amu
44.0 g/mole
CO2
159.6 g/mole
Fe2O3
297.4 g/mole
Ni2(CO3)3
Al(NO3)3 .5H2O

8. Al(NO3)3 .5H2O
1 ( 27.0) + 3 (14.0) + 9 (16.0) (1.01) + 5 (16.0)
Al N O H O
303.1 g/mole
Note H is 1.01 due to 1H and 2H

9. Formula Mass (amu) Molar Mass (g/mol)H
1.0 amu
1.0 g/mole
4.0 amu
4.0 g/mole He
44.0 amu
44.0 g/mole
CO2
297.4 g/mole
Fe2O3
297.4 g/mole
Ni2(CO3)3
303.1 g/mole
Al(NO3)3 .5H2O

10. The molar mass is a new conversion factor that can convert between grams and moles
Avogadro’s number is another conversion factor that can convert between moles and particles
Particles
Moles
Grams
1.00 mole =
6.02 x 1023 particles
Molar Mass
From Periodic Table
? g / mole

11. Convert 56.6 grams of C to moles.
x mole
= moles
12.0 g
Don’t forget sig figs!
3 sig figs

12. Convert 6.9 moles of PbO2 into grams
x g
= 1.7 x 103 g
1 mole

13. Two Step Mole Calculations

14. Convert 2.00 g CH4 into molecules
grams
moles
molecules
2.00 g CH4
x mole
x x 1023 molecules
= x 1022 molecules
16.04 g
1 mole

15. Convert 9.56 x 1026 molecules Cl2 into grams.
moles
grams
9.56x1026 molec Cl2
x 1 mole
x g
= x 105 g
6.02 x 1023 molec
1 mole

16. Convert 692.5 grams Na2CO3 into formula units.
g moles formula units
692.5 g Na2CO3
x mole
x x 1023 FU
= x 1024 FU
106.0 g
1 mole

17. Convert 8.66 x 1024 formula units CaCl2 into grams
formula units moles g
8.66 x 1024 FU CaCl2
x mole
x g
= x 103 g
6.02 x 1023 FU
1 mole
Happy Mole day to You