**Freezing Point Depression Experiment**In this experiment, you have used a solution of an organic compound consisting of 3.6 grams in 100 milliliters. The reduction in the freezing point was recorded at 3.72°C. **Questions:**(a) What is the effect of impurities on the melting point (MP) or boiling point (BP)? (b) What is the molar mass of the compound? *Given: The freezing point depression constant ($K_f$) of water is 1.86°C/m.*

When a solvent or solution contain impurity its boiling point gets elevated whereas the melting point will get reduced in comparison to the solvent or solution without impurity. Increase in boiling point due to presence of impurity is known as boiling point elevation. decrease in freezing point due to presence of impurity is known as freezing point depression. Formula of depression in freezing point is following :- ∆T = m Kf Where m = molality of solution Kf = molal depression constant for solvent. As given in the problem, Freezing point is lowered by = 3.72 oC Kf for water = 1.86 m = ∆T / Kf = 3.72 / 1.86 = 2 Thus molality of solution is 2m Molality = Moles of soluteSolution in Kg As density of water is 1 g/mL , 100 mL x 1 g/mL = 100 g Mass of given solution = 100 g = 0.1 Kg Thus moles of solute = Molality x Solution in Kg = 2m x 0.1 Kg =0.2 moles Mole = Mass / molar massMolar Mass = Mass / Mole = 3.6 g / 0.2 moles = 18 g/mol Answer : Molar mass of organic compound = 18 g/mol

Science

Chemistry

1- In the freezing point depression experiment you have used a solution of an organic compound of 3.6 g in 100 mL. The lowering value of the freezing point was 3.72°C. (a) What is the effect of impurities on the MP or BP? (b) What is www

1- In the freezing point depression experiment you have used a solution of an organic compound of 3.6 g in 100 mL. The lowering value of the freezing point was 3.72°C. (a) What is the effect of impurities on the MP or BP? (b) What is www

Chemistry

10th Edition

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

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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