viously in the two-semester organic chemistry course. Robert Stolow and Leo Joncas of Tufts University (1) have modified the LHASA computer-assisted organic synthesis program developed by E. J. Corey's group (2) a t Harvard University so that it may be used with a limited data base of reactions as an instructional tool. The availability of reasonably priced modems and of software that emulates a variety of Tektronix terminals and runs on either a MscIntosh microcomputer (3) or on an IBM PC-XT micrwomputer or clone (4) equipped with a mouse makes it possible for colleges with a DEC Vax computer to use this excellent instructional tool a t a very reasonable cost. We have found this to be a very effective way of teaching organic synthesis that students enjoy to the point of obsession ("This is a blast"). If Organic Reaction Chemistry could bemodifiedtoallow the instruetor to select his own data base of reactions, the combination of the two programs would work very well in a two-semester organic course. Organic Reaction Chemistry would remove some of the mystery of how LHASA does retrwynthesis. Llterature Clted 1. Stolow. Robert D.; Joneaa, L. J.: d. Chrm. Educ. 1980, X"
ms
2. Corw. E. J.; Lone. A. K. Rubatein.
S. D.;Science
3. TEKALlKE WSK, 512K. XL) and TEXT TERM
m
AND GRAPHICS ( 5 1 2 ~ SIZKE. . PIW, SE, rmm Mesa Graphics, P.O. Boz KO, La.Alam~lam,N M 87544
.~ .
~
4. PC-PLOT from MICROPLOT Swtema Co..
659-H
~,~~~~ ~~~, ~~~
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~
(Not all mice are supported by either of the laat two programs)
Wilmon B. Chipman Bridgewater State Callege Bridgewater, MA 02324
Chemlcal Reactions, Reactions in Aoueous Solution. and Oxldatlon Reduction Reactions J. A. Weyh, J. R. Crwk. and L. N. Hauge, COMPress. P.O. Box 102. Wentwath. NH 03282 Hardware: IMB PC with a color graphics adaoter ~o&onents: 1 disk. 1 back-up disk, and User's Manual Level and Subject: General Chemistry Cost: $50 each Revlew I These programs are intended to provide students with drill and practice in equation writing (including formula writing), equation balancing, and reaction predicting. The material is aimed a t the average student and is suitable for eeneral ehemistrv students at all levels in most rchmls. Theonly prerequisite required is a first rhemrrtry course rovering elrmenb and rompoundn, fundsm~ntal particles, and an introduction to ehemical changes and nomenclature, ~
A172
The programs are extremely easy to use and require very little documentation or knowledge of computers. The documentation provided, however, is extensive and clearly written and aimed at putting the novice at ease. "Getting s t a r t e d was simple: installation of DOS was accomplished according to instructions and running the programs only required following on-screen prompts. The documentation also provides a list of all problems used in the program and will he useful for instructors to plan homework andlor tests. Suggestions far use of the programs given in the documentation include (1) classroom demonstrations, (2) drill, (3) homework, ad (4) tutorials. 1found the programs suitable for drill and homework but not for demonstrations or tutorials. The menus are clear and need no explanation and allow quick access to different sections of the Lessons. Information to helo solve the problems is easily accessed by pressing the Esc key which gives a Help Menu. All other prompta need no explana. tion. In short, the programs are easy to use and perform exactly as described. Generally, the chemistry is accurate and complete and each program is organized well. The exception is "Reactions in Aqueous Solution," where the organization is poor and the chemistry is misleading. The section "Formation of Partially-Soluble Gases" should he removed and the program reorganized around two subheadings: Precipitation Reactions and Formation of Weak Electrolytes. The fact that a gas is produced is not the driving force for the reaction; rather, the important point is that it is a weak electrolyte. In fact NH3, COz, SOz, and H B are reasonably soluble gases. Thus this heading is misleading and will cause confusion to first-year students. The label "(g)" should not he used as is stressed in the documentation since it is the formation of NHs (aq), for example, that is important The help screen listing the partially soluble gases is also inaccurate. For example, beside NH3 (g) the screen shows (NHif OH-) even though the predominant species is NH3 (aq) (remember, Kb = 1.8 X The above criticism applies to only 15 of the 239 problems available in this program. The level of treatment is generally appropriate t o first-year students. In "Chemical Reactions" the level becomes progressively more difficult and thus accommodates students of varying abilities. The other two programs do nut vary the level. It is not likdy that the tearher without proprammine knowledre - would be ahle toslter there programs. As noted above, the pedagogic approach taken is drill and practice. The examples used are extensive and should he valuable to students and teachers. "Help" is availahle by pressing the key for Help with Reactants or Help with Products. Unfortunately, doing this simply gives the correct coefficients
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Journal of Chemical Education
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and formulas. This approach is too much like electronic page turning. It is too easy for the student to obtain the correct answers without struggling to solve the problem. This is like working problems from a solutions manual. The programs would be much more effective if "Help" would be in the form of intelligent prompts or a diaglogue similar tothe one that takes place hetweeu a tutor and student with the computer filling the role of the tutor. Even st the very least the comouter could eo throueh 2 or 3 prompt cycles before glving up the correct answer. This is my main objertinn to these programs and should be a prrority item fur improvement. In the Oxidation-Reduction Program, the method of removing electrons from the halfreactions is annoying. For example, in the tutorial example 2 in acid solution:
