letters General Chemistry: More than a Course in Chemistry To the Editor:
In a recent article (J. Chem. Educ. 1991, 68, 192) addressing the problems of the general chemistry course, Gillespie suggests five major modifications. First, he believes that the present syllabus contains too much material. I agree conditionally. Chemistry, even a t the introductory level, is quite challenging. For most students, mastery of the necessary concepts comes only with drilling and repetition. The present two-semester general chemistry pmgram allows no time for such review. As a result, students leave the course having been "exposed" to an extensive list of chemical topics, but without having developed significant insight into, or appreciation for, the physical laws governing atomic and molecular systems. As educators, we must either reduce the scope of the curriculum somewhat, or, better still, allow for a three-semester program in which the students can he exposed to both the theoretical foundations and the practical applications of chemistry. In either case, we must demand from the students a greater comprehension of the integral topics. Trimming the syllabus, or expanding the timeframe of the course while continuing to pass students with only a superficial command of chemical principles will be a greater transgression than taking no action a t all. Secondly, Gillespie believes that the general chemistry program should not be designed to fulfiil only the needs of the chemistry major. This complaint is valid although the argument is limited. Instructors must remember that they are part of a system of education whose prime directive is to produce enlightened, diverse, inspired, and socially functioning individuals. Whether at the secondary or collegiate level, chemistry is frequently the first academic discipline a student encounters that requires him or her to read critically, reason abstractly, and process data analytically. In addition, these tasks must he performed within the theoretical framework established by the laws governing the system. Pupils often find such an endeavor extremely demanding, yet it will be these skills that will prove to be invaluable to them regardless of their professional interests. Therefore, the development of these talents should be one of the paramount goals of the general chemistry program. The topics selected for inclusion should serve, though certainly not exclusively, as vehicles for the genesis of such skills. In the spirit of my last statement, I must soundly disagree with Gillespie's final three modifications, which basically call for a substantial reduction in theory and mathematics. Having t a u g h t numerous subject matters (physical science, physics, general chemistry, physical chemistry, and mathematics) a t various educational levels (elementary, secondary, and collegiate), I have been astounded by the meager mathematical sophistication and physical insight demonstrated by many of our present students. Undoubtedly, a reduction in the degree of theory and mathematics would meet with student approval, but surely it would not be in their best interests. Rather than abdicate such a responsibility, instructors of science and mathematics should strive to elevate these unacceptably paltry student achievement levels. I agree with Gillespie when he states that some of the topics covered in the present course are not mastered by the average student and therefore serve only to discourage him or her. But I submit
that we. the instructors. must shoulder some of the resoonsibility'fbr this. We must resist the temptation o i t h e "wick fix". Reducinn the mathematical and oroblem-solving components of t h e general chemistry course would probably elevate student test scores. a t least initiallv. However, such an approach would be merely masking tge symptom, while leaving the disease untreated. I do not believe that such a pedagogical tactic would produce more skilled and better educated individuals. And, aRer all, is that not our primary goal? Instead of abandoning such topics as thermodynamics, kinetics. and electrochemistrv. we must brine these t o ~ i c s to life. T&ng a student only that a reaction is spontaneous when the Gibbs free enerw chanee is neeative is all but worthless. To the student,lthe ~ i G b freeinergy s function then becomes nothing but a "magical black box" that generates information by a n unknown means. However, convincing a class (using a simple model of placing balls in boxes and elementary probability theory) that the universe naturally and continuously evolves in a direction of increasing disorder, simply because hsordered states are more probable, provides a more visual, appealing, and com~rehrnsibleaooroach to the second law uf themodvnamics, while simultaneously stimulating the imagiuation. Such a statistical view of thermodvnamics can then be associated with a Gibbs free energy change usingrudimentarv los?ic and minimal mathematics (arithmetic and aleebr;). with such a n approach, the magical box is replaced with ~ h y s i c a linsight. reason. and most im~ortantlv. mean& ~urthe&e,'in an age that faces the iealities nuclear waste, students need to understand the kinetics of nuclear decay. An integrated first-order rate equation is too enlightening and the mathematics not sufficiently intricate (logarithms) to warrant removal from the general chemistry syllabus. In essence, thermodynamics and kinetics an&& two absolutely fundamentai questions: Why do chemical reactions occur and a t what rate? A general chemistry program that does not respond to these basic inquiries would seem to he limited and unfuliilling. Therefore, we must address these queries, hut we must do so with fervor and focus. Having students memorize equations without understanding their origins, without perceiving their applications, and without appreciating their elegance is indeed ~ointless. submit that it is not so much the topics we choose to include in our introductorv course. but rather our Dhilosophical and personal approach in'presenting the& topics t h a t is our shortcoming. We do our students the greatest disservice when we fail to encourage them to see the larger picture. Oftentimes we teach chemistrv. . . physics, biology, geology, mathematics and other dis: ciplines as if they are unrelated, and then we become frustrated, somewhat hypocritically, when our students do not see essential correlations. Also, perhaps more critically, we have indirectly fueled the spread of scientific illiteracy by passing students that have little or no mastery of the material, all in the name of generating that false deity known a s the Gaussian grade distribution. These Door Dedaeoeical habits must be broken. ~ h y & a liaws an> their execution through mathematics have been wonderfidly successful in revealing the elegance of the universe. As Einstein said, "The most incomprehensible thing about the universe is that it is comprehensible." The general chemistry course and the individuals enrolled
