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Unformatted text preview: ir stoppers
and/or stopcocks can be forced out, spilling the liquid. It is even possible for pressure
to burst the vessel.
Use a separatory funnel correctly; if it is equipped with a glass stopcock, make sure
that it is lubricated before using it in an extraction procedure. (Teflon stopcocks
should not be lubricated.) When using a warm or hot extractant in a separatory funnel, wait until the extractant has cooled before continuing with the extraction. When
using a volatile solvent in a separatory funnel, you should first swirl the unstoppered
separatory funnel to allow some solvent to vaporize and expel air. Then close the funnel, invert it with the stopper held firmly in place, and immediately open the stopcock to release air and vapor. Do this with your hand and fingers firmly holding the
barrel of the stopcock in place to keep the stopcock plug securely seated.
Do not vent the separatory funnel near a flame or other ignition source. And of
course, direct the vapors away from yourself and other people; preferably direct them
into a laboratory hood. Then close the stopcock, and with the separatory funnel
inverted the entire time, shake with a swirl and immediately open the stopcock to
vent the air and vapor. Repeat as necessary, following the same venting procedure. If
it is necessary to use a separatory funnel larger than 1 liter for an extraction with a
volatile solvent, the force on the stopper may be too great and expel it. Consider performing the extraction in several smaller batches. Refrigerators
Refrigerators used for low-temperature storage of laboratory chemicals should be
labeled for such use and must be explosion-proof. Never use household refrigerators
for chemical storage.
Laboratory chemicals stored in refrigerators should be placed on a spill tray with
edges sufficiently high to contain the spilled contents of any containers that are
placed in the tray. Always seal and, if possible, double-package all chemicals to be
stored in refrigerators; label each chemical legibly with the name of the material, the
date placed in th...
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This document was uploaded on 02/27/2014 for the course PHYS 1B at UCSD.
- Spring '07