At 20 °C, a 3.13 M aqueous solution of ammonium chloride has a density of 1.0457 g/mL. What is the molality of ammonium chloride in the solution? The formula weight of NH₄Cl is 53.50 g/mol. A)3.56 B)0.0611 C)3.13 D)0.334 E)16.00

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Quizplus · Accepted Answer

To find molality, we need moles of solute per kg of solvent. First, calculate the mass of 1 L of solution: 1.0457 g/mL * 1000 mL = 1045.7 g. Moles of NH4Cl in 1 L = 3.13 mol. Mass of NH4Cl = 3.13 mol * 53.50 g/mol = 167.455 g. Mass of water = 1045.7 g - 167.455 g = 878.245 g = 0.878245 kg. Molality = 3.13 mol / 0.878245 kg = 3.56 mol/kg.