R. J. Kokes The Johns Hopkins University
Baltimore, Maryland
The Present Chemistry Curriculum at The Johns Hopkins University
A s a t most other institutions, the chemistry curriculum a t The Johns Hopkins University is continually evolving. During the past six years, Professor D. H. Andrews and the writer have introduced a number of changes in the introductory chemistry course.' Apace with these changes, parallel changes have occurred in the advanced courses so that the current program of study for chemistry majors bears little resemblance to the program of a decade ago. I t is the purpose of this brief paper t o provide a summary of the current program. It should be realized that much of this is still in the experimental stages. Since the writer has been primarily concerned with the introductory course, this is where the emphasis will rest. The Introductory Course
Most teachers of introductory chemistry will agree that the scientific sophistication of freshman students underwent a discontinuous increase in the period between 1956 and 1958. Even those teachers who would not agree with this statement will certainly agree that the impact of the CBA, CHEh4, and PSSC courses is now being felt. This change is a mixed blessing for often these courses appear t o be presented in emasculated form with t,he result that too frequently we find a college freshman who has heard of many of the topics traditionally taught in the first college chemistry course hut cannot do problems in stoichiometry or even handle logarit,hms. Nevertheless, this prior exposure has taken the edge off of the traditional course, and if student interest is to be maintained, we must try a new tack that will present the fundamentals in a way that is fresh and stimulating. Accordingly, our current course is based on a development of a statistical and thermodynamic treatment, heavily laced with modern structural chemi~try.~At the outset we, in our ignorance, thought our approach was unique, hut recent articles in THIS JOURNAL ( Q , 4 , 6 6) , together with the appearance of thermodynamic texts aimed a t freshman (7, 8 ) and introductory chemistry texts embodying this approach (9,10) have revealed that many others have sought similar solutions to a problem that we consider of paramount importance. Presented as part of the Symposium on Recent Trends in Undergraduate Curricula before the Division of Chemical Education at the 145th Meeting of the American Chemical Society, New York, N. Y., September, 1963. The attendant changes in the laboratory part of the course have already been the subject of articles published in TEIS
The introductory chemistry course a t The Johns Hopkins University has an initial enrollment of about 330, i.e., about 80% of the freshman class. A typical class contains about 115 majoring in biological sciences, 125 majoring in engineering, 75 majoring in physical sciences and 15 to 20 majoring in liberal arts. For a variety of reasons, the lecture and laboratory are given separate course numbers; hence, the student receives two different grades, one for lecture and one for laboratory. I n spite of this formal separation, however, the two courses are an integrated unit that constitutes 28% of the normal credit hour load for engineers and 33% of the normal load for all others. All students meet together three hours per week for the lecture part of the course, Chem 1-2, hut these students may be enrolled in one of two laboratory courses, Chem 3 4 or Chem 5-6, hoth of which meet six hours per week. The first is recommended for physical science majors and chemical engineers; the second is recommended for the remainder of the class. These two courses are identical with the first semester; the second semester those in Chem 3 4 deal with qualitative and some quantitative analysis while those in Chem 5-6 work on experiments meant to provide a sampling of all branches of chemistry. For Chem 3 4 and 5-6, the class is divided into a total of twelve sections each meeting for t n ~ othree-hour periods a week, i.e., a total of 56 sessions per year. During the first semester, one session per week is devoted to a conference; the other is devoted to laboratory experiments of the type described earlier ( 1 , 2). The average conference is divided approximately as follows: (a) 15 minutes--experiments past and future (b) 75 minutes-review of principles, problem solving, and a question and answer period (c) 30 minutes-quiz
In ( a ) we make sure that students are prepared to do the experiment scheduled for the next period and that they understood the results of the previous experiment. Part (b) provides time for informal discussion of theory and for applications previously introduced in lecture. Part (c) serves as a catalyst to make part (b) effective, insofar as it deals with material covered in (b). Since questions are permitted in ( c ) , it is really graded, inclass problem work rather than a quiz. These conferences continue into the second semester for hoth courses, but after four weeks for the Chem 3 4 group and eight weeks for the Chem 5-6 group, the full six hours per week are spent in the laboratory. The grade for the laboratory part of the course is based on a weighted average of the grades for conference quizzes, Volume 4 1 , Number 3, March 1 9 6 4
/
131
