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Mr. Quinn & Ms. Tom January 13, 2014 Aim: How can molecular formulas be found from mass percent data? Do Now: Solve for x : 60x = 240 Find the smallest whole-number ratio: 4:12:8 Find the empirical formula: C: 12 g O: 32 g. Empirical and Molecular formulas are different.
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Mr. Quinn & Ms. Tom January 13, 2014Aim: How can molecular formulas be found from mass percent data?Do Now:Solve for x: 60x = 240Find the smallest whole-number ratio: 4:12:8Find the empirical formula:C: 12 gO: 32 g
Empirical and Molecular formulas are different • Calculate the empirical formula for glucose: • C: 40% • H: 7 % • O: 53 %
The Steps • Determine the empirical formula. • Divide the molar mass by the empirical mass. • Multiply all coefficients by your answer to Step 2.
Calculate the formula of DHAP: • Molar Mass: 90 g/mole • C: 40% • H: 7 % • O: 53 %
Calculate the formula of 1-decene: • Molar Mass: 140 g/mole • C: 85.7 % • H: 14.3 %
Calculating the formula of methylether: • Molar Mass: 46 g/mole • C: 52.2 % • H: 13 % • O: 34.8 %
Exit Ticket • Your calculations lead you to determine that the mole ratio of Cs to O in cesium oxide is 2:1. What is the formula for cesium oxide? • CsO • CsO2 • Cs2O • Cs2O2