Chemistry Form One Notes – Laboratory Techniques and Safety
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LABORATORY TECHNIQUES AND SAFETY
[A laboratory is a room or building specially designed for conducting various scientific
experiments. An appropriate schoo! laboratory has the following features
+ wide table in front of the laboratory room, fited with sinks for experiment
Rules and safety precautions in a chemistry laboratory
laboratory Rules
State laboratory rules
laboratory. Its important 1 read and follow laboratory rules to avoid causing accidents. Your
teacher will teach and give you more rules. The following are some important laboratory rules:
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1. Do not enter the laboratory without permission from your teacher or laboratory
technician
2. Wear safety goggles all the time while inthe laboratory. Obey this rule whether you are
actually working on an experiment or simply writing in your laboratory notebook:
3. Contact lenses are not allowed. Even when worn under safety goggles, various fumes
‘may accumulate under the lens and cause serious injuries o blindness
4. Puton closed shoes and trousers when in the laboratory. Sandals and shots are strictly
prohibited
5. Never walk or run unnecessarily inthe laboratory
6. Tie back long hair when using open flames.
7. ating, drinking, and smoking are strictly prohibited in the laboratory.
8. Don’t perform any experiment not authorized by your teacher of lab technician. If you
are curious about trying a procedure not covered in the experimental procedure, consult your
teacher of laboratory technician
9, Never taste anything. Never directly smell the source of any vapour or gas; instead drift a
small sample to your nose. Do not inhale this vapour directly but take in only enough to detect an
odour if one exists
10, Always wash your hands after experiments
11, Never use your hands to transfer chemicals, Use a spatula instead.
12, Notify your teacher or technician immediately in case of an accident
13, Know what chemicals you ae using, carefully rea the label twice before taking anything
from the reagent bottle, Do not interchange labels.
14, Excess reagents are never to be retumed to stock bottles. Ifyou take too much, dispose of
the excess
15, Many common reagents, for example, alcohol, acetone and carbon disulphide are highly
fMammable. Do not use them anywhere near open flames.
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16, Pour more concentrated solutions into less concentrated solutions to avoid violent
reactions. For example, always add acid to water; not water to acid. If you pour water into acid
instead, the heat of reaction will cause the water to explode into steam, sometimes violently, and
the acid will splash
17, chemicals accidentally splash onto your skin o eyes, lush immediately with plentiful
amounts of water and report to your teacher or lab technician
18, Never point a test tube or vessel that you are heating at yourself or your colleague
19, Dispose of chemicals properly. Unless you are told otherwise, assume that only water
‘may be poured in the laboratory sinks,
20. When an experiment is completed, always clean up your work area and dispose of the
broken glass properly. Retur all equipment to its proper storage places,
21. Never take away anything from the laboratory without your teacher’s permission.
22. Beware of hot glass because it looks exactly the same as a cold glass. Never touch it with
your hand,
23, Always adjust the Bunsen bumer 10 give a luminous flame when not using it (or just
simply turn it off),
24, Use equipment or apparatus only for its designated use
25. Never ea or drink from laboratory glassware
26. Make sure all the bumers are tured off before leaving the laboratory. Check that the gas
tap is off as well
27. Never heat a liquid in a closed container. The expanding gases produced may blow the
container apart, injuring you or others.
28. Use only those chemicals needed inthe activity. Keep all ids closed when a chemical is
not used
29. Do not use the same spatula to remove chemicals from two different containers. Each
container should have a different spatula,
a
from the lame of a Bunsen burner.
the fume chamber. The fume chamber helps to disperse hazardous gases and vapours safely
35. Use a lighter or wooden splint to light burners. Do not use papers. Always strike the
that are notin use
‘The Safety Measures for a Chemistry Laboratory
Explain the safety measures fora chemistry laboratory
‘The chemistry laboratory can be a place of discovery and learning. However, by the very nature
of laboratory work, it can bea place of danger if proper common-sense precautions ate not taken
Effort has been made to eliminate the use of explosives, highly toxic and carcinogenic
substances from the experiments which you will perform, However, there is a certain
unavoidable hazard associated with the use of a variety of chemicals and glassware. You are
expected to leam and adhere to all safety guidelines. This will ensure a safe laboratory
environment for yourself and the people you may be working with or those near you. The
following are important laboratory safety measures to obey
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2. Be familiar with the location, use and limitations of the safety devices. Ths includes fire
extinguishers, fire blankets, fume hood, spill cleanup materials, first aid kit, eyewash stations and
fire alarm,
3. Keep all chemicals in properly labelled containers. This will prevent accidental use ofthe
‘wrong chemical for a particular experiment
4. Be familiar with the appropriate safety measures to take when exposed to different
hazardous materials. Information is available from your teacher or laboratory technician
5. All;chemicals that react with each other must be stored separately
6. Be aware ofthe interaction of laboratory furiture and equipment with chemicals sed or
stored inthe laboratory. For example, oxidizers should not be stored directly on wooden shelves.
