1 Your Safety in the
Laboratory
THE LAB AS A WORK ENVIRONMENT
All of us remember accidents that have happened in our
own home. Perhaps we cut ourselves with a knife or were
scalded with hot water while draining the spaghetti. Maybe
we lost control of a power tool or a small child managed to
open a bottle of cherry-flavored cough syrup.
In a sense, the chemistry lab is a safer place to work than
your own home. Most accidents which are likely to happen
have been foreseen and preparations have been made to
deal with them. Fire extinguishers, eyewash equipment and
safety showers are nearby and kept in working order.
Chemicals are clearly labeled to describe their hazardous
nature. Materials to clean up spills are readily available.
Your instructor will remind you when a particularly
dangerous situation exists. You will be wearing safety
goggles. And you will be working in the company of others if
you need help.
Nevertheless, the kinds of hazards you will be exposed to in
the lab are somewhat different and more numerous. You
will encounter a number of new and unfamiliar substances.
You will need to know how to dispose of unwanted
chemicals, and where routinely used equipment is located
in the lab. The best addition to your safety in an already
safe environment is to be personally knowledgeable and
prepared.
Finally, remember that you are part of the laboratory work
environment. Your diligence in preparing yourself for the
work you are scheduled to do that day, and the rigor with
which you observe the recommended procedures and
precautions, help create a safe place both for yourself and
your colleagues.
2011 update
2 BASIC FIRST AID
1
Working with glassware carries with it the chance of being cut by
broken glass. Clean the wound by letting some blood flow and
washing the cut with clean water. Then apply pressure to stop the
bleeding, using your hand until you can obtain a piece of sterile
gauze. Most bleeding will stop within a few minutes. If the
bleeding is from a foot, hand, leg or arm, elevate the limb so that it
is higher than your heart. Lastly, report the injury and get First Aid.
2
Use cool tap water, not ice, to cool down a burn on your skin.
Report the injury and, if necessary, get First Aid. If your clothing
catches fire, stop, drop and roll to smother the flames. If a safety
shower is nearby, don't hesitate to douse yourself with water.
3
When working with chemicals, and before an accident happens, read the hazard
information on the label to prepare yourself to deal with a chemical bum or spill.
If you spill hazardous chemicals on your skin that might cause burns or
irritation, or might be absorbed through your skin, immediately rinse the
affected area with cool tap water for 15-20 minutes. Meanwhile, report the
accident to your instructor or the technician to get advice about any possible
threat to you from the chemical, and to have a neutralizing agent applied if
appropriate. You may need to remove clothing contaminated with hazardous
chemicals in order to get the substance away from your skin.
If you get chemicals in your eyes, flush them immediately with water from the
eyewash fountain for 15-20 minutes, then get immediate medical attention.
Remember that a person who has an irritating chemical in his or her eyes is
temporarily blinded and may be panicking, making it almost impossible for
him or her to find and operate the eyewash fountain effectively without
assistance. So, if it happens to you, get help. And if it happens to someone
near you, be ready to lead the victim to the eyewash fountain, help him or her
to turn on the water, and direct the flow into his or her eyes while keeping
them open. Summon your instructor at once.
4
If you feel faint, sit down. Notify the nearest person. Put your head between your legs
to allow blood to flow toward your head. If you remain conscious
and feel better, have someone escort you outside to get fresh
air. Try to determine why you felt faint so that, if possible, the
staff can learn and correct the cause.
3 QUIZ --Part I
(Record your answers on the Quiz Answer Sheet, page 27, or on a Scantron Test Form,
as your instructor requests.)
1) A student cut herself on a broken beaker. She immediately applied pressure on the wound
and informed her instructor. What should she have done first?
a) Informed her instructor right away.
b) Begun cleaning out the wound.
c) Sat down to avoid fainting.
2) What is the first thing you should apply to a heat burn?
a) Spray anesthetic.
b) Ice water
c) Cool tap water
d) Rubbing alcohol.
3) What kind of accident involving chemicals requires that you get medical attention
immediately after rinsing the affected part of the body for 15-20 minutes?
a. Chemicals in your eyes.
b. Acid splashed on your arm.
c. Chemicals that release toxic or irritating fumes.
d. Any accident involving chemicals.
4) If you feel faint, the first thing to do is ...
a) Tell your instructor or a classmate.
b) Go outside and get some air.
c) Immediately sit down and lower your head.
PERSONAL HABITS
1
Cultivate a professional sense of safety, orderliness
and deliberate action. Read lab instructions before you
begin your work! Being well prepared in advance helps
promote efficient work and minimizes mistakes and
wasted time.
2
State and Federal regulations require you to wear
safety goggles It. where there is reasonable probability
of injury that can be prevented by such equipment." We
require that you purchase your own personal safety
goggles. They must be chemical splash goggles, the
kind approved by OSHA for working with chemicals, not
just for impact protection. Even at home safety goggles
are useful to have when you are working with tools,
solvents or strong cleaning solutions.
