The ORGANIZATION of IDEAS in GENERAL CHEMISTRY* IRA D. GARARD New Jersey College for Women, Rutgers University, New Brunswick, New Jeney
Little change has been made i n the organization of the work i n general chemistry since physical chemistry was introduced over thirty years ago. AtontiG structure has been treated rather casually by a few textbooks. I n order to facilitate the teaching of the subject and to avoid the confusion due to the great mass of existing chemical knowledge, it i s proposed to organiae the idem to be presented under
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ERY little change has been made in the content or organization of the subject matter in courses in general chemistry since the addition of the elements of physical chemistry over thirty years ago. The newer textbooks indicate that such changes as have been made have consisted of the addition of newly discovered facts or the rather casual treatment of atomic structure. The syllabus sponsored by the Division of Chemical Education of the American Chemical Society and published in 1927 (1) confirms the evidence obtained from the textbooks. The files of the JOURNAL OF CHEMICAL EDUCATION SO far as they concern general chemistry are almost as barren of modernisms as the textbooks. Wildman (2) has pointed out the weakness of the textbooks in their treatment of modem theory and Brinkley ( 3 , 4 )has called attention to some of the difficulties with the present type of course and made some remedial suggestions. Brinkley, also, in his books (5,6) has put his suggestions into more concrete form. The main defects of the present courses in general chemistry are due to the lack of classification of subject matter and the consequent lack of ideas gained by the student. The textbooks contain from thirty to fifty chapters, which means to the student a t least as many subjects to learn, each one of which involves numerous isolated facts. The modern course in general chemistry should meet the following specifications: (1) I t should differ somewhat for those students who have had previous instruction in chemistry and those who have not. (2) It should have a historical introduction. (3) I t should utilize the scientific method and call attention to the method. (4) Theories and hypotheses should be treated as explanations of facts and not as facts themselves. ( 5 ) The entire course should center around a few ideas: certainlv not more than fifteen.
resented
the Division Chemical Education of the A. C. S. at Cleveland, Ohio, September 11, 1934.
twelve main topics and to vary the emphasis and content lo suit the preMration of the stud6nt. The scientific method should be used i n the presentation of a historical introduction, elements, types of reaction and energy, oxides, acids, bases, ammonia, salts, organic substances, solution, analysis, and the elenron theory.
Let us discuss each of these points briefly. (1) Sufficient objective evidence now exists (7-14) and need not be reviewed here, to show that the chemistry of the secondary school affects the college student's work in numerous ways and therefore can be ignored only a t the expense of &ciency. The courses for the two types of student need not diier greatly in plan, but in order to avoid unnecessary duplication they must differ in emphasis and in the distribution of time. The second, third, fourth, and fifth premises of this paper apply equally to both types of course. (2) The significance of chemistry as a science can only be presented when its background is understood. Most textbooks begin with the work of Lavoisier, that is, with the advent of quantitative work, and the enormous amount of descriptive chemistry that preceded Lavoisier is omitted entirely, as well as the experimental data from which the earlier quantitative laws were derived. The practical-arts chemistry of the ancients, the purposeful experimentation of the alchemists, the more modest aims of the iatrochemists and the philosophical phlogistonists combine to give an excellent introduction to the scientific period of the subject. The introduction of the chemical balance and the resulting quantitative ideas culminating in the atomic theory of Dalton serve as excellent material for the introduction of the scientific method. The amount of time devoted to this historical introduction will and should vary with both the teacher and the class, but when the quantitative period is reached, enough actual experimental data should be given to be impressive. A single illustration is not enough. A law is not derived from one experiment and so the student must have sufficient data to enable him to see the generalization expressed by the law under consideration. The conclusions drawn from these data should then be discussed at length. If this is done, the atomic theory or any other theory to explain a given set of data will be an idea of importance'in the Gind of the student. (3) The use of the scientific method in the labora-