7. Use fume hoods /cupboards/chambers whenever possible
8. Never store food in a refrigerator or freezer where hazardous chemicals are stored. Als,
donot eat anything you Find in the laboratory or in the laboratory freezer or refrigerator
9. Make surefire extinguishers are in good condition. Report any broken seals, damage, low
‘gauge pressure or improper mounting to the teacher or laboratory technician, Ifthe seal has been
broken, assume that the fire extinguisher has been used and must be recharged. (Note: Do not
tse fire extinguishers unless you are trained and feel confident to do so)
10. Stored chemicals must be inspected regularly to ensure they have not expired. Note the
date when bottles were received and when were first opened. Note expiry dates on chemicals and
their special storage conditions
11, Eliminate safety hazards by maintaining laboratory work areas in a good state of order.
12, The laboratory must have wide emergeney exits and wide windows. Wide exits facilitate
«easy evacuation in case of emergency. Wide windows allow enough air to enter and circulate in
the laboratory. (Note: Maintain at least two clear passages to laboratory exit)
13, Always keep tables, seats, fume hoods, floors and desks clear of unnecessary material
14, All equipment should be inspected before use. In addition, they should be checked
regularly to ensue they are safe for use.
2
15, If experiments must be left unattended, place a note next to experimental apparatus
indicating the chemicals involved, your name and telephone number on which you can be
reached in case of an emergency
16, Keep the laboratory floor clean and dry a all times, Clean spills of water or chemicals
immediately. Then notify other laboratory workers of potential slipping hazards.
17, The laboratory must be equipped with potable fire extinguishers and other safety devices
with clear instructions on how to use them in case of any emergency
18. Containers for holding or storing chemicals must be inspected for leakages or other
damages. They should have tight stoppers or covers.
19, All experimenters and other persons working in the laboratory should wear protective
‘gears to minimize exposure to hazards. These gears may include lab coats, hand gloves,
gumboots, safety goggles, aprons, et.
20. There should be manual or instruction guides on how to treat spills of different
chemical substances
21. The fume chamber should be labeled. It should be kept in good condition to minimize
unexpected gas leakages or emissions
22. Gas eylinders should be labeled, stored properly, and supported. Moreover, they should
bein good working conditions all the time
23. Each laboratory should be equipped with adequate first aid kits.
24, Equipment for monitoring contamination should be installed to give alerts of any possible
dangers.
NOTE: All the above rules and safety measures are applicable to all research, teaching and
academic laboratories, However, your laboratory may require some more rules that apply to
specific materials and equipment.
First aid and first aid kit
FIRST AID
“
First aid isthe help given to someone who is injured or sick before the vitim gets further
‘medical assistance. This help can be given by any person regardless of his/her knowledge in a
medial profession
‘Whenever an accident occurs, something must be done immediately to help and save life ofthe
victim. You must always be ready o give a hand toa victim whenever an acident occurs close
{0 you. To give sd effectively and sucessfully, one must have elementary knowledge on how to
assist different victims. Ifyou donot know how to help a certain victim, you can ask someone to
assist instead. Do not engage yourself in assisting if you actually do not know where to sat
‘You may find yourself worsening the situation ofthe vitim unknowingly. However, tis should
rot be taken a5 an excuse fr filing to help. Always be ready to render some kind of help First
aid helps wo
Possible Causes of Accidents in a Chemistry Laboratory
demi possible causes of acidents in a chemistry laboratory
Accidents may occur ina schoo! laboratory if utmost care is not taken into account. Accidents in
the laboratory are mainly cus on parts ofthe body such as hands, fingers, legs oF head, Others
axe bums from flames, scald fom boiling Aus, bse and grazes due to accidental fling on
a slippery foo.
Some possible causes of accidents in the laboratory include
+ Failure to follow the correct experimental procedures for example, pouring water into an
chemicals, eating or drinking while nthe laboratory, ete
re
+ Failure to adhere to proper conduct in the laboratory like running unnecessarily and
‘conducting experiments without your teacher’s or technician’s permission and guidance.
+ Improper use or handling of laboratory equipment and apparatus when conducting
experiments, which could lead to breakage and in turn cause cus, bruises, grazes, ete
+ A.slippery laboratory oor which can cause fractures, cuts, bruises, grazes, ete
+ Accidental spillage of chemicals on body parts such as hands, face, eyes, etc, could lead
to burns and damage
‘+ Poor ventilation in the laboratory may cause suffocation (due to inadequate oxygen
supply) and poisoning (by inhaling poisonous gases produced when experimenting)
+ Improper disposal of chemical wastes may result in explosions, burns or even fires,
+ The leaking of gases from taps or cylinders may cause fires or even explosions.
