A One-Semester, Advanced, Integrated Laboratory Course R. Maruca Alderson-Broaddus College, Philippi, WV 26416 Although uncommon, integrated or unified laboratory approaches to the teaching of chemistry laboratory content have been around for several years now. The course described here has been offered continuously for 14years, and one for graduate students a t Northwestern University ( I ) was described 19 years ago. Recently, Goodney, Hudak, Chapple, and Brink from Willemette University (2) detailed a four-semester course for undergraduate students that integrates much of the total undergraduate laboratory work. Because of time and money limitations, our course is a onesemester course for undergraduate &dents covering only advanced laboratory topics. Our experiences with the course are shared because there is no question in my mind but that this approach to the teaching of undergraduate laboratory gives the students a better grasp of the material than the segmented course structure that i t replaces. The drivine forces for these intemated courses are the convictions: i l ) that instrumental -techniques are better learned bv students when introduced as a tool needed to characterize the products of a synthesis or needed for carrying out an experiment designed to obtain some piece of information other than simply how to operate the instrument and (2) that experimental and preparative techniques are better learned when all needed modern instrumental techniques are employed in the investigation. Course Descrlptlon Promamaticallv. the course reolaces instrumental analvsis, pLysical chekistry laboratory, advanced inorga& chemistrv laboratow, and advanced oreanic chemistrv laboratory. i n addition t o this course, ~CA-B the student's laboratory experiences are a freshman chemistry laboratory that includes basic analytical experiments and a large environmental chemistry comuonent, a standard organic chemistry laboratory, anmstr"ment-based biochem&ry laboratory, an introductory quantitative analysis laboratory consisting mainly of instrumental analyses, and required undergraduate research. Generally, the course consists of a series of exercises designed to have the student acquire the following objectives. 1. To have the student acquire the skiUs needed to carry out
experiments requiring the use of vacuum teehniques including vacuum distillations,inert atmosphere techniques, active metal syntheses, dry solvent techniques, high-temperature techniques, constant ionic strength, conductiometric measurements, pH control and measurement, high and Low constant temperatures teehniques, differential solubility separations, the statistical handling of data including graphing, infinite dilution techniques, the proper use and handling of caustic and
corrosive chemicals, and rhdioactive labeling techniques in-
cluding the safe handling and use of radioactive samples. 2. To have the student acquire a basic understanding of the
operation of common lahoratary instruments including, but not limited to, AA, IR, UV,and NMR spectrometers, a Paar bomb calorimeter, Kern polarimeter, Abbe refractometer, a Geiger-Mueller radiation counter, and one or more mieroproeessor-controlledinstruments. 3. To have the student acquire the ability to utilize NMR, IR, UV,and maas spectral data to duddate or prove the identity and structure of unknown compounds. Because of the other things done in the integrated course, all the techniques covered in more conventional instrumental analvsis courses cannot be covered. I t is. therefore. importan& look a t the total curriculum when designing s&h a course to make sure that all the important content in the courses that i t replaces is covered in some course in the curriculum. For example, we cover gas chromatography in the organic chemistry course and electrochemical techniques in the quantitative analysis, general chemistry, and biochemistry courses. Curriculum designers should make sure that the students develop the compentencies to use the basic categories of instruments that they will encounter. There are many different exercises that can be used to help the student meet the above objectives. The type of experiments done is the primary way that the course differs from those that it replaces. The other teaching techniques employed, reading assignments, lectures, problem sets and structure oroblems, are the ones normallv emoloved in ins t r u m e n t i analysis.and organic qualitative anaiy& courses. While the course format sounds the same as that for most other courses, it certainly is not. For credit accounting, the course consists of three 50-min lectures and two 4-h laboratory sessions per week for a full 15 weeks of instruction per semester. While the lecture time normally runs as described even if about 113 of the lectures are hands-on instrumental work sessions or prelab work, the time required for laboratorywork depends on the individual student. Theaverage is on the order of 12 h per week. All experiments must be completed reasonablv successfullv for the students t o have anv hope of obtaining-= "A" or "B" in the course. The numuherbf times a student repeats an experiment in order to complete it reasonably succ&fully is ditermined by hisher abilities. The first two weeks of the lecture are men1 coverine all the experiments in detail, with considerable emphasis being placed on the proper way t o keep a laboratory notebook (3). Objectives for each experiment and data that must be includedand explained in the write-up are given to the student
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in writing so that there are no misunderstandings as to what is to be done; however, experimental details are often communicated verbally. Extreme care is used to communicate effectively where safety is involved as, for example, in the handling and disposal of active metals such as lithium. The last three or four weeks are spent working structural problems using spectroscopic res& like those found inrnost aualitative organic chemistry textbooks (4). The middle two-thirds of ihe course is used t o lecture on the common instrumental techniques covered in a typical instrumental analysis course and for working prohlems (5). The following list gives the experiments required of the students the last time the course was offered. 1. The preparation of a trisethylenediaminecobalt(II1) iodide and resolution into its optical isomers 16). Once prepared, separated and purified,the products are characterized by optical rotation, IR, UV, and a cobalt analysis using AA. The 2.
