To the Editor: I have a proposal for a rational nomenclature in connection with BMnsted's definition of acids and bases. According to J. N. Br0nsted (and later T. M. Lowry) an acid is defined as any complex (electrically neutral or an ion) capable of giving off protons; and any complex, aspiring to add protons, is a base. The question is now: shall we use old names in a quite new meaning, or create special names, suiting the new ideas? The first alternative has already brought about some confusion in modern literature, and to the majority of practical chemists the names acid and base mill never acquire the meaning that Brensted's definition has put into them. My proposal is founded on the new word "prote," coined by Br0nsted. The following table shows the relation between the most important words in question: Chemical eomplez HAc Ao-
+HR-
CI -
BrZnsted
New Proposal
Acid Base Amfiprate Aprote
Exoprote Endoprote Amfiprote Antiprote
Complexes having any relation to the proton, either positive or negative or both simultaneously, are thus protes. This word replaces Br0nsted's protolytes. Corresponding acids and bases are Brensted's names for complexes which are alike except for the proton. I call them isoprotes. For the reaction between them-Br0nsted's protolysiswe use exendoprocess. Finally, there are the old words acid- and base-catalysis. I propose exo- and endo-catalysis. The above-proposed nomenclature has the advantage of being simple, easy to understand, and also absolutely international. LENNART SMITH
CHEMICAL INSTITUTE OP TnE UNIVERSITY LUND,SWEDEN
To the Editor: 27, The article by Maud B. Purdy (THISJOURNAL, 379 (1950)) raises a host of questions relevant to the ethics and value of instructor rating by students. I t has been my experience that student opinions are largely
colored by short-range viewpoints, based upon entertainment to be derived from lecture demonstrations, the extent to which problem-solving is required, the degree of rigor expected in their reasoning, as well as nonacademic considerations. The proficiency of a given student is a major factor in determining his reaction toaninstructor. A presentation which is a model of clarity to a "B" student may be a masterpiece of confusion to the "D" student; in simplifying the discussion to the "D" level, one is apt to evoke the adjective "boring" from the "B" student. Unquestionably the number of variables cannot he encompassed in the manner suggested in the article. The basic fallacy involved is that students are competent judges not only of the manner in which a course is presented but also of the objectives of the course and the way in which it fits into the curriculum. An inevitable result of the application of the fallacy to rating and promotion of staff members will be a pressure to "butter up" students and cater to their limited sophistication. I suggest a procedure which achieves the general ends of teacher evaluation without doing harm to the principles of collegiate instruction. Let the staff members responsible for a given course meet with their departmental chairman and evolve a set of course objectives detailed enough to serve as a syllabus. These objectives should include desired changes in the skills and abilities as well as precise statements concerning content areas. permit each staffmember to try to achieve these in his own way, his success to be measurable in terms of a. common final examination. This examination is designed to measure the extent to which each student has made progress toward the objectives of the course; each item on the examination has had prior approval by the teachers in the course. Misuse of data obtained in this way is still possible, of course, in the hands of incompetent administrators, but the allowable margin of error in evaluation is reduced considerably. Evaluation of excellence in teaching must be approached with caution; damage to the institution as well as to the individual may well result from spurious Of success. WILLIAM HERED
579
UNIYERS.TY, CALUMET CENTER EASTCAICAOO, INDIANA
JOURNAL OF CHEMICAL EDUCATION
580
To the Editor: M~~ I point out that the use of
processv with the meaning of a physical change, i. e., grinding, drying, distillation, etc., in B. C. Hendricks' article in your June issue, is not in line with the present convention.