+ Use of wrong reagents due to incorrect labeling of chemicals of use of reagents or
chemicals that have expired may cause burs, poisoning or damage to apparatus or equipment,
+ Inadequate prior information or knowledge on procedures and hazards associated with
certain practical activities or reactants may result in burns, poisoning or explosions.
+ Loose or improperly plugged electrical appliances may cause electric shock, especially
when touched with wet hands and during fixing of sockets.
In general, it can be concluded that most laboratory accidents are a result of negligence and
carelessness of experimenters. It is also due to failure to follow the laboratory rules and general
safety measures
‘The Items Found in a First Aid Kit
Name the items found ima first aid kit
AA First Aid Kit is a box in which first aid chemicals, tools and instruments are kept. In the
laboratory, the box is usually kept in a place where it can be easily reached in case of an
accident, preferably onthe wall,
6
Each tent mist be familiar wit he tools and chemicals kept in the kit and lam how to wse
them to provide first aida vitim,
Feds
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First aid kt and ts conens
How Each First Aid Kit Item is Used
Demonstrate how each fist aid kt tem s used
The table below shows types of chemicals found ina Fist Aid Kit and their functions.
Foolchencaltom Faction
esti mama Conains uietins on how owe the items ine st i kt
Wor on hands when tending bleting cus or wounds to
ile loves vii’ boty ids
rile resing Stops beding
(Claning snd dition of wounds, cu, hue, gz ot
stip ag blses
. Washing hands, wounds nd equipment
bie camet Preven incon one andes or mart oy
”
hrm ointment Applied on burns wo prevent infection
troleum jelly Soothing broken skin
taster or adhesive bandage Covering small wounds or cus
eile gauze Covering wounds to protet them from dt or gers
ye was solution Flushing the eyes ora a general decontaminant
Hecmometer Recording hody empature
ibioticoweletes oF ction wool ‘Cleaning and drying ets and wounds
eine incre Dressing fresh cus and bruises
rain cliving drugs such as asprin, paracetamol, panadol etc Relieving mild pains
iniment Reducing muscle pin
Treating mild bacterial infections on the skin, ca, nose and
id anos mouth
Appliod on minor wounds and eatment of serious heat
entan volt solution wounds
drogen peroxide olin Cleaning wounds
Methylated sprit (70% alcoho ‘Cleaning cus and bruises
pandages Dressing wounds and cus, and immobilizing injured limbs
cissos or razor blade Cating dressing materials
ental Kit Treatment of broken teeth, oss of crown or filing
ety pias (small and big) Spline removal and securing tiangula bandage sings
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frscror Splinter or stinger removal
sealable oven bag Contain for contaminated ails
Moleskin Applic t blister rho spss
ited clean water Weshing hands and dking
asa pray decongestant Nasal engestion from colds or legis
fons Source of ight
use Blown to call for beip
Basic chemistry laboratory apparatus and their uses,
Instruments used for carying out different experiments in the laboratory are called laboratory
apparatus. Laboratory apparatus ean be classified acconding to ther uses as:
+ apparatus for holding things e.g, test-tube holder, retort stand and clamp, test-tube rack,
‘measuring flask, beam balance, electronic balance, common balance, measuring syringe, beaker
and stop watch;
+ apparatus for heating substances eg, boiling tube, pipeclay triangle, crucible and li, wire
gauze, deflagrating (combustion) spoon, Bunsen burner, spitt lamp, tripod stand, evaporating
dish, wire gauze and stove
+ apparatus for doing chemical reactions (or testing) eg. beaker, test tube, dropper, flask
watch glass, ga jar and thistle Funnel
+ apparatus for filtering e.g filter funnel, filter paper and cotton woot
+ apparatus fr grinding eg. mortar and pestle;
ry
+ apparatus for scooping eg spatula; and
‘The Apparatus Used in a Chemistry Laboratory
Some chemistry laboratory apparatus
A ~
“Triangular ile |
Y T Thistle funnel
Funnel
mee “Mortar and pestle
a
— ‘Water-bath
Crucible and id
2
A PN
| AX f
{___f
ii \ =
i { +
! i =
J 8 Ea
Tripod stand
Measuring cylinder
_f
<< Funnel stand
Bel jar cai
Apparatus Materia ses
1 Testbe Glas Holing chemi, hing shoes
ating iid econ, nd for lraon
2 ne opi purposes
3 Beater Glas oc plastic Molin. ening. and ising gis
3
»
2 Mortar and pestle cay Crushing or grinding substances
2 Wire gauze Metal en distribution of heat during heating
B Spring balance Met Measuring weight
Py Distillation Mask Gis Disilation
2 Combustion spoon Met ‘Buming powder in jars
2%. Thermometer Glass and iguid metal Measuring temperature
2. Delivery ube Glas Allowing gases passthrough
2. Bunsen burner Met Heating substances
». Separating fuel Glas Separation of immiscible liquid mixtures
0. Measuring cinder Gias or plastic Measuring volumes of gids
Sucking in and measuring speciic volumes of
