APPLICATIONS OF TECHNOLOGY IN TEACHING CHEMISTRY
An On-Line Computer Conference
June 14 TO August 20, 1993
PAPER 1
(Revised June 10, 1993)
THE USE OF COMPUTERS IN A JUNIOR-LEVEL ANALYTICAL CHEMISTRY -
PHYSICAL CHEMISTRY LABORATORY COURSE
Donald Rosenthal, Department of Chemistry, Clarkson University
Potsdam NY 13699, E-mail: ROSEN1@CLVM.BITNET
SCHEDULE: Short questions on this paper: June 14, 1993
Discussion of this paper: June 21 and 22, 1993
ABSTRACT:
This paper describes how students use computers and computer
interfaced instruments in a laboratory course. The experiments and
laboratory reports are discussed. The use of word processing,
numerical methods, statistical methods, graphing and other software is
explained and illustrated.
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I. INTRODUCTION
The American Chemical Society's Committee on Professional
Training has established guidelines for undergraduate professional
education in chemistry (1 - see References in Section VII of this
paper). An approved program must include at least 500 hours of
laboratory work in chemistry. Some experiments must involve
instrumental methods of analysis and experimental physical chemistry.
"Laboratory instruction should include practical experience with
instrumentation for spectroscopy, separations techniques,
electrochemical methods and computerized data acquisition and
analysis. . . . It should give students . . . competence to . . .
analyze data statistically and assess reliability of results . . .
interpret experimental results and draw reasonable conclusions . . .
communicate effectively through . . . written reports." (1)
There are many standard textbooks describing the theory and
practice of instrumental analysis (2-6) and experimental physical
chemistry (7-8). Surveys of and recommendations for the content of
instrumental analysis courses have recently been made (1,9-12), and
considerable revision of the traditional physical chemistry laboratory
course has been proposed (13).
This paper describes an Instrumental Laboratory course
(instrumental analysis - physical chemistry) which I have taught to
second semester juniors for over twenty years at Clarkson University.
During this period of time the experiments, instruments and nature of
the experimental reports have changed. In this paper I will describe
the course as I last taught it during the spring semester of 1991. In
order to place the course in proper perspective, the computing
background of the students and the relevant curriculum will be
described in the next two sections of this paper.
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II. COMPUTERS AND COMPUTING BACKGROUND OF THE STUDENTS
Since 1983 every entering freshman at Clarkson University has
been issued a personal computer. The computer was initially a Zenith
Z-100, later a Zenith Z-248, and for the last few years students have
been issued an IBM PS/2. The PS/2 computer has 1 megabyte of memory, a
30 megabyte hard disk and a 3 1/2 inch disk drive. MS DOS is the
operating system and Word Perfect is currently provided to each
student. Appropriate additional software is provided as needed.
In addition, each student receives an instructional access code
which permits access to electronic mail, file transfer and printing
services on a campus-wide Novell network. The network contains a
Software Distribution System which permits students to download
software to 3 1/2 (or 5 1/4) inch floppy disks for use on their
personal computers. An instructor may supplement these services by
granting access to other computing systems which contain specialized
services and facilities.
All undergraduates are required to take a three credit
introductory computer course as first semester freshmen. This course
emphasizes programming and the use of applications software.
Beginning in the early 1970's and for many years, I taught the course
to chemistry majors on a PDP-8 which belonged to the Chemistry
Department and an IBM main frame. In the early days there was not a
great deal of applications software available and an introduction to
programming in BASIC and FORTRAN was provided. The students were
asked to write t-test, linear least squares and other programs they
later used in their laboratory courses. Presently, our chemistry
students learn to use Word Perfect and Quattro or Lotus-1,2,3 in the
introductory course.
I have distributed some CAI, plotting, numerical and statistical
analysis software to my students in general and analytical chemist via
the Software Distribution System. Another faculty member has helped
developed some molecular modelling software which is used in organic
chemistry. One faculty member is using Hyperchem in his organic
course using a Departmental computer.
There are terminal rooms connected to the network distributed
around campus and several computers available in the chemistry
laboratories.
