REPORT of the NEW ENGLAND ASSOCIATION of CHEMISTRY TEACHERS' COMMITTEE on COLLEGE ENTRANCE EXAMINATIONS ALFRED R. LINCOLN Technical High School, Springfield, Massachusetts RUSSELL V. CORSINI North High School, Worcester, Massachusetts
HELEN S. FRENCH Wellesley College, Wellesley, Massachusetts BURTON L. CUSHING East Boston High School, East Boston, Massachusetts
DOROTHY W. GIFFORD The Lincoln School, Providence, Rhode Island
CHRISTINA B. M C K E Dorchester High School For Girls, Dorchester, Massachusetts LAURENCE S. FOSTER. Chairman Brown University, Providence, Rhode Island
INTRODUCTION
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HE purpose of giving college entrance examinations is to make i t possible to select the candidates who give promise of being able to profit from four years a t college and to eliminate those who do not. The examination in chemistry should assure the college instructor, furthermore, that the students who have been given entrance credit in chemistry possess sufficient maturity of viewpoint to be able to handle the work in a more advanced course than the usual introductory freshman chemistry. The examinations should be planned, therefore, to test the ability of students to apply what they have learned. The examinations set by the Board should not dictate the entire content of the secondary-school chemistry course, but should be of such nature that students who have been well trained in certain minimum fundamental topics will show up well on them, but those who do not think logically about chemistry will fail. Those who have studied the matter agree that students remember the principles they have studied long after they have forgotten most of the facts. They will recall only the facts which appealed to them particularly strongly. But if they have learned to think in terms of chemical principles and logical theories, they will retain much of this ability for a long time. The chemistry course should be designed so that plenty of time is allowed for the mastery of a few im~ o r t a n chemical t ~rincioles. The develoument of the topics should be' logi& and as exact' as possible, keeping the distinction between experimental evidence 46
and theoretical explanation quite clear. The uart of the work dealing with applic&ons of theoryshould be started early and emphasized continually throughout the year. In an elementary course i t is necessary to cover thoroughly only a minimum of such theoretical topics, hut they should he taught with the fundamental postulates of the scientific method kept constantly in mind. The distinction between the experimental evidencethe f a c t s a n d the theoretical explanationthe theoryshould be kept crystal clear. The theoretical topics which are selected.for inclusion should be of fundamental importance and general application. Obviously, it is possible to cover only a few, but they furnish an adequate basis for examination. Such theoretical topics shonld constitute only a small fraction of the total content of the course. The teacher will wish to enliven his course with the introduction of topics of local and current interest. The student will be presented with hundreds of facts, but it is unimportant which'facts he ultimately remembers. It is logical to expect, however, that the successful student will he able to interpret data and correlate it in terms of his theoretical background. The time has arrived when it is desirable to eliminate from the secondary-school course much theory which is no longer of service to chemistry, even though it is historically interesting. The Committee does not disagree with those who wish to trace the development of an idea using a historical approach, but it believes that the student should finally be brought up-to-date and left with the broadest viewpoint at the end of discussion. A case in point is the Arrhenius theory of the
"degree of ionization" of salts. If the student is not resented with data which does not follow the Arrhenins Theory, and is not presented with some of the more successful ideas used in explaining the data, he does not have the opportunity to reach his own conclusion concerning the material. If he is taught the Arrhenius Theory as a fad rather than a historically interesting theory which was successful in explaining the rather inaccurate data available a t the time of its promulgation, he is not being prepared adequately for college work in chemistry, and he is not being imbued THE I
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OUTLINE OF THE PLAN FOR THE SYLLABUS RECOMMENDED B Y TEE NEW ENGLAND ASSOCIATION OF CHEMISTRY T E A ~ R S 'COMMITTEE ON COLLEGE ENTRANCE EXAMINATIONS
Part I.-An outline of general topics which all elementary courses in chemistry should cover, whether a oneyear course in chemistry, or a two- or three-year course in the physical or biological sciences. Emphasis should be placed upon the distinction between experimental data and theoretical explanation. Part 11.-An outline of the descriptive materiel which
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with the scientific approach. I t is more important to the student to have acquired a scientific viewpoint than to have memorized a handbook of data. If a theory is worth introducing into the secondary-school course, it should be developed logically and not presented as a theology. Furthermore, it is unsound to teach students principles which must be unlearned later. It either leaves them with the feeling that their secondary course was no good, the teacher incompetent, or develops in them a distrust for science and its methods in general. The modernization of the secondary-school course can be accomplished only by the immediate introduction of a more scientific viewpoint with respect to the theories of the science. The plan which the Committee of the New England Association of Chemistry Teachers submits is divided into three parts. By grouping the subject matter into these three categories, the Committee feels that the course can be made more flexible. It allows the teacher to bring his own viewpoint to bear more strongly through his selection of the topics in which be and his students are most interested and upon which he will do his best teaching. The college instructor does not care what descriptive material the student has studied, provided he has had thorough drill in the important generalizations of elementary chemistry and an opportunity to appreciate the value of the scientific method of thought. The committee would emphasize very strongly its belief that it is not essential to examine the student upon all the topics which have been introduced into the course.
