The use of CAI for High School General Chemistry Courses is less clear. Only 50% of the material is covered at a level that the average high school student would understand. There are more appropriate software packages available far the average high school student. I t is recommended that hieh school teachers involved in Advanced I'lacement ot Enrichment Programs carefully examine the wntcntaofthir wftware todetermine i f i l will meet the needs of their classes. Patricia L. Barker Minisink Valley High School Slate Hill.
Route 6 NY 10973
Review I1 "Computer-Aided Instruction for General Chemistrv." - . a comnlete set of instructional program9 written for Commodore I'Rr, is intend~dtu wide utudenh thrwgh drill and practice sessions in general chemistry. I t consists of two 5114 in. diskettes and an accompanying program guide that lists topics, subtopics, objectives, and completion times. Topics covered match those of chapters in a t y p i d general chemistry textbook. For many topics, the student requires a calculator andlor textbook. To use the instructional package, students require simple directions. Far the Commodore system, they are ar easy as flipping one switch and typmg LOAD "PRO(;RAM." h c h disk herins witha cable oin,nlmrs: and " from that point on, controlof the program is by menu. At the beginning of a session, students are reminded that they can access the tahle of contents by typing "HOME" or using the "M" key. The system is well protected so that an incorrect or a null input does not permit the program to crash. A t w i d session with one of the ten tooies on ea% diskette is predicted to require Gi)to 90 minutc,.Thix is realistic for a student who is not well versed in the topic. Each topic is divided into subtopics that can he chasm in any order and terminated at any time. As the student completes the subtopic, the percent of the correct resnonses is disnlaved . . on the menu. No oermanentrecord of nerformance is maintained. A subtopic can he repeated: the same questions are asked but the variables are changed. The variety of variables provides the student with a unique series of questions. The suhtopics can be divided into the followine instructional cateeories: renew. simulation, and queathm and answer. About 8000 of the program ir question end answer, of w h ~ half h are numerical problems, and the rest are problems that require short answers. A correct answer results in a response of "very good" and the program proceeds. After an incorrect response, the program leads the student through the solution of the nmhlem. =Approximately 25% of the suhtopics presented include a review of the material. Although more topics could have benefitted hy review sections,they appear limited in nature and presume previous exposure to the topic. There are two particularly attractive fea~~~~~
~
~~.~~ ~
~~~
~~~
~.~
~
~~~
-
A272
Journal of Chemical Education
at will and any inappropriate items can he exercises involvine-theneriodie table. A ne" . omitted. nodic cable ~sbull1 on the screen and queuThe programs contain a numher of minor tium are then asked about the per~udirtnhle flaws that studenw are not likely to notice. In and trend, in prupertles. The other feature a few rases, significant f i w e conventions are is simulation. In two topics simulations are not followed in solutions to problems. An presented with bar graphs representing the interesting situation arises immediately folconcentration of several species. When two lowing scientific notation. When a numerical reagents are mixed, the dilution effect is inout is exoeeted and scientific notation is displayed, followed by concentration changes "red, the response implies wrongly that an that result from a chemical reaction. The student is able to select a variety of starting incorrect numlrer of signilkant iigures has materials for several chemical systems that Iwen wed. Later on, significant figures are not analyzed. In the structure and bonding exhibit varying extents of reaction. The section, the first question asks far the central concepts of stoichiometry and equilibrium are well presented in this type of display. atom in C2H1 OI CZHZ.These are poor examples since there is no "central atom." In Question and answer suhtopics are well that same tonic. students are asked to nredict written and easv to internret. The resnonse the fmnula fur'such compounds as ~ e ~ , n n d to short answer quest~onsusually requires a 13Rrl. The hasla for thp predicthm ir that dnumher; wme questims, however. require ements generally obtain eight outer electrons. answers that are difficult to type. For PxamThis is fine, if you consider them to he ionic ple, in response to a question on electronic species. In the next section where Lewis configuration the student must type in the structures of BeCh and BC13 are investigated, next lowest noble gas with the appropriate bervllium and boron are said to have four and capital letters and brackets, followed by the sir electrons. respectively, around them. principal quantum number, orhital, and Them are too many conflicting statements nnmher of electrons. all, with appropriate and exceptions to the rule in these sertiuns. spaces. This may not be trivial for students In a few cases, responses to students' inwho are inexperienced a t the keyboard. A correct answers are incomplete. The equation multiple choice question involving a set of given for the solution of a weak acid prohlem possible configurations would he as valuable is [H+I2 = KA([HA] - [H+]). Students