B Determining Capillary-Tube Melting Points

Preparation Sign in at www.cengage.com/login to answer Pre-Lab Exercises, access videos, and read the MSDSs for the chemicals used or produced in this procedure. Read or review Sections 2.7 and 2.9. Plan to prepare two melting-point tubes if you are determining the melting points of unknown compounds. 

Apparatus Capillary melting-point tubes, packing tube, and melting-point apparatus. 

Protocoi Select one or more compounds from a list of available compounds of known melting point and determine the melting-point ranges. Repeat as necessary until you obtain accurate results and are confident with the technique. 

Protocol Accurately determine the melting range of an unknown pure compound supplied by your instructor. 

Sample Preparation Prepare a sample for mixed melting-point determination by introducing 5-10% of a second substance as an impurity into a solid whose 

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