A Thermal Analysis Experiment for Introductory Chemistry A simple eutectie phase diagram experiment using biphenyl and naphthalene has recently 41, 96 (1964)). We have found the preperetion of the tin-lead been reported (THISJOURNAL, phase diagram to he adaptable as a group experiment for the generd chemistry laboratory. Each pair of students was issued a n &in. Pyrex test tuhe containing 100 g of pure lead or tin or aepeeified mixture of the two components. An empty 400-ml beaker is supported on an asbestos pad on the ring of a ring stand. The test tuhe clamped to the stand is positioned 1 in. from the bottom of the heaker. A 360°C thermometer, in P p e x tubing sealed a t one end as a well, is used to measure the temperature. The well tube also can he used as a stirrer. The contents of each tuhe is heated to 350°C by directing the flame onto the lower rrortion of the test tuhe. Vermiculite or elass wool is thenolaced around the test tuhe. ~emperaiuresare recorded every 15 see until 180°C is reached. & o h g curves are drawn. From the assemhled data, each student plotted two phase diagrams, one using weight per cent and a second using mole fraction.
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