What is the molality of a solution that contains 74.2 g of 1,4-dichlorobenzene (C₆H₄Cl₂)in 492 mL of carbon tetrachloride (CCl₄)? The density of CCl₄ is 1.60 g/mL. A)0.158 m B)0.642 m C)0.151 m D)0.094 m E)1.64 m

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Quizplus · Accepted Answer

First, calculate the molar mass of 1,4-dichlorobenzene (C6H4Cl2): C (12.01 g/mol) * 6 + H (1.01 g/mol) * 4 + Cl (35.45 g/mol) * 2 = 147.01 g/mol. Then, find the mass of the solvent (carbon tetrachloride, CCl4) in kg: 492 mL * 1.60 g/mL = 787.2 g = 0.7872 kg. The number of moles of 1,4-dichlorobenzene is 74.2 g / 147.01 g/mol = 0.5047 mol. Finally, molality (m) = moles of solute / kg of solvent = 0.5047 mol / 0.7872 kg = 0.641 m, which rounds to 0.642 m.

What Is the Molality of a Solution That Contains 74