3.
specific ionic conductance at infinite dilution is measured for one isomer. The hydrolysis of N,h-dimethyl-4-nitrosoanilinein basic solution (7). The student determines the rate expression,the value of the specific rate constant at three controlled temperatures, and the activation energy for the reaction. All measurements are made at constant ionic strength and all data is treated using proper statisticalmethods. Preparation, purification and identification of Z-trimethylsilyl-l-methoxynaphthalene(8).The purified product is characterized hv ,IR. - ~UV.~. NMR. . . and refractive index. This moieet . . inrorporater an active metal ryntheais, inert atmosphere techniques, and vacuum distrllstion. Synthesis and characterization of adamantme (9).Characterization ofthe product includes NMR. IR, mp,and the detennnatiun of the AHo of t'ormation from the heat of combustion which is measured using an adiabatic oxygen bomb ralorimeter. This project employs a high-temperaturesynthesis. The use of radioactive tracers in e model degradation (10). In this project the student converts a labeled acetic acid to acetophenone followed by degradation of the acetophenoneto iodofarm and benzoic acid. By determining the Location of the label in the degradation products, the position of the label in the acetic acid can be determined. ~
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I t is important to have experiments that the students can eomoletesuccessfullv. but thev should not be so easv that they do not represent the rear world. A rule of thumb for iudeineanexneriment is that it isabout riaht when40 to6090 of the students are able to complete i t s&cessfulIy the first time and all students can get it to work acceptably in no more than three times. ~~
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Course Evaluation The course is graded conventionally except that the laboratoryreports and the laboratory notebook account for 53% of the fmal grade. In addition, there are many times when the laboratory work finds its way directly onto the exams. For example, exams frequently include questions that require the student to go to the lab and make a series of measurements and then analyze the data obtained on the exam. The students write UP each experiment and submit it for grading. The write-upskust be In accordance with the ACS recommendations for articles submitted for publication in the Journal of the American Chemical Society (11). The due dates for reports are specified a t the beginning of the semester with the first report due in about five weeks and the other reports due a t two- or three-week intervals. I t
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is important to give the students ample time to get accustomed t o working a t their own pace. Each experiment is graded for accuracy of results, quality of laboratory techniques evidenced and the adequacy of the written report. Purity of sample, percent yield, and accuracy of spectral results are used to measure some of the lab art techniaues that are difficult to auantifv. The followine eener& sc&e is used as a guide in hading experiments. Yield, 10-15 pts., purity of sample, 10-15 pts., write-up layout, 10 pts., discussion of results, 10 pts., obtaining all data required, 10-20 pts., and correctness of results, 10-20 pts. There are seven or eight problem sets which are collected and eraded, five to eight instrumental organic structural probiems, which are assigned, collected a d graded, and a laboratory notebook, which is collected, graded, and kept by the instructor for future reference. Conclusion While quantitative studies have not been done concerning the effectiveness of this course. some aualitative conclusions can be drawn. The course is sufficientlvdifferent so that not all faculty and students will be comfbrtable with it. The experiments are variable and the outcomes hard to measure. Therefore, faculty members and students that need lock-step procedures and easily measured outcomes that follow a predictable pattern are-generally unhappy. The course progresses in what a t times approaches utter confusion. The trick is to have that helm the student work his - - ~- structured~onfusion way through the material and experiments and come out a more mature chemist than if thev were t o eo - throuah - the more conventional sequence of courses. With the drawbacks of time for faculty and students involved, the costs for materials, and the fact that some faculty and students are uncomfortable with the course, why do we still offer it, and why are we strongly recommending i t to others? The simple reason is that i t works! This is the message that our graduates relate to us one to two years after graduating. Every graduate that this author has talked with about his or her undergraduate work rates advanced lab as the most useful course that he or she had. Without a sinele exce~tion.thev relate that thev felt better prepared for &e work' world orUgraduateresearch than students from other schools mainlv because thev had had this advanced lab experience. while these discussions with the graduates have resulted in some changes in the experiments done and techniques emphasized, they have not changed the basic direction of the course. ~
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Lllerature Cited I. Chem. Eng News 1910.48 (411.47. 2. Gmdney, D. E.: HudaL, N. J.;Chapple, F. H.;Brink, C. P. J. C h m . Edm. 1986.63,
703-706. ington, 1985.
3. Ksnarc. H. M. WritingfheLoborofon Notebook;American Chemiesl Soeiaty: Wsah-
4. Siluerstein,R. M.;Bassler,O. C.:Morrili,T. C.Specfromtrir id~nfifirotionofOrganic Compounds. 4th ed.: Wilay: New York, 1981. 5. Willard. H. H.: Merritt. L. L.. Jr.; Dean. J. A. Imfnrmental Methods of Amivs&, 6th
Ed.: M ~ G ~ ~ W - H ~ I I1&0: : N Vol. ~ ~ VI, Y pp ~ ~18%186. ~ , F.M.;Adsms, M. L.;J.Am. Cham. SOE.1953. 75.459WM). R Gi1rnan.H Morton..l. W..Jr. 1nO~sonicReactions:Adams.R..Ed.: Wi1ev:NewYork. 7. Miiler,