4 It also makes good sense to protect your clothing by wearing a lab coat, apron, or even
an old shirt. Shoes must be of the type which completely enclose your foot, top as well
as bottom, to protect your feet from spills. Shoes must be worn at all times when
working in the laboratory. You are required to wear gloves when handling carcinogens
such as chromates and dichromates. You would be wise to use them for many other
experiments as well
3
Report all injuries. Inform your instructor or the technician of any cuts, chemical
injuries and spills, foreign materials in your eyes, or personal discomfort.
4
Food and drinks are not permitted in the lab work area. It is easy for traces of chemicals to contaminate your hands as well as food or food containers without your
noticing it. Careful laboratory workers learn to avoid touching their face, mouth or
eyes, and they wash their hands frequently.
5
Use the sinks only for washing glassware and washing your hands. Keep used
matches, paper, glass, pieces of metal and other discarded solids out of the sinks.
6
Do only the experiments you are assigned, and under supervision! Chemical reactions
are sometimes violent and unexpected, and even experienced scientists can be
suddenly surprised by sudden and unexpected chemical or physical changes which
can cause serious harm.
Students themselves can be laboratory hazards if they
come to work unprepared, neglect safe practices, or
possess a penchant for mischief.
Examples of immature or dangerous behavior include
such things as mischievous use of a wash bottle,
annoying a classmate with some noxious substance, or
endangering others or their possessions with corrosive
or poisonous chemicals. Our policy is to remove such
hazardous individuals from the laboratory, and summon
security personnel if necessary to escort the offender
from the premises.
QUIZ --Part II
5) Wearing of safety goggles while working in the lab is actually required by State Law.
a) True.
b) False.
6) Drinking a cup of coffee during an early morning chemistry lab to help you remain alert is
acceptable laboratory practice as long as you keep the coffee at least three feet away from
any chemicals or apparatus.
a) True.
b) False.
5 7) Doing a non-assigned or non-supervised experiment of your own design is ...
a) Permitted and encouraged if you have finished your assigned work and have extra time.
b) Not permitted at any time.
c) Punishable by death.
USE OF THE LABORATORY
To begin with, acquaint yourself with the layout of the chemistry lab and the surrounding
workrooms and preparation area, especially the location of the safety equipment. Select the
floor plan below which corresponds to the lab you will be using (1802 or 1805), then locate
and mark the following features, using the abbreviations suggested.
6 REACTING TO EMERGENCIES
1
Don't panic! Panic may nullify your best intentions. Staying calm is important in order
to control the situation and allow you to be helpful to others.
2
Chemicals on your skin should be washed off immediately with tap water. Most
chemicals enter the pores of the skin to some extent but are not immediately harmful.
Some chemicals irritate the skin and even decompose it. A few can even penetrate
the surface of your skin and enter your bloodstream.
3
The label on the bottle, which you must read before you use the chemical, will have
given you clues about the type of action you may need to take. But the general rule is
this: Flush your skin with running water for 15-20 minutes. Alert your instructor or the
technician to determine whether further attention is needed, or whether a neutralizing
compound (a solution of baking soda for acids on the skin or clothing, household
vinegar for bases) needs to be applied.
Chemicals on your clothing need to be washed off, especially if the clothing brings the
chemical in contact with your skin. You may also need to remove the article of
clothing, and your instructor or technician will help you do this with as much privacy as
possible under the circumstances. The safety shower should be used if the chemical
you spill on your skin or clothing is highly corrosive, such as concentrated sulfuric acid.
Keep in mind that the shower delivers about one gallon of water per second, and does
not shut off until you forcefully push the handle upward.
Be sure to alert your instructor or the technician of any such accident!
4
Remember that a person who has an irritating substance in his eyes is temporarily
blind, and may be panicking. That person must get to an eye wash station immediately, and needs your help both to get there and to operate the device. Ideally, he
should have to be preoccupied only with holding his eyelids open in the stream of
water. A second person should be there to supervise the rinsing.
As in the case of a chemical spill on your skin, the
irritant should be washed out for 15-20 minutes. If
the irritant is a solid fragment, such as a chip of
glass, do not use the eye wash! Keep both eyes
shut and have someone take you to the hospital
immediately for professional attention. If you believe
the fragment is contaminated with a chemical, wash
your eyes without rubbing them and get help quick!
5
Many people routinely wear contact lenses, and if you do, there are some
important considerations to keep in mind. If you get chemicals in your eyes,
7 valuable response time can be lost trying to remove the lenses. Meanwhile, if the
chemical is drawn behind the lens by capillary action, greater damage to your eye
may occur. Furthermore, contact lenses are made of plastic: plastics absorb some
chemical vapors, and many solvents routinely encountered in lab work, especially
in organic chemistry, can readily dissolve plastics.
6
If a fire extinguisher ever needs to be used, leave that task to the college staff and,
after alerting the staff and others, evacuate the area. However, here is useful information regarding fire extinguishers.
