Natasha was trying to identify 452.1 g of an unknown non-electrolyte sample. Given the limited instruments in their laboratory,she decided to mix the sample into 500.0 mL of water to determinethe sample's effect on its boiling point and freezing point. The tableshows the data she collected for the experiment (Kb= 0.512 °C/mandKf=1.86OC/m)Trial 1 (°C)Trial 2 (°C)Trial 3 (°C)Mean (°C)Boiling point104.20103.80104.10104.03Freezing point-14.71-14.65-14.63-14.66What is the molality of the unknown sample?8.9 m9.1 m10.5 m7.9 m

Mass of solute = 452.1 g Volume of water = 500 mL Mass of water = 500 g Kb = 0.512 oC/m Kf = 1.86…

latasha was trying to identify 452.1 g of an unknown lectrolyte sample. Given the limited instruments in their laborat he decided to mix the sample into 500.0 mL of water to detern e sample's effect on its boiling point and freezing point. The t hows the data she collected for the experiment (Kb= 0.512 ° nd Kf= 1.86 Trial 1 (°C) Trial 2 (°C) Trial 3 (°C) Mean (°C) Boiling point 104.20 103.80 104.10 104.03 Freezing point -14.71 -14.65 -14.63 -14.66 What is the molality of the unknown sample? ) 8.9 m 9.1 m 10.5 m

latasha was trying to identify 452.1 g of an unknown lectrolyte sample. Given the limited instruments in their laborat he decided to mix the sample into 500.0 mL of water to detern e sample's effect on its boiling point and freezing point. The t hows the data she collected for the experiment (Kb= 0.512 ° nd Kf= 1.86 Trial 1 (°C) Trial 2 (°C) Trial 3 (°C) Mean (°C) Boiling point 104.20 103.80 104.10 104.03 Freezing point -14.71 -14.65 -14.63 -14.66 What is the molality of the unknown sample? ) 8.9 m 9.1 m 10.5 m

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter11: Solutions

Section: Chapter Questions

Problem 47P

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A student determines the molar mass of a liquid unknown by the method used in this experiment. She found that the equilibrum temperature of a mixture of ice and water was 1.0 degrees C on her thermometer. When she added 11.1 g of her unknown sample to the mixture, the temperature, after thorough stirring, fell to -3.0 degrees C. She then poured off the solution through a screen into a beaker. The mass of the solution was 90.4 g. Kf=1.86 degrees C/m How much water was in the decanted solution? What did she find to be the molar mass of the unknown liquid, assuming she made the calculation properly?
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