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III. CHEMISTRY COURSES TAKEN BY CHEMISTRY MAJORS
Chemistry majors learn to perform some gravimetric and volumetric
analysis in the freshman chemistry laboratory course and subsequent
courses. As first semester sophomores a three credit lecture course
in Spectroscopy and a three credit Spectroscopy Laboratory course are
required. These courses cover atomic emission and absorption
spectroscopy, fluorescence, visible-ultraviolet, infrared and mass
spectroscopy and nuclear magnetic resonance. Some of the
spectroscopic techniques are used in the three credit organic
chemistry laboratory courses which are taken in the second semester of
the sophomore year and the first semester of the junior year. The
organic chemistry lecture course is taken during both semesters of the
sophomore year. In the first semester of the junior year chemistry
majors take two three credit lecture courses - Separations,
Radiochemistry and Electrochemistry; and the first semester of
Physical Chemistry. The second semester Instrumental Laboratory
course is designed to illustrate principles and provide practice in
techniques considered in the two first semester courses and in second
semester Physical Chemistry (taken concurrently with Instrumental
Laboratory).
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IV. LABORATORY ORIENTATION LECTURES AND ASSIGNMENT
Instrumental Laboratory has two three-hour laboratory meetings
each week. The first three laboratory sessions were used for
laboratory orientation lectures.
A. First Laboratory Orientation Session
During the first session the experimental report, errors and the
use of statistical and numerical methods computer programs were
discussed and a problem assignment was handed out.
1. Word Processing
Students were familiar with and were expected to use a word
processor in preparing the text of their reports and a plotting
program for all plots. Since the preparation of tables can be
tedious, students were told they could prepare tables by hand.
2. Preliminary Report
A hand-out describing the nature of the experimental report was
distributed and discussed. In order to insure that each student
thoroughly understood the experiment he or she was to perform, a
Preliminary Report had to be prepared and turned in to the teaching
assistant at least a day before the experiment was performed. The
Preliminary Report contains the following:
a. A brief statement of the Objective of the Experiment
b. A Schematic or Block Diagram of the Apparatus (hand drawn)
c. Basic Principles and Equations - Mathematical equations and
sketches used wherever possible.
d. An outline of the Typical Procedure in Making a Measurement
with the Equipment.
e. A list of Precautions
The Preliminary Report was no more than three pages in length and
was read by the assistant prior to the student's beginning
experiments. Corrections, additions and other comments were made on
the Preliminary Report. If the Preliminary Report was seriously
flawed, the student was asked to re-write the Preliminary Report and
submit it with their final report.
During the orientation session the Preliminary Report for a
specific experiment was discussed.
3. Final Report
The final report contained the Preliminary Report (2a through 2e)
plus the following:
f. Data - The laboratory data sheets (carbon copies torn from the
laboratory notebook)
g. Summary of Results in tabular and graphical form
h. Precision and Accuracy - t-test, least squares, estimate of
random and residual error and total error.
i. Answers to any specific questions asked in the instructions
for each experiment.
4. Errors and Problem Assignment
Time was spent during the orientation session discussing random
errors, residual errors, the propagation of errors, and estimating the
total error. A problem assignment was distributed which provided
practice in error analysis and the use of the computer programs.
5. Computer Programs
A number of computer programs were available to the students on
the Novell Network's Software Distribution System. These were
programs developed over a period of years specifically for this
course. These programs could be downloaded to disk and used by the
students on their personal computers. Also, the programs were
available on computers in the laboratory. The following programs were
available:
a. t-test
Values of x(i) are input. The program calculates the mean
(average), standard deviations (S.D.(x) and S.D.(mean)) and
the random error at the 90% level (t S.D.(mean)).
b. linear least squares
Values of x(i),y(i) are input and the program least squares
fits the data either to the equation y = ax or y = ax + b.
The least squares slope and y intercept (for y = ax + b)
are calculated. The standard deviations of the slope and
intercept and standard deviation from regression are
calculated. (See Figure 9 for typical program output).
c. roots of a quadratic equation
The numerical values of A, B and C for the equation
A X^2 + B X + C = 0 are input. The two roots are
calculated and printed.
d. Root of f(x) = 0
This program can be used to find a real root for any equation
of the form f(x) = 0. A statement y = f(x) is inserted in the
program. The user specifies a "reasonable" minimum and
maximum value of x and the percent accuracy to which the root
is to be calculated. The program finds a value of x which
makes y very small or equal to zero, or indicates no root was
found. (14)
e. Simultaneous linear equations with two unknowns
The numerical values of a(1),b(1),c(1) and a(2),b(2),c(2) are
input for the equation a(i)x + b(i)y = c(i). x and y are
calculated.
f. A plotting program
Clarkson University has a site license for IDPS (Interactive
Data Plotting System - Version 4.0 - Copyright 1986 Unicorn
Micro Ware). This program permits a user to read multiple
data files containing x-y pairs and plot them. The user has
control of text and numeric labels, line style, markers, data
display range and can select a logarithmic mode. Linear least
squares lines can be generated for a given set of data. IDPS
has considerable versatility in providing different kinds of
plots for different kinds of printers or plotters.
