Potpourri: Ideas t o Muse and Use Compiled by Margaret Merritt from reports by Erwin Boschmann, Agnes Green, Jerrold ~ o k e n s ~ a rand d , Margaret Merritt As the needs and background of students takmg general and organic chemistry change, there is a need to change the content and formation of courses as well. This isn't easy. We all eet set in our wavs and assume that the wav we learned an idea represents the ;ay to teach it. It is inevitake that suggestions for changing content will meet with resistance and spirited debate. Such was the case a t the Conference when various authors suggested modification in the ideas that we teach and the terminology that we use to teach them. Laswick (4) presented an argument for the elimination of the Arrhenius concept of acids and bases and the substitution of the more consistent Brdnsted definitions. It was not the suggestion that Bry(nsted concepts be taught that hrought discussion, hut the length to which the author wanted to go. He would eliminate ter"inology such as neutralization since acid-base reactions seldom result in neutral solutions and he would limit the equilibrium constants in general use to K,, Kb, and K,, . The author suggested that few of us have really gone through our mental file of acid-base concepts and thoroughly expurgated those that derive from Arrhenius while suhstituting a self-consistent set derived from Brdnsted. Is molarity properly defined as amount of solute/volume of solution? In discussing the pop quiz given to the participants, Davies (1) argued that it is. The audience was reluctant to agree. Davies pointed out that S I units and IUPAC approved terminology call for the mole (abbreviated moll as the unit for amount of substance, even though in common usage, units such as grams (a mass unit) are common. He contended that it is time for a change. Davies also pointed out that common terms such as gram molecular weight, gram-atom, and even molecular weight are obsolete and should be expunged from our oral and written vocabulary. Another point made by Davies that hrought reaction from the audience was that statements such as "2 mol Or = 64.0 g 0 2 " are invalid because they equate quantities that have different kinds of units (amount of substance in the one case and mass in the other). Teachers who use factor-label in solving stoichiometric nrohlems will have trouble acceotine . " this sueeestion! Even though many chemical educators will find these suggestions based on SI and IUPAC recommendations remenant and difficult to follow, Davies' paper certainly suggests that we need to look a t these recommendations seriouslv and change our presentations so that they are as consistent with those recommendations as we can, with clear consciences, make them. In "Balancing Equations by Simultaneous Equations," Druding ( 2 ) suggested that teaching students to balance e~uationsfirst bv inspection and later hv redox is unnecessary ilmw all-well, altnr,sr aIl-rl1emim1 equationr can he balanced using simultaneous equation;. \Vhile the ilrility o l ' s ~ h a mrthK wns nrknowlc.dged, two major ohjertions to it u,ere : I I I thestudent's mind is divorced from the rhemistr? of atoms and molecules during the balancing process, making the problem an abstract mathematical one rather than a chemical one. and (2) there is so much room for error in solvine simultaneousequations that the manipulative difficulties ma; negate the utility of the process. It was clear from the discussion that followed the presentation that the suggestion was not entirely new and that it was not foolproof. Several members of the audience called attention to equations which are either imnossihle or extremelv difficult to halance hv this method or, for that matter, any other. The paper which called for the greatest revision of course
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18 / Journal of Chemical Education
content was presented by McGrew ( 6 ) .Since most students taking organic chemistry are life science and pre-med majors, the content of the course should reflect their need to learn the characteristic reactions of the various functional groups rather than the uncharacteristic and often unique reactions of interest only to chemistry majors. The elimination of material of interest only to professional chemists would allow more time for the chemistry of hiomolecules. Those in the audience seemed to favor modification along the lines suggested hut expressed concern over the extent to which such topics as spectroscopy should he retained and whether the content of such a course would he compatahle with standardized exams such as the MCAT's. Each of the changes suggested above requires some revision of existing textbooks. The authors noted that such revisions will not become available until there is sufficient demand by chemical educators. Are