Determination of Freezing Pt

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Determination of Freezing Point and Verification of Freezing Point Depression for a Mixture by Linah Richer Partners: Maike Blakely CHM317 Preformed: Nov. 8th, 2013 Report: Nov. 19th, 2013 Abstract: The purpose of this experiment is to determine the freezing point of the solvent, biphenyl, and verify the freezing point depression equation ΔTf=-ikfnsolutemsolvent. The addition of solute will lower the vapor pressure of the solvent/solute mixture resulting in the lowering of the freezing point for the mixture solution. The experiment resulted in the experimental difference in the two trial freezing points to be 0.08 K leading to a calculated change in temperature freezing to be -1.92 E -5 K, and an overall decrease in temperature freezing of the solute/solvent solution compared to the pure solvent solution. Introduction: Experimentally it is understood that the addition of a nonvolatile solute to a solvent will lower the vapor pressure, raise the boiling point and lower the freezing point. In this experiment, the freezing point for the solvent biphenyl will be determined theoretically and experimentally, as well as the verification of the freezing point depression equation for a solvent/solute mixture. Represented by the equation kf=RTf2MΔHf , the freezing point depression will be constant for a solvent despite whether a solute is involved in the experiment. The freezing point equation can later be used to calculate the temperature the solvent freezes represented by the equation, ΔTf=-ikfnsolutemsolvent . The freezing point of the solvent containing a nonvolatile electrolyte will be equal to the addition of the freezing point depression to temperature of the pure solvent and will always be lower than the freezing point of the pure solution. Because the freezing point depression is a colligative property, the higher the concentration of

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