(See Figures 8 and 10)
g. Quadratic least squares
Values of X(I),Y(I) are input to the program. Least squares values
of A(1), A(2) and A(3) and their standard deviations are calculated
for the equation Y(I) = A(1) + A(2) X(I) + A(3) X(I)^2.
(See Figure 14 for typical program output)
h. Numerical integration
This program was specifically designed to integrate current
versus time data to determine the number of coulombs required
to oxidize or reduce a compound in the controlled potential
electrolysis experiment (see below). The time in seconds and
voltage in millivolts is input together with the resistance
of the stardard resistor. The current is calculated using
Ohm's Law. The integration is performed and includes an
extrapolation to zero current. The total number of coulombs
required to oxidize or reduce the compound is calculated.
(See Figure 11)
A demonstration of the use of these programs was provided in the
orientation session together with some printed instructions.
In recent years a spreadsheet (Quattro Pro or Lotus-1,2,3) and
other applications programs have been used in the freshmen programming
course. These programs have been used by some students in preparing
their final reports.
B. Second Laboratory Orientation Session
Instructions for Instrumental Analysis Experiments
In the second orientation session the printed instructions for
the first six experiments were distributed and the experiments were
discussed. These experiments use techniques considered during the
previous semester in the Separations, Radiochemistry and
Electrochemistry course. The students pair up to form a group. Up to
six groups (twelve students) can be handled in a laboratory section.
(We have had as many as three sections in this course.) Each group
works on a different experiment.
The six experiments in the first half of the course are:
1. Gas Chromatography - Qualitative and Quantitative Analysis
and Column Characteristics (6 laboratory hours)
2. High Performance Liquid Chromatography - Qualitative and
Quantitative Analysis and Column Characteristics (6 hours)
3. Liquid Scintillation Counting - Quantitative Analysis for C-14 and
H-3 labelled compounds; and Activation Analysis and
half-life determination of an unknown (6 hours)
4. Gamma Radioactivity - Gamma ray spectroscopy and Quantitative
Analysis (3 hours)
5. Controlled Potential Electrolysis - The reduction of
p-cyanoacetophenone, determination of n and identification
of the reduction product using infrared and ultraviolet
spectroscopy. (6 hours)
6. Polarography - Reduction of metal ions, oxidation or reduction of
organic compounds, limiting currents, and quantitative
analysis using conventional and differential pulse
polarography. (12 hours)
Experiments 5 and 6 were devised by Professor Petr Zuman. I
developed instructions for the other experiments.
C. Third Laboratory Orientation Session
Answers to the Problem Assignment
The third orientation session was held during the second week of
the semester. At this session the answers to the six problems handed
out during the first session were discussed. At the end of the
session the assignment was collected for grading.
The purpose of this problem assignment was to make certain the
students were able to use the t-test, linear least squares and
plotting programs and understood the concepts of error analysis and
error propagation. A knowledge of this material was needed in
preparing the laboratory reports.
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V. SEPARATIONS, RADIOCHEMISTRY AND ELECTROCHEMISTRY EXPERIMENTS
AND REPORTS
During the next seven weeks students performed the six
experiments list in section IV-B. At any given time each group was
working on a different experiment. At the beginning of the experiment
the Preliminary Report was returned to the students and a teaching
assistant and/or I would talk to the individual groups briefly about
the experiments they were to start. The final report for each
experiment was due one week after completion of the experiment.
Rather than describing all these experiments, one experiment -
Gas Chromatography - will be described in considerable detail.
Another experiment - Controlled Potential Electrolysis - will be
Mentioned more briefly.
A. Gas Chromatograpy Experiment
A Perkin-Elmer Sigma 2000 gas chromatograph interfaced with a
computer (or data station) was used for this experiment. A flame
ionization detector and a six foot OV-101 column was installed in the
instrument. The instrument was controlled and monitored by the data
station.