tory work of general chemistry has been discussed elsewhere (15) and has since been more fully developed in the author's laboratory with considerable improvement in results over the older type of laboratory work. In the class work the scientificmethod should be used consciously and impressed upon the student a t every opportunity until i t becomes as much a part of his thinking processes as i t is the habitual method of thought of the trained chemist. An examination of any textbook now in use fails to exhibit the scientific method and only a few even mention it. This is true both as shown by the classification of subject matter in the table of contents and, with very little exception, in the presentation of individual topics. Most colleges require all students to take one or more courses in a scientific subject before graduation. The object of this requirement is to introduce the student to the general field of science and its method. If the course in chemistry does not leave the student with the scientific method of thought his own, then the course has been a failure as far as the college requirement is concerned. Furthermore, the use of scientific procedure in study and later in laboratory work by the young chemist would serve to avoid many mistakes due to an effort to remember the facts that he has learned. (4) Before any theory or hypothesis is presented the facts that demand explanation should be laid before the student in some detail; the theory should then be given as an explanation of these facts. For example, the atomic theory should be given as an explanation of the quantitative laws of definite and multiple proportions. This development of a theory is the third step in the scientific method, and its implications can be discussed together with the experiments that have been made to prove them. (5) The historical introduction to the course can be treated with considerable unity centering around the use of the scientific method applied to the constitution of matter and the changes it undergoes. Therefore, this is one topic of the few that constitute a modem course. A second topic, which should follow the work of Dalton, is the chemical elements-all of them. An element can be d e h e d as a chemical substance that cannot be decomposed quantitatively, and so a t once we have a definite portion of all chemical substances set aside for study. Metals and non-metals, the periodic table, and the electromotive series are all methods (and all the methods) of classifying the elements. The development of atomic weights from Dalton to Cannizzaro is an obvious and logical outgrowth of the atomic theory and of course the atomic weights are properties of the elements. Modern work on atomic weight determination can be introduced if the instructor considers i t desirable with his particular class. The introduction of formulas and their experimental determination together with ideas of simple valence can be taught as part of this general topic. This topic should confine itself to the preparation and properties of the elements. The gas laws are properties
of gases and therefore of the gaseous elements, and the kinetic theory is an explanation of the properties of gases. The properties of compounds of the elements should be omitted a t this point. Only two reactions must be taught--combination and replacement-although substitution and oxidation by strong acids may be included here if there is a desire to be more comprehensive. This may appear to be a large chapter if considered as part of a textbook, but there are not so many elements that require individual mention. A large supply dealer's catalog lists sixty-eight elements in either free or combined form but not over fifty are of any importance a t present, and less than thirty are of importance in the free state. With the similarity of properties among the metals and only two to four types of reaction this topic is by no means impossible. While studying the properties of the metals the most important idea in applied chemistry can be taught; namely, the selection of a material for a given purpose and the creation of a metallic substance (an alloy) when no metal is found suitable. Our second topic, then, involves the elementary substances and their behavior. The amount of time devoted to it should be much greater with beginners than with those who have had an elementary course as the latter will be familiar with symbols, atomic weights, formulas, and the properties of several of the elements. The next topic to be presented should be the types of reaction and the relation of energy to each type. The ideas of equilibrium, stability of compounds, oxidation and reduction, and the chemical action of light can be introduced and will then be available for the discussion of the reactions of the various classes of substances that follow. In connection with energy, some practical suggestions of methods of heating would be of immense help to most students of chemistry. The temperatures that can be reached by different kinds of equipment and the necessity for them is a great mystery to many chemists, while to the novice the use of a crucible, a wire gauze, an asbestos sheet, a blast lamp, an electric furnace, or a water bath is a mystery of the first order. Any adequate idea of the application of energy to chemical reactions wiU be both novel and desirable. Speed of reaction and catalysis can be presented in connection with types and conditions of reactions. Compound substances can be classified as oxides, acids, bases, salts, and organic substances. There are very few exceptions to this classification. Ammonia is the most important exception and may be placed in a misceUaneous list with other compounds of non-metals or treated separately. The oxides are comparatively simple and their formation wiU already have been mentioned in connection with atomic weight determination. The occurrence, formation, and properties of the oxides together with the practical importance of carbon monoxide, carbon dioxide, lime, sand, hematite, water, hydrogen peroxide, and some other oxides can be treated as one topic. The classification of oxides into acidic and basic anhydrides
