Organic 2 Review Problem 77

Organic 2 Review Problem 77 - METHODS A ND M ANIPULATION 61...

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METHODS AND MANIPULATION 61 of the capillary tube, then remove the source of heat and, as the bath cools, take as the b.p. that temperature at which the liquid recedes into the inverted tube B. Determination of Melting-points. The determination of the melting-point, as described on pp. 2-4, is of course in itself a micro- method. Even so, when working on a very small scale it is advantageous to use either: (a) Electrically heated melting-point apparatus (Fig. 33), or (b) Microscope hot stage apparatus (Fig. 34). (a) Electrically heated melting-point apparatus. With this type of apparatus (Fig. 33) high temperatures can be reached with safety and the dangers of hot oil or concentrated sulphuric acid are avoided. Electric Light Bulb m.p. Tube Thermometer FIG. 33- fixed in front of the horizontal tunnel so that minute changes can be A metal cylinder A contains two small holes. Into one of these the thermometer, is placed and into the other (arranged centrally) is placed the melting-point tube. The
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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