The percent composition by mass of an unknown chlorinated hydrocarbon was found to be 37.83% C, 6.35% H, and 55.83% Cl by mass. What is the empirical formula of this compound A) C₂H₄Cl B) C₃H₇Cl C) C₃H₆Cl₂ D) C₄H₉Cl E) C₅H₁₁Cl

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To find the empirical formula, divide the percent composition by the atomic mass of each element to find the mole ratio: C (37.83%/12.01 = 3.15), H (6.35%/1.008 = 6.30), Cl (55.83%/35.45 = 1.57). The ratio of C:H:Cl is approximately 2:4:1, making the empirical formula C2H4Cl.

The Percent Composition by Mass of an Unknown Chlorinated Hydrocarbon