Name
Class Period
LABORATORY PROCEDURES – Lab Safety and Techniques
The best way to become familiar with chemical apparatus is to actually handle the
pieces yourself in the laboratory. This experiment is divided into several parts in
which you will learn how to adjust the gas burner, use a balance, handle solids,
measure liquids, filter a mixture, and observe chemical reactions. Great emphasis is
placed on safety precautions that should be observed whenever you perform an
experiment and use this apparatus. Several useful manipulative techniques are also
illustrated throughout this lab and in A Special Message on Safety. In many of the
later experiments, references will be made to these sketches and procedures. You
will also be referred to many of the safety precautions and procedures explained in
all parts of this experiment. It is important that all students develop a positive
approach to a safe and healthful environment in the laboratory.
OBJECTIVE
After completing this experiment, you should be able to use laboratory equipment
safely and skillfully.
Safety
Take the necessary safety precautions before beginning each part of this
experiment. Always wear safety goggles, apron and closed-toe shoes when in the
laboratory. Get into the ‘good habit’ of always putting on this standard safety
equipment as soon as you enter the lab. It is important that you and your
partner observe all safety precautions while conducting experiments.
Clean Up
At the end of each part of this lab, all glassware and ceramic evaporating dish must
be cleaned and given a final rinse with distilled water. All your personal lab
equipment must be securely locked in your equipment drawer. All common items
must be returned to their original location, either under the hood, or common
cabinet as directed by your instructor.
PART 1:
THE SCALE – Massing solids
Apparatus
Analytical Scale
Weigh paper
Spoon
Materials
Nickel Sulfate
1
Procedure
1. When a scale is required for determining mass, you will use an analytical
balance. See Figure 1 below. Analytical balances vary in sensitivity from
0.1gram, 1.01gram to 0.001 gram. For this lab we will be utilizing the scale
that is sensitive to 0.100 gram. This means that all your mass readings
should be recorded to the nearest 0.001 gram.
Figure 1
2. The scale should only be moved by your instructor.
3. Before using the scale, always check to see that the digital readout is at zero.
If the pointer is not at zero, gently press the zero button and wait for the
balance to zero. Whenever weighing chemicals, always use weighing paper or
a glass container, NEVER place chemicals or hot objects directly on the
balance pan. They can permanently damage the surface of the balance pan
and affect the mass weighing.
CAUTION
Do not touch chemicals with your hands. Always wear safety goggles, apron and
gloves when handling chemicals. Carefully check the label on the reagent bottle
or container before removing any of the contents. Never use more of a chemical
than directed. You should know the locations of the safety shower and eyewash
and how to use them in case of an accident.
4. Make sure that the reading on the scale is set at zero by following procedure
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a. Gently blow onto the weighing surface of the balance. Record your
observation:
5. Zero the balance again. Obtain a piece of weigh paper and place it on the
scale pan. Determine the mass of the paper. Record the mass of the weigh
paper to the nearest 0.001g.
6. Using a spoon, obtain a spoonful of nickel sulfate from a reagent bottle,
under the hood, and place it on a separate piece of weigh paper. Take this
back to your lab table to mass.
7. Now slowly pour the nickel from the weigh paper onto the weigh paper on
the balance pan, until the scale reads approximately 1.5 grams.
8. Record the mass of the weigh paper and nickel sulfate to the nearest 0.001g.
9. Calculate the mass of the nickel sulfate you have measured out.
10. Take your nickel sulfate sample and weigh paper off of the balance. Zero the
balance.
11. Another method of massing can be completed by taring the scale.
12.To tare, means to remove the mass of the weigh paper. Place a piece of
weigh paper onto the scale. Press the zero button on the scale.
13.Now slowly pour the nickel sample from the weigh paper, step 8, onto the
weigh paper on the scale pan.
14.Record the mass to the nearest 0.001g.
15.What is the mass of the nickel sulfate you have measured out.
