Transcript LABORATORY GLASSWARE AND EQUIPMENT LAB 2 Welcome • Welcome to the chemistry lab! • Chemistry is a lot of fun, but can be even more.

LABORATORY
GLASSWARE AND
EQUIPMENT
LAB 2
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 in use, 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. 65 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.
• Why do we start and finish each experiment with
clean glassware?
• Your instructor will address 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
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.
Glassware
• The use of many pieces of glassware is intuitive. You will
not be shown how to use a beaker, graduated cylinder,
medicine dropper, or filtering flask.
• Other pieces of glassware are highly specialized. You will
now be shown how to properly prepare and utilize the
following pieces of glassware:
• Volumetric pipet
• Buret
Experimental Procedure and Report
• Follow the instructions starting on page 72.
• Record your responses starting on page 85.
• Do not leave the lab until you have followed all of the
instructions under Part 7.
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 next quiz.
• Submit your Lab 2 Report at the start of next week’s lab.