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is of course obvious, and a great help in teachmg their properties. Metallurgy in so far as it concerns the reduction of oxides belongs here, as well as the introductory study of industrial pigments. The purification of liquids and criteria of purity should be treated here unless it was introduced with the liquid elements. In the discussion of oxides as well as the later discussion of salts, the use of mineralogical names for chemical substances should be incidental because any emphasis on them serves to distract the student from the chemical nature of the mineral. I t should be pointed out, however, that they are from the terminology of another science because the constant occurrence of ite (hematite, calcite, pyrolusite, etc.) is confusing when the student has learned the chemical meaning of this suffix. The study of the oxides having been completed, the acids will constitute the fifth topic. At this point the presentation should be confined to the acidic properties of the few acids that are widely used as such in the laboratory and in industry. The action of acids on metals, bases, oxides, carbonates, and sulfides, as well as the number of common laboratory and industrial acids are rare ideas in the minds of young chemists. In case the oxidizing action of nitric and sulfuric acids was not treated under types of reaction, it should be left for a later topic. The manufacture and physical and acidic properties of hydrochloric, nitric, sulfuric, acetic, citric, and phosphoric acids will serve to emphasize the main acids of importance as such. The general relation of acids to the non-metals, the anhydrides, and the bases is sufficient treatment of all other acids for most students. Since acids are compounds of non-metals it may be desirable to introduce ammonia as the next topic and include or not, as the course demands, phosphine, silicon carbide, or any other compounds of non-metallic elements. For most courses ammonia alone is sufficient and its synthesis offers an excellent opportunity for returning to the idea of equilibrium. This seems to me to be the logical place to teach ammonia, although some will prefer to leave this topic until after bases have been taught. Bases constitute a seventh topic and only a few of them need individual attention, possibly sodium, potassium, ammonium, barium, and calcium hydroxides and the precipitation of insoluble bases. Acidimetry and alkalimetry belong at this point. Salts constitute the eighth subject. Their preparation and properties, together with the study of such individuals as the course provides time for, should be included. Since there are so few common acids, a much better grouping of salts is provided by the negative radical. Acid and basic salts, general solubilities, and the principles of precipitation belong here. A topic that is usually sadly neglected in general chemistry is the purification of solids and tests for their purity. There is no other place to present this important subject in the usual chemistry curriculum and the neglect of it is apparent in the ideas exhibited by many
young chemists. Purification as taught in organic chemistry does not carry over to inorganic substances, and, furthermore, crystallization is a general process and so belongs in general chemistry. The idea can be introduced with the elements, except for the practical diiculty of the insolubility of most of them. Salts are the first substances encountered in this outline that lend themselves generally to crystallization. Organic substances should be introduced as a separate topic. The number of subclasses of this group that can and should be included will not be very great in any case. Three or four should be sufficient. The hydrocarbons, alcohols, aldehydes, and acids are all that are necessary and even the aldehydes and acids can be omitted. The essential properties of these few types of organic substances should be brought out in order to provide data for theoretical treatment in the later presentation of the ionization and electron theories. With the completion of these nine topics, the student should be quite familiar with the physical and chemical characteristics of the six classes of chemical substances, the experimental derivation and the use of formulas and equations, the ideas of energy, catalysis, and equilibrium, as well as the use of the scientific method. In other words these nine topics serve as a few ideas about which all descriptive chemistry