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16.Are the masses in steps 9 and 15 the same or different? Why?
17. Place your massed nickel sulfate sample into a 250ml beaker.
18.Cover your beaker with a piece of parafilm and place into your equipment
drawer. We will use this sample in Part 2.
CAUTION
Never discard chemical or broken glassware
important safety precaution against fires,
anyone who empties the wastepaper
contamination, never pour unused chemicals
PART 2:
into the wastepaper basket. This is an
and it prevents personal injuries to
basket. As a precaution against
back into their original bottles.
MEASURING LIQUIDS
Apparatus
Graduated Cylinder
Buret Clamp and Buret
Pipet
Ring stand
Beakers
Materials
Water
Figure 2
CAUTION
Safety goggles, apron and gloves must be worn whenever you
measure chemicals. Never pour a liquid directly from its reagent bottle
into the buret. You should first pour the liquid into a small beaker that
is easy to handle. Then pour the liquid from the small beaker into the
buret. This simple method will prevent unnecessary pillage. Never pour
any unused liquid back into the reagent bottle.
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Procedures
1. Burets, fitted with a stopcock, a pinch clamp, or a glass
bead, are used for delivering any desired quantity of liquid
up to the capacity of the buret. Any burets are graduated in
tenths of milliliters, See Figure 2. When using a buret, follow
these steps:
a) The buret has been clamped into positions on a ring stand and filled
with water. See Figure 2. Bring a 50ml beaker with you to the buret.
DO NOT move the buret or ring stand.
b) Place the 50ml beaker at the bottom of the buret. The beaker serves
to catch any liquid that will be drawn off.
c) Observe that the surface of the liquid in the buret is slightly curved. It
is concave if it wets the glass, convex if it does not wet the glass. Such
a curved surface is called a meniscus. If the liquid wets the glass, you
read to the bottom of the meniscus as shown in Figure 3. Locate the
bottom of the meniscus when reading the volume level in the buret.
The volume measurement is read from the BOTTOM of the meniscus.
The buret reads from 0.0ml at the top to 50.0ml at the bottom. The
buret reading in Figure 3 would be recorded as 15.7ml.
Figure 3
d) Record your buret reading.
e) Open the stopcock and allow between 8ml and 10ml to dispense into
your beaker. Close the stopcock.
f) Read and record you final buret reading below.
________
___
g) Subtract your measurements from d) and f) to obtain the actual
amount of water dispensed. Show your work.(Keep this water for the
next part)
2. Pipettes are made in many sizes, see Figure 4, and are
used to deliver measured volumes of liquids. A pipet is fitted with
a suction bulb used to withdraw air from the pipet while drawing
up the liquid to be measured. See Figure 4. Always use the
suction bulb – NEVER pipet by mouth.
Figure 4
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 Use your thumb and forefinger to press on valve "A" and squeeze
the bulb with other fingers to produce a vacuum for aspiration. Release
valve "A" once the bulb is completely deflated.
 Hold the pipette close to its upper end and insert into the bottom
of the propipette. WARNING: Extreme care should be taken not to place
stress on the pipette or it may shatter.
Figure 5

Insert the pipette into the beaker of water you dispensed from the buret. Press on
valve "S". Suction will draw liquid up into the pipette. Continue pressing valve "S"
until the liquid reaches the desired level. Carefully adjust the fluid level so that the
bottom of the meniscus coincides with the calibration line on the pipette.
Note: Press directly on the letter A, S, or E when opening valves. Applying pressure away
from the center of these valves will damage them.

Draw the water from the beaker up into the pipette. When the water
has been sucked up, read and record the volume of water in the pipette.
3. You will now dispense this water into a graduated cylinder, Figure 6.

Press on valve "E" to expel liquid into your graduated cylinder.
 Carefully remove the pipette (see warning in step 2.) and touch the tip of
the pipette to the inside of the receiving flask to drain the last bit of solution.

Figure 6
Read and record the volume of water in the graduated cylinder.