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should be used to illustrate the generalizations. There might be considerable deviation from such a list in case of the second level examinations. This section can be modified for preparation for examinations in the physical and biological sciences. This present list represents in the best judgment of the committee what should ddnitely be included in the one-year course in chemistry in preparation for the first level examinations. Part 111.-An outline of sufifilementnry topics. (Specific questions on these topics would not be placed on the examinations.) In addition to the laws and theories in Part I and to the factual material in Part 11, the individual teacher should select for the enrichment of his course suitable topics which may be found in any good chemistry textbook. (A large number of such topics are included in the "Outline of Essentials for a Year of HighEDUCASchool Chemistry," JOURNAL OF CHEMICAL TION, 13, 175 (Apr., 1936) written by B. S. Hopkins, L. W. Mattern, W. Segerblom, and N. E. Gordon. Reprints may be obtained for fifteen cents from the JOURNAL OF CHEMICAL EDUCATION, 20th and Northampton Streets, Easton, Pennsylvania.) At the present time in following the College Entrance Examination Board Syllabus, the teacher finds that he must cover all of the "Supplementary Topics" just as thoroughly as those in the main list, since he does not know where the lightning is going to strike. It is the hope of the committee that by limiting the factual content of the examination to the topics in Part 11, the teacher will be freed of the grim task of covering superficially "everything in the book."
shared with other atoms. Emphasize essential nonionic nature of non4ectralytes. 3. Coordmate covalencea covalence bond in which both electrons of the pair are furnished by only one of the atoms. (Illustrated in the formation of an ammonium ion from an ammonia molecule.) *I). Balancing of Simple Chemical Equations (bv . . insoection .
NEW ENGLAND ASSOCIATION OF CHEMISTRY TEACHER'S PLAN FOR A SYLLABUS OF TOPICS TO BE COVERED BY COLLEGE PREPARATORY STUDENTS UPON WHICH THE COLLEGE ENTRANCE EXAMINATION BOARD WOULD BASE ITS EXAMINATIONS
PART I.
GENERAL
CHEMISTRY
only). E. Quantitative Relationships in Chemical Reactions. *l. Laws of combining proportions. *2. Gay-Lussac's Lsw of combining volumes. *3. Problems based upon chemical equations. *(a) Weight relationships. *(b) Volume relationships.
I . Periodic Lew and I& Relation to Atomic Numbers. A brief treatment only is desired, but the student should he aware of the variations in properties of the elements as one proceeds horizontally and vertically through the periods and families. The long type (expanded form) of the table is mare useful than the older MendelCeff type. (Cf. FOSTER.L. S.. Rept. Neu Eng. Assoc. Chem. Teachers, 39,23 (Sept., 1937).) (A printed Periodic Table should be supplied each examinee for use during the examination.) tNotes: Topics upon which calculations are permitted are marked with an asterisk. The topics are not arranged in order of presentation in the classroom. Topics marked with a represent those which may be considered common to both physics and chemistry.
V. Solutions.
A. Definition of terms; saturated, supersaturated, unsaturated, concentrated, and dilute solutions. 1. Experimental method for distinguishing between such types of solutions. B. Solutions of Electrolytes. 1. Complete dissociation of salts and strong acids. 2. Deeree of ionization of weak acids. -~ -~ 3. Modern definition of acids and bases Acid 5 Ht Base 4. Hydrolysis of saltsReactions of ions with water. 5. Reason why ionic reactions go t o completion. (a) Formation of a weakly ionized product. (b) Formation of an insoluble gas or solid. ?6. Electrolysis of aqueous solutions (use as examples those substances onlv in which the final products are the result of the direct discbaree of the salute ion: e. g., CuCIS. 7. Electrolysis of fused salts (either when pure or in mixtures).
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II. Structure of Atoms. tPA. Nudear charge and the major groups of the extra-nuclear electrons only. (Restricted to the first twenty elements.) B. Explanation of the periodicity in properties of the elements in terms of atomic structure. C. Ionic valence and its relationship t o the inert gas structure. (In the 6rst three periods of the table only.)
