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Data Table:ed.ow Mass of lauric acid (g) Mass of residual lauric acid in weighboat (g) 5.0024 q 43.98°C 0.7416 q 0.00719 0.7389 Baro 38.12°c Mass of lauric acid in test tube (g) Freezing point of lauric acid (°C) Mass of unknown (g) Mass of residual unknown in weighboat (g) Mass of unknown in test tube (g) Freezing point of mixture (°C) Data Analysis Calculate the molar mass of the unknown solid using equations 2.2 through 2.5. Show all of your work.

Data Table:ed.ow Mass of lauric acid (g) Mass of residual lauric acid in weighboat (g) 5.0024 q 43.98°C 0.7416 q 0.00719 0.7389 Baro 38.12°c Mass of lauric acid in test tube (g) Freezing point of lauric acid (°C) Mass of unknown (g) Mass of residual unknown in weighboat (g) Mass of unknown in test tube (g) Freezing point of mixture (°C) Data Analysis Calculate the molar mass of the unknown solid using equations 2.2 through 2.5. Show all of your work.

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Chemistry
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ISBN:9781305957404
Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste
Chapter1: Chemical Foundations
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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Calculate the molar mass of the unknown solid using equations 2.2 through 2.5. Show all your work. I don’t know how to find the value for Kf either. Please help
(mm)x (kg solvent) = moles solute (2.4) mass solute moles solute = molecular mass of solute (2.5) In this experiment, you will determine the molar mass of the unknown by measuring the freezing-point depression observed in a solution in which the solvent is lauric acid. Procedure and Collection of Data You will watch a You Tube video in which an experiment briefly described in the introduction is carried out. The video can be found by clicking on the following link: https://www.youtube.com/watch?v=10DrYceYwzA Record the data in the table below. Note that the temperature at the end of each experiment is the freezing point of the substance. There is no need to consider all of the time and temperature data that was collected along the way. Data Table: Mass of lauric acid (g) Mass of residual lauric acid in weighboat (g) 5.0624 q 43.98° 0.74116q 0.00714 0.7389 Mass of lauric acid in test tube (g) 190 tuld Freezing point of lauric acid (°C) villsio Mass of unknown (g) Mass of residual unknown in weighboat (g) Mass of unknown in test tube (g) Freezing point of mixture (°C) 38.12°c Data Analysis Calculate the molar mass of the unknown solid using equations 2.2 through 2.5. Show all of your work.
Transcribed Image Text:(mm)x (kg solvent) = moles solute (2.4) mass solute moles solute = molecular mass of solute (2.5) In this experiment, you will determine the molar mass of the unknown by measuring the freezing-point depression observed in a solution in which the solvent is lauric acid. Procedure and Collection of Data You will watch a You Tube video in which an experiment briefly described in the introduction is carried out. The video can be found by clicking on the following link: https://www.youtube.com/watch?v=10DrYceYwzA Record the data in the table below. Note that the temperature at the end of each experiment is the freezing point of the substance. There is no need to consider all of the time and temperature data that was collected along the way. Data Table: Mass of lauric acid (g) Mass of residual lauric acid in weighboat (g) 5.0624 q 43.98° 0.74116q 0.00714 0.7389 Mass of lauric acid in test tube (g) 190 tuld Freezing point of lauric acid (°C) villsio Mass of unknown (g) Mass of residual unknown in weighboat (g) Mass of unknown in test tube (g) Freezing point of mixture (°C) 38.12°c Data Analysis Calculate the molar mass of the unknown solid using equations 2.2 through 2.5. Show all of your work.
General Chemistry II CHM 122 Laboratory 2 Determination of Molar Mass by Freezing-Point Depression Purpose The purpose of this experiment is to determine the molar mass of an unknown compound by measuring the freezing-point depression observed in a solution of the compound. Introduction c The vapor pressure of a liquid is determined by the ability of solvent molecules to move from the liquid phase to the gaseous phase. In a solution, however, some of the spaces at the surface of the solution are occupied by the solute particles. As a result, fewer solvent particles are in positions from which they can move into another phase, and therefore the solution's vapor pressure is lower than that of the pure solvent. This means that the solution will have to be heated to a higher temperature before its vapor pressure reaches that of the atmosphere, therefore resulting in an elevated boiling point. Similarly, since the solution has a lower vapor pressure, the solution will have to be cooled to a lower temperature for the solution to freeze. The extent of freezing-point depression is proportional to the amount of solute present in a given mass of solvent. The concentration unit employed is molality, symbolized by a lowercase m. Molality is defined as the number of moles of solute per kilogram of solvent. moles solute (2.1) m = kg solvent The difference between the freezing point of the solution and that of the pure We can solvent is called the freezing point depression and is given the symbol Atr. express the relationship between the difference in freezing point and the molality of the solution in Equation 2.2: At, = k, x m (2.2) where kf is the freezing-point depression constant in units of °C-kg/mol. Equation 2.3 shows that by measuring the freezing-point depression of a solution, you can determine the solution's molality. Knowing the experimentally determined molality and knowing how the solution was prepared (i.e., what mass of solute was combined with what mass of solvent), you can obtain the molar mass of solute according to the following equations. At (2.3) mexpil k,
Transcribed Image Text:General Chemistry II CHM 122 Laboratory 2 Determination of Molar Mass by Freezing-Point Depression Purpose The purpose of this experiment is to determine the molar mass of an unknown compound by measuring the freezing-point depression observed in a solution of the compound. Introduction c The vapor pressure of a liquid is determined by the ability of solvent molecules to move from the liquid phase to the gaseous phase. In a solution, however, some of the spaces at the surface of the solution are occupied by the solute particles. As a result, fewer solvent particles are in positions from which they can move into another phase, and therefore the solution's vapor pressure is lower than that of the pure solvent. This means that the solution will have to be heated to a higher temperature before its vapor pressure reaches that of the atmosphere, therefore resulting in an elevated boiling point. Similarly, since the solution has a lower vapor pressure, the solution will have to be cooled to a lower temperature for the solution to freeze. The extent of freezing-point depression is proportional to the amount of solute present in a given mass of solvent. The concentration unit employed is molality, symbolized by a lowercase m. Molality is defined as the number of moles of solute per kilogram of solvent. moles solute (2.1) m = kg solvent The difference between the freezing point of the solution and that of the pure We can solvent is called the freezing point depression and is given the symbol Atr. express the relationship between the difference in freezing point and the molality of the solution in Equation 2.2: At, = k, x m (2.2) where kf is the freezing-point depression constant in units of °C-kg/mol. Equation 2.3 shows that by measuring the freezing-point depression of a solution, you can determine the solution's molality. Knowing the experimentally determined molality and knowing how the solution was prepared (i.e., what mass of solute was combined with what mass of solvent), you can obtain the molar mass of solute according to the following equations. At (2.3) mexpil k,
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