you listening out there? If you want a change, you will have to work for it. Orna's paper (8) dealt, not with the elimination of material, hut with the inclusion of a seldom-discussed topic, the chemistry of color. "Why is KMn04 purple?" the author asked in developing her point. Unfortunately, her time expired hefore she had an opportunity to tell us. (Do you know the answer?) The author mentioned several areas of chemistry in which color phenomona could be discussed; among them, spectroscopy, oxidation and reduction, mixed-valence systems and non-stoichiometric compounds. Perhaps the best argument for increased emphasis on the chemistry of color is that color is fascinating. Students can get hooked on chemistry through the observation of color changes. Ramette commented that he became a chemist when he first saw the brick-red color produced when he tested for a reducing sugar in his biology course. If Orna can promise that her chemistry of color will convince more people like Ramette to become chemists, we will all heed her advice! The papers that we have just discussed argued for changes in the content of chemistry courses. Three other papers argued for changes in the lahoratory program. Rich's (10) poster paper showed a novel approach to qualitative analysis in which the analysis scheme corresponds rather closely to positions of elements in the periodic table. Unfortunately, this reporter was not able to discuss the paper with the author and consequently, can provide no details concerning the procedure. Interested individuals should write to the author. Thirteen institutions in Arkansas and Kansas have found one answer to the high cost of providing students with hands-on exposure to modern instruments. They share the cost of a mobile spectroscopy lahoratory (a van containing nmr, ir, uv, mass spec, and gc equipment). The problems and promise of this cooperative venture were discussed by the authors and others from small institutions may be interested in obtaining additional information (11). Open-ended experiments are certainly not new. Many of us have tried to find a compromise between follow-the-directions-and-get-the-right-answer lahoratory exercises and complex, semester long research projects which are impractical in beginning courses. MacInnes ( 5 )described a procedure that has worked well for him and might work for you as well. A concise description would not convey his ideas and we recommend that interested readers contact the author. We are all interested when chemical research happens to fall in an area in which there are obvious and immediate practical implications. Conference participants were treated
to a discussion by Rowland (12) of how he became the center of controversv surrounding aerosol spravs. H~nvlanrlu"tlined how his back&unh in radiation chemistry led him UI see the simiticnnc~:of a h d y ot meaurements on trace components i n t h e atmosphere which showed that CC12F2and CClaF were building up and becoming widely distributed around the elobe. Toeether with M. J. Molina, he studied the uv absorption ran& of these compounds and predicted that they would dissociate in the stratosphere a t a rate which would provide enough atomic chlorine to act as a catalyst in the destruction of ozone. The destruction of even part of the ozone layer could result in increases in skin cancer and unknown effects on weather. A major concern related to this research is the time involved in reversing damage that may occur; by the time any corrective action can he taken, the build-up of the chlorofluorocarbons may he sufficient to affect the ozone layer for the next fifty years. Rowland contends that the research mnductpd since his original papvr two years ngo tends 1*, confirm his original cslculariuns, and he still nmiiders the nrnhlem to he sufficientlv imoortant to demand ~ r o m p t action to eliminate the release of ~hlorofluorocarhonsinto the atmosnhere. As our t:nal papera in this section of the report, we turn tu the nrnhlem ot tenchine, the teachers. Mans large institutions use graduate studentsin do much of the teaching in undergraduate courses. Few beginning graduate students know any more about teaching than the undergraduates they are asked to instruct. They are often frightened a t the prospects or unjustifiahly confident of their ability. Project TEACH (Training in Education for Assistants in Chemistry) has pnxlucnl ma~rr~;tls in scveral media t o help'l'A's learn how 11, teach (Dj.'l'his isdone usincvideoraped segmentsot actual teaching incidents with thtt infusion 01' prdagugical thwrv. l'roiect TEACH has been dpscrihed in a recent issue of / h i s ~ o u m a and l the reader is referred to that article for a discussion of the project. New teachers are not the only ones that need help in improving their teaching. We all face the task of keeping up and the job cannot he done entirely through conferences and short courses. ACS offers audio and film courses through Project CEDS (Continuing Education Delivery Service) (7). These courses are either audio-visual or computer augmented using a national computer network. In spite of their orientation toward industrial chemists, they can he of value to teachers and the information obtained from the documented development of this program should prove useful for those who prepare and use materials in self-paced instruction. ~
