Physical
Chemistry Lab 303/307 - Fall 2009
Revised October 12, 2009 see the section in red.
Instructor:
Dr. I. Francis Cheng
26A Renfrew Hall
Office Hours: M&T 2:30-5:30, you are welcome to stop by
my office anytime
Teaching
Assistant:
Aaron Stancik
Office: 27 Renfrew Hall
Office Hours: R 2:30-4:30
Physical Chemistry Lab is one of the most important parts of an undergraduate's University training. Some of the goals of this course are to:
- expose students to classical physical chemistry methods
and concepts.
- help students develop important experimental skills.
- train students to observe experiments and record their
observations.
- show students how to analyze data critically.
- teach students how to present experimental results.
- encourage students to write clearly, concisely and
cogently.
In general, we expect students in this course to perform experiments, analyze data, and present the results in a clear and scholarly manner. This process forms the heart of conducting meaningful scientific research and the skills learned in this lab will last a lifetime. Students are expected to conduct the experiments with minimal assistance from the lab TA and to use their own creativity to solve problems.
In this course, students are expected to conduct three investigations; one in the area of thermodynamics, one in equilibrium and one on transport and bulk properties. A list of experiments is attached. Procedures for these experiments can be found in any number of Physical Chemistry lab books and a selection of these lab books are on reserve in the library. Students are expected to prepare for the lab and to have a detailed procedure before beginning the experiment. Students will work in pairs for each experiment.
Lab Reports:
- Experiment #1 Long Written Report (100pts) Lab period
dates August 31-September 30
This report will be team written, 12 pages maximum including figures and tables. Authors should strive to present their material with the utmost conciseness consistent with clarity. The introduction should contain only enough background material to show why the work was done. Experimental descriptions should be referenced and only significant details described. The discussion and conclusion sections should be clear and to the point. The report layout should follow the Journal of Physical Chemistry A/B/C format described, see http://pubs.acs.org/journals/jpcafh/index.html. Ignore the synopsis section, but be sure to include a conclusion clearly stating what was learned from the experiment. Make sure that the reports are present in a modern professional format. Learn how to use the equation editor in your word processor for example superscripts should be presented as
Please see me or the TA if you should have questions about your equation editor.
Due Dates
- Sept. 25th 5:00 pm: Introduction (15 pts.) and Experimental (15
pts.)
- Oct. 2nd 5:00 pm: Abstract (15 pts), Results (10 pts.),
Discussion (20 pts.), Conclusions (10 pts.), References (10 points).
Both a hard copy and a MS Word .doc or .docx file need to be turned in.
- Experiment #2 Short Written Report (100pts) October
5-28
Week of Sept. 29th Lab Lecture on Error Analysis.
After completing the second experiment, each team will submit a written report in an abbreviated
3-page format, These reports should be written independently, but co-workers
should be listed as co-authors. This report will include an abstract,
instead a full written procedure only a reference, calculations and an error
analysis for the lab.
Due Date: November 6th.
Both a hard copy and a MS Word .doc or .docx file need to be turned in.
**Added October 12, 2009**
Other Topics in Error Analysis
·
R2
·
Uncertainty of Least Squares Fitted Lines (from MathWorld), Problem (Excel Spreadsheet answer)
·
The t-test for assessment of two different groups of data.
Wikipedia
·
A t-test calculator (for comparison of two sets of
data)
·
Horwitz Trumpet (link 2, 3)
- Experiment #3 Oral Report 100pts
After successful completion of the third experiment, each group will present a 15 minute oral report (using Power Point, overheads, charts or slides) to the rest of the class on the important features of the experiment. For this report, students are encouraged to focus on procedures and calculations with an eye toward helping other students successfully complete this experiment.
Presentation Week: December 7th.
The .ppt or .pptx file need to be turned in.
v General Lab Skills 50pts
v Total points possible: 350
Each of these reports will be graded based on the following criteria:
- organization
- clarity
- completeness
- graphics
- references
- format
- believability
- understanding
- results
Late reports will not be accepted.
It is assumed that all students have an active e-mail account, access to word processor and spread-sheet software. If you have questions about any of this, please feel free to contact me either in person or electronically.
Important Dates:
|
Week of |
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August 31 |
Lab Lecture, set up first lab,
write experimental, begin experiments |
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Sept 7 |
Labor Day week no labs |
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Sept 14 |
Continue Lab 1 |
|
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Sept 21 |
Lab 1 |
Introduction and
Experimental sections due Sept 25 at 5 pm by email. |
|
Sept 28 |
Lab 1 |
Abstract, Results, Discussion,
and Conclusions Due Oct 2 at 5 pm by email |
|
Oct 5 |
Begin Lab 2 |
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Oct 12 |
Lab 2 |
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Oct 19 |
Lab 2 |
|
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Oct 26 |
Lab 2 |
|
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Nov 2 |
Begin Lab 3 |
Lab report due Nov 6 at 5
pm by email |
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Nov 9 |
Lab 3 |
|
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Nov 16 |
Lab 3 |
|
|
Nov 23 |
Thanksgiving week, no labs |
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Nov 30 |
Lab 3 |
|
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Dec 7 |
Oral Presentations |
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Description
of Projects:
v Thermodynamics
1.