3 Measuring syringe Plastic liquids
Plastic or glass and
2 Stopwatch metal Accurate measurement of time
Used a surface to evaporate some liquids, 10
hold substances being weighed or observed, o as
3 Watch las Gas atcover fora beaker
4s a large test tbe used 10 heat substances
equirng song heating, when the sample is
a Boiling tube Gis too large for atest tube
3s Evapoating dish Ceramic eating and evaporating liquids and solutions
6 Fite paper Paper Fitaton
2s
y. Testtube rack Wood o plastic Placing test tubes,
*. Reagent ote Gas String diferent chemicals
». Wash bot Piast String distil water
Protecting eyes from chemical spill, strong light
0. Safety gogales Glas and harmfl vapours
Kesping gases, moisture, ai, cle of erating
4 Bell jar Glas sacuums
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No \
Ron one thm
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amy \U 7
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Iron stand Water bottle separating funnel
Chemistry Laboratory Apparatus According to their Uses
»
Common Chemistry Laboratory Apparatus
7
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dnerates sii clamp pinch clamp fannel
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rae a
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Procedure
Note: to obtain the mass of an object, we subtract the mass of an empty watch glass from the
‘mass ofthe watch glass and the substance. That is, Mz~ Mi
For example
Weight of watch glass = 2.6 grams
Watch glass + stone = 4S grams
Therefore, mass of stone = (4S — 2.6) = 42.4 grams
Warning signs
Chemical warning signs are safety symbols found on containers, especially those used in the
laboratory. The symbols are also found on tanks or containers that are used to carry, store oF
transport certain chemicals. Containers holding flammable fuels such diese, petrol and natural
25, a8 well as those containing toxic chemicals normally bear warning symbols. These symbols
indicate the danger (hazard) likely to be caused by the chemicals they contain if carelessly
handled
When performing experiments in the laboratory itis important to read the safety signs on
chemical containers. This will minimize the chances of causing aecidents in the laboratory.
‘The Basic Chemical Warming Signs
raw and label the basic chemical warning signs
Some chemical warning signs
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emaael Irritant Toxic
The Concept of Warning Signs
»
Toxic
Toxic substance include those that can poison you or the other person working close to you in
the laboratory. These substances can kill within a shot ime o after some few days. They should
rot be allowed to get into your body through body orifices (month, nose, eyes, eas, te). Neither
should they be allowed to contact your skin. They become even more dangerous when they get
into the body. If it happens that these substances touch your skin accidentally, wash it
immediately with ample wate,
Corrosive
They cn also corrode wood or metals. One can become blind if such substances accidentally get
int hisher eyes they contact your skin, wash it immediately with alot of water. Examples of
corrosive substances commonly found in a school laboratory are concentrated mineral acids such
as sulphuric acid, hydrochloric acid and nitric acid, and concentrated alkalis such as sodium
hydroxide, potassium hydroxide and ammonia,
Flammable
‘These chemicals catch fie easily. For this case, they shouldbe kept away from flames o fies.
They canbe set into fire by any kind of sparks, bei rom welding or fre. When working with
flammable chemicals inthe laboratory all burners must be put off. These chemicals are usually
‘very volatile. The containers usd to carry them must be stoppered immediatly afer every use.
Examples of fammable chemicals are methylated spit eer, acetone and methanol.
Explosive
Explosive chemicals are those that explode rapidly upon detonation (st into fre or ignited,
Because the reaction i rapid, it results into throwing off particles ata high speed. For this
reason, they should not be kept in glass containers. This is because during explosion the particles
will disperse around and cause serous injuries to people. Those explosive chemicals tht can
react without extemal detonation are even more dangerous
2
Oxidizing agents
These chemicals can stimulate a burning substance to burn efficiently and faster. Therefore, they
‘must be kept away from fies no matter how small that fire may be. An example of oxidizing
agent is oxygen gas,
Harmful or irritant
Harmful substances are those that can impair your health or make you fall sick. They do not
‘normally kill instantly but have detrimental effects following a long exposure to them. These
chemicals do not kill immediately. However, care must be taken when handling or dealing with
them. Isitating substances cause pains when in contact with the body, They are dangerous to
health when in contact with the body surface fora long period of time
2