Both fire extinguishers in this building are
suitable for fighting Class A, Band C fires
(see the chart at the left). Dry chemical
extinguishers discharge a very fine
powder, ammonium phosphate, which
smothers a fire like a blanket, but leaves a
big mess.
Halon fire extinguishers are sometimes
used near electronic equipment. This type
discharges a colorless gas which is
heavier than air and also smothers flames
by displacing oxygen in the room, then
dissipates into the atmosphere. But it can
also smother you if you inhale it in a
poorly ventilated room. Also, Halon
chemicals are hydrocarbons which may
react with some burning materials and produce toxic by-products of combustion. They also
cause damage to the earth's ozone layer. We no longer have Halon extinguishers in our
science labs, but if you must ever use a Halon-type extinguisher, evacuate the room as soon
as the fire is out.
8 If you ever need to use a fire extinguisher, remember to pull the locking pin or
ring, aim the nozzle at the base of the fire and squeeze the discharge handle or
trigger. Remember the acronym, "PASS"Pull the locking pin or ring
Aim the nozzle at the base of the fire
Squeeze the discharge handle
Sweep back and forth to cover the conflagration
7
A non-combustible fire blanket is stored in a red metal box on the wall near the safety
shower and eyewash fountain. If your clothing catches fire, stop, drop and roll to
smother the flames. If a safety shower is nearby, don't hesitate to douse yourself with
water. We are required to keep a fire blanket on hand, but in an emergency, going
quickly to the blanket box will just fan the flames, and you would need help from a
bystander to remove it from the box and wrap yourself in it. In addition, one
disadvantage of fire blankets is that they may create a chimney effect when they are
wrapped around your body and cause oxygen to be sucked in at the bottom, thus
accelerating the burning.
QUIZ –Part III
8) Before working with any chemical, you should know its hazards. But if a chemical does get
into your eyes, the first thing you should do is...
a) Keep your eyes closed and get medical attention.
b) Immediately flush your eyes with running water at the eye wash fountain.
c) Inform your instructor or technician and get medical attention.
d) Wipe your eyes with tissue paper.
9) In Question 8, the second thing you should do is...
10) Which of the following is the best advice about the wearing of contact lenses in the
laboratory?
a) If a chemical gets in your eye, the contacts should be removed immediately.
b) If a chemical gets in your eye, the contacts should be left in place to protect the cornea.
c) Contacts may be worn in place of safety goggles. d) It would be better not to wear contact
lenses at all.
9 11) If you spill a chemical on your skin and clothing, you should remove the affected parts of
your clothing and rinse your skin and clothing for 15-20 minutes, and use the safety shower if
necessary and it is nearby. What else should you do?
a) Alert your instructor or the technician.
b) Warn other students about the spill if it affects their work area.
c) Consider whether a neutralizing compound is necessary in addition to water.
d) All of these.
12) A Halon-type fire extinguisher smothers flames by releasing...
a) A white powder which is relatively harmless.
b) A colorless liquid which doesn't burn.
c) A colorless gas which is hazardous to breathe.
13) What kind of extinguisher is OK to use on electrical equipment and computers?
a) Dry chemical.
b) Dry chemical or Halon
c) Halon or powder.
d) Powder or dry sand.
14) What kind of extinguisher is OK to use on water-reactive chemicals, such as burning
sodium, magnesium, or phosphorus?
a) Water.
b) Dry chemical or Halon.
c) Halon or powder.
d) Powder or dry sand.
PROTECTING CHEMICALS FROM YOU
1
Before we discuss the ways chemicals can harm you, let's mention some of the
ways you can harm the chemicals!
The chemicals you will use in the laboratory possess a degree of purity which will
guarantee dependable performance in your experiments. It is important to maintain the
integrity of these chemicals by avoiding contamination. It is easy to inadvertently
contaminate a perfectly good solid chemical or solution by using a contaminated scoop
or dropper when measuring it out; by setting the jar cover or bottle cap on your work
surface in such a way that contamination from the surface can be picked up; or by
adding the chemical to a test tube or beaker which has not been kept clean.
2
Another common mistake is to return a chemical to the container from which it supposedly came --often the chemical ends up in the wrong container. So never return a
chemical to its container. Look for a waste container designated for that chemical, or
offer it to another worker who might need more.
10 3
Leaving the top off a jar or bottle can also change the composition of a chemical. Some
chemicals absorb moisture from the air, notably sodium hydroxide and calcium chloride.
Some which are supposed to contain water of hydration may lose some of the water into
the atmosphere. In both cases, this change in the mass of the chemical causes slight
weighing errors which can be critical in careful work. Sometimes an entire bottle of
chemical can be rendered useless.
Other chemicals, especially sodium hydroxide, also absorb carbon dioxide from the
atmosphere and actually change into a different chemical (sodium hydroxide becomes
sodium carbonate). Others, such as sodium sulfite, react with the oxygen in the air and
deteriorate. Some chemicals are so sensitive that air in their containers should be purged
and replaced with a non-reactive gas, such as nitrogen or argon, prior to storage.