reports, unknowns, and an estimation grade by the, instructor. A schedule for the lecture part of the course is given in the table. At the very beginning the student is introduced to model thmking; for example, the treatment of radioactive decay includes the derivation of the first-order decay law with particular attention to the implication that the process is governed by probability considerations. Development of this aspect of chemistry is continued with a discussion of atomic structure in which an effort is made to connect quantum numbers of atoms to the physical observables and their relation to the periodic chart. Treatment of molecular structure is followed immediately by the application of covalent bond theory t o compounds of carbon in the belief that numerous concrete examples show the student that these principles help provide a framework on which to hang chemical facts. After an interval dealing with gases, the structural theme reappears in the lectures on crystal structure, which includes the structure of ionic crystals, molecular crystals, and oxyanions. Lecture Schedule 1
2;
Mt~thematicalPreliminaries The Nucleus and Radioactive Decay A+,omie S t~ n ~~ h ~-r ~ n . -..~ Stoichiometry Molecular Structure including Organic Stereochemistry and Resonance Gases includine Boltzmann's Distribution Crystal StGcture Metals and the Structure of Oxides Vapor Preasure the Free Volume Theory Solution Theory and Colligative Properties Thermodynamics, 1st and 2nd Lam Chemical Equilibrium in Gases Second semester Chemiml Kinetics Equilibrium in Solution including Structures of Acids snd Bases Electrochemistry Redox Equations Chemistry of Metals excluding Transition Metals Chemistry of Non-Metals Structure of Non-Metals including Allotropy and Nonaqueous Solvents Complex Equilibria in Solution Transition Elements Metals and Alloys including Coolmg Curves and Phase Diagrams Complex Ions including Stereochemistry and Crystal Field Theory Organic Chemistry Nuclear Chemistrv ~~~~~~~~~~~
In lme with the commitments to models, discussion of molecular motion, Boltzmann's distribution, and a simplified statistical theory of liquids, solutions, and solubility precedes the discussion of the First and Second Laws of Thermodynamics. This clearly has disadvantages. It requires the introduction of temperature, energy, and enthalpy before they can be clearly defined, and it is more time consuming than the thermodynamic approach. On the other hand, this does provide a reservoir of information about states of matter that can he drawn on for illustrative examples, and it permits us to dwell on the interrelation of statistics and thermo132 / Journal o f Chemical Education
dynamics. It can he argued that this approach results in a hodgepodge in which the elegance of thermodynamics is corrupted by statistical arguments which are in the main qualitative. We disagree. For an introductory class as heterogeneous as ours, we feel that the relatively abstract thermodynamics should be tied as closely as possible to a physical picture. Throughout the remainder of the course an effort has been made to apply thermodynamic principles. Applications of thermodynamics to electrochemistry nre obvious. Other applications appear in the discussions of the limiting form of rate expressions a t equilibrium, catalysis, strong versus weak electrolytes, alloys as an example of an ideal solution, allotropy, and nonaqueous solvents. Finally, existing thermodynamic data can be utilized in the discussion of descriptive chemistry to reduce the facts to a semblance of order. It is believed by the writer that this procedure is effective insofar as it gives the student a feeling for modern chemistry, but of course, this is a prejudiced view. Nonetheless, in view of the increasing use of thermodynamics in introductory chemistry courses, it appears that others have reached a similar conclusion. There are a t present a variety of conflicting views as to how thermodynamics should he presented; nodoubt, in time this conflict will be more fully resolved. When this occurs, thermodynamics in introductory chemistry will be as common a topic as the geometry of molecules. Advanced Courses
Introductory quantitative analysis is no longer a required course for chemistry majors. I n part, the techniques learned therein have been shifted to introductory chemistry; most of the remaining techniques appear in other courses. The normal chemistry course for sophomores is organic chemistry. This course, under the direction of Professor A. H. Corwin and Dr. M. Bursey, is undergoing considerable revision. I n broad outline, the first semester deals with structural organic chemistry; the second semester deals primarily with mechanisms. At present they are working from lecture notes. In his junior year, the chemistry major is usually enrolled in the physical chemistry course, which has no lab, and a new course entitled Junior Chemistry Laboratory. The latter is scheduled for six hours per week and brings together many of the experiments formerly carried out in advanced quantitative analysis and the physical chemistry laboratory. More than this, however, the student carries out experiments with a variety of spectroscopicand other techniques that are in common use by research workers everywhere. I n his senior year, the chemist takes a one-semester course in Inorganic Chemistry and a one semester course in Organic Qualitative Analysis. The remainder of his time is spent on independent research together with one of the graduate courses in Chemistry. I n conclusion, it might be noted that although the introductory course as outlined above has been in its present state for several years, the programs cited for sophomores, juniors, and seniors are essentially new this year. Accordmgly, meaningful evaluation of their impact will have to wait the test of time.
Literature Cited
J., DORFMAN, M. K., J. CHEM.EDUC.,39, 16 (1962).
(1) KOKES,R.
AND
ANDREWS,D. H.,
(2) KOKES,R. J., DORFMAN, M. K., AND MATHIA,T., J. CREM. EDUC.,39, 18, 20, 90, 91, 93 (1962). (3) "Editorially Speaking," J. CHEM.EDUC.,38, 333 (1961). (4) STEINER,L. E., J. CHEM.EDUC.,38, 490 (1961). (5) BENT,H. A,, J. CHEM.EDUC.,39, 491 (1962). (6) BURTON, M., J. CFIEM.EDUC.,39,491 (1962).
