What Is Wrong with the General Chemistry Course? Ronald J. Gillespie McMaster University, Hamilton. ON. Canada L8S 4M1 There has been a mowine concern in recent years that something is wrong h t h the general chemistry course. Among students i t has the reputation of being one of the most difficult first-year college courses. T o many of them it seems uninsoirina, . . uninteresting, and irrelevant. There is also much concern about the decieasing number of students opting to major in chemistry and the consequent acute shortage of qualified chemists that i t is forecast we will be faced with in a few years. And we as chemists are concerned that the eeneral ouhlic and the media have verv little under~-~~~~ standingand appreciation of chemistry. In m y h e w the high school and first-vear colleee chemistrv- courses must take much of the blame for this situation. I t has been said. with considerable iustification, that chemistry is the central science. certainiy courses in many other disciolines have chemistry as a requirement. So we havean enormous captive audience hut yet only a very small oercentaee of the hundreds of thousands of students in our k r ~ t - ~ e acourses ; opt to continue in the major chemistry program. In addition to the need for more chemistry majors there is also a vital need for a chemically literate public. A substantial improvement in the public understanding of science denends on imorovements in science education a t the e l e m e n k y and high' school level. But i t is not unreasonable to hope that a t least all science, engineering, and medicine graduates would have a basic knowledge and appreciation of chemistry, not only to understand its applications in their own field but also so that they can understand and intellieentlv discuss the many oroblems that humankind faces as ;he earth's population-sows, environmental pollution increases, and our resources diminish. I t seems that in our introductory courses rather than exciting students' interest in chemistry and all its important applications we are only discouraging them and killing any interest in chemistry that they might have. I am sure that many of you have had the experience, as I have had many times, of having a new acquaintance say: "Oh, so you are a chemistchemistry was the most difficult-or the most boring-subiect that I took at college." They seem to be amazed that an otherwise normal ~ e r i o ncould have become interested in such a difficult and &dl subject! What is wrong with the course? A few months ago a letter in Chemical a n d Engineering News described the course and the textbooks on which they are based as "some agglomeration of hahy physical chemistry and a screaming race through what every chemistry major should know". The writer was absolutely correct. In my opinion there are a t least five major problems with the general chemistry course at the present time. ~
1. The course contains too much material. 2. The course content is determined too much by the perceived
needs of chemistry majors and not enough by the needs of the maioritv , .of the students in the course. 3. The course is nor n general chemistry course hecnuae thew is too much emphasis on physical chemlatry and not enough on inorganic and organic chemistry. 4. There is too much difficult and abstract theory. 5. There is too much emphasis on the solving of numerical problems. Let us now consider each of these points in more detail. 192
Journal of Chemical Education
Too Much Materlal
Thirty or more years ago a substantial part of the general chemistry course consisted of inorganic chemistry, that is, a discussion of the properties of the elements and their compounds. But starting in the early '60's substantial changes were made to the course. and the inoreanic chemistrv was largely eliminated and replaced by a m;ch expanded ireatment of "or~ncioles".These o r ~ n c ~ o llnclude es eas laws and kinetic theory, atomic structure, atomic orbitals, chemical hondine. molecular eeometrv. acids and bases, redox reactions, e&ilibrium, erectrochk&istry, thermodyhnics (first and second laws) and reaction rates. Thus the emohasis in the course shifted strongly from inorganic chemistry to elementary physical chemistry. And over the years these principles have been expanded to include other topics such as molecular orbital theory and ligand field theory so that virtually all the inorganic chemistry was eliminated. But about 10 years ago i t began to be realized that students who had taken this type of course did not know any simple reaction chemistry. They appeared to he ignorant of the properties and reactions of the commonest substances. Many teachers became persuaded that the elimination of inorganic chemistrv was the main oroblem with the course. and so it has been rektroduced under the name .'descriptive" chemistry. Rut the addition of this material has not suhstantiallv. imoroved . the situation, and in some ways it has made it even worse, because nothine has been omitted to make room for it. The textbooks are now around 1000 pages in length and are almost twice as long as they were 25 years ago. There is far more material in these books than a studentcan reasonably be expected to master or that can be