Chemische unterrichtsversuche

Ralph R. Wright, Associate Professor of Electrical Engineering. Virginia Polytechnic Imtitute, BlacIrobug, Virginia. The Ronald. Press Company, New Yo...
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OCTOBER. 1950 0

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ELECTRONICS, PRINCIPLES AND APPLICATIONS

Ralph R. Wright, Associate Professor of Electrical Engineering. Virginia Polytechnic Imtitute, BlacIrobug, Virginia. The Ronald Press Company, New York, 1950. ix 387 pp. 314 8 9 . 16 tables. 16 X 23.5 cm. $5.50.

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Acconnmo to the preface, this book was intended as a text for a basic course in electronics for nonelectrical engineering students, though it has been used in the instruction of electrical engineering students as well. The author has presented four chapters on basic principles and eight chapters on basic applications of electron tubes. Ten problems and an extensive bibliography follow each chapter. The MKS syatem of units is used throughout; debitions of eleotricrtl terms follow the recommendations of the AIEE and the abbreviations and symbols those of the IRE. The author's selection of material, his clearcut explanations, and excellent diagrams should make this a valuable text for the instruction of physics and chemistry majors who require or desire such a course. For avoiding the "highly msthematicd approach" and, in many cases, simply giving the equations concerned with the phenontcnon under consirlrntion, the author will be prxi3ed by tho*? demanding util~tysnd ~ ~ m d e n mby ~ dthose who eontend that a linear diRerenrial equ:rtion of the fimt order hss never hurt anyone. It is highly ;mprobahle that anyone teaching a basic course in this subject will follow a suggestion in the preface -that the chapter on circuit analysis, i. e., d.-c. and a.-c. theory, may be left to the student as his responsibility. It seems unfortunate that the author does not consider the snhject of "camplex notation" of sufficient importance to devote a few pages to its use in the solution of problems of phase relations, yet devoted sixteen pages to polyphase rectifiers. A small sectlon might have been accorded point-contact crystal rectifiers and dry-disc rectifiers, in view both of their history and extensive presenkday use. Nevertheless, this is one of the best trestments of basic electronic principles which has cmne to tho attention of the reviewer. No recommendation is made with regard to the laboratory work to be performed in the course for which this book is intended, though it is safe to say thzt regardless of the actual experiments chosen for the basic course the theory behind them is trested in this text. The hook contains remarkably few errors; it bas been well prepared, printed, and proofread.

numerals, and punctuation marks. Such armye, or ciphers, completely designate all details of molecular trt~cturalformulas as ordinarily written. The ciphers can be readily typed. As a starting point for developing his rules, Dr. Dyson has chosen the well-known LiBpGeneva system far open chain structures and the Ring Index designations for condensed ring systems. A surprisingly concise shorthand system for designating and enumerating the carbon skeleton of molecules is developed and an ingenious and equally concise system of notation for functional groups is proposed. The inherent simplicity of the new notation is illustrated by application to those less complex compounds with which every chemist is familiar. The power and scope of the Dyson s~%tetem are demonstrated by applying it to more complicated molecules exemplifyinga wide variety af structural features. The ability of the new notation to generate a system of spoken nomenclature is discussed and exemplified. The possibility of using mechanical sorting devices, e. g., punched cards, to search coded files of organic structures is also briefly discussed. In this second edition a number of important changes in Dr. Dyion's orighrl propods have twrrr ma&. 'l'lere vhxn~es were drvrlo,wd in colinlwmtion nitb Dr. .\usrin 11. Patterson, Dr. H. S . Xuttine, nnd other chen&ts i~.tereswrlin nomenelaturc problems. I t sh&d he noted that the revised notation system served as the basis of the paper on the Dyson notation which appeared in J. CHEM.EDUC.,26, 294403 (1949).

CHEMISCHE UNTERRICHTSVERSUCHE

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H. Rheinboldt, Professor in Sio Paula, Brazil. Verlag von Theodor Stehkopff, Residene&asse 32, Dreaden Bl., Germany, 1948. Revised edition, by 0. Schmih-Du Mont. xviii 352 pp. 122 fiqs. 17 X 24 cm.

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FORtwo reasons this bwk is tops: its thoroughness and its historical value. Concerning the latter, each of the 300.odd experiments carries literature references to the original discoverers. For this reason alone this handbook should be on the shelves of every demonstrator in freshman chemistry. That it is in German is no handicap, for the equations and diagrams are self-explanatory, and the German is simple. We join Bunsen E D M U N D B. THOMAS (1855) in preparing lithium by the electrolysw of molten LiCI, Prieatley (1773) in making HCI from salt plus sulfuric acid, M m h and Liebig (1837) in the Marsh test (although we learn that arsine was first discovered by Scheele in 1775), and Berthollet (1788) in forming Eau de Javelle which was named in 1792. 0 A NEW NOTATION AND ENUMERATION SYSTEM This reviewer found the following experiments of special interFOR ORGANIC COMPOUNDS eat because they are not usuallv described in American reference G,~ ~ D ~ rechnical l ~ ~~~ i ~~~~ ,~ ~ chemicals l~ i t ~ ~~end~~ books, , h or because their experimental procedures were unique: Biologicals, Ltd., Loughborough, ~ ~ ~ second l ~ edition. ~ d . Carbon monoxide detected by PdClrpaper turning black from Pd., Reduction of nitrobenzene vapor to aniline with ~ ~ ~ ~1949, ix +~~1-33d deposited , ~ L ~G~~~~and ~ co,, =ondon, ~ ~l ~ pp. IUustrated. 15.5 X 24.5 cm. $2.25. hydrogen. Heating HgO in a "bayonekbaped tube" so that the a. n.ho .-.H r whioh . -...aomes ...~~ -- nff - ..r.. - ranoht, ----...in ...+ha ...-hmd . ...- of -.the havnnot,~ -..., .THEremark about a rose smelling as sweet regardless of the all of the HgO being decomposed. Burning oxygen in sulfur nomenclature used may be an aesthetically satisfying answer to vapor, as well as sulfur in oxygen. Influence of ohlorophyll, the question "What's in a namel" A new factor enters the situa- CO. and light on the formation of oxygen from green water cress. tion, however, when names are used as aids for locating needed Preparation of ozone by eleotrolysis of sulfuric acid. Ozone information-in other words as seient,ific tools. Then clumsv from moist ~hos~horus.Reaction of owme with tetramethvlnomenclature-like a dull mw-is an exasperating source of base-paper. -~eiompositionof Os by heat and by MnOn &awasted effort. The resulting loss in efficiency becomes inereas lyst. HgS CIS, testing the product with Ag+. Phosphorus ingly intolerable to chemists as the record of chemistry continues glow in a condenser when steam-distilled. Ba-Ph alloy by therto exoand. mit process. Lithium by electrolysis of molten LiCl. Concen~ i i Hercules, e confronted by the Augean stables, Dr. Dyson tration (electrolytic) cells. Heat reaction during displacement proposes to use fundamentally simple, yet inherently powerful of CuC+by Fe. Excellent experiments with HI. Preparation means to remedy the organic nomenclature situation. He pro- of HI from Mg steam. Thermal dissociation of HB. Blood poses that the inherent logic of molecular architecture be used as turned green by H2S. HIS methylene blue. Volumetric d i e the basis for desimting molecular structnres. His svstem of sociation of H$ by an electric spark. Formation of NHI from notation consists, in esseke, of a set of rules with who& aid any the elements by an electric spark; and its thermal dissociation. given structuml formula is interpreted as a linear amay of lettera, Electrical conductivity of ??a dissolved in the nonconductar

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