centers. Solution is a tenth topic consisting largely of physical chemistry that can now be introduced and studied intelligently. The diierence (practical diierence at least) between physical and chemical solution should not be neglected because much chemical literature uses the term solution to cover both processes with resulting confusion on the part of the student. Raoult's laws can be taught and with them in mind the student will be able to see clearly what Arrhenius tried to explain with his famous theory. After this theory is established it can be used to explain the familiar behavior of ionic solutes, includimg the use of pH for the expression of acidity. If the fundamentals of qualitative analysis are to be presented in general chemistry they belong as part of the work on solution or as a separate topic immediately following it, preferably the latter. I t should be 'emphasized that the classification for analytical pnrposes is a classification of limited ionic behavior and not of all the properties of the elements both free and combined. If this were borne in mind much time that has been spent trying to correlate the analytical classification with the periodic table would not have been wasted. Finally, the electron theory should be presented, preferably historically as regards supporting evidence, but with a minimum of experimental detail. It should be left in the form of a compromise among the different theories that have been proposed similar to that of Lewis (16). This can be done easily and quickly and then the theory can be used to explain electrochemical action, oxidation and reduction, some differences in the properties of organic and inorganic substances, fractional atomic weights, and radioactivity. I t may
also be used to great advantage in the construction of a periodic table (17) from the atomic numbers since this constitutes the only means by which such a table can be made without having a great mass of descriptive chemistry at hand. The organization of the course in general chemistry as presented here is a matter of the opinion of the author, and the order in which the topics are presented may not be the best, but these twelve topics might constitute twelve chapters in a textbook instead of the usual thirty to fifty. They would diier greatly in length, but there is no important reason and certainly no scientific one for dividing the subject matter arbitrarily into chapters of approximately equal length. Nor is there any apparent reason why the descriptive chem-
istry of the elements should be scattered through twenty-four of fifty-two chapters as one textbook does. The practice of chemistry consists in the solution of problems and the trained chemist solves the problem of the moment with the aid of a small number of ideas that he can muster a t any instant and a greater or less mass of information, most of which must be obtained from his library or his laboratory when it is needed. We should expect no more of the student. Neither should we expect the student to comprehend a law or a theory without some knowledge of the experimental facts without which the principle could never have been discovered. These two principles form the foundation upon which any modern course should be established.
LITERATURE CITED
COMMITTEE REPORT, "Correlation of high-school and college chemistry," J. CHEM.EDUC.,4, 640-56 (May, 1927). WILD-N, ERNEST A,. "Modern conceptions and the teaching of general chemistry,'' ibid., 9,9>8 (Jan., 1932). BRINKLEY, STUART R., "Objectives of the course in general chemistry," ibid., 7, 1869-75 (Aug., 1930). BRINKLEY, STUART R.. "The freshman course in chemistry for students who had secondary-schaol chemistry,n ibid., 8, 28&9 (Feb., 1931). BRI-EY, STUART R , T n t m d u c t ~ r ygeneral chemistry," The Mamillan Co., New York City, 1932, 565 pp., STUART R., "Principles of general chemistry," BRINKLEY, The Macmillan Co., New York City. 1933, 585 pp. SMITH, Orro M., "The organization of freshman chemistry classes," J. CHEM.EDUC.,9, 1946-4 (Nov., 1932). STEINER, L. E , "Contribution of high-school chemistry toward success in the college chemistry course," 9, 530-7 (Mar., 1932). HERRMANN, GEORGE A,, "An analysis of freshman college chemistry grades with reference to previous study of chemistry," ibid.. 8, 1376-85 (1931).
(10) GLASOE,P. M., "The deadly parallelism between high(11) (12) (13) (14) (15) (16) (17)
school and college courses in chemistry," ibid., 6, 5 0 k 9 (Mar., 1929). MATTERN,Lours W., "The correlation of high-school chemistry with first-year college chemistry," ibid., 5, 1627-33 (Dec., 1928). COM~ITTEE RBPORT,"Correlation of high-school and collegechemistry," I n d . Eng. Chem., 15, 118941 (1923). SM~TH,ALEXANDER, Science, 43, 619-29 (1916). B. GATES."High-school GARARD,IRAD. AND TKALIA chemistry and the student's record in college chemistry," J. CHEM.EDUC.,6,514--7 (Mar., 1929). D., "scientific method in general chemktry G,laboratory work," ibid., 1 1 , 4 2 4 (1934). LEWIS,GILBERTN., "Valence and the structure of atoms and molecnles," The Chemical Catalog Co.,Inc., New York City, 1923, 172 pp. GAR-, IRAD., "A simple rule for the classification of the elements," J. CHEM.EDUC.,3, 5 4 2 4 (May, 1926).
