GENERAL LABORATORY
INSTRUCTIONS
All laboratory work involves common consideration for the safety and
convenience of oneself and others. In addition, certain laboratory techniques
are so common and some procedures such as record-keeping so important
that they apply very generally to chemical experimentation in research or
course work. These topics are brought together in this and the following
sections.
Safety
The potential hazards associated with laboratory work are serious, and every effort
must be made to avoid accidents. It is not enough for us simply to say "be careful,"
because you may not be sufficiently informed about the materials and practices for which
care is needed. The following list itemizes the precautions that must be taken to
minimize danger to yourself and others.
1. Undertake no unauthorized experiments.
2. Wear safety glasses.
3. Wear shoes that fully cover the feet; sandals are inadequate.
4. Wear protective clothing; lab aprons or lab coats are best, but old clothes are
satisfactory.
5. Know the location of these pieces of equipment and how to operate them.
(a) fire extinguisher
(b) safety shower
(c) eye fountain or spray
6. Observe the following simple laboratory practices.
(a) Never taste a chemical.
(b) Never pipet a liquid by mouth; always use a rubber bulb.
(c) Never smell the vapors of a chemical except by gently fanning some
of the vapors toward your face; do not breathe deeply.
(d) Never generate poisonous or strongly irritating gases except under a
hood that has strong ventilation.
(e) Never pour water into a concentrated acid; always slowly pour the
acid into the water with stirring.
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(f) Never heat material in a test tube unless the mouth of the test tube is
pointed away from both you and your neighbors; even so, heat gently
on the side rather than the bottom.
(g) Never insert glass tubing into a cork or rubber stopper unless the end
of the tube is fire-polished, the glass and rubber are lubricated with
water or glycerine, and your hands are protected by toweling and held
away from the end of the hole through which the tube will emerge.
If an accident does occur, you should be prepared to cope with it as adequately as
possible. The following list includes basic first aid instructions. The first aid cabinet is
located in the stockroom. All accidents must be reported to the instructor.
1. If a person's clothing catches on fire, he or she should go (or be guided to) the
safety shower and be drenched. Do not run or permit her or him to run.
2. If a fire occurs at the laboratory desk, get a CO2 fire extinguisher as quickly as
possible and direct the CO2 at the base of the fire, not at the flames.
3. If chemicals get into the eyes, immediately drench the eyes with water,
preferably at an eye fountain or eye spray. Assist any person who cannot see to do this by
himself or herself. Do not be concerned about possible loss of contact lenses; it is crucial
to drench the eyes first and look for the lenses later if necessary. If there is any question
whatever about possible harm to the eyes, immediately consult a doctor at the Student
Health Services or in private practice. Especially in the case of an alkaline solution in the
eye, it is a poor policy to "wait until tomorrow."
4. If concentrated acid splashes on skin, wash it off immediately with water
followed by application of a sodium bicarbonate solution. In case of serious acid burns
(blisters) or the involvement of extensive skin area, see a doctor as soon as possible.
5. If small burns (blisters) are suffered because of picking up hot ironware or
glass tubing, for example, wash the skin and apply a small amount of ointment that
contains a local anesthetic. Butesin picrate is a good common ointment. This is available
in the first aid cabinet in the Stockroom
6. If minor cuts are suffered, wash thoroughly, apply some effective antiseptic
(available in the first aid cabinet) and cover with a Band-Aid. Major cuts and profuse
bleeding should be treated by a doctor.
7. No student should be permitted to go by himself or herself to Baxter Medical
Building.
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Cleanliness
The chances of accident will be reduced and the chances of good analytical results
will be increased if the laboratory is kept in shipshape condition and habits of neatness
are developed. The following practices will contribute to achieving this objective:
1. Waste materials should be disposed of in the proper manner:
(a) Acids, bases and soluble solids should be poured into the sink and
down the drain along with a large excess of running water.
(b) Certain materials will need to be disposed of in special hazardous
waste containers. Your instructor will inform you in these instances.
(c) Paper, used matches, broken glass, and insoluble solids should be put
in the special containers provided for this purpose, not in the sink.
2. Spillage at the side shelf or reagent shelf should be cleaned up immediately by
the person who does the spilling; it takes but a minute.
3. When taking chemicals from a bottle, either hold the stopper between the
fingers, Fig. 1(a), or, if possible, lay it on its flat top, Fig. 1(b). Do not leave it on its side
on the bench top. Never interchange bottle caps or stoppers.
4. Take only the amount of a chemical that you really need from a bottle. In case
you take too much, do not return the excess to the reagent bottle so that the possibility
of contaminating the entire bottle is avoided.
Figure 1
5. A liquid should not be removed from a reagent bottle by inserting your
pipet into the bottle. Pour the approximately correct amount into a clean dry beaker or
flask and pipet the correct amount from this container, discarding any excess.
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6. It is especially important that the analytical balances be cleaned immediately
when chemicals are spilled in or near the balance. These delicate and expensive
instruments can be seriously and permanently corroded by chemicals which are not
quickly cleaned up.
7. Hang extra clothing (coats, hats, rain protection, etc.) in the area provided for
the purpose; do not lay them on desk tops, etc.
8. Do not waste distilled water.
Consideration
It is a matter of courtesy that consideration be given to the others who share the
laboratory with you. In particular, you should:
1. Wash your desk top and wipe it dry before you leave the lab for the day.
Leave it the way you would like to find it when you come to the lab.
2. Leave at the side shelf the reagents that are used in common by the whole
class. Do not take them to your desk for your personal convenience. If you spill a
reagent, please clean up the spillage immediately.
3. When people are waiting to use the electronic analytical balances, especially at
the beginning of an experiment, only do one weighing so that others will have a chance to
get started on the experiment. Subsequent weighings usually do not introduce a serious
conflict in the use of the balances. If you spill a chemical in or around a balance, please
clean up your spillage immediately.
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