Lab Equipment

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Lab Equipment
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Beaker
Beakers hold solids or liquids that will not
release gases when reacted or are unlikely to
splatter if stirred or heated.
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Erlenmeyer Flask
Erlenmeyer flasks hold solids or liquids that may
release gases during a reaction or that are
likely to splatter if stirred or heated.
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Florence Flask
Rarely used in first year chemistry, it is used
for the mixing of chemicals. Narrow neck prevents
splash exposure.
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Graduated Cylinder
A graduated cylinder is used to measure volumes
of liquids.
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Gas Collecting Bottle
We use gas collecting bottles when large volumes
of gases are produced, and must be collected by
the displacement of water.
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Test Tubes
13 x 100 mm test tubes
Ignition tube
10 x 75 mm test tubes
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Test Tube Holder
A test tube holder is useful for holding a test
tube which is too hot to handle.
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Test Tube Brushes
Test tube brushes are used to clean test tubes
and graduated cylinders.
Forcing a large brush into a small test tube will
often break the tube.
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Test Tube Racks
Test tube racks are for holding and organizing
test tubes on the laboratory counter. Plastic
racks may melt in contact with very hot test
tubes.
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Rubber Stoppers
Rubber stoppers are used to close containers to
avoid spillage or contamination.
Containers should never be heated when there is a
stopper in place.
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Spot Plates
Spot plates are used when we want to perform many
small scale reactions at one time. We will use
these many times during the year.
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Watch Glass
A watch glass is used to hold a small amount of
solid, such as the product of a reaction.
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Glass Stir Rod
A glass rod is used to manually stir solutions.
It can also be used to transfer a single drop of
a solution.
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Medicine Dropper
A medicine dropper is used to transfer a small
volume of liquid (less than one mL).
On top of each medicine dropper is a rubber bulb
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Litmus Paper
Red litmus paper is used to identify bases.
Blue litmus paper is used to identify acids.
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Forceps
Forceps (or tweezers) are used to pick up small
objects.
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Funnel
A funnel is used to aid in the transfer of liquid
from one vessel to another.
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Mohr Pipet
A Mohr pipet measures and delivers exact volumes
of liquids.
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Wash Bottle
A wash bottle has a spout that delivers a wash
solution to a specific area. Distilled water is
the only liquid that should be used in a wash
bottle.
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Spatulas
Spatulas are used to dispense solid chemicals
from their containers.
Chemicals should never be transferred with your
bare hands.
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Beaker Tongs
Beaker tongs are used to move beakers containing
hot liquids
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Bunsen Burner
Bunsen burners are used for the heating of
nonvolatile liquids and solids.
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Evaporating Dish
The evaporating dish is used for the heating of
stable solid compounds and elements.
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Crucible
Crucibles are used for heating certain solids,
particularly metals, to very high temperatures.
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Clay Triangle
The clay triangle is used as a support for
porcelein crucibles when being heated over a
Bunsen burner.
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Crucible Tongs
For handling hot crucibles also used to pick up
other hot objects. NOT to be used for picking up
beakers!
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Ringstands and their Components
Ringstands are a safe and convenient way to
perform reactions that require heating using a
Bunsen burner.
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Ringstands and their ComponentsIron Rings
Iron rings connect to a ringstand and provide a
stable, elevated platform for the reaction.
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Ringstands and their ComponentsUtility Clamps
Utility clamps are used to secure test tubes,
distillation columns, and burets to the ringstand.
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Ringstands and their ComponentsDouble Buret
Clamps
Double Buret clamps are used to burets long
graduated tubes used in titration.
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Ringstands and their ComponentsWire Gauze
Wire gauze sits on the iron ring to provide a
place to stand a beaker.
On older wire gauze, the white material is
asbestos!
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Strikers
Strikers are used to light Bunsen burners.
The flints on strikers are expensive. Do not
operate the striker repeatedly just to see the
sparks!
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Measuring

• Volume
• Temperature
• Mass

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Reading the Meniscus
Always read volume from the bottom of the
meniscus. The meniscus is the curved surface of a
liquid in a narrow cylindrical container.
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Try to avoid parallax errors.
Parallax errors arise when a meniscus or needle
is viewed from an angle rather than from
straight-on at eye level.
Correct Viewing the meniscusat eye level
Incorrect viewing the meniscusfrom an angle
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Graduated Cylinders
The glass cylinder has etched marks to indicate
volumes, a pouring lip, and quite often, a
plastic bumper to prevent breakage.
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Measuring Volume

• Determine the volume contained in a graduated
  cylinder by reading the bottom of the meniscus at
  eye level.
• Read the volume using all certain digits and one
  uncertain digit.

• Certain digits are determined from the
  calibration marks on the cylinder.

• The uncertain digit (the last digit of the
  reading) is estimated.

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Use the graduations to find all certain digits
There are two unlabeled graduations below the
meniscus, and each graduation represents 1 mL, so
the certain digits of the reading are
52 mL.
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Estimate the uncertain digit and take a reading
The meniscus is about eight tenths of the way to
the next graduation, so the final digit in the
reading is .
0.8 mL
The volume in the graduated cylinder is
52.8 mL.
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10 mL Graduate
What is the volume of liquid in the graduate?
6
6
_ . _ _ mL
2
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25mL graduated cylinder
What is the volume of liquid in the graduate?
1
1
5
_ _ . _ mL
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100mL graduated cylinder
What is the volume of liquid in the graduate?
5
2
7
_ _ . _ mL
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Self Test
Examine the meniscus below and determine the
volume of liquid contained in the graduated
cylinder.
The cylinder contains
7
6
0
_ _ . _ mL
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The Thermometer

• Determine the temperature by reading the scale
  on the thermometer at eye level.
• Read the temperature by using all certain digits
  and one uncertain digit.

• Certain digits are determined from the
  calibration marks on the thermometer.
• The uncertain digit (the last digit of the
  reading) is estimated.
• On most thermometers encountered in a general
  chemistry lab, the tenths place is the uncertain
  digit.

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Do not allow the tip to touch the walls or the
bottom of the flask.
If the thermometer bulb touches the flask, the
temperature of the glass will be measured instead
of the temperature of the solution. Readings may
be incorrect, particularly if the flask is on a
hotplate or in an ice bath.
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Reading the Thermometer
Determine the readings as shown below on Celsius
thermometers
8
7
4
3
5
0
_ _ . _ ?C
_ _ . _ ?C
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Measuring Mass - The Beam Balance
Our balances have 4 beams the uncertain digit
is the thousandths place ( _ _ _ . _ _ X)
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Balance Rules
In order to protect the balances and ensure
accurate results, a number of rules should be
followed

• Always check that the balance is level and
  zeroed before using it.
• Never weigh directly on the balance pan. Always
  use a piece of weighing paper to protect it.
• Do not weigh hot or cold objects.
• Clean up any spills around the balance
  immediately.

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Mass and Significant Figures

• Determine the mass by reading the riders on the
  beams at eye level.
• Read the mass by using all certain digits and
  one uncertain digit.

• The uncertain digit (the last digit of the
  reading) is estimated.
• On our balances, the thousandths place is
  uncertain.

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Determining Mass
1. Place object on pan
2. Move riders along beam, starting with the
largest, until the pointer is at the zero mark
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Check to see that the balance scale is at zero
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Read Mass
1
1
4
? ? ?
_ _ _ . _ _ _
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Read Mass More Closely
1
1
4
4
9
7
_ _ _ . _ _ _