Novel concept of physical chemistry laboratory - Journal of Chemical

Projects in the Physical Chemistry Laboratory: Letting the Students Choose. Paul D. Buckley ... Journal of Chemical Education 1997 74 (5), 549. Abstra...
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Novel Concept of Physical Chemistry Laboratory R. Bareta and H. Buchowski Department of Physical Chemistry, Technical University (Politechnika) of Warsaw, Poland In recent vears a considerable decrease of interest in technical univerBity studies, including chemistry, manifested by a decreased number of candidates, with weaker disposition toward university studies, has been observed. ~ i t t l ecan be done by the universities to reverse this trend. However, it is possible to modify the syllabuses of university courses to make them more attractive and give the students deeper knowledge demands bf and better training to cope with the modern science and technology. The new syllabus should also include modification of the forms and programs of lahoratory classes for students. I n this naoer we nresent a successful new conceot of ~ h v s concept of 1aborator;classes also may apply to some student laboratories in courses other than chemistrv. The former traditional system acquainted students with only some methods employed in physico-chemical investigations and/or illustrated lectures by exemplifying certain individual ohenomena. No matter how modern the lahoratorv

classes. Thus, each team plans and supervisesthe measurements necessary to solve its "own" problem and simultaneously participates in investigating the other ones. the results obtained during the term by the "teams in charge" and by the other teams are the basis for a written report presenting the solution of the problem chosen at the beginning of the term. Submission of final reports is required to credit students with the physical chemistry course. a closing seminar at which students present 20-min,reports including the results obtained and the discussion,complemented with the literature data, ends the term. Twelve apparatus sets, only slightly simplified in comparison with the research equipment, are placed a t the students disposal, allowing application of the proper and correct methodology of measurements. The students are also provided with material informing them about the problems that could be solved, the references, and the working.instructions for the apparatus. Some of the research problems are specified below (unit experiment and variables are given in parentheses followed by reference numbers):

eralizations, and the methods involved had little in common with the real research work methodolow. (1,2).

applicability of iso-equilibrium relation to description of phenol dissociation (determinationof acidity constant using UV-VIS spectrophotometry; temperature, substituent in benzene ring)

are decisive for effectiveness of the lkarning process, namely:

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increased self-reliance by participation in planning experiments, collaborative work, useful to a particular student and to the others, open discussion of the problems, individualizationof work and possibility of self-development.

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Moreover, the introduced changes are aimed at:

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acquainting students with the wide range of problems of modern physical chemistry, ensuring maximum correctness of methodology.

The main feature of the new laboratory system is the possibility of investigating problems that require repeating a single experiment several times under partially changed conditions; e.g., a t different temperatures, in various solvents, for different comnounds heloneine " " to a homoloeous series. etc. Each experiment forms an integral unit, is carried out in the course of one laboratorv class. and is credited to the students. At the same time it f o r k s a part of a wider research problem to be solved. The present scheme of physical chemistry laboratory is as follows:

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students work in two-person teams, at the beginning of a term each team undertakes a wider research ~roblemto be investigated by means of the laboratory equipment -~ available, in consultation with the tutor, the team plans the necessary measurements and carries out the first one. ~

Preliminary report was presented at Biennial Chemical Education Conference, Ljubljana, 1977.

thermodynamics of gas-solid adsorption (determinationof adsorption isotherms using gas chromatography; temperature, adsorbent, adsorbate) ( 4 ) . relation between molecular structure and dipole moment (determination of dipole moment by means of Guggenheim-Smith method; compound, solvent) (5). aoolication of Barker's method for the descriotion of moor-liauid component mixture) (6). solubility of noneleetrolytes in mined solvents (determination of solubility of solids in liquids using synthetic method; substance, composition of mixed solvent) (7).

Since elaboration of the results is tedious and time-consuming work, the students use a minicomputer to perform necessary calculations. For the easier procedures, programs are written by the students; in other more difficult cases the students are obliged to work out an algorithm for the calculations. The new uhvsico-chemical lahoratorv (14 laboratorv classes) is preceded by the introductory part (6 classes) helb in traditional form. D u r i n ~the traditional classes. students are given time to make a choice of problems to hesolved by them, to mepare a ~ l a of n measurements, and-last but not . . least to I n v a n e tamilim with tlte l ~ l n ~ r ; ~2nd t ~ ~the r ytutur-. I> hi> tu,o-sraae l a l a m t ~ ~a\.,r,ml ry rtsolts i l l better and int,rt2 effective uticzation of the~possibilitiescreated within the advanced laboratory classes.

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Conclusions All the innovations in the system of laboratory work have been approved of both by the students and tutors, although the changes involve the need for increased efforts from both parties. As a consequence, we have observed the growth of the Volume GO

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students' interests and activities. The results of tests and the level of final reports and lectures prove that the majority of students avail themselves not only of textbooks but also of monoeravhs and chemical iournals. The prowink? accuracv of results obtained by students indicates tbeir increased conscientiousness and sense of duty. The possibility of individualization of work is another advantage of the system. This is narticularlv imvortant for the better students, whose interests and ambitions cannot be satisfied within the traditional laboratory. Grading stratification has now become possible. It should be stressed here that the equipment already available in typical physico-chemical laboratories will be quite adequate for the new purposes; the introduced changes concern mainly "software" and not "hardware." And last but not least, in the opinion of all participants, our modified laboratory system has another advantage, for it is by no means boring.

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Journal of Chemical Education

Literature Cited (1) Kmg, E. J., "Acid-Base Equilih~ia?Pergamon Press, New YO& 1965. (2) Shorter,J.,"Conelation Anslysi~inOreanicChemistry.An Intrduction toLinear Free Eneryi Relatianships,"Oxford Chemistry Series, Oxford University Press, New York, 1973. (3) Hammeft. L. P., "Physical Oqanic Chemistry," Znd Ed., Mffiraw-Hill, Now York, 1970: Exner, 0 , ChernickeLisly. 67,135 11973). 14) Kisielew, A. W., and Jasryn, J. I.. "Adsorpcyjm chromatografis gazowa,(. PWN, Warwawa, 1973 (tianslated from Russian); Oscik, J., "Adsorpcjs," PWN, Warsraws. 1979: Paryjnsk, T.. "Chromafografis gazowaw bsdaniach edsomcji i kstdizy? PWN, Warssawa, 1975: Everett, D. H., Trans. Porodoy Sac., 46,453,942 (1964). (5) Minkin, W. I., Osipow, 0 . A , and Zdanow. I. A.,"Momenty dipolowe w ehemii organicmej,"PWN, Wanzawa. 1970 (translated fmmR-ian); Weissbs~er,A.."T~hnique of Organic Chemistry. Physical Methods of Organic Chemistry? Vol. I, Part IV, Wiley-Interscience. New York, 1972. (6) Malanow3ki. S., 'Romowaga ciece-para," PWN, Warszswa, 1971: Hsla, E.. Fried, V., Pick, I.. and Yilim, 0.. "Vapour~LiquidEquilibrium," Pergsmon Press,Oxford. ,at, .o"..

(7) Hildebrand, J. H.. and Scott, R. L., "Solubility of Non-Elsctrolytes,i) Reinhold, New York, 1950: Hildobrand, J. H., J. Phys. Chem., 20, 190 (1952); Hilderand, J. H., Prausnitz. J. H., and Scoff. R. L., "Regular and Related Solutions? V.N.R.C., New York, 1970.