4
Some chemicals tend to release vapors into the atmosphere. For example, hydrochloric
acid is actually a solution of hydrogen chloride gas in water. Irritating, corrosive fumes of
hydrogen chloride readily escape from the acid into the laboratory atmosphere, which not
only makes the air in the lab unhealthy to breathe but also weakens the concentration of
the acid. Ammonia, chlorine, bromine and iodine dissolved in water also gradually escape
into the air, again weakening the concentration of the solution and eventually rendering
the solutions useless. Some chemicals, such as iodine, silver nitrate and potassium
permanganate, are affected by light and must be kept in dark bottles. For all the
reasons cited above, get in the habit of keeping the jars and bottles tightly closed
when you have finished using them.
QUIZ --Part IV
15) One of the following choices is the wrong thing to do with some chemical which you no
longer need for your experiment. Which choice is the wrong one?
a) Carefully pour it back into the original supply bottle.
b) Offer it to a student who might need more of the same chemical.
c) Pour it into a special container designated for chemical waste.
16) One example of a chemical which can absorb water from the atmosphere and actually
dissolves in that water is...
a) Hydrogen chloride.
b) Sodium hydroxide.
c) Sodium sulfite.
d) Iodine.
17) One example of a chemical which can absorb carbon dioxide from the atmosphere and
thereby change its chemical composition is...
a) Calcium chloride.
b) Sodium hydroxide.
c) Ammonia.
d) Silver nitrate.
11 18) One example of a chemical which can escape into the atmosphere if its container is not
tightly stoppered is…
a) Sodium carbonate.
b) Potassium permanganate.
c) Hydrogen chloride.
d) Silver nitrate.
19) One example of a chemical which, if not properly stored, can both escape into the
atmosphere and deteriorate by exposure to light is…
a) Hydrogen chloride.
b) Sodium hydroxide.
c) Sodium sulfite.
d) Iodine.
HAZARDS OF USING CHEMICALS
1
Chemicals can be hazardous to you in four principal ways: they can be toxic,
flammable or combustible, capable of reacting with other chemicals in a dangerous
way or corrosive to your skin, mucous
membranes and clothing.
There are chemicals around the house which
fall into one or more of these categories. Most
insecticides, weed killers, cleaning agents and
solvents are poisonous, and even medicines
and vitamins taken in excess dosages can
make you seriously ill or even kill you. Some
substances, like household ammonia, release
vapors which might harm you and irritate your
throat and nasal passages. Some can pass
directly through your skin into your fatty tissues
and bloodstream.
2
Gasoline, fingernail polish remover, ordinary
rubbing alcohol are examples of flammable
chemicals commonly found in households.
3
Many chemicals react with other chemicals. Baking soda reacts with acids to produce
a gas which causes baked goods to rise. Acids and moisture also react with metals,
causing corrosion. Some fertilizers need to be kept away from combustible materials
to avoid a fire. Some household chemicals react together to produce harmful gases or
explosions. People taking certain medications are warned to avoid taking them in
combination with alcohol or other medicines, because of harmful interactions which
might occur inside their bodies.
12 4
Lastly, many household chemicals will attack your skin, such as battery acid or drain
cleaners, or at least cause irritation, a rash, or an allergic or toxic reaction.
UNDERSTANDING LABELS
1
Most of the chemicals you will use in the laboratory are reasonably safe to use if they
are used in the way prescribed in your experiments, and if you follow the most basic
rules about handling chemicals.
The label on a jar or bottle of a chemical tells you certain· important information you
need to know in order to use that chemical safely. Read the label before you Use the
chemical. The chemical whose name is on the label illustrated above is sodium
sulfide. But it is not the same as "sodium sulfite" and "sodium sulfate", which are
different chemicals having similar names but important and significantly different
chemical behaviors and hazards.
2
In many instances, a chemical will be referred to by its chemical formula rather than by
its name. For this reason, and also because of the similarity between the names and
formulas of some chemicals, it is wise to glance at the formula to double-check your
selection of the correct chemical.
3
Solutions or dilutions of a chemical will be indicated by a symbol in the lower left
corner of the label. Household hydrogen peroxide is a 3% dilution in water; household
bleach is a 5.25% solution of sodium hypochlorite in water. Percent concentration tells
you how many grams of a substance are dissolved in 100 milliliters of the solution. In
the chemistry laboratory, a unit of concentration called molarity is very commonly used.
This measurement of concentration is based on the formula weight of the chemical, and
tells you how many "moles" of a substance (or fraction of a "mole"), expressed in grams
are dissolved in one liter of the solution. The concept of the "mole" is something very
13 important which you will learn about later in your study of chemistry. The symbol for
molarity is M or M. A simple way to estimate the concentration of a chemical by its
molarity is to remember that the lower the number, the lower the concentration.
Concentrated sulfuric acid is 18 M; concentrated hydrochloric acid is 12 M; frequently
used acids and bases are kept on hand in dilutions of 6 M. The most commonly used
dilution of chemicals in our laboratory is 0.1 M. But regardless of whether the
concentration appears to be high or low, potential dangers should not be ignored; be
sure to read the label before using any chemical.
