PERCENTAGE COMPOSITION 1. pptx

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1. Percentage Composition

2. Percent Part Whole X 100% Mass of element Mass of compound X 100% Percent by mass =

3. Percent Composition use chemical formula & assume 1 mole divide mass each element by formula mass (FM) of compound

4. Percent Composition of H 2 O 2 H’s = 2 x 1.0 g = 2.0 g 1 O = 1 x 16.0 g = 16.0 g Molar mass = 2.0 g + 16.0 g = 18.0 g/ mol % H = 2.0g x 100% = 11.11% 18.0g % O = 16.0g x 100% = 88.89% 18.0g

5. Percent Composition of C 6 H 12 O 6 6 C’s = 6 x 12g = 72g 12 H’s = 12 x 1g = 12g 6 O’s = 6 x 16g = 96g Molar mass = 180.0 grams/mole % C = % H = % O = (72g/180g) X 100% = 40.00% (12g/180g) X 100% = 6.67% (96g/180g) X 100% = 53.33% 100%

6. Percentage Composition Remember to calculate FM ! Nowhere in word problem will it tell you that! Sum of individual element %’s must add up to exactly 100%