Introduction to the “Mole”

What is a MOLE?

A mole is 6.02 x 10^23 particles of a pure substance. This is called Avogadro’s number. We use Avogadro’s number and the “mole” the same way we use 12 and a “dozen”. Mole is abbreviated as mol.

• mol does NOT mean “molecule”

What is Molar Mass? How do I calculate it"?

Molar Mass is the mass of 1 mole of a compound. Its units are grams (g/mol)

To calculate molar mass of an element or compound:

1. Make a chart of the elements present and how many atoms of each there are.

2. Use the periodic table to determine the molar mass of each element

3. Multiply across the chart

4. Add up the totals

Na: 2 x 22.99 = 45.98

S: 1 x 32.07 = 32.07

O: 4 x 16 = 64 +

142.042 g/mol

1. You decide to electroplate your old rims on your 1977 Cadillac Eldorado with a bright silver finish and fins a nickel color to be your favorite. The substance used for electroplating is called nickel (II) phosphate. Determine the molar mass of nickel(II) phosphate.

Practice problems

1. Calculate the molar mass of Zinc.

Answer

65.38 g/mol

2. What is the molar mass of barium nitrate?

Answer

261.338 g/mol

3. You decided to electroplate your old rims on your 1977 Cadillac Eldorado with a bright silver finish and find a nickel color to be your favorite. The substance used for nickel electroplating is called nickel(II) phosphate. Determine the molar mass of nickel(II) phosphate.

Answer

366.019 g/mol