5.4 Poly(ethylene glycol), PEG, is soluble in water. A series of tests were done to determine the average molecular weight of PEG by measuring the boiling point of solutions of PEG in water at different concentrations, as given below: C (g/dL) 0 (pure water) 0.062 0.148 0.370 0.623 Tb (°C) 100.00000 100.00015 100.00031 100.00052 100.00058 A. What is the repeat structure of PEG? B. Which type of average molecular weight is determined from the data given? C. What is the average molecular weight of this PEG sample?

5.4 Poly(ethylene glycol), PEG, is soluble in water. A series of tests were done to determine the average molecular weight of PEG by measuring the boiling point of solutions of PEG in water at different concentrations, as given below: C (g/dL) 0 (pure water) 0.062 0.148 0.370 0.623 Tb (°C) 100.00000 100.00015 100.00031 100.00052 100.00058 A. What is the repeat structure of PEG? B. Which type of average molecular weight is determined from the data given? C. What is the average molecular weight of this PEG sample?

Fundamentals Of Analytical Chemistry

9th Edition

ISBN:9781285640686

Author:Skoog

Publisher:Skoog

Chapter7: Statistical Data Treatment And Evaluation

Section: Chapter Questions

Problem 7.26QAP

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In the determination of molar mass of an unknown substance by ebullioscopic constant, 30 mL of acetone (C3H6O) was placed in a test tube with thermometer and glass tubing and subjected to water bath. Upon boiling, the temperature reads 56 deg C. For the boiling point of unknown-acetone solution, you prepared the solution by mixing 1.60 g of unknown solute in the 30 mL acetone and subjected it again to water bath. The boiling temperature of the solution is 56.68 deg C. The density of acetone = 0.9849 g/mL and the Kb of acetone = 1.67 degC/kg
In the determination of molar mass of an unknown substance by ebullioscopic constant, 30 mL of acetone (C3H6O) was placed in a test tube with thermometer and glass tubing and subjected to water bath. Upon boiling, the temperature reads 56 deg C. For the boiling point of unknown-acetone solution, you prepared the solution by mixing 1.60 g of unknown solute in the 30 mL acetone and subjected it again to water bath. The boiling temperature of the solution is 56.68 deg C. The density of acetone = 0.9849 g/mL and the Kb of acetone = 1.67 degC/kg What is the value for delta Tb or the change in boiling temperature (in degrees Celsius)?
In the determination of molar mass of an unknown substance by ebullioscopic constant, 30 mL of acetone (C3H6O) was placed in a test tube with thermometer and glass tubing and subjected to water bath. Upon boiling, the temperature reads 56 deg C. For the boiling point of unknown-acetone solution, you prepared the solution by mixing 1.60 g of unknown solute in the 30 mL acetone and subjected it again to water bath. The boiling temperature of the solution is 56.68 deg C. The density of acetone = 0.9849 g/mL and the Kb of acetone = 1.67 degC/kg What is the value for delta Tb or the change in boiling temperature (in degrees Celsius)? Final answer must be rounded off to 2 decimal places, and shall NOT have any unit.