G. R. Bakker, 0. 1. Benfey, W. J. Stranon, and 1. E. Strong Earlham College Richmond, Indiana
I
I
1962. (9) HELLER,L. A,,
AND HERBER,R. H., "Principles of Chemistry," MoGmw-Hill Book Co., New York, 1960. (10) BROWN, T., "General Chemistry," Charles E. Merrill Books, Inc., Columbus, Ohio, 1963.
The Earlham Chemistry Curriculum
Time was when individuel chemists were broadly aware of developments over the whole of the eoienoe. True, the division of chemistry into organic, inorganic, physical, and anrtlytied ~sectiansis of very long standing, but specialists in any one of these used to be an familiar terms with the others. But that time has long passed, thanks mainly to the explosive growth of our science during the past 50 years and the fantastic increase in factual knowledge that bas accompanied it. The practitioners of the various branches have drawn more and more apart with the passage of time, and only a few yeaxs ago the average organic chemist's knowledge and familiarity with, say, physical chemistry effectively terminated a t the undergraduate level. But within chemistry, just as in science ss a whole, most of the major developments me now occurring in the borderland areas between the traditional divisions, and we can therefore no longer live happily segregated if we me to progress further. This, of course, poses s real problem in the education of the chemist. The plain truth is that we must re-think the whole matter of training courses and the traditional divisions of the science on which our university and college courses have been based. This is no easy matter I know, but we must all apply ourselves to it and to the related problem of the ancillary subjects of study, for chemistry is also advancing in the borderlands between it and, for example, the biological sciences.'
For the past seven years a t Earlham College we have been puzzling over the problem of developing an effective M resent at ion of chemistrv to undereraduates. Our iniGal plan was described in"1958.~ hi essential feature of the plan for a four-year curriculum was that Presented as part of the S,ymposium on Reoent Trends in Undereraduate Curricula before the Division of Chemical Educetion st ;be 145th Meeting of the American Chemical Society, New York, N. Y., September, 1963. We are indebted to Reino Hakala (current Address: University of Syracuse) who taught in the department and contributed
For two years, a grant by Smith, Kline, and-Frenbh Foundation aided -ereatlv . in freeine fseultv time and eauin~ine . " laboratories for new courses. Grants from the E. I. duPont de Nemours & Company m d from the Lubrizol Foundation have also been of assistance. ' From Lord Todd's IUPAC Presidential Address, Chem. Eng. News, Aug. 5, 155 (1963). STROW.L. E., AND BENFEY,0. T., J. CHEM.EDUC., . 35.164 .
-
(7) MAHAN, B. M., "Elementary Chemical Thermodynamics," W. A. Benjamin Inc., New York, 1963. (8) NASH,L., "Elements of Thermodynamics," Addison Wesley Publishing Company, Inc., Reading, Massachusetts,
A.
(1958). 3 BRTIRER, J.S. "The Process of Education," Hanrrtrd University Press, Cambridge, Mass.. 1960, p. 11.
a sequence of courses should be based on the major ronrepts that rurrcnrly structure rhemisrry. Thr us1131 ~'hemistrv curricuIum is bawd not so much on conceptual patterns as i t is on certain technical skills, exemplified by analytical procedures, or on arbitrary classification schemes which produce such dichotomies as organic versus inorganic. Fortunately, chemists have been able to move a considerable distance toward a unified view of chemical reactions based on principles of electrostatics and mechanics. To what extent can present developments provide a usable basis for the study of chemistry as a science? The first step toward developing a curriculum seems to be to recognize that there is no agreed upon rationale or theory of learning to guide the organization of a sequence of courses. Whatever may be said about chemistry as a science, it is certainly true that developing a chemistry curriculum is fundamentally an empirical procedure. It is, therefore, in a spirit of curricular empiricism that we have been developing a set of chemistry courses. Our approach to instruction in chemistry is consistent with a statement by Jerome B r ~ n e r . ~ Students, perforce, have a limited exposure to the materials they are to learn. How can this exposure be made to count in their thinking for the rest of their lives? The dominant view among men who have been engaged in preparing and teaching new curricula is that the answer to this question lies in giving the students an understandine of the fundamental structure of whatevents one encounters outside a. classroom . . . .
The development in students of an understanding described by Bruner would seem to require a curriculum based on a set of major concepts. These we have formulated in the following way:
t u r d and energetic changes. The direction and extent of a. chemical reaction can be related to energy and entropy changes. The rate of a. chemical reaction can be interpreted by a mechanism which describes the path of the reaction. Volume 41, Number 3, March 1964
/
133