1. Qualitative Analysis and Column Characteristics
In the first laboratory period the instrument is turned on and
programmed so that the retention times of a series of seven
qualitative knowns (heptane, octane, nonane, decane, undecane,
4-methyl-2-pentanone and cyclopentanone) could be determined. The
chromatograms of a mixture of the seven knowns, an unknown and
charcoal lighter fluid or unleaded gasoline was obtained. Temperature
programming was employed so that good separations were obtained and
the complete elution of the sample was obtained within eight minutes.
Also, the retention times were obtained for the isothermal separation
of the seven component mixture. Finally, students were asked to
devise a temperature programming scheme to separate hexane from
heptane.
The instrument provides (via the data station) a table of peaks,
their retention times, peak areas and peak heights. A plot of each
gas chromatogram was obtained. Figure 1 shows the gas chromatogram
obtained for the seven component mixture. The table obtained for
the seven component mixture is shown in Figure 2.
Figures 3 and 4 show the data obtained for the same mixture when the
column was maintained at a fixed temperature. (Most figures are
taken from student reports.) Figure 5 summarizes the retention time
data. (N.B. Figures 1, 3, 7, 8, 10 and 12 have been added to this
paper to provide participants with practice inviewing figures. While
these figures add more detail to the paper, they are not essential.)
Students were given data obtained with another instrument using a
different column, a thermal conductivity detector and different
conditions (See Figure 6). The retention times and the order of
elution of constituents were different. Students were asked to
discuss and compare these two sets of data in their final reports.
Students were asked to calculate the number of theoretical plates
(P) using two different equations (See Figure 7). From P the height
of an equivalent theoretical plate (H.E.T.P.) was calculated. P and
H.E.T.P were calculated using the Sigma 2000 isothermal elution curves
for heptane and decane. The resolution was calculated using some of
the data.
A plot of ln(adjusted retention time for the isothermal data) vs
the number of carbon atoms in the chain for the saturated hydrocarbons
was used to obtain the Kovats indices for 4-methyl-2-pentanone and
cyclopentanone (equal to 100 times the value of n - see Figure 8).
2. Quantitative Analysis
During the second laboratory period the chromatograms of six
quantitative knowns was obtained. In addition, each student obtained
the chromatogram for his individual unknown. 0.1 uL of each solution
was injected. Each solution contained heptane and octane with nonane
as an internal standard and decane as the diluting solvent.
Each student was asked to include a table in his final report
which contained the peak height and area for each heptane, octane and
nonane peak. The heptane/nonane and octane/nonane ratio of peak
heights and peak areas were calculated and tabulated for the knowns
and the unknown. Linear least squares fits of the peak height, peak
height ratio, peak area and peak area ratio vs concentration for
heptane and octane. Also, plots were made. (see Figures 9 and 10).
Four least squares fits were obtained for heptane and four fits for
octane. The students were expected to examine the results of each
least squares calculation and decide whether there was a linear
relationship (of the form y = a x). Each student was asked to use
each fit to obtain an estimate of the number of grams of heptane and
octane in the unknown. (There were four estimates for heptane and
four estimates for nonane). The students were asked to give a "best
estimate" of the amount of heptane and octane in the unknown and an
error estimate. The "best estimate" is not necessarily the average of
the four estimates. The students were expected to explain how they
decided on a "best estimate".
3. Numerical and Statistical Methods Programs Used
A t-test, linear least squares and plotting programs were used
for this experiment.
4. Error Analysis
Each student was asked to estimate the error in the determination
of heptane and octane in the unknown. They were expected to consider:
a. the variation of volume of sample injected,
b. random error in peak height and peak area,
c. effect of using height ratios and area ratios,
d. error associated with use of the calibration curves
(standard deviation in the least squares slope),
e. error in preparing the unknown solution,
f. any other significant sources of errror.
B. Controlled Potential Electrolysis Experiment
In this experiment the contolled potential reduction of 2 E-3 M
p-cyanoacetophenone (4-acetylbenzonitrile 1443-80-7) in 10% ethanol -
0.5 M sulfuric acid is carried out in a cell with a mercury pool
working electrode (cathode) and a platinum wire anode. A
silver-silver chloride reference electrode is used. Nitrogen gas is
used to remove and then exclude oxygen. The solution is stirred with
a magnetic stirrer. The electrode reaction is:
- +
R + ne + nH ----> P
where R is p-cyanoacetophenone and P is the product of the reaction.
The nature of the product is deduced from the determination of n (the
number of electrons per molecule of R) and the ultraviolet and
infrared spectra of the product (15).