DIVISION of CHEMICAL EDUCATION MINUTES OF BUSINESS MEETING, CLEVELAND, SEPT. 13, 1934
MINUTES OF THE EXECUTIVE COMMITTEE
A VOTE of thanks to the local assistants and all members of the Cleveland Section responsible for arrangements for the meeting was passed. The following officers were elected for 1934-35: Chairman, R. E. Swain; Vice-chairman, R. D. Reed; Member-at-large of the Executive Committee, W. Segerhlom. (The Secretary and Treasurer continue in office.) The Committee on Tests was given specific authority to cooperate with the American Council of Education in its work on the construction and use of tests in chemistry. After a general discussion relating to programs and papers for subsequent meetings adjournment followed. N. W. RAKESTRAW, Secretary
PRESENT: R. A. Baker, Chairman: N. W. Rakestraw, Virginia Bartow, W. Segerblom, J. N. Swan, 0. Reinmnth. The Chairman reported briefly on the activities of the Division during the year, especially those concerning the JOURNAL OF CHEMICAL EDUCATION.One of the most important problems in this connection was the stimulation of subscriptions, upon which a fair amount of progress was made. He spoke of the efforts to improve the programs a t the meetings of the Division, and of the correspoudeuce between the Division and Section C of the A. A. A. S. with respect to a symposium on chemical education before the latter organization. A report was received from the Board of Publication indicating an improvement in the financial condition of
the TOURNAL and announcing for its further im- plans . provement. The Secretary spoke of membership in the Division, calling attention to the fact that now, subsequent to the reorganization, there are thirty-one associate members carried on the roll. The Treasurer's report was as follows:
CHAIRMAN R. E. SWAIN
The new Chairman of the Divison of Chemical Education is Professor Robert Eckles Swain, of Stanford University. Not only has he been head of the Department of Chemistry there since 1916, but he served as Acting President of the University from 1929 to 1933, during the absence of President Wilbur as SecreCash in bank March 20,1934 $222.74 tary of the Interior in Washington. He has been acReceipts tive in teaching and research in the fields of both inDues from active members 16.00 organic and biological chemistry and has been in freDues from associate members 10.00 quent demand as an industrial consultant. Most Emergency Fund for editorial office of the JOURNAL OF
CHEM~CAL EDUCATION
408.53
657.27
Expenditures 0. Reinmuth-J. CHEM.EDUC.Fund March 2WSeptember 1 R. A. Baker-expense of St. Petasburg meeting J. CHEM.EDUC.-from associate members' dues R. E. Bowman-reprints, committee of non-collegiate type M. V. McGil1-xpense of Cleveland meeting Nellie H. Seed-secretarial work for R. K. Bowman, committee of non-collegiate type Check returned Tax on checks
425.00 25.00 12.00 5.63 25.00 3.90 5.00 .60
502.13
Receipts less expenditures 155.14 Cash in hank September 1, 1934 155.14 Respedfuly submitted. VIRGINIA Bmrow. Treasurer
It was voted that the officers of the Division be listed in each issue of the JOURNAL and that the list of committees, with their personnel, be printed once a year. Reports from the following committees were received and accepted: Special Conference Committee on the Place of Science in Education (Committee continued) Minimum Standards (Committee discharged) Chemical Education by Radio (Committee continued, with one change in its personnel) Premedical Requirements (Committee continued) Study Courses for Womens' Clubs (Committee continued) Tests (Committee continued) CoBrdination of High School and College Chemistry (Committee continued) Minimum Equipment (Committee continued)
ROBERT
RCKLFS SWAIN
It was voted that members of the Division be urged noteworthy have been his contributions to the problem of Atmospheric Pollution, which led to the award of the to patronize advertisers in the J~~~~~~ cHEMICAL Chandler Medal to him by Columbia University in as far as possible. EDUCATION 1923. By his experience as an educator, as well as by The following appropriations were made: his attainments in the field of chemistry, he is adFor the office of the Chairman, for 193435 $25.00 mirably fitted to lead the Division of Chemical EducaFor the office of the Secretary, for 1934-35 $50.00 tion. He brings to his new position an insight into the To cover expenditures by the Chairman during 1933-34 894.71 problems of higher education which few of his predecesAdjournment. sors have had. The Division honors itself in its new N. W. RAKESTRAW, Secretary Chairman.
At the s p r h g meeting of the A. C. S. i n N e w York City, a part of the program for the Division of Chemical Education will consist of a symposium on the general subject: The Lecture Demomfrafion Method versus Zndividual Laboratory IBork i n Elementary Chemistry. Xembers of the Division who may desire to present papers i n this symposium are requested to communicate with the secretary, Norris IB. Rakestraw, Department of Chemistry, Brown University, Providence, R. I.
