Table 2. OuantltaNve Analysis Frograms In Spanlsh Laboratory Experiments 1)
Determination of the Water Content of a Sample iron
2) Gravimetric Determination of 3) Determination of Soda Ash
Determination of the Equivalent Weight of an Organic Acid 5 ) Photometric Titration of Cu(ll) with EDTA 61 Determination of lron in Mineral Ores by Potentlametric Titration with Potassium Dichromate 7) Photometric Determination of Manganese in Steel 81 Photometric Determination of iron 9) Potentiometric Determination of Chloride in Commercial Products Using a Chloride ion-Selective Electrode 10) Evsiustion af Commercial Antacids 4)
Program WATER FEGRAV
SODASH PH
CUSPEC FEREOOX
MNSPEC FESPEC CL ANTI
centration of desired component, etc. The programs, in addition, tabulate mean values and relative average deviation (parts per thousand). Six of the programs have plotting routines. These allow for potentiometric titration curves and derivative curves, spectrophotometric titration curves, the absorption spectra for manganese and iron, and the calibration curves for the iron and chloride analysis to be shown graphically on the monitor. The programs have the option of making a hard copy of the graphs if the student desires ao. Two of the programs, the spectrophotometric titration and the chloride analysis, allow for a least squares fit of the data. These programs have proven useful in instructing beginning students in quantitative analysis. They also give students practice in working with computers, many thought that the computer was a good way to learn. The oroerams are written in BASIC for a TRS-80 Micro. " computer. All instructions to a student user are in Spanish. Available from SERAPHIM.
Computerized Quizzeswith Instant Grading and Response Analysis Donald A. Bath and Ben G. Hughes Western Illinois University Macomb. IL 61455 Since purchasing a mark-sense-card reader for addition to our TRS-80, Model I microcomputer system, the Department of Chemistry a t Western lllinois University has found many ways to use this device. Whenever data can be easily presented on marked cards and rapid turnaround is needed, the card reader has proved to be a most useful peripheral on our system. A specific application of the card reader is the administration and evaluation of pop quizzes for small classes of students (about twenty each). The software for this application, called INSTQUIZ, consists of a master program that accepts the data input through the card reader, locates the student in a file of names and grades, calls the correct answers for the quiz from a file of answers, evaluates the students' responses, and records the results in the students' grade file. Supporting programs are required to set up the student record files, to set up the answer files for the various quizzes, and to read and evaluate each of the grade files after the quizzes have been given. INSTQUIZ allows answers for ten different quizzes to he stored, with the ootion of wine one or as manv as all ten simultan~ously.hec cards have space for ten answers which mav be either multiole choice or numerical. Provision is made for'accepting answers within a rangeestahlished by the instructor for each individual question. Awarding of partial credit is also possible. Obtaining results of the quizzes given to various classes is accomplished through two additional programs. The first of these reads out the student files, totals the scores for each 734
Journal of Chemical Education
student and allows assignment of grades. The second presents an analvsis of the answer files showine the numher of students that goi each answer right, the numbkr that got it wrong, and the percentage gi\,ing t he (.i~rrectanswer. JSS'I'QI'JZ cont,#ln>?It; Iinw (gf HASl(' in one maswr program and four supporting programs. It was designed for the Radio Shack TRS-80 Model I with one disk drive. NEWDOS-80, Version 2, is the operating system hut files are set up and read in the random file format compatible with TRSDOS. The card reader is an MR-500 from Chatsworth Data Corporation. Copies of the listing and documentation are available for a self-addressed stamped envelope sent to the authors a t the above address.
Computer Simulation of Elementary Chemical Kinetics Martha L. Nase and Kurt Seldman Randolph-Macon Woman's College Lynchburg, VA 24503 The authurs have developed several computer programs that simulate chemical kinetics for elementary first- and second-order processes. These programs can he used to generate kinetic data that can then he analvzed hv the student in a variety of ways. We have found these programs to be a much more beneficial learnine exoerience for the students than other programs which, more &pically, analyze the data for the students. In addition. the nroerams can he used toillustrate several kinetic principles.hecause of the unique way in which they generate the data. Each of the above-mentioned programs treat one of the following general elementary reactions: A
A
+A
A
+B
-
products
(1)
products
(2)
products
(3)
A description of the program that treats first order kinetics, reaction (11, follows. The same general approach was used with the second-order programs with some slight modifications that will be briefly described later. The oroerams were written for a Radio Shack TRS-80 . ,. h l d e l 111 computer. 'l'ht, video disfrlil).uith these ctmputws is Imken into d erid of trlocks. 'l'hr rrid cunllsu 111.18rows nnd 128 columns, fo; a total of 6144 hiocks. These hlocks can he assessed individually. That is, a command can he issued to turn any one of theblocks on or off. We decided to let the bottom 39 rows of hlocks represent reactant molecules: the top 9 rows are used to display-a clock. A block that is off (unlit) represents an unreacted reactant molecule, while a hlock that is on (lit) represents a reacted molecule. As the "reaction" proceeds, the computer randomly selects a hlock of the grid. If the hlock is off, then it is turned on. If the block is already on, then another block is randomly selected. As the "reaction" proceeds, a clock is displayed a t the top of the video display that keeps track of the elapsed time. The computer maintains a running total of the number of hlocks that have been turned on. Thus, as the reaction proceeds, the student can actually observe the reactant mol&ules being consumed. One of the trends that becomes readily obvious from this type of display is that the rate a t which the reactant is consumed decreases as the reaction proceeds. The length of time that the reaction is allowed to run can he varied bv the student in one of two ways: the student can either select the numher of seconds the reaction is to run or the numher of blocks that will be lit when the reaction is complete. The latter method is useful for checking a reaction half-life. When the reaction is complete the number of lit hlocks (reacted molecules) and the elapsed time are stored. The student can then perform another run. When the student has completed a sufficient numher of runs, the elapsed time and the numher of unlit hlocks for each run