4. Carefully pour the contents of the graduated cylinder into a 50ml beaker.
a. Read and record the volume of water in the beaker.
b. Compare and contrast the volume measurements made using the four
devices.
c. Identify one advantage and one disadvantage of using a buret to
measure liquids.
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d. Identify one advantage and one disadvantage of using a graduated
cylinder to measure liquids.
e. Hypothesize a reason why a beaker is NEVER used to measure liquids.
5. Empty the water from your 50ml beaker into the sink.
6. Carefully measure 25.0ml of distilled water, using your graduated cylinder.
7. Slowly pour the distilled water into the beaker containing the nickel sulfate
from part 1. Stir gently with the glass stirring rod to until all of the solid has
dissolved.
8. Record two observations that you made while the reaction was taking place:
9. Hypothesize as to what has happened to the solid crystals. Explain your
reasoning.
10.If you are not continuing on to Part 3, cove the beaker with parafilm and lock
securely in your lab equipment drawer.
PART 3:
FILTRATION
Safety
Take the necessary safety precautions before beginning each part of this
experiment. Always wear safety goggles, apron and closed-toe shoes when in the
laboratory. Get into the ‘good habit’ of always putting on this standard safety
equipment as soon as you enter the lab. It is important that you and your
partner observe all safety precautions while conducting experiments. Read all
safety precautions while conducting experiments.
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Apparatus
Ring stand
Stirring rod
Iron Ring
Evaporating dish
Funnel
Matches
Iron Ring
Filter Paper
Ceramic-centered Wire gauze
Materials
Sodium Hydroxide, NaOH, 1M
Hydrochloric Acid, HCl, 1M
Nickel sulfate compound from Part 2
Figure 7
Procedures
1. Sometimes liquids contain particle of insoluble solids, present either as
impurities or as precipitate formed by the interaction of the chemicals
used in an experiment. If the particles are insoluble and denser that
water, they soon sink to the bottom. Most of the clear, supernatant
(swimming above) liquid may be poured off without disturbing the
precipitate. Such a method of separation is known as decantation.
The soluble salts are in the supernatant liquid which has been
decanted into the beaker.
2. Fine particle, or particles that settle slowly, are often separated
from a liquid by filtration. Support a funnel on a small ring on the ring
stand as shown on Figure 7. If the ring is too large place a clay
triangle on top of the ring to support the funnel Use a beaker to collect
the filtrate. Adjust the funnel so that the stem of the funnel just
touches the inside wall of the beaker. This will speed up the filtration
process by decreasing the dropping, hence increases the continuous
flow through capillary action due to the intermolecular force, hydrogen
bonding.
Figure 8
3. Fold a circular piece of filter paper along its diameter, and then
fold it again to form a quadrant. See Figure 8. Separate the folds of
the filter, with three thicknesses on one side and one on the other;
then place it into the funnel. The funnel should be wet before the
paper is added. Use your plastic wash bottle to do this. Then wet the
filter paper with a little water and press the edges firmly against the
sides of the funnel so no air can get between the funnel and the filter
paper while the liquid is being filtered.
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4. EXCEPTION: A filter should not be wet with water when the liquid to be
filtered does not mix with water. WHY?
______________________________ _
5. Using your graduated cylinder, measure 25.0ml of hydrochloric acid,
HCl.
6. Place your beaker containing the nickel sulfate compound, from Part 2,
under your personal hood.(This is the white box on the wall next to
your lab station. Each lab group has its own personal fume hood).
Carefully pour the hydrochloric acid into this beaker. Stir gently.
7. Record one observation from this reaction.
8. The contents of your beaker contains nickel (II) chloride and water.
Rinse your graduated cylinder with distilled water. Then use it to
measure 25.0ml of sodium hydroxide, NaOH.
9. Pour the sodium hydroxide into the beaker containing the nickel (II)
Chloride. Stir gently and record one observation.