1. Choice of Potential
The current versus potential curve was determined from 0 to -1.2
volts vs the Ag-AgCl reference electrode. A potential was selected in
the range where the first first wave showed a limiting potential.
2. Controlled Potential Electrolysis
The electrolysis was performed on freshly prepared solution.
The current was determined by measuring the voltage drop across a
one ohm standard resistor every 30 seconds until the current has
dropped to about 5% of its original value.
For a simple electroreduction carried out (with 100% current
efficiency) at controlled potential, uniform stirring and constant
temperature, the current should theoretically decrease exponentially
with time. A plot of log i vs. t should be a straight line. n can be
calculated from the y intercept, slope and original concentration of
the p-cyanoacetophenone. In practice, linear plots are sometimes not
obtained. Deviations from linearity can be due to non-uniform
stirring and/or a change in temperature. In addition to making the
log plot, students were asked to determine the total number of
coulombs of electricity required to reduce the p-cyanoacetophenone by
determining the area under the current versus time curve (numerical
integration - see section IV-A-5-h above).
The controlled potential electrolysis was performed during the
first laboratory period. The spectra were obtained during the second
laboratory period (see below).
3. Spectra of the Product
The U.V. spectrum of the product solution was compared with the
spectra of p-cyanoacetophenone and acetophenone.
A portion of the solution containing the electrolysis product was
neutralized with sodium hydroxide solution. The product was extracted
with chloroform and evaporated to form a thin film on a salt plate.
The infrared spectrum of the product was obtained using a Perkin Elmer
Model 1430 Ratio Recording Infrared Spectrophotometer and Data
Station.
From the determination of n and the spectra students were asked
to deduce the reduction product and to write a balanced half reaction
for the controlled potential electrolysis. (Four electrons are
involved in the reduction process. It can be deduced from the spectra
that only the CN group is reduced in this initial four-electron step
(15).)
4. Computer Programs and Error Analysis
Each student was asked to plot and perform a linear least squares
analysis of log i vs t. From these results, each student was expected
to decide whether current decreased exponentially with time. If there
was an exponential decay, n was obtained from the data. Also,
students were asked to calculate n from numerical integration of the i
vs t data (see Figure 11). Values of n (number of electrons), k (in
the equation i = kC) and io (initial current) were reported and an
estimate of the error in these quantities was expected.
C. The Use of Computers in the Other Experiments
Word processing, linear least squares and plotting programs were
used in preparing the final report for every experiment. The t-test
program was frequently used. Simultaneous equations were solved in
the quantitative analysis segment of the Liquid Scintillation Counting
experiment. Numerical integration was used in the coulometry
experiment (Controlled Potential Electrolysis) as described above.
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VI. PHYSICAL CHEMISTRY EXPERIMENTS AND REPORTS
A. Orientation Session
After the Separations, Radiochemistry and Electrochemistry
experiments were completed, five weeks were devoted to the remaining
experiments. A laboratory period was used to discuss and hand out
instructions for the experiments. These experiments were:
7. Infrared Gas Spectrum (1 laboratory hour)
A diatomic gas (hydrogen chloride) is prepared, dried and used to
fill a 10 cm infrared gas cell. The vibrational-rotational
spectrum is obtained using a Perkin-Elmer model 1430 infrared
recording spectrophotometer interfaced with a computer (data
station). The spectrum is printed and the peaks are tabulated by
the instrument. Students use this data to determine the moment
of inertia and bond length using a quadratic least squares
program. The analysis is based upon the harmonic oscillator -
rigid rotor approximation with added terms to correct for
anharmonicity, and vibrational-rotational interaction.
8. X-Ray Diffraction (3 laboratory hours)
A Norelco X-Ray recording diffractometer is used to obtain the
diffraction pattern of a powdered crystalline unknown compound
belonging to the cubic system. The interplanar distances are
calculated using the Bragg equation. The Miller indices for each
diffraction line is determined and the unit cell dimension is
calculated. From the Miller indices the student determines
whether the unit cell is body-centered, face-centered or
primitive.
9. First Order Kinetics - The Inversion of Sucrose (3 hours)
The acid catalyzed hydrolysis of an aqueous sucrose solution to
fructose and glucose was followed using a precision polarimeter.
The angle of rotation was measured as a function of time for a
suitably thermostated solution. The pseudo-first order rate
constant was determined by a suitable linear least squares fit of
the data.