Choosing the correct concentration is very important. Dilute sulfuric acid (usually
labeled "6 M" or "3 M") mixed with water produces little or no reaction, while concentrated sulfuric acid (18 M) mixed with water will get dangerously hot. Some
reactions will not take place or may not be observable unless the concentration of the
reactants is correctly chosen.
4
On the right half of the label you will find a signal word and a brief description of the
hazardous nature of the chemical. Sometimes there follows a summary of the precautions you should take in using the chemical, and steps to be taken if you spill the
chemical on your skin, clothing or work area.
5
More information about the hazards of the chemicals you will work with is available
from Material Safety Data Sheets (MSDS), which the technician has on file in the
preparation room. Don't hesitate to ask your instructor or the technician to see them.
A copy of a typical MSDS sheet is included on pages 23-24.
UNDERSTANDING THE HAZARD CODE
1
Finally, there is a 4-digit code at the upper right corner of the label which gives you a
quick overview of the potential hazards of a chemical. This assumes, however, that
you know how to read the code.
The first digit describes the chemical's potential to harm your health --that is, how dangerous
it is if it be swallowed, inhaled, or absorbed through your skin.
The second digit tells you whether the chemical is a flammable substance. The third
whether it reacts with other chemicals, and the fourth, whether it is a contact hazard, that
is, corrosive to your skin, mucous membranes or clothing.
14 On a scale of zero to four, a higher digit indicates a greater the hazard. A '4'
designates an extreme hazard, '3' a severe hazard, '2' a moderate hazard, and '1'
only a slight hazard.
Furthermore, you might see on the label an additional
label warning you about a carcinogen (a substance
which causes cancer), a substance that must be kept
away from water, or some other unusual property.
2
The National Fire Protection Association (NFPA) uses a similar system of labeling
chemicals, as well as storage areas and trucks conveying chemicals. This symbol is
diamond-shaped. The rating numbers, however, might not be identical to those· you
see on labels in the lab, since the NFPA code is directed at the needs of firefighters,
not chemists. Also, the digit in the bottom-most quadrant is replaced by an
abbreviation for special information. "COR" stands for corrosive, "e" for carcinogen, 'V'
for chemicals which release harmful vapors, "OXY' for a special
class of reactive substances known as oxidizers, and so on.
Furthermore, different manufacturers of chemicals might use a
similar 4-or 5-digit code but rate the degree of hazards
differently, so don't expect complete agreement.
QUIZ --Part V
20) An experiment calls for you to use "6 M nitric acid". The only bottle of nitric acid the
technician has placed in the lab is labeled "Nitric acid, 16 M". What is the best thing to do?
a) Assume that there is a misprint in the experiment directions and use the 16 M.
b) Consult the instructor or technician.
c) Dilute the 16 M acid to the correct concentration.
21) On a bottle of a chemical you might use in this lab, the space at the lower-left corner of
the label is reserved for…
a) The chemical formula of the substance:
b) The 4-digit hazard code
c) Information about the concentration
d) Safety and spill control information.
The next four questions refer to the illustrations of the labels on this page and the next page.
22) Which one of these chemicals is an extreme
contact hazard?
a) Barium chloride
b) Benzene
c) Hexane
d) Sulfuric acid
e) Potassium nitrate
15 23) Which one of these chemicals is an extreme health hazard?
a) Barium chloride
b) Benzene
c) Hexane
d) Sulfuric acid
e) Potassium nitrate
24) Which one of these chemicals should not be used
near an open flame?
a) Barium chloride
b) Hexane
c) Sulfuric acid
d) Potassium nitrate
e) Lead acetate
25) Which one of these chemicals is a reactivity hazard?
a) Barium chloride
b) Benzene
c) Hexane
d) Potassium nitrate
e) Lead acetate
26) Which one of the following hazard codes describes a
chemical which is a slight health hazard, a severe
flammability hazard, a moderate reactivity hazard, and a
slight contact hazard?
a) 0-2-1-0
b) 3-4-1-2
c) 1-3-0-2
d) 1-3-2-1
e) 2-3-1-0
CHEMICAL HYGIENE
1 Never bring food or beverages into the laboratory work area.
2 Avoid touching your face. Get in the habit of washing your
hands frequently while you work with chemicals, and especially
when you finish your work or pause for a break.
3 Never taste a chemical. If you are directed to smell a chemical
or the vapors emitted by a chemical reaction in a test tube, do
so by holding the bottle or tube about six inches away from your face, and use your other
hand to waft some of the vapors toward your nose. Approach the odors cautiously.
16 4 Avoid contamination! Never pour reagents back into their original containers. Estimate
in advance about how much of a reagent you might need and take only that amount
back to your work area in your own clean beaker, flask or test tube.
5
After you have removed the top from a bottle
or jar, avoid setting the top down. Either hold
the top between your fingers, or rest it on the
table so that the bottle-end does not touch the
table and risk picking up contamination.
