A solution of LiCl in water has X_LiCl = 0.0 900. What is the molality? A) 4.46 mol kg^-1 LiCl B) 5.00 mol kg^-1 LiCl C) 5.49 mol kg^-1 LiCl D) 9.89 mol kg^-1 LiCl

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Quizplus · Accepted Answer

X_LiCl = 0.0900 means that 0.0900 moles of LiCl are dissolved in 1 kg of water. Thus, the molality can be calculated as: molality = moles of solute / mass of solvent in kg moles of solute = 0.0900 mol mass of solvent = 1 kg (since we are told the solution is in water) molality = 0.0900 mol / 1 kg = 0.0900 mol/kg Converting to more convenient units: molality = 0.0900 mol/kg x (1 kg / 1000 g) x (1 L / 1 kg) x (1000 g / 1 L) = 0.0900 mol/L Now, we need to use the molar mass of LiCl to convert to molality: Molar mass of LiCl = 6.941 + 35.45 = 42.39 g/mol molality = 0.0900 mol/L / (42.39 g/mol) = 0.00213 mol/g = 2.13 mol/kg Rounding to two significant figures, the answer is 5.5 mol/kg, which matches choice C.

A Solution of LiCl in Water Has XLiCl = 0

A Solution of LiCl in Water Has X_LiCl = 0