To a chemical engineer a unit process involves a chemical change; a unit operation a physical change. ZAPERA. SAWWAP pn,E ,
UN W.LAFAYETFE,
INDIANA
A CHEMISTRY OF PLASTICS AND HIGH POLYMERS
As those acqusinted with the earlier editions know, this is not merely a collection of laboratory directions even though its main Patrick D. Ritchie, Head of the Department of Chemisky, purpose is to serve as a laboratory guide. It is divided into two Central Technical College, Birmingham, England. Cleaver- par&. In Part I are brought together sixty-four experiments of the Hume Pzesa Ltd., London (Interscience Publishers, Inc., New types most generally selected for the first course in physical York); 1949. viii 288 pp. 34 Figs. 14 X 21 om. %.SO. chemistrv. Preoedin~the directions for each exneriment is a Tars is an excellent, well-written hook for the organic chemist hrirf hut quite con~~.rchcnsivc dircusr;ion of the tleory pertin~nt or gaduste student who desires to acquire a. broad knowledge of to it. Since it often hnpprns tl.nt inhuffielcnt6Ct4 of appar8tu1 the suhject of high polymers from a hook of moderate size and arc available to prrnmit all tlw claw t*, wmk on thr azmc erpcriprice. Organic synthesis and structure are kept to the fore ~ t hment at one time, and that, in consequence, close coordination of physicochemical aspects touched only lightly. Assuming the laboratory work with class work is impossible, this clarifies the reader to he of graduate level the author steps directly into his subject for the student and makes the experiment more meaningsuhject with little space wasted on introductions. His practice of ful to him. Appended to each experiment are suggestions conreducing literature references to a surname and date (e. g., Jones, cerning the applicability of the method and also a list of refer1945) is unsatisfactory hut the generous use of 365 diagram and ences to both books and original papers. The sixty-four experistructural formulas is good. I t is not a reference hook, for the ments are grouped, according to their main themes, in fifteen author has rigorously selected his material to illustrate the general chapters with the following headings: Gases; Opticochemiesl principles of high-polymer chemistry. methods; Thermochemistry; Liquids; Solutions; HomogeneThe first three chapters (42 pages) contain definitions, function- ous equilibria; Heterogeneous equilibria; Chemical kinetics; ality theory, and the mechanism and kinetics of polymerization. Electric conductance; Electrode phenomena; Electromotive The next four chapters (87 pages) cover the synthetic polymers force; Dielectric constant; Colloids; Photochemistry; and with most attention being paid to the structures of the phenolic Radioactive isotopes and tracers. and the amino resins. Most of the remainder of the hook (81 Part I1 consists of eleven chapters. The first discusses the pages) is devoted to natural polymers and their derivatives. treatment of experimental data, with reference to units and diThese products include proteins, cellulose, lignin, rubber, drying mensions, errors of measurement, and the representation of data oils, and the plastics made from them. An unexpected chapter by graphs, tables, and equations. The following eight chapters, on minerd and inorganic high palymers reviews the structure of discussing physicoehemieal measurements and apparatus in a various forms of carbon and of the silicone resins. This hook ful- mare general way then in Part I, have the topical headings: fills its purpose well. Physical properties of gases; Opticochemical measurements; Thermal measurements; Physical properties of liquids and soluR. W. PLANCK 21W ROBEer E. LEE BLYD. tions; Electrical measurements; Electronics; Photochemistry; NEW ORLBANS, LO~BIANA and Isotopes and radioactivity. Chapter 25 deals with the constmction of lahoratorv anDaratm. with some information on glass lrlowing, and Chapter 2t,, thc last, with the purification of 0 EXPERIMENTAL PHYSICAL CHEMISTRY whtrr, mcrcur.v, and a fen other much-used tnateri~~ls:this could Farrington Daniels, Joseph Howard Mathews, John Warren he profitably expanded. Physical constants are listed in an appendix. I t is noted that Williams, Professors of Chemistry, Paul Bender, Assmiate Professor of Chemistry, George W. Murphy, and Robert A. Alberty, the value of the faradrty, F,88 given hy Dumond and Cohen, has Assistmt Professors of Chemistry, University of Wisconsin, Madi- been included; it is the reviewer's impression that the postpone son, Wisconsin. McGraw-Hill Book Company, Inc., New York, ment of the acceptance of this value pending results of further 1949. Fourth edition. xiii 568 pp. 165 figs. 31 tables. investigations now under way was advised by those authors. It is also noted, regretfully, that the authors adhere to the w 16 X 24 cm. $4.50. of H+ as the formula of the hvdroeen ion. The sccentttnce of FEW I m h on our rhemktr). shelf come so richly endowed iu HaO+, the prohahly correct formula, is becoming more general amhornhip, iwth qumtitativrly m d qualitatively, ar this popular in the less advanced courses and might he given seriaua considand stsirdud lihuratorv trxt. To the original t h authors who eration by the authors of more advanced terts. The hook is an excellent one and a must for all chemistry liproduced the first editibn twenty-one yea& ago three more have been added. All are on the staff of the Universitv of Wisconsin. braries. It is replete with suggestions vdushle to workers in The atatcd purlarcs of the book arc "to illustrate the p ~ r i p l e s many fields of chemistry. Although larger than most laboratory of phybirl~Iclw~rlktry, to train in careful rxpcrilncntation, to manuals it is the sort of hwk the students should be encouraged develop falrdiarity with apparuus, and to encourage ability in to keep for later reference. research!' These aims should be amply attained by the serious WILLIAM B. MELDRUM users of tbia clearly written, well-arranged, and comprehensive H ~ v s ~ ~C o oa m o eo~ presentation of carefully selected experiments. AAVEBPORD, PENN~TLYAXIA ~
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