10. Second Order Kinetics - Saponification of Ethyl Acetate (3 hours)
The reaction of an aqueous solution of ethyl acetate with sodium
hydroxide at constant temperature was studied using an AC
conductance bridge, a 1000 Hz oscillator and an oscilloscope
(null detector). The rate constant for the forward reaction was
determined by suitable least squares fits of the data. An
optional part of the experiment involved determining the rate at
different temperatures. The activation energy could be obtained
from the rate constant - temperature data using the Arrhenius
equation.
11. Gas Viscosity (3 hours)
A mercury-displacement gas viscosity apparatus is calibrated at
constant temperature using dry air as the viscosity standard.
The viscosities of pure helium, nitrogen and argon were
determined using the standardized viscosimeter.
12. Vapor Pressure of Water (3 hours)
The vapor pressure of water was measured at ten to fifteen
temperatures between room temperature and 75 degrees Celsius
using an isoteniscope. The average heat of vaporization is
determined from a Clausius-Clapeyron plot of ln P vs 1/T.
13. Preparation and Molecular Weight Determination of a Polymer (8
hours)
Nylon-66 is prepared, purified and dried. Solutions of various
concentration are prepared using concentrated sulfuric acid as
the solvent. The viscosities of pure sulfuric and solutions of
Nylon-66 in sulfuric acid is determined using an Ostwald
viscosimeter. The intrinsic viscosity is determined from
extrapolation of suitable plots involving viscosity and
concentration. The average molecular weight of the polymer is
calculated from the intrinsic viscosity.
B. Infrared Spectrum of HCl Gas
An experiment like this is included in many of the physical
chemistry laboratory texts (7,8,13).
The Perkin Elmer data station was programmed and used so that the
infrared spectrum (Figure 12) was plotted and the peaks were tabulated
(Figure 13). The data were least squares fitted to a quadratic
equation (Figure 14). From the least squares constants the moment of
inertia and bond length in HCl can be calculated. The degree of
interaction between vibration and rotation can be deduced from the
magnitude of one of the least squares constants. The standard
deviations of the least squares constants can be used to determine the
random error in the bond length and other quantities. The Fortran
program which performs the least squares calculation also provides a
crude plot.
C. Use of Computers in the Other Physical Chemistry Experiments
Word processing, the t-test, linear least squares and plotting
programs were used in preparing the final report.
For the second order kinetics experiment each student was asked
to write a program to convert the resistance R(t) measured at time t
to the concentration of ethyl acetate (x) which had reacted at time t
and the logarithmic term used in the second order rate expression (and
linear least squares plot). The program and a table of t, R(t), x and
ln[(a-x)/(b-x)] was to be included in the final report. Students have
submitted programs written in PASCAL, BASIC, FORTRAN or a spreadsheet
language.
While not specifically required students were encouraged to write
programs or develop spreadsheets to perform the repetitive
calculations involved in many of the experiments. Hand (electronic)
calculators and computers were used to perform calculations.
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VII. REFERENCES
1. American Chemical Society's Committee on Professional Training,
"Undergraduate Professional Education in Chemistry: Guidelines and
Evaluation Procedures", ACS, Washington, DC, fall 1992.
2. D.A. Skoog and J.J. Leary, "Principles of Instrumental Analysis",
4th ed., Saunders, Philadelphia, PA, 1992.
3. H.H. Willard, L.L. Merritt, J.A. Dean, and F.A. Settle,
"Instrumental Methods of Analysis", 7th ed., Wadsworth, Belmont,
CA, 1988
4. R.D. Braun, "Introduction to Instrumental Analysis", McGraw-Hill,
New York, 1987.
5. H.A. Strobel, "Chemical Instrumentation: Systematic Approach to
Instrumental Analysis", Wiley, New York, 1989.
6. D.T. Sawyer, W.R. Heineman and T.R. Beebe, "Chemistry Experiments
for Instrumental Analysis", Wiley, New York 1984. 7. D. P.
Shoemaker, C. W. Garland and J. W. Nibler,"Experiments in Physical
Chemistry", 5th edition, McGraw-Hill, New York, 1989.
7. D. P. Shoemaker, C. W. Garland and J. W. Nibler,"Experiments in
Physical Chemistry", 5th edition, McGraw-Hill, New York, 1989.