presented in a course. And it is the inorganic (descriptive) chemistry that is often left out. It seems to me that there are three reasons for this: rl! Instructors are used to covering all the principles to a certain level, and they feel under some obligation, perhaps because of oressure from colleaeues teacbine" hieher - level courses,to continue to doso. (2) The inorganicchemistry has often been added at the end of the text, and, because of the lack of time, it is frequently not reached. (3) The term descriotive chemistrv has a bad imaee, namelv that it is a dull catalog of facts that are not interesting td teach and that have to be memorized by the students. Even though not all the material in the textbooks is utilized in a course, students are often overwhelmed by the sheer amount of it, so they resort to just memorizing whatever facts, theories, and equations seem essential to pass the reauired tests and examinations. Thev end un with a verv superficial acquaintance with a large amount of material of which thev have verv little real understandine and of which they re& very littie when the course is finyshed. For the maioritv of students the course is laraelv a waste of time. I t is a hurdie to he overcome and then forgotten as quickly as oossihle. Not only do many students not like the course, but many instructors do not enjoy teaching it because the; feel under constant pressure t o rush through all the material. And, if the instructor does not enjoy giving the course, it cannot be expected that the students' interest in chemistry will be stimulated. The most obvious change that should be made to the course is to reduce the amount of material considerably.
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Too Much Theory
Too Orlented toward the Perceived Needs ofChemistry Malors
Many of the topics covered in the course are there mainly because it is considered that they are necessary preparation for other courses that chemistry-majors will take. But do all studentswho will not becontinuing into the chemistry majur program need to struggle throughmolecular orbitals, ligand field theory, dubious derivations of AG = AH - TAS, integrated rate laws, and so on? All these topics are essential for thechemistry major, but are they necessary for theintroductom course-do thev enhance a students' understandine of the basic ideas of ckemistry and its applications? Do ihey stimulate a students'interest in chemistrv? Do they prepare him or her to be a chemically literate citizen? I submit they do not. But we should not just arbitrarily cut material. I do not think that the detailed content of the freshman course has been seriously questioned for at least 30 years, although chemistrv has chaneed enormouslv in that time. Of course. some changes have'been made, unfortunately mostly addi: tions, but there bas been little discussion about what topics might be most useful to students continuing into biology, geology, and engineering, for example, and what topics mightbe best forensuring that futurescience and engineering graduates will also be chemically literate citizens. Such changes as there have been, have been mostly dictated it seems by the needs of chemistry majors. We need to formulate clear aims and objectives for the course in order to have a rational basis for deciding what changes to make in the course. ~
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Concepts such as hybrid and molecular orbitals and the equations of thermod&amics are too abstract and too difficult for an introductory course. Moreover, thev are unnecessary. Although such topics are essential fir a chemistry major, we have to ask if they belong in the general chemistry course. The theoretical concepts that should be in the general chemistry course are those that are needed to explain the inorganic and organic chemistry that is in the course, not those that might be needed at some time in the future by the chemistrv maior. ~olec;lar orbital theory, for example, is very useful in the interpretation of electronic spectra. ESR soectra. and ohotoelectron spectra but not for discussing and ;xplaikng structure, reactions, and oroperties at the introductorv level. For dealing with structire A d molecular geometry;lewis structures and the VSEPR theory are oerfectlv adeauate. Some understanding of energy and entrdpy changes in'reactionsis necessary, but most of the thermodvnamiceouations that are given or "derived" in current courses are'too abstract for the students and, moreover, are not necessary for an understanding of properties and reactions a t the introductory level. So little time can be devoted to these difficult concepts that at best students acquire only a very superficial understanding that often involves misconceptions that need to be unlearned if the student continues in further chemistrv courses. And at worst students just memorize the appropriate jargon needed to pass tests and examinations and they understand and remember almost nothing. Too Many Numerical Pmblams
TOOMuch Physical and Not Enough lnorganlc and Organlc Chemlstw
