MOLAR MASS CALCULATIONS
I. TO DETERMINE MASS OF SPECIFIC ELEMENT AND TOTAL MASS OF
A COMPOUND

Make a list of each element and the number of atoms of each element
present in the compound.

Using the periodic table, determine the mass for each element (round
to a whole number, easier for your calculations).

Multiply each mass by the number of atoms in the formula.

Add up the results to get the total molar mass for the entire
compound.

Example: H2SO4
1. H = 2
S=1
O=4
2. H = 1g
S = 32g
O = 16g
3. H = 2 * 1g = 2g
S = 1 * 32g = 32g
O = 4 * 16g = 64g
4. 2g + 32g + 64g = 98g

Complete these: H2O, NH3, C2H4O2, K2Cr2O7
II.
PROBLEMS INVOLVING MOLES
45 moles of H2O = ? grams of H2O



Determine specific amount (mass) of each element
Find total mass of compound
Using fence method, convert moles to grams
III. PROBLEMS INVOLVING ATOMS
9.4 x 1035 atoms of AmO = ? grams AmO




Determine specific amount (mass) of each element
Find total mass of compound
Using fence method, convert atoms to moles, then moles to grams
Recall 6.02 x 1023 atoms = 1 mole (no matter the substance,
element, compound)