3 General Chemistry 3.2 Molar Mass
Determination of molar masses via a measurement of the boiling point elevation (ebullioscopy)
P3021900
Equation to demonstrate the ebullioscopic constants of solvents with known molecular weight.
Principle
Apparatus for elevation of boiling point
Didactic setup to train and demonstrate the determination of molar masses by way of a measurement of the boiling point elevation. The boiling point elevation of aqueous solutions of different substances is determined using. The ebullioscopic constant of water is calculated from the experimental results. Tasks 1. Determine the boiling point elevation of aqueous solutions of different substances. 2. Calculate the ebullioscopic constant of water from the experimental results. What you can learn about ▪ ▪ ▪ ▪
Molar mass Boiling point elevation Ebullioscopy Ebullioscopic constant
Main articles Temperature meter digital, 4-2 Heating mantle for roundbottom flask, 250 ml, 230 V, with safety switch Apparatus for elevation of boiling point Desiccator, Wertex, diam. 150 mm Power regulator Temp. probe, immersion type, Pt100, stainless steel, -20...+300 °C Set of Precision Balance Sartorius CPA 623S and measure software, 230 V
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Function and Application Apparatus for determining molar mass, boiling point method.
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Equipment and technical data: ▪
2 glass vessels of DURAN glass. The outer vessel has an inlet for introduction of vapour from the solvent mixture.
A thin tube lies along the side of the inner vessel almost reaching the bottom. This also allows the circulation of the escaping vapour. 36820-00
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