If the course is to be a general introduction to chemistry and to interest as many students as possible, surely it should include roughly equal amounts of organic, inorganic, and physical chemistry. But it would be a serious mistake to divide the course into three separate unrelated courses, each taught by a specialist in a particular subdiscipline. We need a true general chemistry course that integrates the organic, inorganic, and physical chemistry and shows how the physical theorv and princioles can be used to rationalize and explain dbsemaiions bn the properties of substances. So many. orcanic substances are encountered in everyday life and are constantly mentioned in the media that it is essential for a chemically literate citizen to have some knowledge of simple organic chemistry. Surely it is also necessary for the chemically literate citizen to have some knowledge, for examole. of the structures and oro~ertiesof the oxides of &lfu;anh nitrogen if he or she is.m have any appreciation of the . oroblems of acid rain and ohotochemical smog. - In other words, we need some simple inorganic chemistry in the course. And we need to consider what place biochemistry, polymer chemistry, and environmental chemistry, for examole. should have in the course. 1'n order to formulate anew curriculum, we need the cooperation of organic, inorganic, and physical chemists. With a few notable exceptionsthere are very few organic chemists teaching genera1 chemistry. In my opinion organic chemists are losing afine opportunity to introduce their discipline to a large number of students and in so doing to persuade some of them to become chemists, some who might perhaps have been less attracted by other branches of chemistry. I have heard some professors of organic chemistry say that they are not familiar enough with some of the material in the course to feel comfortable in teaching it. What better proof do we need that this material should not he there? If it is too difficult or not of any interest for a professor of organic chemistry, it is too difficult and not of any importance for a freshman student.
I have serious doubts that the heavy emphasis on the solving of numerical problems on stoichiomeiry, equilibrium, pH, solubility products, eleotrochemical cells, etc., does verymuch to enhance a student's understanding of chemistry. No one would dispute that problem solving is an important aspect of a scientific training, but problem solving should mean more than plugging numbers into equations and doing the necessary algebra and arithmetic. In chemistry it means thinking in terms of the atoms, molecules, and properties. and ions in a svstem and about their structures... . reactions,ihat is. thinking about a problem in the way that is uniaue to chemists and chemistrv. The numerical and alaebra; aspects of a problem are just dull routine, and yet these aspects often seem to dominate the solving of the problem foi a student. This is particularly the case when, aseo often happens, students just memorize an equation and learn to insert thegiven numbers into it. The problem becomesnothing more than simple algebra and arithmetic, and the chemistry is almost completely ignored, and, of course, if the data given cannot be directly fitted into the memorized equation, the student is at a comolete loss. Even when a student has understood the chemis&y behind a problem, small numerical or aleebraic slips can be verv frustrating and time cousuming Gefore the; are discoverid and corrected. Numerical problems are often justified on the grounds that "chemistry is a quantitativesubject". Thisis true butin a limited sense. A student learns to calculate the theoretical yield of a reaction, but how often in practice does one get a theoretical yield? A student learns how tocalculate the solubility of a substance in water using the solubility product concept, but how realistic is the answer, given that activity effects are often ienored and that the simnle eauilibrium that is assumed ofien ignores several other zkociked equilibria? I believe that the heavy emphasis on such calculations gives the student the incorrect impression that chemistrv is a verv mathematical subiect. and it does nothing to encourage h o s e who might turn out to be "green-fingerh" synthetic chemists. Students may well get the impression from the general chemistry course that studying chemistry means dealing Volume 68 Number 3 March 1991
193
with an endless series of dull numerical calculations. Students usually do not get to see that chemistry often involves the solving of challenging and interesting problems about the structures and reactions of molecules by using a range of largely qualitative concepts, such as electronegativity and nuc~eoohilicitv,and bv relatine observations to the known behavibr of d a t e d substances.We should also guard against the temptation to emphasize numerical prohlems just because they are relatively simple t o grade for assignments and examinations. We must think seriously how best to test the more descriptive qualitative material. A New Dlrdlon for General Chernlstn
