This document discusses molar mass and provides examples of calculating the molar mass of common compounds like sodium chloride, water, and aluminum sulfate. The molar mass of a substance is the mass of one mole of that substance. It demonstrates how to determine molar mass by adding up the atomic masses of each element in a compound's chemical formula based on the number of atoms present. Knowing molar mass allows one to measure out exactly one mole of a substance.

1. Molar Mass
Chemistry

2. Objective
Measure out exactly 1 mole of a substance by
determining the molar mass of some common
compounds.

3. Molar mass
The molar mass of a substance is the mass of 1 mole of that
substance.
Remember that 1 mole of a substance is equal to 6.02x1023
particles (atoms or molecules).

4. Molar mass - Sodium Chloride
Sodium chloride: NaCl
Atomic mass of Na: 22.99 x 1 atom of Na = 22.99 g/mol
Atomic mass of Cl: 35.45 x 1 atom of Cl = 35.45 g/mol
Molar mass of NaCl: 22.99 g/mol + 35.45 g/mol = 58.44 g/mol

5. Molar mass - Water
Water: H2O
Atomic mass of H: 1.01 x 2 atoms of H = 2.02 g/mol
Atomic mass of O: 16.00 x 1 atom of O = 16.00 g/mol
Molar mass of H2O: 2.02 g/mol + 16.00 g/mol = 18.02 g/mol

6. Molar mass - Aluminum sulfate
Aluminum Sulfate: Al2(SO4)3
Atomic mass of Al: 26.98 x 2 atoms of Al = 53.96 g/mol
Atomic mass of S: 32.06 x 3 atoms of S = 96.18 g/mol
Atomic mass of O: 16.00 x 12 atoms of O = 192 g/mol
Molar mass of Al2(SO4)3: 53.96 + 96.18 + 192 = 342.14 g/mol

7. Measure out exactly
1 mole of each of
the compounds
from the example
Problems.