6 Chemists often remove samples of
chemicals from a bottle by means of a glass
tube called a pipet ("py-pet"). It used to be
common practice to fill the pipet by mouth
suction. However, common sense warns
you that this is an unwise practice! Always
use a pipet bulb or an automatic pipet filler
when using a pipet.
7
Traces of chemicals are commonly found dripping down the sides
of a bottle, or in rings left behind on a work table where a bottle
once rested, or as residual dust scattered at your work area.
Some of these chemicals, such as sodium hydroxide or barium
chloride, are corrosive or poisonous. Some, like sulfuric acid,
never evaporate, but remain where they are spilled until some one
cleans them up accidentally up with their shirt sleeve or textbook
or lab report. Others, such as silver nitrate and potassium
permanganate, will stain your skin and clothing. Be aware of these
dangers and practice chemical hygiene.
8 If you notice a spill or some broken glass, or water that
has been splashed on the floor, avoid an accident by
warning other students about the hazard and taking
steps to get it cleaned up.
QUIZ --Part VI
27) When smelling a chemical or the products of a chemical reaction, you should…
a) Swirl the substance around several times in the test tube, place your nose up to the mouth
of the test tube, and inhale deeply.
b) Put a small amount on a ball of cotton and hold it under your nose.
c) Fan a little of the vapors toward your nose.
17 28) Select the one best answer: A stopper or cap from a reagent bottle should be ... while you
are removing a sample of the chemical.
a) Held in your hand or between your fingers.
b) Placed bottle-end down on the table.
c) Placed bottle-end up on the table.
d) Protected from contamination in whatever way is safe and convenient.
29) Which of these liquids is/are safe to draw up into a pipet using mouth suction?
a) Methanol.
b) Sodium hydroxide solution.
c) Sodium chloride solution.
d) Benzene
e) No chemicals at all!
GOOD LABORATORY PRACTICES
1 When using flammable liquids, make sure that there are no open flames anywhere in the
vicinity. If a flammable liquid needs to be heated, do so in a water bath or on an electric
hotplate, not over a flame, and preferably under a fume hood.
2 When mixing chemicals, it is a safe practice to combine them very slowly and tentatively
until you determine whether a vigorous reaction might occur. Never mix chemicals unless
the experimental procedure directs you to do so.
3 An old chemists' adage is: "Do what you oughta --add
acid to water." (Hint --Pronounce "water" as "waw-ta".)
Not the other way around. This really pertains to
chemicals which are heavier than water and react with
water, such as sulfuric acid or 50% sodium hydroxide.
When these chemicals are mixed with water,
considerable amounts of heat may be produced. If they
are poured into water, the heat will diffuse safely
throughout the water as the acid sinks.
On the other hand, if water is poured on top of them, the
water will tend to float on top of the chemical; heat will
build up at the interface between the acid or base and
the water, possibly causing the mixture to boil and spurt
out of the container, or causing a glass container to
break.
Sodium and potassium hydroxides are solid bases
which generate a good deal of heat when added to
water, and should be dissolved in small quantities at a
18 time, accompanied by constant stirring and even cooling the container in a bath of cold
water.
4 Treat glassware cautiously. Even though we use highly heat-resistant Pyrex glassware
almost exclusively, a hidden flaw may cause the bottom to fall out of a beaker, or a test
tube to shatter while it is being heated, even during normal use. Wear chemical splash
safety goggles rated for work with chemicals, not just for impact protection.
5 Wash your glassware after each use so that chemical residues do not dry on it and spoil
a future experiment. In the long run, it will also save you time. Often it is not necessary to
wash your glassware with detergent. Most chemicals can be rinsed away just with tap
water; then give your glassware a final rinsing with a small amount of demineralized
water to avoid questionable hard water spots.
6 If you ever need to insert a thermometer or a piece of glass tubing into a rubber stopper,
it is safer to lubricate the glass and the hole in the
stopper with a drop or two of glycerol, or even
water. Ordinary water is an effective lubricant if
you are connecting glass tubing to elastic tubing.
As an additional precaution, protect your hands
with a towel, as shown in the illustration above.
7 Review the correct way to smell a chemical, as
described on page 15.
8 A gas valve is "off' when the handle is at a full right angle to the nozzle. It is "on" when
the handle is lined up in the direction of the nozzle. This pattern is also true of the valve
on the gas meter outside your home - in case you ever need to shut off this valve in an
emergency. Always be sure to turn off the burner completely, so that explosive
gas does not slowly leak into the room!
9 Never walk away from a lighted gas burner, or
from an electric hotplate in use. If an accident
occurs while you are heating something --for
example, the contents of a beaker boiling over
or catching fire, or an electric hotplate shorting
out --immediately turn off the burner or unplug
the hotplate. Beware of any breeze that might
blowout a gas flame, allowing explosive gas to
leak into the room.
If an electrical device shorts out or begins
smoking,
immediately pull out the plug and inform the instructor or technician. Grasp the plug itself,
not just the cord.
