Calculate the freezing point of a solution containing 5.0 grams of KCl and 550.0 grams of water.The molal-freezing-point-depression constant (K_f)for water is 1.86°C/m. A) -0.45 ^oC B) +0.45 ^oC C) -0.23 ^oC D) +0.23 ^oC E) 1.23 ^oC

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To find the freezing point depression (∆Tf) of the solution, we use the formula: ∆Tf = Kf * molality where Kf is the molal-freezing-point-depression constant for water and can be found in the question, and molality is given by: molality = moles of solute / mass of solvent (in kg) First, we need to convert the mass of KCl to moles: moles of KCl = 5.0 g / 74.55 g/mol = 0.067 moles Next, we need to convert the mass of water to kilograms: mass of water = 550.0 g = 0.55 kg Now we can calculate the molality: molality = 0.067 moles / 0.55 kg = 0.122 mol/kg Finally, we can calculate the freezing point depression: ∆Tf = 1.86°C/m * 0.122 mol/kg = 0.227 ^oC (rounded to 0.23 ^oC) Since we want to find the freezing point of the solution, we need to subtract the freezing point depression from the freezing point of pure water (which is 0°C): freezing point of solution = 0°C - 0.23 ^oC = -0.45 ^oC

Calculate the Freezing Point of a Solution Containing 5