Todefine the objectives and content of a new introductory course is the challenee before all of us who teach chemistw. not only those iuvolGed in the general chemistry course. in my opinion the course should be more general, less abstract. and I& mathematical. It should emphasize more that chemistry is concerned with the properties of substances and their reactions and uses and that chemical reactions are the basis of life and the basis of modern civilization. I am not advocatine that students iust memorize hundreds of facts. Theorv an% principles have an essential place in the course, and thk challenge before us is to formulate the right combination of facts and theories and principles. These theories and princioles should be those that are needed to discuss and exolain properties and reactions a t an introductory level and not because they will be useful in some following course. Moreover, the theory and principles should be integrated with the facts. The concepts, theories, and principles that we use in chemistry cannot be appreciated except in the context of some facts and ohservations that we wish to explain or rationalize, and the facts and ohservations cannot be understood and remembered unless there are some theories or orincioles with which to rationalize them. The course should not he so clearly and artificially divided into theory and orincioles on the one hand and what has been called descrioiive chemistry on the other as i t so often is. The term descriotive chemistrv imolies a descriotion of the oro~erties . . andreactions of s;bst&s, and so it is not surprising that this term has a bad imape. But the reintroduction of inoreanic chemistry into the course does not mean a simple des&iplive listing of facts. It should mean a discussion of properties and reactions in terms of theories and principles, in other words, an integration of principles and descriptive chemistrv. An important aim of the course should be to train students to think like chemists. or at least to understand how chemists think, in attempti& tounderstand the material world in terms of atoms and molecules and their motions and rearrangements. An ability to memorize a large number of facts or an ability t o solve numerous numerical oroblems is not is necessary f i r such an understanding. ~ h a i i important s that studentsgain at leaslaqualitative understandineof the more important basic conceits in chemistry and aknowledge of a basic set of facts to which these concepts can be applied and to which other facts and observations that they encounter can be related. What are the basic concepts of chemistry that should be included in the course? My suggestions are:
184
Journal of Chemical Education
Atoms and Molecules Moles and Stoiehiometry Bonding-Lewis structuresand VSEPRno hybrid and molecular orbitals, no ligand field theory. Gases, liquids and solids-intermolecular forces Reaetions-including acid-base and redax Periodic table Energy and entropy-tbermochemistry but no quantitative treatment of entropy and free energy Equilibria Reaction rates, mechanism, and catalysis-mainly qualitative-no integrated rate equations This list covers many of the principles and concepts that are in the course at the present time. But not all of them can be treated in such detail or in such depth as they are now. A more qualitative and less mathematical treatment is all that is necessary. These concepts and general principles should be introduced by and used in the discussion of a basic set of factual material (descri~tivechemistrv) makinr extensive reference to applicationiof chemistry in everyday life and in other sciences. Similarly the course cannot include a very extensive or detailed treatment of inorganic or organic chemistry. There is no need, for example, to discuss all the groups of the periodic table. Only a few selected elements can be treated in any detail. Similarly the organic chemistry should he based only on the more important functional groups and a few examples of synthesis and mechanisms. This basic set of "descriptive" chemistry might consist of the following: Inorganic chemistry ofa few selected elements ntonmetals: H.N, 0, halogens. P.S. Si metals: Na. K. Mr. Ca. Al. Fe. Cu Organic ehe&ist&hydrocarbons, some simple functional groups and some simple examples of synthesis and mechanisms and a selection of material from the following areas: Biochemistry Polymers Geochemiatrv Solid state &d materials science Cosmochemistry This list of descriptive chemistry topics includes several that are barely mentioned in most courses and yet they are areas in which there is much activitv and interest a t the present time. Surely a t least some of these topics should be included in the eeneral chemistrv course if we are to capture the interest of The students and if we are to educate our students to become chemically literate citizens. Of course the treatment of these topics should not he entirely descriptive and the opportunity should be taken to introduce or further illustrate the appropriate concepts, principles and theories. Not everyone will agree with my suggestions and the discussion of the content of a new general chemistry course will be long and difficult, hut it is essential that it should begin immediately. Without a serious revision of the course, such as that sueiested here. comolaints about the course. about the chemiEhy illiterate students that i t is said to be turning out, and about the shortage of chemistry majors will continue.
