Lab 2

Report
LABORATORY
GLASSWARE AND
EQUIPMENT
LAB 2
Outline
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Welcome
Reading a Meniscus
Types of Glassware
Reading and Recording Volumes
Cleaning Glassware
Digital Thermometer
Using Glassware
Using a Buret
Using a Pipet
Using a Volumetric Flask
Cleanup
Next Assignment
Welcome
• Welcome to the chemistry lab!
• Chemistry is a lot of fun, but can be even more so
if you are familiar with the equipment you will be
using in lab.
• Remember – whenever there’s glassware or
chemicals out in lab, everyone has to wear
goggles!
Reading a Meniscus
Meniscus and Parallax
Types of Glassware
• Graduated glassware
• Volumetric (non-graduated) glassware
Graduated Glassware
• Beakers
• Use: To contain certain volumes of solutions
• Filtering Flasks
• Use: To contain certain volumes of solutions
• Graduated Cylinders
• Use: To measure out exact volumes.
• Burets
• Use: To dispense exact volumes.
Volumetric (non-graduated) Glassware
• Volumetric Pipets
• Use: To measure out exact volumes. This is the most
accurate glassware in lab.
• Volumetric Flasks
• Use: To make up specified volumes and concentrations of
solutions.
Reading and Recording Volumes
• We use significant figures to indicate the accuracy
and precision of glassware.
• Significant figures for graduated glassware are
determined differently from those of volumetric
glassware.
Significant Figures:
Volumetric Glassware
• Use the Tolerance table on p. 71 to determine
glassware tolerance, unless it is printed on the
glassware.
• For example:
• The 50 mL volumetric flask has a tolerance of ± 0.05 mL.
Whenever you use your 50 mL volumetric flask, you will
always report two zeros after the decimal, i.e. 50.00 mL.
Volumetric Flask
When this volumetric flask
is filled to the calibration
mark, what volume should
be reported?
Volumetric Pipet
When this pipet is used to dispense solution, what volume should be
reported?
Volumetric Pipet
When this pipet is used to dispense solution, what volume should be
reported? And to which line should the pipet be filled?
Significant Figures:
Graduated Glassware
1.
2.
3.
Look at the glassware in question.
Find the smallest graduation.
Report your volume to the closest 10% of the
smallest graduation.
Reading Graduated Glassware
Reading Graduated Glassware
Reading Graduated Glassware
Reading Graduated Glassware
Reading Graduated Glassware
Reading Graduated Glassware
Smallest Graduation
• A. Calculate major graduation – major graduation
• B. Determine the number of spaces between two
major graduations
• Smallest Graduation = A / B
Reading Beakers
What volume should be reported?
Reading Beakers
• Smallest graduation: 10 mL
• 10% value: 1 mL
• Volume to the closest 10% of the SG:
48 mL
Reading Graduated Cylinders
What volume should be reported?
Reading Graduated Cylinders
• Smallest graduation: 1 mL
• 10% value: 0.1 mL
• Volume to the closest 10% of the SG:
52.8 mL
Reading Burets
What volume should be reported?
Reading Burets
• Smallest graduation: 0.1 mL
• 10% value: 0.01 mL
• Volume to the closest 10% of the SG:
40.05 mL
Cleaning Glassware
• Each student has glassware at their individual
stations. Each student is responsible for the care of
their glassware.
• Your instructor will demonstrate the appropriate ways
to:
• Wash glassware with soap and a brush
• Rinse glassware with tap water
• Do a final rinse with very little distilled water from the
distilled water faucet or from your water bottle
• Dry your glassware
• Return glassware to the APPROPRIATE drawer
Cleaning Glassware
• Now it is your turn…
• Remove a 400 mL beaker from your glassware
drawer.
• Wash the 400 mL beaker with soap, brush, and
water.
• Do a final rinse with distilled water, then dry it
completely.
• When you are finished, add approximately 200 mL
tap water to the beaker and return to your station.
Using Glassware
• Volume is space. The volume of a liquid, solid, or
gas is the space occupied by that substance.
• The base unit of volume in the metric system is the
liter (L).
• All of the glassware in this lab have volume
measurements in milliliters (mL).
• There are 1000 mL in 1 L.
Using a Digital Thermometer
• Carefully remove your digital thermometer from your
glassware drawer.
• We use digital thermometers in lab to determine
the temperature of solutions.
• Our digital thermometers can measure temperature
in degrees Celsius (ºC) or degrees Fahrenheit (ºF).
• Eventually you should be able to interconvert
between these two scales. Kelvin will also be
addressed in class.
• Your instructor will point out all major features of this
unit.
Part 1:
• Assemble the following equipment on your bench:
• 400 mL beaker (filled with 200 mL of tap water)
• digital thermometer
• Determine the temperature of the tap water in your 400
mL beaker in both temperature scales.
• Record these values in your lab manual.
Part 2:
• Read through the procedure for using a beaker,
filtering flask, and graduated cylinder on page 78-79.
• Assemble the following equipment on your counter:
• 400 mL beaker (fill with about 200 mL of tap water)
• 100 mL beaker
• 50 mL graduated cylinder
• 250 mL filtering flask
• Medicine dropper (to bring glassware to level)
• From the 400 mL beaker, fill each of the other pieces
of glassware with exactly 50 mL of tap water.
• Ask your instructor if you need help.
• Answer the questions in your lab manual.
Using a Buret
• Remove a 25 mL buret from your glassware drawer.
• Notice the reverse graduations on it.
• Burets are used to dispense a very precise
volume of solution and is therefore read
differently.
• Your instructor will demonstrate how to set up the
buret clamp and stand. Pay close attention!
• Read through the procedure for using a buret on
pages 79-80.
Part 3:
• Now it is your turn…
• Practice using the 25 mL buret by adding tap water
from your 100 mL beaker and dispensing it into a 400
mL beaker.
• Answer the questions in your lab manual.
Using a Pipet
• Most glassware is really easy to use. The pipet,
however, takes a little bit of practice.
• The pipet dispenses a very exact volume.
• Remove a 5 mL pipet and pipet bulb from your
glassware drawer.
• Read through the procedure for using a volumetric
pipet on pages 81-82.
• Your instructor will demonstrate appropriate pipetting
technique. Pay close attention!
Part 4:
• Now it is your turn…
• Practice pipetting 5.00 mL of tap water from your 100
mL beaker and dispensing it into a 400 mL beaker.
Do this several times.
• Answer the questions in your lab manual.
Using a Volumetric Flask
• Remove a 25 mL volumetric flask from your
glassware drawer.
• The volumetric flask is used to make solutions of
known (and accurate) concentration.
• Read through the procedure for using a volumetric
flask on pages 83.
• Your instructor will demonstrate the proper technique
for making a solution using a volumetric flask. Pay
close attention!
Part 5:
• Now it is your turn…
• Practice making a solution using a 25 mL volumetric
flask.
• Be sure to use the medicine dropper to fill the flask to
volume.
• Answer the questions in your lab manual.
Part 6:
• Determine the temperature of the remaining tap
water at your station in both temperature scales.
• Answer the questions in your lab manual.
Cleaning
• Carefully clean and dry all of the equipment you used
today.
• Glassware gets slippery when wet, so hold on!
• Place your equipment / glassware in the appropriate
locations in the glassware drawer.
• If you are unsure of their proper location, refer to the
blue binder in the bottom drawer.
Next Assignment: Lab 3
• Read the required reading sections in your textbook and
lab manual.
• Complete and submit your pre-lab questions by the
deadline.
• Study for the quiz.
• Turn in your Lab 2 Report for preliminary grading at the
start of next week’s lab.

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