This preview shows page 1. Sign up to view the full content.
Unformatted text preview: 6 2 PRACTICAL ORGANIC CHEMISTRY C, is then placed firmly on the slide. The latter is then inserted into the stage in such a position that the sample is directly above the light opening. A glass baffle, B, is placed over the sample, so as to protect the microscope lens from too much heat. A large glass cover is then placed completely over the rim B. The sample is now brought into sharp focus and the temperature raised by adjustment of the rheostat. As usual when taking melting-points, the temperature should be almost stationary at the actual melting-point. FIG. 34. Heating under Reflux. For this purpose, a glass water-condenser of length ca. 25 cm. can be used. When boiling very small volumes of liquid under reflux, the "cold finger" A (Fig. 35) is of great value. The cold finger, if provided with a shoulder, can rest on the rim of a test- tube or flask, or it may be inserted through a cork having the usual groove cut in the side to allow escape of gas (cf. Fig. 37)....
View Full Document
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.
- Fall '06
- Organic chemistry