Computer Enhancements of General Chemistry and Quantitative Analysis Laboratories We have initiated in the fall of 1977 a computer enhancement program in two of our undergraduate chemistry laboratory courses. The program was designed'in an effort to correct problems with data manipulations that we had noted previously in these courses. In mite of the wide soread ownershio of oocketcalculators. students did not alwavs comnlete calculations hcforr Irsving thc lshhdtory, and thr inck oiundwstnr&i of the rnlrular~onsor I he drrrrrion of pcr;r qunlti~ut dnta surticed s i ~ w r frrqumr rmnptm~lmnlrrrnrz t w l a t r for instrurtur al;sirtonreor rollrrting mow dntn l n q u a n r ~ t a t i ~ ~ ~ n n n l vohsrrvrd w h ~ r hrequired the return of reports t u .tudrnts for sub-rqurnt rrgmding This d r l n y d calcul.~rimsof ihp class mcrngr result, effecting a delay in feed-back from determinations, and increasing the instructor work load. I'hont rxtrn\ionq werr installrd in the general rhcrn~stryand qunnruntwr onnlysw Iahorororw:. We acquired one vide 'I'V set, whwh u e "ilme shared" hetween tprminal kcylward module. an nnmsr~mllgcoupled modem nnd one mzsd~t~ed lls~np.n lcwaltele~honenumher, we have a r r e i i to an H P L(HIO ACCESS isitem whrrecxtrndrd Ha\ic rhr twu lnl~omrc~rwz programs (saved on a disc) can he d i e d and run. These programs can he protected and made run only if desired so that the intent of the nroeram leheckine a student's own comoutation) cannot be defeated.
years. When errors are encountered, the computer programs are designed to tell the student where he probahly went wrong, but do not give him the correct answer. This sort of checking assures the student, before he leaves the laboratory, of two thines. First, that he does have an acceptable data set. When this proves not to be the case, there is often sufficient time for additional experimental data to be coileeted. Second, a successfulcheck indicates at least one calculation has been correctly executed before the student leaves the laboratory and while assistance from the laboratory instructor is still available. Programs were witten to check the student's arithmetic using his raw data for all the quantitative analysis experiments. Although there is no way to cheek laboratory technique, such programs can catch erroneous molecular weights, mole ratios, formulss, etc. These programs weremade run-only so listings were not possible. It was necessary for the student to demonstrate an understanding of the calculations t o obtain successful results using these programs. Input included data and results and indicated if the result was correctly calculated from the data provided. A policy of not regrading experiments was instituted if calculation e m s were made. Of course help with calculations was alwars available from the instructor during the laboratory period as was the ease before. However, instituting this procedure virtually eliminated computational errors in the students reports in quantitative analysis. Although instituted on an experimental basis this year, student response has been very favorable; while this program has been totally voluntary in the general chemistry laboratory, virtually 100% of the class used the checking programs for any given experiment. Although some degree of congestion has been observed, we have been quite successful when 20-30 students used one video terminal. In the future we plan t o introduce dedicated miero-computers, with Basic programs stared on cassette tape. This would eliminate the dependence on the phone linelacoustic coupler combination and would probably represent no more cost than if individual terminals were acquired. We are experimenting this spring semester with one such micro computer system. We will make a selection of listings of these Basic programs available t o interested readers.
T h e University of North Carolina a t Greensboro Greensboro, 27412
654 / Journal of Chemical Education
Harvey B. Herman J. A. Dilts
