From: fosselius@sbcglobal.net
Date: Sat Oct 09 2004 - 16:55:39 PDT
Message-ID: <000b01c4ae5b$7b100180$93e87d43@Nicodemus> From: <fosselius@sbcglobal.net> Subject: Re:Burets Date: Sat, 9 Oct 2004 16:55:39 -0700
Yes, Rebecah
The (old) glass stoppered burets must be lubricated (petroleum jelly if you
don't have a tube of Silicone grease) just a tad on the narrow end of the
taper and a tad on the wide end, avoiding any where the holes meet.
Remember "reading the bottom of the meniscus"? A piece of electrical tape on
a 3x5 card brought up below the meniscus horizontally and behind the buret
will help make the meniscus stand out.
It's also helpful, if you don't have o-rings or locks to hold the taper in,
to manipulate the stopcock with the opposite hand--meaning hold the handle
with the fingers of the hand surrounding the valve, rather than the hand on
the same side of the valve as the handle. This helps hold the taper in its
socket.
No lubrication on Teflon needed.
Nearing the end point, you can add "half a drop" to the flask by letting it
out to hang on the buret tip and touching to the (in)side of the flask,
(washing down with your distilled water wash bottle).
George Fosselius
shop guy Summer Teacher Institute, retired chem techer
reply to: george@mdsc-ic.org
This archive was generated by hypermail 2.1.3 : Mon Aug 01 2005 - 16:06:45 PDT