Leave Out the Magnetic Bar When Weighing Magnetic stirring is used universally in chemical laboratories, and often the magnetic bar is left in the container during weighing operations and treated as a part of the tare. I have found, however, that the bar itself can introduce significant errors in weighing. A series of ex~erimentswas done with three sizes of Teflon'coated stirring hars 0 x 2 A ( 6 , and 1'2 X I . ; in.1, using Imth single-pan merhani~31 (one M,
The Daw Chemical Company Midland. MI 48640
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Journal
of
Chemical Education