19 10 Beware of anything hot! When moving hot objects, use the insulated gloves stored on the
utility counter in your lab. Your locker contains a wire gauze with a ceramic center. Use it
as a place to set down hot glassware, wire or tubing. Seldom can you tell something is hot
just by looking at it.
11 Apply heat gently to a test tube at first. Point tubes you are
heating away from yourself and your colleagues.
12 As a rule, reagent bottles should be used at the place
where they are stationed for the use of each student. Leave
them there; ordinarily, determine how much of a chemical
you will need, pour that amount into your own clean
container, and return to your work station. If it is necessary
to remove the bottle, return it immediately after you use it.
13 Never work in the lab unless you are being supervised by an authorized instructor. The
technician is not legally authorized to supervise your work. And
remember ...
QUIZ --Part VII
30) Which one of these is generally a bad laboratory practice?
a) Adding an acid to solutions containing water.
b) Heating a beaker of alcohol over a gas flame.
c) Heating a beaker of alcohol on a hotplate.
d) Inserting glass tubing into a hole in a rubber stopper.
31) A student is diluting concentrated sulfuric acid with water. Sulfuric acid is more dense
than water. She should…
a) While wearing safety goggles measure out the water, then the acid and slowly pour the
acid into the water while stirring the mixture.
b) While wearing safety goggles measure out the acid then the water, and slowly pour the
water into the acid while stirring the mixture.
32) When a gas burner is being used for heating…
a) It should always be attended and flammable liquids should be kept away.
b) It may be left unattended only for short periods of time.
c) You may use flammable liquids as long as you are keeping an eye on the burner and know
what to do in case of a fire.
20 33) The safer way to heat a solution in a test tube over a gas flame is …
a) To apply full heat for maximum effect.
b) To stopper the tube to prevent spurting or evaporation.
c) To heat it gently, move the tube around in the flame, and point the tube in a safe direction.
34) The best thing to do with hot glass is…
a) Put it on the cold table surface, away from anything combustible.
b) Wave it around in the air to cool it. .
c) Put it on a hot pad or wire gauze until it is cool enough to handle.
d) Hold it under running water to cool it down.
CLEAN-UP AND DISPOSAL OF CHEMICALS
1 Know, from reading the labels in advance and your
instructor's supervision, the hazards associated with each
chemical you are using so that, if you should spill a
chemical, you should have some idea about what clean-up
procedure to use.
2 California State law now says that NO chemicals can be
washed down the drain. All lab waste must be collected and
processed by experts in waste disposal.
Waste containers will be provided so that waste can be sorted
into categories for disposal:
a. Inorganic acidic reaction products – solids and aqueous solutions of salts, acids
and metal complexes that are acidic.
b. Inorganic basic reaction products – solids and solutions of various salts, bases,
and metal complexes that are basic
c. Organic/flammable – solutions with flammable, organic solutions. Halogenated
organics were once separated in the classroom, but now are separated at a
waste treatment facility. Non-halogenated flammable wastes are processed
and recycled by waste handlers. Halogenated wastes create toxic gases if
incinerated, so receive expensive, special treatment.
d. Solid waste residues- residues on filter paper, disposable labware, broken
glass, paper towels, etc are collected for permanent storage in special landfills.
e. “lab pack” – certain chemicals such as mercury and some other heavy metals,
many radioactive materials, carcinogens, etc. must be separated for individual
disposal.
f. biological waste, especially if it contains human blood or body fluids.
Chemicals spilled on a balance or balance pan should be brushed into a small pile with
one of the small brushes provided in the weighing room and put into the proper waste
21 container. Chemicals spilled on a balance or the surrounding area can cause serious
harm to the balance and should be cleaned up promptly!
3 We have special materials for neutralizing spilled acids and bases, and for absorbing
spilled liquids, especially if they are flammable. If the need for these materials arises,
immediately contact your instructor or the technician.
4 Remember never to return a waste or surplus chemical to its original container!
If a chemical should not be washed down the drain, the technician will place a special
container in the lab, either near the original source of the chemical or in another
appropriate location. Such containers will be designated for specific wastes; for example,
'Waste containing lead", or "Waste containing chromate", etc. As you go about your work,
be alert for the presence of these containers.
Besides the special waste basket designated for chemically contaminated paper, separate
receptacles have been set aside for “clean” and “dirty” broken glass. Glassware is
expensive, so please work carefully and ask an instructor if broken items can be repaired
or fire-polished.
QUIZ --Part VIII
35) Based on the list provided above, which of the following chemicals is legal to wash down
the drain with lots of water?
a) Lead acetate.
b) Potassium permanganate.
c) Sodium hydrogen carbonate (baking soda)
d) none of the above
36) Based on the list provided above, for which of the following chemicals should you expect
to find a specially designated waste bottle?
a) Dihydrogen monoxide.
b) Silver chromate.
c) Potassium chloride.
d) Iron (II) sulfate. .
37) Judy has about 100 mL of a chemical left over from an experiment and is trying to decide
what to do with it. Which one of these is NOT an acceptable choice?
a) Pour it back into the original container.
b) Find out if it can be washed down the drain.
c) Pour it into a container set aside for waste containing that chemical.
d) Offer it to another student who might need more of the same chemical.
