and B. E. Christensen Oregon State University Corvallis, 97331
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An lntegrated Laboratory for Nonmaiors
Several successful integrated laboratory programs have been developed for the main-sequence science major students. A significant portion of our students are, however, involved in a shorter sequence of chemistry courses, and it was toward this group of students who take only the general, analytical, and short organic courses that our attention was directed in the past two years. For some time, we have deferred the laboratory work for one term in the nonmajor general course and then added an interim term of laboratory work between the general and analytical course. Consequently, the nonmajor laboratory work has consisted of the following 2 credits of laboratory in latter two terms of general chemistry 2 credits of labaratow in a seoarate course 2 credits of laboratory in the analytical course 2 credits of laboratory in an organic course
This sequence is pursued by a variety of students majoring in agriculture, pharmacy, home economics, and other such areas outside the sciences. Our plan was to integrate these 8 credit hours of laboratow work for these students into two 4-credit laboratory co&ses called Experimental Chemistry. Hopefully, this would achieve a more effective experience by avoiding the fragmentation, duplication, and overlapping of experiments that are more inherent in four separate laboratories administered as adjuncts to lecture courses. A separate 2term sequence of laboratory concentration would also permit the development of experiments more relevant to the students' needs. Furthermore, the visibility of a separate laboratory course would orient the students to the importance of this type of work. In practice, we modified our plan by excluding the 2 credits of laboratory in the general course but added the 2 credits of classwork equivalent to that usually included in analytical chemistry. This left the total of 8 credits unchanged and resulted in conducting the class with one lecture and two 4-hr laboratories per week for two terms. This arrangement then replaced the interim separate course, all of the analytical course, and the organic laboratory course. The lntegrated Laboratory Experiments By combining the separate laboratories and capitalizing on the equivalent of about 100 hr of laboratory time, we selected and developed the most meaningful experiments for this group of students. The newly designed experiments were tested by two graduate students, and several established experiments were modified to fit the level of preparation expected of the students. We aimed a t experi-
620 / Journal of Chemical Education
ments in separations, synthesis, determination of structure, and quantitative studies of reactions, all liberally flavored with as much relevancy as possible to the students' interests. This is the list of experiments pursued in the 2-term sequence 1) Acid-base titration: the neutralizingcapacity of antiacid pills 2) Analysis of vitamin C: titratian with 2.6-dicbloraindophenol
3) Silver chemistry: reactions in the photographic process 4)
5) 6) I) 8) 9) 10) 11) 12) 13) 14) 15) 16)
Water analysis: cations, solids, phosphate; calcium by flame photometry Soap films and one flotation: detergency Calorimetry: beat of formation Separation of solutions: gas chromatography Avogadro's number: electrical and Perrin methods Crystallization and melting point: hydrazones Synthesis: t-butyl chloride Thin layer chromatography:cholesterol acetate An unknown acid: isolation, equivalent weight, pK., derivstive Ethanol: fermentation, oxidation, ether, derivatives Distillation: fractionation Spectrophotometry:vanillin in ice cream Grignard synthesis
Along with specially prepared descriptions of the theory and procedures for these experiments, the students referred to a traditional texthook on quantitative analysis, particularly for the theory and procedures of instrumental analysis. Results The students' response to this course was, on the whole, favorable. This response is biased by the fact that the students enrolled in the trial run of this course were selected through advising, hence no valid statistical evaluations can be made a t this time. One student, however, who dropped college and took industrial employment after the course volunteered the response: "I've used the spectrometer, lots of titrations, balances, glc, and more. It's great to really be able to apply knowledge that I gained a t school in the lahoratory course." A significant response by a majority of the students strongly favored a laboratory course separate from the usual lecture course. Thev based this reference on both their prior experience and the concurrent experience of their friends who continued in the traditiunal courses. From the instructors' view, this kind of integrated laboratory course greatly increased the efficient use of laboratory time and made possible the inclusion of a wider variety of experience than is usually achieved in the traditional, separate laboratory courses. ~
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