c101_f10_1013

c101_f10_1013 - Percent composition (mass percent, percent...

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Percent composition (mass percent, percent composition by mass) Mass % = mass of component in substance (grams) x 100 mass of substance (grams) What is the mass % composition of 10 g water? MM (H 2 O) = 18.0152 g/mol MM (H) = 1.0079 g/mol MM (O) = 15.9994 g/mol %H in water = 11.21% H %O in water = 88.79% O If you have 18.015 g of water, what is the mass % composition of water? Does mass % composition of a substance depend on the amount of substance you have? Why?
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Chemistry 101 Fall 2010 2 We went from chemical formula (H 2 O) to percent composition. We can also go from percent composition to the chemical formula. You have 100 grams of a compound, and you find out it has a mass % composition of: 75.7% C 8.8% H 15.5% O. How many moles of C, H, and O do you have?
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3 Mass % composition of: 75.7% C, 8.8% H, and 15.5% O. yields these molar ratios … mol C : mol H : mol O, which is the same as saying … atoms C : atoms H : atoms O. Atoms do not combine as fractions or pieces (0.30, 0.7, 0.969), so we must scale up to reach whole atoms (whole numbers). Divide by the smallest number to reach 1 for at
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c101_f10_1013 - Percent composition (mass percent, percent...

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