-
~~
+
the program requires the user to multiply the tirst equation by 4 and the serond equation bv 2. Surelv the student and the Droly the &st gram &I h a n d ~ ~ s i m pmultipying eouation hv 2 and then addine the eouatiunr. Tutorial example 2 in base is sncgther example. When the two hall-reactions are written: C10,-
- -+
+ H,O + 2es2-
S
C10,-
the program tells the student to multiply each equation by 2. Then these coefficients are reduced to one! This is ridiculous. The program actually considers lack of an integer as a n incorrect entry. This carries through when the problems are worked. A final minor point: the print function is useless, because it tells the students only the problem numbers that have heen completed successfully. The oromams will he used in the Fall of 1988 in'1h;'~rop-ln-centre (Hesourre Centre, for our large first-year rhcmistry course (1400 students). I feel this. and home use, will he the most appropriate. Despite these criticisms, which can be remedied easilv, thisset of drill and practice exercises is definitely worth using. students using these programs will actually learn some ehemktry and, after all, that is the objective. Robert J. Balahura hlph-Waterloo Cemre faQaduate Work in Wlernisny Unfverstly of Guelph Cuelph. Ontario N1G 2W1, Canada Review Ii Does anyone remember, know, or care what the first chemistry CAI program was that was written for a mainframe computer system? The answer t o all three parts of this rhetorial question may be a resounding
Summary Ratlngs: Reviewer
cat.gaY Ease of Lhe S u b W Maner Content Pedagogic Valus: Student Reaction:
+ 20H-
2e-
I
Excellent Gwd God Gwd
Rerlewer I1
Ood AverageIOood AverageIOwd GoodIExcellent
"NO!", hut there is a good chance that such a program dealt with the balancing of chemical equations, the subject of the three programs reviewed here. The programs in question, Chemical Reactions (CR), Reactions in Aqueous Solution (RAS) and Oxidation Reduction Reactions (ORR) are ell by the same authors and are availahle separately. Since they share many common features and pedagogical approaches I will discuss them as a package, giving examples from each program where appropriate. The level of chemical sophistication expected from the student increases from program t o program in the order above. Taken together, the three programs cover the balancing of chemical equations a t the level expected for students completing a year of college level introductory chemistry. Many college level courses that require one or more years of high school chemistry as prerequisites will assume that students are familiar with the suhject matter of these programs; consequently, they could he used in both the high school and college courses. All three programs use a common user interface, one that is fairly easy to master, and which is the suhject of a tutorial session on each of the disks. Unlike many programs dealing with equation balancing, these programs have very strict requirements regarding the use of super- and subscripts. Suhscripts, where required, are entered using the function keys; F1 for a subscript of 1etc. Superscripts are entered with a combination of the Alt key and a number of + or - as appropriate, e.g., AM, Alt+ for the superscript an calcium ion. Ions with more than one unit of charge must he mitten with the magnitude preceding the sign of the charge, the currently accepted practice. The screen in each program is divided into a region for the problems statement and an answerlinteraction response area. Each program also comes with a set of tables that can be recalled by the student a t any time. For CR those tables are common cations, common anions, diatomic elements, and common acids and common covalent compounds. RAS includes several of the ahove plus solubility rules and weak electrolytes and partially soluble gases. One of the few points about the chemistry in these programs with which I quihhle is found in the tahle of anions in RAS. The form shown for hypochlorite is OCI-, and that is the only form that the program will accept. A survey of recent introductory and inorganic chemistry texts shows CIO- as the accepted form by a margin of more than 21. Of course one could argue that there are many ways of writing the formulas of various oxyanions depending upon the point that one was trying to make. Any program which deals with formulas should contain asufficiently flexible thesaurus to recognize any acceptable variations an the theme of an ionic formula. The first program in the series, CR, is representative of all three. The user is presented with a menu of initial choices: a tutorialan the use of the keyboard, a tutorial on chemical reactions and five choices of problems: combination reactions, decomposition reactions, replacement reactions, ionic reactions, and general reactions. For each type of problem there are three choices of level: balance the equation given the formulas of reactants and products; given the names of reactants and products, write the formulas