22 38) Biodiesel is synthesized from vegetable shortening in a lab activity. Where should you
dispose of the reaction product?
a) rinse it down the sink with lots of water.
b) pour it into the nearest trash can.
c) pour it into a container labeled Organic/Flammable reaction products
39) Broken glass in this lab should be disposed of…
a) In a special sink reserved for it.
b) In any garbage can except for the one designated for chemically contaminated paper.
c) In a waste basket designated for broken glass.
d) In a crock kept on hand in the preparation room.
UNDERSTANDING A MATERIALS SAFETY DATA SHEET (MSDS)
Questions 40-50 pertain to the Materials Safety Data Sheet on pages 23-24. Refer to it and to
the information about labels on pages 12 and 13 -in order to locate the information needed to
answer the questions.
QUIZ --Part IX
40) What is another name for this chemical?
a) Corrosive sublimate.
b) Lye.
c) Soda ash.
d) Potash.
41) Is this chemical a flammability hazard?
a) Yes.
b) No.
42) What number on the four-digit hazard code suggests that this chemical can cause severe
wounds if you get it on your skin?
a) 0.
b) 2.
c) 3.
d) 4.
43) In which section of the MSDS sheet will you find information about the melting point and
solubility of this chemical?
a) 1 (Product Information)
b) 3 (Hazards Identification)
c) 5 (Fire Fighting Measures)
d) 7 (Handling & Storage)
e) 9 (Physical & Chemical Properties)
44) Does this chemical dissolve in water?
a) Yes.
b) No
23 24 25 45) Is this chemical known to be capable of causing cancer?
a) Yes .
b) Not as far as the document indicates.
c) Under certain circumstances.
46) Which of the following substances is the only one that should be administered if the
compound is swallowed?
a) Egg whites to coagulate the compound.
b) Water to dilute the compound.
c) Vinegar to neutralize the compound.
d) Syrup of ipecac to induce vomiting.
47) Does this chemical react with water?
a) Yes.
b) No.
48) Which of these substances should NOT be stored in proximity with this chemical?
a) Hydrochloric acid used to adjust pH in swimming pools.
b) Magnesium used as a filler in welding operations.
c) Freon, a halogenated hydrocarbon used to fill air conditioners and refrigerators.
d) All the above.
49) What kind of fire extinguisher seems to be most appropriate for use in a place where
plastic bottles containing this chemical are stored in cardboard cartons on wooden shelves?
(Refer to page 7 for information about fire extinguishers; be prepared to defend your decision
in class.)
a) Water.
b) Dry chemical.
c) Halon
d) Powder or dry sand.
50) In which section will you learn about the lethality of this
compound if it is administered to a laboratory animal?
a) 1 (Product Information)
b) 3 (Hazards Identification)
c) 6 (Accidental Release Measures)
d) 8 (Exposure Controls & Personal Protection)
e) 11 (Toxicological Information)
Before you are permitted to work in the laboratory, you
must complete this quiz and return it to your instructor.
Your instructor also requires that you agree to, sign and
turn in the Rules Agreement on page 28.
26 REVIEW OF THE LABORATORY AND ITS FACILITIES
Locate, and check off as you find them, each of the following items in this review of your
chemistry laboratory:
Exits
Off-limits area (except in emergencies)
Instructor's office (if applicable)
Weighing room
First Aid kit
Eyewash stations
Safety showers
Fire blanket
Spill compounds and materials
Fire extinguisher
Receptacle for broken glass
Receptacle for chemically contaminated paper
Drop-down ventilation hoods
Open/close damper on ventilation hoods
Ventilation hood operational control switches
Conventional fume hood (if applicable)
Emergency gas shut-off
Natural gas outlets
Compressed air outlets
Vacuum outlets
Demineralized water faucets
Hand soap dispenser
General laboratory detergent
General utility counter
Key board for locker keys
Thermometer storage rack
Buret storage rack
Ringstand cubby
Hotplate/stirrer storage shelves
Drawers for storage of clamps and other utility hardware
Gas burner storage drawers
Drying oven
Jim Adams
Las Positas College,
Livermore, California
12-30-04
All Rights Reserved
Updated Fall 2011
27 28 Safety Rules Agreement
Las Positas College Chemistry Laboratory
I hereby agree to ...
Follow all instructions given by the instructor and technician.
Protect my eyes, face, hands and body while working in the laboratory.
Respect the safety of my fellow students.
Observe good housekeeping practices in my locker and in my work environment.
Know where to get help.
Know the location of First Aid and emergency equipment.
Conduct myself in a responsible manner at all times in the laboratory.
I, _____________________________________ have studied and understand the safety
Print name
regulations given to me by the chemistry staff, and completed the safety quiz with my own
answers. I also agree to abide by these regulations, and also any additional instructions,
printed and verbal, given by my instructor or the technician.
Date _____ Signature ______________________________________