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The gas is likely to be…
Goes out completely
Carbon dioxide or nitrogen
Re- ignites or glows brighter sometimes oxygen
accompanied by a “pop”
Explodes (in the form of a loud “pop”) but hydrogen
does not glow brighter
To perform this test, there are only a few things to keep in mind. Be sure the test tube or
container is set in a holder; not held by you. If you are holding it and it “pops,” you could be
Dakota State University Page 43 of 232 Basic Laboratory Procedures General Chemistry I and II Lab Manual startled into dropping it. Simply take a glowing splint (looks like a tongue depresser), and start it
on fire in a Bunsen burner. Allow it to burn for a few moments, so when you gently blow or
shake it out, the wood is hot enough to continue to glow. Put the glowing part of the splint into
the top of the test tube or container, but do NOT drop it or allow it to touch the liquid (remember
you are testing the gas, not the solution). Note the IMMEDIATE reaction of the splint; if you
wait too long, there will not be enough oxygen to support the glow, and the splint will give a
false-positive for carbon dioxide or nitrogen.
Remember that the hydrogen test is an explosion; we must keep it contained. Never use
any container other than a test tube unless otherwise instructed to do so.
Like the pipette, the buret is a precision instrument for measuring volumes of liquid.
However, the buret is different in two major differences; first, the volume it measures is variable.
Secondly, even though the buret is often read to four significant figures as well, it is not quite as
accurate as the pipette. Because of human error, there tends to be larger variance in the last
Careful inspection of the buret reveals that the
volume measurements appear to be “backwards”,
with 0 at the top, and the maximum volume (we will
use mainly 50 mL burets) at the bottom. This is
because the buret is designed to show how much
volume has been delivered, rather than how much it
contains (like a graduated cylinder, for example).
There is a special clamp and ring stand for use
with burets. Because burets are primarily used for
titrations, and titrations usually require the ability to
see a color change (indicating the endpoint), when you use a buret, you want to take a ring stand
with a white ceramic base. Avoid using these ring stands for anything else, because the more
stained they become, the harder they are to use. The clamp has two positions for burets, and is
designed to hold the buret(s), and to be very easy to
take the burets out of the clamp. This is for safety
reasons; you must never fill a buret while it is in the
Notice the valve at the bottom. The valve is
open when it is parallel with the buret (vertical), and
closed when it is perpendicular (horizontal). Begin
by cleaning the buret by standard methods. To fill
the buret, take the buret out of the clamp. Check
the valve to be sure it is closed. Pour the reagent
from a beaker into the top of the buret. A funnel
may be used if necessary, but is discouraged
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