and balance the equation, and given the names of the reactants, predict the products and halance the equation. These multiple levels of balancing are not availahle in the other programs. In RAS the student is asked to write the molecular, total ionic, and net ionic reactions for each equation. If desired one can proceed directly to the net ionic reaction. Choices in CR come from a data hase of 165 equations distributed over 12 categories, four reaction types, and three approaches to writing the equations. In RAS there are 239 different equations, mostly precipitation reactions with afew weakelectrolyte and partially soluble gas reactions. In ORR there are 70 reactions, 50 in acid, and 20 in hase. In CR the category "ionic reactions" is somewhat misleading as what is heing balanced are net molecular reactions, all of the classical double displacement type. In CR there is no requirement to enter the state of the products although that is essential in the other two programs. When an error is made in a problem a messagds) is produced that identifies the source of the errorb) in reactants andlor products and specifies whether a given error is in formula or coefficient. Other error messages include "you have tw many products" etc. In ORR, which uses the half-reaction method, students who tested the program were constantly getting error messages hecause they forgot to put a charge on the electron(s). If the error is repeated so is the messsaee. In some cases the oroeram eventually tffers help hut in athers, such as the charge on the electron, the same error message is repeated ad infinitum. The ESC key calls up a help menu which in the case of CR has the choices of the aforementioned tables, a keyboard review help with reactants or help with products. In the latter two cases the term help is somewhat specious, for the student is given the correct information with no further prodding. A case where students found the error messages somewhat misleading occurred in RAS where the state of the products must he specified. Correct entry of the formula far iron(II1) chromate produces a message "error in formula"when what was missing was the state of the suhstance. After that messaee was reneated three time the correct information wasgiven to the student. The documentation that comes with the program, intended far the instructor, is complete and unambiguous. It includes a listing of the equations in a given program by numher enabling the instructor to assign particular problems. If specific problems are assigned a printout of the numbers of successfully completed problems can he generated before the student leaves the program. My students and I have tried these programs on a variety of computers ranging from a generic IMB PC with cdor monitor toa 16 MHz R02Rfi AT clone. In all cases the programs have worked as advertised. The programs appear as "crash proof' as one can reasonahly expect. The students who used the programs ranged from those having just completed a semester of introductory chemistry toseveral seniors in an advanced inorganic chemistry course. All of them found the programs reasonably easy to use, once the keyboard layout was mastered, and saw that they would he useful at several levels in the eurriculum. The seniors felt that they would
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provide an effective review, prior to the inorganic course, of both equation balancing and some of the descriptive inorganic chemistry they had not seen, and had generally forgotten, since their first year. Students in the introductory chemistry course were also enthusiastic about their use in a course where no lecture time is devoted to this tonic. While agreeing with the students in all respects, and while I would recommend that chemistry departments have these programs available for their students to use, I have several reservations. There is no ohvious way of adding extra equations to the programs. This is particularly problematic in ORR where there are only 70 equations and the difficulty level remains relatively low, hut my concern is applicable to all of the programs. Secondly there is the matter of cost. I find the programs to he relatively expensive and certainly would find it difficult torecommend that any department buy mare than one copy. That alone limits the utility of the programs in very large courses. Finally let me return to the query of the opening paragraph and close with another rhetorical question. Given the time and hardware and software advances since the early CAI programs were written, should we expect more than these programs? While I am not sure of the answer, it seems a point that must he kept in mind whenever such programs are written or reviewed. William F. Coleman Wellesley College Wellesley. MA 02181
Essentials of Medlclnal Chemistry, Second Edltlon Andrejus Korolkovas. Wiley: New Ywk. NY. 1988. xii 1204 pp. Figs. and tables.
+
19 X 26 cm. $125.00.
The second edition of Essentials of Medicinal Chemistry by Andrejus Karolkovas is such a major revision of the first edition which was coauthored with Joseph H. Burckhalter in 1976 that it is more nearly a new treatise on the suhject. The first edition was nearly 700 pages. This edition is 1200 pages in length. The reason for the broad reorganization of the material is that the author has onted to use the latest World oharmaeoloeieal clasHealth ~re&ization -~ "~~ ~-~~~~~ aifiration of drugaratierrhan theolderclassification used in the first edition and other texts. He has also included the methods of chemical synthesis for numerous drugs as well as brief historical sketches that were not included in the first edition. The weakest point of the text is an extremelv brief table of contents which consists of one pageof titles fur the 22 chapters. As in the first edition, the first three chapters cover the principles of medicinal chemistry. The remaining 19 chapters cover the various drugs, using the major World Health Organization classification headings. The division of the material according to the major headings of the WHO classification results in a wide divergence of chapter lengths from nine pages for Chapter 14, Gastrointestinal Tract Drugs, to 291 pages for Chapter 16, Antidefective Agents. Internally, Chapter 16 is divided into 18 major topic headings. The brevity of the tahle of contents is more than compensated for by (Continued on page A174)
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Volume 66
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Number 6
June 1969
A173