Heat of Combustion.
– Benzoic Acid, Naphthalene, Anthracene and Biphenyl
o Simes p420
o Modifications
§ Do at least 3 runs of 4 compounds.
§ Benzoic Acid
§ Napthalene
§ Anthracene
§ Biphenyl
§ Use 0.5-g of each
§ In your report comment on
the structural features, including resonance energies
§ The calorimeter constant can be obtained from the combustion of benzoic
acid.
§ 
§ Where C is the calorimeter constant, Qb is the heat of
combustion of benzoic acid (26435.8 J/g), mb is the mass of benzoic
acid in grams, cFe is the combustion of the iron wire (5858 J/g), cN
is the formation of nitric acid (57.7 J/g) and ΔT is the corrected
temperature rise in the calorimeter.
§ Note that if precautions are taken cN can be ignored.
§ Clean the bomb calorimeter thoroughly
§ Flush the bomb with air, then fill to 20 atm of O2, slowly
releasing the contents and repeat at least three times. Calculate averages and discard outliers (Q-test). Do more runs if
necessary.
§ Attach the nichrome wire through each terminal contact and through the
sample but do not let the wire make contact with the pan.
§ Attach the electrical connections to the bomb and place it inside the
calorimeter bucket.
§ Start stirrer.
§ Start the temperature program and a constant temperature baseline.
§ Start ignition, obtain temperature vs. time data.
§ Weigh unburned wire.
§ Iron Wire should be free of bends and extreme kinks.
§ Calculate Resonance Energies
§ Make sure that Electrical Connections remain dry then fill with H2O.
2.
Heat capacity Ratio
of Gases.
o Garland p104
3.
Heats of Ionic
Reactions.
o Garland p167
o Modifications
§ Apparatus in Figure 1
§ Delete compressed air - use
stir bar
§ Use thermocouple instead of
thermometer
§ Slowly add solution B into
A
§ Ignore apparatus in Figure
2
v Equilibrium
1.
Monomer-Dimer
Equilibrium
o Simes p545
o Notes
§ Standardize 0.1M NaOH with KHP, make several titrations.
§ Use 10 125 mL Erlenmeyer flasks
§ Make at least 250 mL aqueous stock solution of salicylic acid.
§ Add 25 mL of this solution to each of the 5 flasks
§ Dilute each with 8, 15, 25, 50, 75 of H2O
§ Make at least 250 mL of saturated salicylic acid in toluene. Make sure
this is done in the hood.
§ Repeat dilutions as above
§ Shake vigorously and let stand for one week. This allows the solutions to
come to equilibrium.
§ Take out 10 mL aliquots from each flask and titrate with the standardized
NaOH (about 0.05 M)
§ When titrating the toluene solutions add 25 mL of H2O and stir
rapidly while doing so.
§ Calculate equilibrium constants.
2.
Conductance of
Solutions.
o Simes p558
o Modifications
§ Ignore Wheatstone Bridge
Setup
§ Use conductance meter
3.
Binary Liquid-Vapor
Phase Diagram.
o Garland p208
o Modifications
§ Use cyclohexane and ethanol
§ Construct a calibration curve (mole fraction of one of one component, 0,
0.25, 0.5, 0.75, 1 and total volume 5-10 mL vials)
§ Find RI and plot vs. concentration
§ Distillation
§ Add 25 mL of ethanol, distill to a constant temperature and obtain a
residue sample and the liquid. Determine their R.I
§ Add 2-mL repeat
§ Add 4, then 6, 8 and 12-mL
§ Repeat Distillation starting with pure cyclohexane and obtain the other
side of the azeotrope
§ Determine azeotrope compositions and compare to literature
§ Determine Heterogeneous vs. homogeneous attractions
§ Calculate Van Laar constants and the activity coefficients.
v Transport
and Bulk Properties
1.
Partial Molar
Volume.
o Garland p172
2.
Surface Tension of
Solutions.
o Garland 292
o Notes
§ Clean capillaries by soaking in HNO3, moving it up and down in
the acid solution. Rinse with 18 MΩ-cm water.
§ Determine the radius by measuring capillary rise of pure water. (71.8
dynes/cm at 298K).
3.
Adsorption of
Acetic Acid by a Solid.
o Sime p528