A solution with a final volume of 500ml was prepared by dissolving 25.00mL of me

Question

A solution with a final volume of 500ml was prepared by dissolving 25.00mL of methanol (CH3OH, density = 0.7914 g/mL) in chloroform. calculate the molarity of methanol in the solution. the solution has a density of 1.454 g/mL. find the molality of methanol. I WANT TWO ANSWERS WITH COMPLETE SOLUTION :)

Explanation / Answer

Methanol = solute Chloroform = solvent First, we solve for the mass of methanol: 25.00 mL x 0.7914 g/mL = 19.79 g Now, we can solve for the moles of methanol from the grams: 19.79 g x 1 mol/32.04 g = 0.618 moles Molarity = moles of solute / L of solution Molarity = 0.618 moles / 500 mL x 1000 mL / 1 L Molarity = 1.24 moles / L --> 1st answer Now, we find the volume of the solvent from the volume of the total solution and the volume of methanol: Total volume of solution = 500 mL volume of solute + volume of solvent = 500 mL volume of solvent = 500 - 25 = 475 mL From the volume of the solvent, we can solve for the grams of the solvent using the density: 475 mL x 0.454 g/mL = 216 g 216 g x 1 kg/1000 g = 0.216 kg Molality = moles of solute / kg of solvent Molality = 0.618 moles / 0.216 kg Molality = 2.86 moles of methanol / kg of chloroform --> 2nd answer Hope this helps! :)

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