not and more convenient. In nomenclature qucstiuna, typing names and, part~r~~larly, only have difficulty with this type of prohlem hut have difficultv internretine the solution. typing furmulas is an inconvenient way tu In addition,subsiitution in rhpequarrm ~ n respond. This is especially true since not only wlves a value x that is not explained in the are typing errors considered incorrect, hut setup. A tahlr rhowing initial concentration, also the typed input cannot involve subthe change tinvolving x), and final cunccnscripts. tmtion should Ire included as in the topics Numerical problems require a numerical mvulvmr.equilil,rium and solubilitv. In the input-in some cases, exponential notation . section on reactions in aqueous solution, the in the form of 1.3e-8. For difficult problems, chemical eouation is left ineamnlete students are given a second chance. The throughmt the question and a,lutron. The program checks for correctness; an answer cumplete renrtiun rhuwn wlth the aoluthm within +5% of the correct answer is acceptwould help reinforce theconcept of preripiable. The program makes no attempt to tate formation and gas evolution. identify the source of the student's problem. In several cases, the computer's responses This inability to focus on the areagiving the to incorrect answers seem inappropriate. student difficulty and to provide individuWhen the student resnonds to the auestion alized instruction is a practical limitation of asking for the number of moles in 36.0gofC the program. This is a level of sophistication incorrectly, the screen displays, "Hrcause that a machine is yet unable to attain. For the atoms are .w small, a large quantity must be most part, the programs provide detailed, present in order to weigh or measure them:' stepwise solutions that most students should The relevance of this statement is not ohunderstand. nous. It is only after several more statements There are a few areas where the program are flashed on the screen that it takes on confronts the student with puzzling situameaning, hut by then the original prohlem tions. On one occasion in the electrochemistry statement has disappeared. When oxidation topic two identical half reactions were prenumbers are being examined, an incorrect sented. The following questions were then response elicits a complete set of rules. The asked: "Which reaction would proceed in the student must search to find the rule that reverse direction if an electrochemical cell applies. A similar prohlem exists in the secwas made from them? Which reaction would tion dealing with ehemical reactions in take place at the anode? Which half cell aoueous solutions. The camouter has the would involve metal reduction?" A propower to indivdualize thp response to the gramming change is needed to prevent sispecii~rsituation and that ahility should be multaneous appearances of two identical half maximized. renl.th,nu. Another pn,hlem arises when the The current focus on computers does not perhdic table 1s displayed with one of the necessarily translate into an interest in using fimt :lfi elements blanked out and the student this medium as a learning method. The best is asked to identify that element. Some stutest of an educational package is, ultimately, dents may enjoy this exercise, hut many are the response of the student-both in attitude overwhelmed by it. This goes beyond what is and knowledge gained. The package of normally expected of students. There are "Computer-Aided Instruction for General topics that may not he high priority in mast Chemistry" has been available locally for general chemistry courses, such as: van der student use on a voluntary basis. A limited Waal's gas equation, numerical values for number of students have used the programs electranegativity, the order of boiling points and the response has been favorable. They for five diatomic gases, and the solvent syshave enjoyed the programs and found them stem of acids and bases. The nature of the
..
~~
~
~
~
.
~~
helpful in learning the material. This set of programs is very attractive because it is a &-written, complete packag for an entire general chemistry course. Topic can he chosen as desired and the program can he used repeatedly without duplicatior Drill problems are well presented and ar suited for this type of instructional formal Although there are limitations as note above, students enjoy working with the dy namic.. resnonsive medium available in thi package. There are enough unique graphic and simulations to prevent students fror being bared by the drill and practice rou tines. Jerry L. Wals Uniwnity of Nom Carolina at ewnsbor Greensboro, NC 2741
.
Tltrator David R. Dice, Dlgipac Computer Consul ing. 907 River Street East. Prince Alber Saskatchewan S6V.OB3, Canada Hardware: 48K Apple II, 1 disk drive Software: Appleson Components: 1 disk Level and Subject: General chemistry Cost: $23.95
/
SUMMARY RATINGS Revlewer l Reviewer ll Excellent Ease of USB Average Good (as a Good Subjaa ~lrnuiatlon content exerci~e) Category
value Student reactim
Very g w d l Excellent
Revlew I "Titrator" is a concise program that alloa the user to simulate the titration of either strong or weak acid with a strong base. Th rate of addition of the hase from a huret i controlled by the use of agame paddle, whic can serve as an analog to the control of th buret stoncock. As hase is added from th huret m theacid, thecorrespondina titratio curve is plotted on the rlght-hand side of th video screen. The student is a h k t
