Computer Applications in the Freshman Laboratory Glenn E. Palmer University of Prince Edward Island Charlottetown, P.E.I. Canada C I A 4P3 The organization of the laboratory component of our first-year chemistry program has evolved as a result of the oressures of lack of manpower and space in relation to student bopulation. The exigencies of time and space forced us to isolate those goals which we considered both important and attainable, and to concentrate on achieving these. Two such goals were identified and laboratory experiments chosen accordingly. Our objectives were to provide students with (1) practical experience in the application of the concept of logical sequence and deduction in a chemical context, and (2) closely supervised practice in the techniques and applications of volumetric analysis. T o satisfy the first of these, qualitative analyses for the cations of Groups I, 11, and I11 were included. T o achieve the second, experiments designed to analyze familiar materials (e.g., vinegar, household bleach) and requiring the utilization of primary and secondary standards were chosen. In addition, experiments to measure the rate of a reaction and to examine multiple dissociations of a polyprotic acid were included to illustrate the extension of volumetric techniques beyond simnle ~ ~analvsis. ~ The introduction of this course generated a number of orohlems. two of which seemed to us amenable to solution through application of computer techniques. In qualitative analvsis exoeriments. students became so intent on the " physical manipulations that the logic of the test sequence became lost to them. In the quantitative analyses, the students concentrated on the mastery of technique to the point where data collection became the only tangible goal. The ultimate disposition of these data received scant attention during the experiment. Although each experiment could be completed in-a reasonable time period, the time to calculate results stretched out inordinately. In both cases, the obsession with "how" rather than "why" seriously interferrd with the students' understanding of the experimental design and of the chemistry involved. T o alleviate the difficulty in the qualitative analyses, we attempted to provide a better focus for the students through computer simulation. A number of examples2 of such proera& have been noted. Ours differ onlv in that thev are based &redly on the procedures described idour laboratky manual and stress the lozic of the seauence of steps. Students must choose reagents Fo be used, and in some cases the phase of a svstem to test. in the proper . . order. Incorrect choices key resbonsrs indicating the source of the error and dirrctinistudents to tht: proper route. Indications of when trntntivr and final conclusions may be drawn have bren inchalrd to help the student understand the purpose of each separatiun and test. Each student is pro\.ided with a unique unknown idrntifier and is required to prrirnt a print-out of a surcessful simulation heiure he or shr is allowed to begin the nrtual experiment. 'I'he "mindless-collection-of-data" syndrome has been attacked using the ability of the computer to produce individualized problrms. One week before an experiment is scheduled, each student is pruvided with a dummy set of data for it. The data clusely mimic in both magnitude and precision those to br collected durinx the analysis. These criteria are satisfied rasily hy generating the value for each datum as a
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random number between fixed limits, and through application of the PRINT USING statement to establish the number of significant figures to be presented. As with the simulations, the student must submit an acceptable result calculated from these data before the actual analysis may be started. In some cases, the values for quantities which represent the completion of key stages in the calculation are also required so that sources of difficulty may be isolated. Student reaction to these simulations and pre-lab exercises has been positive. A formal interrogation hv auestionnaire indicated'that over 85% of the studknts perceived these as heloful both in understanding the procedures and in completing the analytical reports. Therewere no overt objections to the imposition of these external laboratory requirements and initial dissatisfaction with the mark value assigned to them was arbitrated successfully. More interesting and significant has hew an adventitious response. Studentsoften arrive with a number of qualitative si&dation orint-outs besides the one reouired. These extras are nearly always the source of queries concerning aspects of the testine-seauence. and in manv cases have led to the addi. tion to the programs of explanatory asides to prevent confusion. Discussion disclosed that students were assaving their ability to reason through analyses other than tha