10.Measure an additional 25.0ml of sodium hydroxide, NaOH, into your
graduated cylinder, and slowly add to your beaker. Gently stir and
record one observation.
11.The solid that forms from the mixing of two solutions is called a
precipitate.
12.
To separate the precipitate from the solution, pour the beaker
contents into the filtering system you set up in Part 3 steps 1-3.
a) The filter paper should not extend above the edge of the funnel.
It is better to use a filter disc that leaves about 1cm of the funnel
exposed.
b) Do not over fill the filter. It must never overflow. The liquid must
never go above the paper line.
Figure 7
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c) Try to establish a water column in the stem of the funnel thus
excluding air bubbles, look at step # 2, and then add the liquid just
fast enough to keep the level about 1cm from the top of the filter
paper.
d) When a liquid is poured from a beaker or other container, it may
adhere to the glass and run down the outside wall. This may be
avoided by holding a glass stirring rod against the lip of the beaker, as
shown in Figure 7. The liquid will run down the rod and drop off into
the funnel without running down the side of the beaker.
e) To remove the remaining precipitate from the beaker. Hold the beaker
with its spout down towards the funnel and squirt your wash bottle up
into the beaker, behind the precipitate, to wash out the solid product.
This is a useful skill.
The precipitate is retained on the filter paper. What PROPERTY
of the precipitate enables it to be separated from the water by
filtration?
What does the filtrate contain?
13. If you are not completing Part 4 today, cover the beaker contents, filtrate,
with parafilm and store in your lab equipment drawer.
14.If you are not completing Part 4 today, carefully place the filter paper, along
with the precipitate, into a different beaker. Cover the beaker with parafilm
and store in your lab equipment drawer.
15.At the end of this part of the experiment, all equipment you store in the lab
drawer should be completely cool, clean, dry, and arranged in an orderly
fashion for the next lab experiment.
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PART 4 THE BURNER
Apparatus
Heat Resistant Mat
Crucible tongs
Burner
Matches
Evaporating dish
Materials
Copper wire, 18 gauge
Procedures
1. The Bunsen or Tirrell burner is commonly used as a source of heat in the
laboratory. Although the details of construction vary among burners, each
has a gas inlet located in the base, a vertical tube or barrel in which the gas
is mixed with air, and adjustable opening or ports in the base of the barrel.
These ports admit air to the gas stream. The burner may have an adjustable
needle valve to regulate the flow of gas. In some models the gas flow is
regulated simply by the flow of gas. The burner is always turned off at the
gas valve on the supply line, never at the needle valve. Look at Figure 9 as
you examine your Bunsen burner and locate these parts.
Figure 9
CAUTION
Before you light the burner, check to see that you and your partner have taken
the following safety precautions against fires: Wear safety goggles, and aprons.
Confine long hair and loose clothing: Tie long hair back at the back of the head
away from the front of the face, roll up long sleeves on shirts, blouses and
sweaters away from the wrists. You should also know the locations of fire
extinguishers, fire blanket, safety showers, and sand buckets and how to use
them in case of a fire.
2. In lighting the burner, partially close the ports at the base of the barrel, light
the match. Hold the lit match just below the top of the barrel. Turn the gas
full on and slowly raise the lit match toward the top of the barrel. The gas
flow may be regulated by adjusting the gas valve until the flame has the
desired height. If a very low flame is needed, remember that the ports
should be partially closed when the gas pressure is reduced. Otherwise, the
flame may burn inside the base of the barrel. When improperly burning in
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this way, the barrel will get very hot, and the flame will produce a poisonous
gas, carbon monoxide.
CAUTION
Carbon monoxide is a poisonous gas. If the flame is burning inside the base of
the barrel, immediately turn off the gas at the gas valve. Do not touch the barrel
of the burner, for it is extremely hot! Allow the barrel of the burner to cool off
and then proceed as follows:
Begin again, but first decrease the amount of air admitted to the burner by
partly closing the ports. Turns the gas full on and then relight the burner.