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Annotated Bibliography (1) Davies, W. G., Moore, John W., and Collins, Ronald W., Calculating with Clarity: A Case f o r S I Units a n d Quantity ~ a l c n l n si n Beginning Chemistry, Department of Chemistrv, Eastern Michigan University, The use of SI units, especially that of the mole, can remove a major source of confusion brought on by those who insist up& equating two quantities with different dimensions such as moles and grams. "Road map" methods to replace the present factor-label method are presented. (2) Druding, Leonard F., Balancing Equations by Simultaneous Equations: T h e E a s e a n d Logic of It All, Department of Chemistry, Rutgers University, Newark, NJ 07102. This method is applicable to all equations for which a unique system of balance exists; thus, it virtually eliminates the need to teach balancing by both inspection and some redox method. (3) Haight, G. P., Jr, Quo Vadis Chemical Education?,
School of Chemical Sciences, University of Illinois, Urhana, IL 61801. An eclectic summation of conference happenings. (4) Laswick, John A,, Isn't It Time to systematize AcidBase Chemistry?. Deoartment of Chemistrv. .. Clarion State College, ~ l a r i o n16214. , ~ ~ The confusion surrounding aqueous acid-base chemistry needs to be cleared up. One way of doing this is to use the Brdnsted definitions rather than teaching those of Arrhenius. This would result in a redudion of terminology as well as the pedagogical advantages of a more consistent theory. (5) MacInnes, David Jr., Open Ended Experiments in t h e Introductory Laboratory Program-Successful Examples a n d How to Use Them, Department of Chemistry, Guilford College, Greensboro, NC 27410. The place and use of open-ended experiments in the chemistry lab are discussed. Some suggestions on how to create and run open ended experiments are given. (6) McGrew, John G., Teaching Organic Chemistry: T h e Challenges We Face, Department of Chemistry, Alderson-Broaddus College, Philippi, WV 26416. The present population of introductory organic chemistry courses consists of mostly life science majors and pre-meds. The curriculum of these courses should be modified to meet their needs rather than those of the few chemistry majors. (7) Morgan, Patricia, ACS Continuing Education-A Service to t h e Academic Community, Department of Educational Activities, American Chemical Society, Washington, DC 20236. Attention is directed toward Project CEDS, which involves the development of mure individualized materials, mostly with industrial audiences in mind. (8) Orna, Mary Virginia, T h e Chemistry of Color: An O r p h a n Neglected, Forgotten a n d Treated with Short Shrift, Department of Chemistry, College of New Rochelle, New Rochelle, NY 10801. Color phenomena are often referred to in introductory chemistry, but only rarely are the fundamentalreasons for color discussed. The color phenomenon provides a perfect link between an easilv observed and described ohenomenon and the underlyrng thwry (such as mmed valence systems and conjugated systems). (9) The Project TEACH Staff, Project Teach, Department of Chemistrv, .. Universitv of Nebraska. Lincoln. NE 68508. Project TEACH consists of written materials, videotapes, and an audiotape which were prepared as supporting media to he used by those faculty supervisors responsible for the training of teaching assistants. (10) Rich, Ronald, Qualitative Analysis a l a Periodic Table, Plus Miscellanea, International Christian University, Mitaka, Tokyo 181, Japan. A novel approach to qualitative analysis has the analytical groups correspond to groups in the periodic table. Maintaining the pedagogical advantage of the classical H2S scheme, the approach uses CHZSH-C02H,HBr, CdCN)6:'-, CsHsN20r- and F- as reagents. (11) Roberts, T. D., One Idea a n d O n e T r u c k a f t e r O n e Year: Problems Associated with Construction a n d Operation of a Cooperative Mobile Spectroscopy Laboratory, Department of Chemistry, University of Arkansas, Fayetteville, AR 72701. (12) Rowland, F. S., What Goes U p Stays Up: Models f o r Stratospheric Chemistrv. Deoartment of Chemistrv. -. university of California, k n e ; CA 92664. Deals with the role of chlorofluorocarbons in the destruction of ozone layer.
Volume 54. Number 1, January 1977 / 19
