1. Percent Composition

2. Percent Composition – the percentage by mass of each element in a compound Percent = _______ Part Whole x 100% Percent composition of a compound or = molecule Mass of element in 1 mol ____________________ Mass of 1 mol x 100%

3. Percent Composition Example: What is the percent composition of Potassium Permanganate (KMnO 4 )? Molar Mass of KMnO 4 K = 1(39.1) = 39.1 Mn = 1(54.9) = 54.9 O = 4(16.0) = 64.0 MM = 158 g

4. Percent Composition Example: What is the percent composition of Potassium Permanganate (KMnO 4 )? = 158 g % K Molar Mass of KMnO 4 39.1 g K 158 g x 100 =24.7 % % Mn 54.9 g Mn 158 g x 100 = 34.8 % % O 64.0 g O 158 g x 100 =40.5 % K = 1(39.10) = 39.1 Mn = 1(54.94) = 54.9 O = 4(16.00) = 64.0 MM = 158

5. Percent Composition Determine the percentage composition of sodium carbonate (Na 2 CO 3 )? Molar MassPercent Composition % Na = 46.0 g 106 g x 100% =43.4 % % C = 12.0 g 106 g x 100% =11.3 % % O = 48.0 g 106 g x 100% =45.3 % Na = 2(23.00) = 46.0 C = 1(12.01) = 12.0 O = 3(16.00) = 48.0 MM= 106 g

6. Percent Composition Determine the percentage composition of ethanol (C 2 H 5 OH)? % C = 52.13%, % H = 13.15%, % O = 34.72% _______________________________________________ Determine the percentage composition of sodium oxalate (Na 2 C 2 O 4 )? % Na = 34.31%, % C = 17.93%, % O = 47.76%

7. Percent Composition Calculate the mass of bromine in 50.0 g of Potassium bromide. 1. Molar Mass of KBr K = 1(39.10) = 39.10 Br =1(79.90) =79.90 MM = 119.0 79.90 g ___________ 119.0 g = 0.6714 3. 0.6714 x 50.0g = 33.6 g Br 2.

8. Percent Composition Calculate the mass of nitrogen in 85.0 mg of the amino acid lysine, C 6 H 14 N 2 O 2. 1. Molar Mass of C 6 H 14 N 2 O 2 C = 6(12.01) = 72.06 H =14(1.01) = 14.14 MM = 146.2 28.02 g ___________ 146.2 g = 0.192 3. 0.192 x 85.0 mg = 16.3 mg N 2. N = 2(14.01) = 28.02 O = 2(16.00) = 32.00