Control the height of the flame by adjusting the gas valve. By taking these
steps, you should acquire a flame that is burning safely and is easily regulated
throughout the experiment.
3. Once you have a flame that is burning safely and steadily, you can
experiment by completely closing the holes (ports) at the base of the burner.
Describe what the flame looks like when the ports are completely closed.
4. Using the crucible tongs, carefully hold an evaporating dish in the tip of the
flame (underside to the flame) for about 3 – 5 minutes. Place the dish on the
ceramic pad, allow the dish to cool, and then examine the underside.
Describe the results and suggest a possible explanation for this observation.
Such a flame is seldom used in the laboratory. For laboratory work, you should
adjust the burner so that the flame will be free of yellow color, nonluminous,
and also free from the ‘roaring’ sound caused by admitted too much air.
5. Regulate the flow of gas to give a flame extending roughly 8cm above the
barrel. Now adjust the supply of air until you have a quiet, steady flame with
a sharply defined, light blue inner cone. This adjustment gives the highest
temperature possible with your burner. Using the crucible tongs, inset a 10cm piece of copper wire into the flame just above the barrel. Lift the wire
slowly up through the flame. Where is the hottest portion of the flame
located?
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6. Hold the wire in this part of the flame for a few seconds. Observe both the
flame and the wire. Describe the results of each.
7. Shut off the gas burner. Now think about what you have just observed in
procedures 4-6. Why is the nonluminous flame preferred over a yellow
luminous flame in the laboratory?
8. Now that you have mastered the Bunsen burner, you will be using it to
evaporate the filtrate from Part 3.
9. Set up the evaporating equipment as shown in Figure 9. Do NOT place the
Bunsen burner under the wire gauze and do NOT light the Bunsen burner
yet. Do NOT place the evaporating dish onto the wire gauze at this time.
10.Using your graduated cylinder, measure 15.0ml of your filtrate and
pour into your evaporating dish.
11. Place the Bunsen burner NEXT to the evaporation set up, NOT
underneath it. Light the burner and adjust the burner until you have a
blue cone that is about 1 ½” tall. Contact your instructor if you have
difficulty doing this.
12.When evaporating, the tip of the blue cone should just touch the
surface of the wire gauze. Because the flame is NOT under the wire
gauze, you can adjust the height of the iron ring and gauze without
getting burnt.
Figure 9
13.Once the adjustment is complete, carefully place the evaporating
dish and filtrate onto the wire gauze.
14. NOW you may move the Bunsen burner into position under the wire gauze
by grabbing at the base and sliding it into position.
15.Soluble products can be recovered from the filtrate by pouring the filtrate
into an evaporating dish and evaporating it nearly to dryness.
16.Pay close attention as the filtrate begins to boil. Continue heating until most
of the liquid portion has been removed.
17.Turn off the burner BEFORE all the liquid has been removed. The evaporation
set up is extremely hot. Do NOT attempt to move any equipment while it is
hot.
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18.Record two observations from the evaporation process.
19.Provide a possible explanation for what you observed
20.What PROPERTY of salt prevents it from being separated from the water by
filtration?
21.When the evaporating dish has completely cooled, discard the contents of the
evaporating dish into the sink along with the unevaporated filtrate in your
beaker.
22.At the end of this part of the experiment, all equipment you store in the lab
drawer should be completely cool, clean, dry, and arranged in an orderly
fashion for the next lab experiment.
23.Check to see that the valve on the gas jet is completely turned off. Wash
your hand thoroughly before leaving the lab.
PART 5 Dissolving a Precipitate
Apparatus
Beaker
Graduated Cylinder
Stirring Rod
Materials
Nickel precipitate from Part 3
Ammonia, NH3 6M
Procedures
1. This procedure MUST be done under your personal fume hood. This is the
white box on the wall next to your lab station. Each lab group has its own
personal fume hood.
