Cryoscopic Molecular Weight Measurement Cell

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https://www.instructables.com/Measuring-Freezing-Point-Decrease-of-Water-Solutio/ It is a well-known fact that the freezing temperature of water decreases if it has dissolved substances, which is why adding salt to the snow is liquefied. This is because the approach of water molecules to form the ice crystal is hindered by the presence of molecules other than water, which causes a lower temperature to be required to solidify. This decrease in the freezing point of a liquid due to the fact that another substance (solute) is dissolved is part of the so-called colligative properties and, in the case of diluted solutions that can be considered an ideal solution, does not depend on the nature of the solute but only on the number of particles of the same. For dilute solutions this decrease in freezing point is described by Blagden's law. ΔTF = KF · b · i (Equation 1) where: ΔTF, the freezing-point depression, is defined as TF1 (freezing-point pure solvent) − TF2 (freezing-point solution). KF, the cryoscopic constant, which is dependent on the properties of the solvent, not the solute. For water, KF = 1.853 K·kg/mol). b is the molality (moles solute per kilogram of solvent). i is the van 't Hoff factor (number of ion particles per formula unit of solute, e.g. i = 1 for glucose, i = 2 for NaCl and i = 3 for BaCl2). If we consider that molecular mass (M) is defined as the weight in grams of one mole of molecules we can express the above equation in terms of molecular mass as shown below: M = (KF · WSolute·i ) / (ΔTF ·WSolvent) (Equation 2) where: · WSolute is the weight of the solute in grams · WSolvent is the weight of the solvent in kilograms The objective of this work is: Apply Equation 2 to measure the molar mass of water-soluble substances using temperature sensors controlled by an Arduino microprocessor. Design a measuring cell (crioscope) that allows at least three simultaneous determinations (repetitions) of the freezing point of aqueous solutions under conditions as controlled as possible. The cryoscope, which will be contained in a closed freezer, will need to emit the measured data via bluetooth outside the freezer for online analysis. Design an application for cell phone using the PhyPhox app that allows to capture via bluetooth the temperature data measured by an Arduino microprocessor to be able to analyze them online.