8. R.J. Sime, "Physical Chemistry: Methods, Techniques and
Experiments", Saunders, 1990
9. H. Stroebel, J. Chem. Educ. 1992,69,A266.
10. B.T. Jones, J. Chem. Educ. 1992,69,A268.
11. D.C. Locke and W.E.L. Grossman, Anal. Chem. 1987,59,829A.
12. J.P. Walters, Anal. Chem. 1991,63,977A,1077A,1179A.
13. R. W. Schwenz and R. J. Moore (editors),"Physical Chemistry:
Developing a Dynamic Curriculum",American Chemical Society,
Washington, DC, 1992.
14. D. Rosenthal and P. Zuman in "Treatise on Analytical Chemistry",
I.M. Kolthoff and P.J. Elving (editors),2nd ed.,
Wiley-Interscience, New York, 1979, Part I, Vol. 2, Chapter 18.
15. P. Zuman and O. Manousek, Collect. Czech. Chem. Commun.
1969,34,1580.
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VIII. SOME QUESTIONS
I would be interested in learning what other participants are
doing at their colleges and universities. Perhaps some of you would
respond to one or more of the following:
1. How are instrumental analysis and physical chemistry laboratory
taught at your school?
2. Briefly describe one or more experiments which you consider to be
particularly effective.
3. Describe how computers and computer software are used in these
courses. Is the use of specific software optional or required?
4. What do you consider to be the strengths and weaknesses of your
courses?
5. Are there any additional references you would like to add to
Section VII?
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IX. FIGURES (Sent as separate files)
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Acknowledgment: I would like to thank Thomas O'Haver for helping to
prepare the figure files.
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Paper 1 - Figure 1
Gas Chromatography Experiment
Perkin Elmer Sigma 2000 elution data for 7 Component Mixture
Temperature Programming
Data as obtained directly from the Data Station printer
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Paper 1 - Figure 2
Gas Chromatography Experiment
Perkin Elmer Sigma 2000 elution curves for 7 Component Mixture
Temperature Programming
Data as obtained directly from the Data Station printer
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Paper 1 - Figure 3
Gas Chromatography Experiment
Perkin Elmer Sigma 2000 elution data for 7 Component Mixture
Isothermal elution
Data as obtained directly from the Data Station printer
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Paper 1 - Figure 4
Gas Chromatography Experiment
Perkin Elmer Sigma 2000 elution curves for 7 Component Mixture
Isothermal elution
Data as obtained directly from the Data Station printer
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Paper 1 - Figure 5
Gas Chromatography Experiment
Summary of Temperature Programmed GC Data from a Student Report
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Paper 1 - Figure 6
Gas Chromatography Experiment -
Addendum from the laboratory instructions
Data obtained using the Aerograph Autoprep
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Paper 1 - Figure 7
Gas Chromatography Experiment
Number of theoretical plates (P) and resolution (R)
Equations and elution curve taken from the laboratory instructions
2
2.35 t ' (t ' + t )
r r i
P = ___________________________
2
t
1/2
2
16 (t ' + t )
r i
P = ____________________
2
w
t ' - t '
r2 r1
R = ___________________
(w + w )/2
1 2
H.E.T.P = Length of the column / P
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Paper 1 - Figure 8
Gas Chromatography Experiment
Plot of ln(adjusted retention time) vs. number of carbon atoms
for saturated hydrocarbons
Used for the determination of the Kovats index for
4-methyl-2-pentanone and cyclopentanone
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Paper 1 - Figure 9
Gas Chromatography Experiment
Least squares fit of peak area vs concentration for octane knowns
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Paper 1 - Figure 10
Gas Chromatography Experiment
Plot of area under peak vs concentration for octane in the knowns
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Paper 1 - Figure 11
Controlled Potential Electrolysis Experiment
Integration of i vs t data
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Paper 1 - Figure 12
Rotational-Vibrational Infrared Spectrum of HCl gas
Obtained using a 10 cm gas cell with a Perkin Elmer Model 1430
infrared recording spectrophotometer with a data station.
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Paper 1 - Figure 13
Table of HCl Gas Infrared Absorption Peak Maxima (in Wavenumbers) and
Percent Transmittance as Obtained from the Perkin Elmer Data Station
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Paper 1 - Figure 14
Quadratic Equation Least Squares Output for Data From Figure 13
Y values are absorption maxima (in wavenumbers)
X values are integers (m) related to the rotational quantum numbers
(J)
See Reference 7
THE END