2. Place your 250ml beaker containing the filter paper and precipitate under
your personal fume hood.
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3. Using your graduated cylinder, carefully measure 50.0ml of NH3,
ammonia.
4. Slowly pour the ammonia directly into the beaker containing the filter
paper and precipitate.
5. Gently move the filter paper around with a glass stirring rod, to ensure
that all the precipitate has dissolved.
6. Using your forceps, hold the filter paper above the solution and rinse
gently with distilled water to wash all ions back into the solution.
7. Dispose of the filter paper in the garbage can.
8. Record two observations from this part
9. Provide a possible explanation for what you observed
10. Discard of the contents of your beaker as directed by your instructor.
PART 6 Making a Solution
Apparatus
Beaker
Graduated Cylinder
Volumetric Flask
Stirring Rod
Scale
Weigh Paper
Materials
Nickel Nitrate Hexahydrate, Ni(NO3)2*6H2O
Ethylenediame (10ml/100ml Solution)
Hydrochloric Acid, HCl, 6M
Procedures
1. Using the proper procedure, mass out 4.75 grams of nickel chloride
hexahydrate. (Note: Hexahydrate means that water molecules are bonded
to the nickel chloride).
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2. Carefully add the nickel compound to a clean, dry 100ml volumetric flask.
3. Add distilled water to HALF-FILL the volumetric flask and swirl the
contents until the solid has been completely dissolved.
4. Once the solid is dissolved, slowly add distilled water to the volumetric
flask, until the bottom of the meniscus is at the etched line on the neck of
the flask. This indicated that you have exactly 100ml of solution.
5. Due to hydrogen bonding, it is difficult to thoroughly mix the solution in
the volumetric flask. Pour your solution into your 250ml beaker and stir
gently with your stirring rod.
6. Using your graduated cylinder, measure 5ml of the solution into four
separate test tubes.
7. Test tube #1 is your control.
8. Rinse your graduated cylinder.
9. Measure 5 drops of the Ethylenediamine and pour it into test tube #2.
10.Measure 15 drops of Ethylenediamine and pour it into test tube #3.
11.Measure 30 drops of Ethylenediamine and pour it into test tube #4.
12.Record your observations
13.Provide an explanation for your observations.
14.To test tubes #2, 3, and #4, add the hydrochloric acid, HCl, dropwise to
each until you observe a change back to the original color.
15.Note how many drop of HCl were required for each test tube.
Test Tube #1
None
Test Tube #2
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Test Tube #3
Test tube #4
16.Provide a possible explanation for your observations.
17.Dispose of the product as directed by your teacher. At the end of this part
of the experiment, all equipment you store in the lab drawer should be
completely cool, clean, dry, and arranged in an orderly fashion for the
next lab experiment.
QUESTIONS
Answer the following questions using complete sentences. Remember, all answers
should be your own words.
1. As soon as you enter the lab, what standard safety equipment should you put
on immediately?
2. Before doing an experiment, what should you read?
3. Before you light a burner, what safety precautions should always be
followed?
TRUE or FALSE
Read the following statements and indicate whether they are true or false. Place
your answer in the space next to the statement.
1. Never work alone in the laboratory.
2. Never lay the stopper of a reagent bottle on the lab table.
3. At the end of an experiment, save all excess chemical and
pour them back into their stock bottles.
4. The quickest and safest way to heat a material is a test
tube is by concentrating the flame on the bottom of the test tube.
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5. Use care in selecting glassware for high temperature
heating. Glassware should be Pyrex or a similar heat-treated type.
6. Safety goggles protect your eyes from particle and chemical
injuries. I do not need to make my teacher aware of the fact that
I wear contact lenses.
7. Never use the wastepaper basket for disposal of chemicals unless
told to do so by your teacher.
8. First aid kits may be used by anyone to give emergency
treatment after an accident.
CHEMICAL APPARATUS
Identify each piece of apparatus. Place your answers in the ell with the picture in it.
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