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will be better served not by substantially reducing the levels of theory and mathematics but by bringing dynamism and relevance to these topics, thereby convincing the stuthat such intellectual dents of the beauty and grandeur . tools unveil. Vincent M. Stumpo West Virginia University Morgantown, WV 26506-6045
To the Editor: Vincent Stumpo argues in his letter that general chemistry is more than a course in chemistry. I agree that it can and, indeed, should help a student to learn how to "read critically, think logically, and process data analytically". But I do not agree that the development of these talents should be the paramount goal of the general chemistry course. Nor should we choose the topics of the general chemistry course orimarilv on the basis that thev will h e l ~ studeutsUtoacquiie these-skills. Students sho2d acquire these skills in anv colleee or universitv course whether it be in history, ~ n i l i s hlitkrature, mathkmatics, or philosophy. There is nothing special about chemistry as a vehicle for these skills. The primary goals of the general chemistry course should be to educate students to become chemicallv literate citizens and to give them a basic knowledge of thk facts and concepts of chemistry that they will need in their future studies bf medicine, engineering, biology, geology, chemistry, etc. There is no reason why topics chosen with these aims in mind should not form the basis for acquiring the important skills of reading critically,thinking logically, and processing data analytically. Indeed no student can really understand and appreciate even the minimal amount of basic chemistry in the general chemistry course without having acquired these skills. I t is our fault as teachers if, as Stumpo says, "we fuel the spread of scientiiic illiteracy by passing students with little or no mastery of the material." Stumpo and I are not as far apart as he seems to think. I did not advocate abandoning thermodynamics, kinetics, and electrochemistry as he implies. I only suggested that these subjects should be treated in a less formal, less rigorous, and less mathematical way. I agree entirely with his view that the important and fundamental ideas of thermodynamics can betaught "using rudimentary logic and minimal mathematics". In other words dubious derivations of AG = AH - TAS and the meaningless substitution of numbers into this and similar equations are neither necessary to nor helpful in acquiring an understanding of the basic ideas of thermodynamics. I have never advocated that students should memorize equations without understanding their origin. Thermodynamics and in particular the fundamental ideas of enerm and e n t r o ~ vcan be a ~ ~ r e c i a t e d without many of theseiquations a i d any that are considered necessary must a t least be iustified bv qualitative ar-
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It is true that many bemning students have vew little mathematical sophistication and physical insight but chemistry is not mathematics and chemistry professors should not be spending their time teaching mathematics. General chemistry requires only minimal mathemnticol skills. but we can. throueh chemistrv. helo students to acquire'the physicai insigh; that they obGously lack when thev enter the course. E m ~ h a s i son mathematical skills in thLgeneral chemistry coirse only enhances the students feelings of inadequacy in this area and does nothing to at-
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Journal of Chemical Education
tract them to chemistry If we can succeed in attracting some students to continue further studies in chemistrv bv showing them what an exciting and important field i"t is, thev will have the incentive to acquire the necessarv mathematical skills later. At the outset they are only &scouraged by a mathematical approach and a n emphasis on numerical problems through which they do not acquire the physical insight that both Stumpo and I consider to be important. t In short I w e e with much that Stumpo . says . e x c e ~that 1 believe tha; the primary aim of the gcneral chemistry course is to help students to understand and appreciate chemistrv and its relation to the other sciences. We .--should ~~-~~ be teachfng the basic facts and concepts of chemistry. If students w i n some real understandine of ehemistrv thev will necesiarily have learned "to read c>tically, thi& lo*callv. and Drocess data analvticallv". The traeedv todav is that many students do not"acquire these basic skills Lor any real understanding of chemistry but only a very superficial and readily forgotten knowledge that enables them to pass our superficial tests and examinations. ~~
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Ronald J.Gillespie McMaster Ln verstty Hamilton. Ontarlo Canaaa LBS 4M1
Very Large Hydrogen Atoms, Indeed To the Editor: Professor Emeritus John Arenta of The City College of New York has graciously informed me of an error in my article "Very Large Hydrogen Atoms in Interstellar Space" [1991, 68, 454-4553, in which I give the radius of the H atom as 5.29(nJ2 nm, where no is the orbit for an excited nm. electron. The correct value is of course 5.29 x 10-~(n,)~ Alter converting from angstroms w nanometers and triplechecking the result 1 failcd to include the 10 factor in the cauation! T h ~ snediaence causes all of the calculated H atbm radii in the ffrtke to be 100 times too large, and my self-esteem to be reduced by the same order of magnitude. Thus the excited H atom of the n = 253-252 transition (paragraph 8) has a radius of only 0.00339 mm, not the reported 0.339 mm, and thus would be theoretically visible with a good microscope but not by the unaided eye. The maximum size of an excited H atom detectable by an earth-based radio telescope (paragraph 91, assuming a lower limit of 10 MHz in the radio window of the atmosphere, would be 0.0400 mm, not 4.00 mm. A dime-size (radius 9.00 mm) H atom (paragraph 9) would hypothetically emit radiation in the region of 2.96 kHz rather than at the stated 2.969 MHz, and the transition would be from then = 13,043 orbit rather than from n = 1303. At the stated value of 2.969 MHz the atom's radius would be only 0.0900 mm, 100 times smaller than dimesized. In a desperate attempt to salvage some credibility (motivated by a fit of Panglossian optimism) I can only hope that my simple-minded exclusion of the lo-' factor in the equation for the H atom radius will provide a shin in^ (daring may be the better word) example of the devastat&effect; of the Ignored Decimal Place in unit conversion!
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David B. Clark Pennsylvania College of Technology 1 College Avenue Willlamsport, PA 17701
