Molar mass indicates the total of all of the masses of the elements that make up a compound. The molar mass indicates the number of grams per one mole of that
compound. Knowing the grams per mole allows chemists to convert a compound from moles into grams.
Instructions
1.
2.
3.
Look up the atomic mass of all of the elements in the compound using the periodic table. For instance, note that on a periodic table, the atomic weight of carbon equals
12.01 grams and oxygen's atomic weight equals 16.00 grams for the compound of CO2.
Note the number of each element in the compound and multiply each of the atomic weight by the number of atoms of that element in the compound. For example, CO2
contains one carbon and two oxygen atoms. Multiply carbon's atomic weight (12.01 grams) by the number of carbon atoms in the compound (1) to find: 1 x 12.01 = 12.01
grams. Repeat the process with oxygen to find: 2 x 16.00 = 32.00 grams.
Add all of the weights of the elements in the compound together to find the molar mass. For the example, add 12.01 + 32.00 = 44.01 grams/mole (g/mol) for the molar
mass of CO2.
Example
Name
sulfur dioxide
Dinitrogen dioxide
Formula
SO2
N2O2
Name
1.
sulfuric acid
2.
sodium chloride
3.
glucose
4.
5.
H2SO4
C6H12O6
chlorine dioxide
PCl5
carbon monoxide
8.
9.
Formula
CCl4
6.
7.
Molar Mass
64.07 g/mol
60.00 g/mol
BaCO3
silver bicarbonate
10.
Cl2
11. helium
12. iron(III) bicarbonate
13.
14. sodium hydroxide
NH4ClO4
Name
iron III oxide
ammonium nitride
Formula
Fe2O3
(NH4)3N
Molar Mass
Molar Mass
159.70 g/mol
68.12 g/mol
Name
15. hydrochloric acid
Formula
HCl
16. barium bromide
17.
NO2
18. ammonia
19.
CS2
20. hydrogen
21.
SiO2
22. tin(II) chloride
23.
Ba(OH)2
24. iodine
25.
Ag2S
26. magnesium hydroxide
27.
Zn3(PO4)2
28. ammonium nitrate
29.
O2
30. potassium iodide
31.
KNO3
32. hydrogen peroxide
33.
F2
34. sodium acetate
35.
N2
36. ammonium phosphate
37.
Br2
38. zinc sulfite
39.
40. dihydrogen monoxide
CaI2
Molar Mass
Answer Key
Name
Formula
sulfur dioxide
Dinitrogen dioxide
Name
SO2
N2O2
Formula
Molar Mass
64.07 g/mol
60.00 g/mol
Molar Mass
Name
Name
Formula
iron III oxide
ammonium nitride
Formula
Molar Mass
Molar Mass
159.70 g/mol
68.12 g/mol
Fe2O3
(NH4)3N
Name
Formula
Molar Mass
sulfuric acid
H2SO4
98.09 g/mol
hydrochloric acid
HCl
36.46 g/mol
oxygen
O2
32.00 g/mol
sodium chloride
NaCl
58.44 g/mol
barium bromide
BaBr2
297.13 g/mol
potassium iodide
KI
165.99 g/mol
glucose
C6H12O6
180.18 g/mol
nitrogen dioxide
NO2
46.00 g/mol
potassium nitrate
KNO3
101.09 g/mol
carbon tetrachloride
CCl4
153.81 g/mol
ammonia
NH3
17.03 g/mol
hydrogen peroxide
H2O2
34.02 g/mol
chlorine dioxide
ClO2
67.45 g/mol
carbon disulfide
CS2
78.15 g/mol
fluorine
F2
38.00 g/mol
phosphorous
pentachloride
carbon monoxide
PCl5
208.22 g/mol
hydrogen
H2
2.02 g/mol
sodium acetate
NaC2H3O2
82.04 g/mol
CO
28.01g/mol
silicon dioxide
SiO2
60.09 g/mol
nitrogen
N2
28.00 g/mol
barium carbonate
BaCO3
197.34g/mol
tin(II) chloride
SnCl2
189.61 g/mol
(NH4)3PO4
149.09 g/mol
silver bicarbonate
AgHCO3
168.89 g/mol
barium hydroxide
Ba(OH)2
175.35 g/mol
ammonium
phosphate
bromine
Br2
159.80 g/mol
chlorine
Cl2
70.09 g/mol
iodine
I2
253.80 g/mol
zinc sulfite
ZnSO3
145.48g/mol
helium
He
4.00 g/mol
silver sulfide
Ag2S
247.81 g/mol
calcium iodide
CaI2
293.88 g/mol
iron(III) bicarbonate
Fe2(CO3)3
291.70 g/mol
magnesium hydroxide
Mg(OH)2
58.33 g/mol
dihydrogen
monoxide
H2O
18.02 g/mol
ammonium
perchlorate
sodium hydroxide
NH4ClO4
117.49 g/mol
zinc phosphate
Zn3(PO4)2
386.17 g/mol
NaOH
40.00 g/mol
ammonium nitrate
NH4NO3
80.04 g/mol