Question

Hi, I need some help with Chemistry.

Q1:

Q2:

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You add 0.0336 moles of benzoic acid solute to 16.00 g of an unknown solvent, which lowers the freezing point of the solvent by 8.6 °C. Calculate the freezing point depression constant (Kf) of the unknown solvent. You dissolve 1.00 g sample of an unknown solute is in 8.00 g of lauric acid, which lowers the freezing point by 5.0 °C. Please calculate the experimental molar mass (g/mol) of this unknown solute. When a solute is dissolved in a solvent, the freezing temperature is lowered in proportion to the number of moles of solute added. This property, known as freezing-point depression, is a colligative property; meaning that it depends on the ratio of solute and solvent particles, not on the nature of the substances themselves. The equation that shows this relationship is as follows: Where At is the freezing point depression, Kf is the freezing point depression constant for a particular solvent, and m is the molality of the solution. The molality is calculated as follows: moles of solute kg of solvent In this experiment you will be using the solute benzoic acid and the solvent lauric acid. The Kf of lauric acid is 3.9 °C-kg/mol.1 You will determine the experimental molar mass of a solute by measuring the following values: mass of the solute, mass of the solvent, freezing point of the pure solvent, and freezing point of the mixture. You will then calculate the percent error to assess the accuracv of this method, grams of solute moles of solute experimental molar mass-

Answer 1

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