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III. Physical Properties of Solids, Liquids, and Gases. PA. Kinetic-Molecular Theory. Dependence of the kinetic energy of motion of molecules upon the temperature. Differences between solids, liquids and gases from kinetic-molecular viewpoint. B. Properties of Solids. Crystal Lattices--presence of ions in crystals of salts. C. Properties of Liquids. 1. General properties of liquids. 2. Presence of ions in fused salts. D. Properties of Gases. ?*l. Effect of changes in temperature and pressure on the volume of gases and the explanation in terms of the kinetic-molecular theory. *2. Partial pressure of gases in a mixture. P*3. Reduction t o standard conditions, including correction for vapor pressure of water. 4. Avogadro's Law-*derivation of gram-molecular volume.
I V. Chamicel Changes A. Compounds, Elements, and Mixtures. 1. Nature of chemical changes. P2. Definition only of atom, moleczrlc, ion, and radical. 3. Types of chemical reactions. ?4. Electrochemical series (an electrochemical series table should be supplied each examinee for use during the eusmination). B. Chemical Combination Explained in Terms of Atomic Structure. 1. Combination and displacement reactions in terms of electron transfer. 2. Sharing d electrons in formation of un-ionized compounds. 3. Ionic nature of substances entering double decomposition reactions. C. Valence. 1. Ionic valence (electro-valence) equal to the charge possessed by the ion. Emphasize essential ionic nature of salts. 2. Covalence-qua1 to number of pairs of electrons
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PART It.
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DESCRIPTIVE CEEMISTRY
Chemistry of Some Non-Metals and Their Common Compounds-Oxygen. Hydrogen, Nitrogen, Sulfur. Carbon, and Halogen Family.
This topic should he expanded to give a more complete list of properties and reactions which should be included. The Committee feels that in view of the uncertainty of the outcome of this report, if the College Entrance Examination Board wishes additional data, this question should be referred back t o a committee of teachers for amplification.
Composition of Air. Relation of Air to Combustion and Life Processes.
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III. Water; Its Composition and P v r i ~ t i o n . Chmnistry of Five Metals and Their Common Compounds Sodium, Aluminum, Iron, Zinc, and Copper. 1. Definition and properties of metals in general. 2. Occurrence of these five elements and their extraction from
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V . Qualitative Analysis. 1. Test for ions in solution in the ibsence of interfering ions. (a) . . Anions: Cll-; Brl-; I$-; SO4'-; 32-; COs'-;
s0sa(b) Cations: Ag'+; NHaLC;Baa+; CuB+;Few; Fe"; Ma+; Zn2+ (6) Flame tests for NaIC; K1+; BaZf The reader should bear in mind constantly that the plan is not
intended to be an outline for the course, but is an outline of the maximum requirements for preparation for the College Entrance Examination Board's examination in chemistry on the first level and for combined examination in chemistry and physics and chemistry and biology on the second level.
wornmend: That the syllabus issued by the College Entrance Examination Board t o guide the student have the general form and content of the plan described in this report. That on the College Entrance Examination Board examinations, questions covering the descriptive material be of the objective type. The examination should include a selection of facts which would be covered by most courses in chemistry, following Part I1 of the plan submitted here. (The Committee is in fair agreement over the topic of choice questions and believes that it is possible t o prepare fair examinations upon which there is no choice. If choice questions are eliminated, the present form of the examination would have to be profoundly modified.) That the part of the examination covering the principles of chemistry attempt to test the student's ability to reason about chemical situations, rather than his skill in remembering pat answers t o trite examples. The College Entrance Examination Board should feel free to include simple calculations (as indicated in Part I of the plan) and to use
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any other technic which can be shown to measure this quality of the student's mind. That no problems be introduced an the examination in which transfer from one type of unit to another is incidental to the working of the problem. That individual laboratory work be required as preparation for the examination. The College Entrance Examination Board syllabus, however, should not attempt to state which experiments merit inclusion, as the planning of the course should, in general, be left t o the teacher. (a) That, with regard t o the conduct of examinations, a t the beginning of the examination period, the student be presented with a pamphlet in which is printed a 4-place logarithm table, a set of atomic weights, a periodic table (preferably the long type), an electrochemical series and set of selected physical constants far reference purposes. (b) That during the examination the use of slide rules for arithmetical calculations he permitted. That the syllabus finally proposed by the College Entrance Examination Board be submitted to teachers for criticism before adoption.
