1. Percent composition

2. Find the percent composition of calcium nitrate. Step 1: write the formula: Ca 2+ NO 3 1- Ca(NO 3 ) 2 Step 2: find molar mass Step 3: divide by molar mass and multiply by 100 1 mol Ca x 40.08g = 40.08 g/mol / 164.10 g/mol x 100 = 24.42 % Ca 2 mol N x 14.01g = 28.02 g/mol / 164.10 g/mol x 100 = 17.07 % N 6 mol O x 16.00g = 96.00 g/mol / 164.10 g/mol x 100 = 58.50 % O 164.10 g/mol

3. Assignment Determine the percent composition for the following: 1.Ibuprofen C 13 H 18 O 2 2.Beryllium acetate Be(C 2 H 3 O 2 ) 2 3.Dinitrogen hexoxide N 2 O 6 4.Aluminum chromate Al 2 (CrO 4 ) 3 5.Potassium sulfate K 2 SO 4