VOL. 5. NO. 1
RECENT BOOKS
therefore, that it follows conventional lines, nor does this in any way detract from its value. This review consists of brief statements in place of the topics of the syllabi and the pupil, therefore, finds important items readily. T h e diagrams are chiefly of laboratory apparatus. Questions of about the same type as those in most elementary texts are included in each chapter; the answers t o mast of these can be found in the body of the review itself. Answers t o the numerical problems are found in the appendix. The appendix also contains *'important definitions," chemical tests for common ions and radicals, formulas, common and chemical names for chemical compounds, etc. Among the definitions we find that a saturated solution "contains all the solute it can hold a t the given temperature and pressure" and that a suspension is a "mixture of a solid and a liquid in which the solid particles settle out on standing." We find also that an "emulsion is a 'suspension' of one liquid in another." Pupils will probably find t h a t this review will help them t o pass examinations and many teachers will like i t for this reason. BARNARDS . BRONSON Oxidation-Reduction Reactions in Inorganic Chemistry. ERIC R. JETTE, Ph.D., Assistant Professor of Chemistry, Washington Square College, New York University. The Century Com152 pany, New York, 1927. xvi pp. I0 figures. 12.5 X 19 cm. $1.10.
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The author conceives the purpose of the hook t o he the presentation of "a comprehensive discussion of oxidationreduction readions for the student who has had enough training in chemistry to understand ordinary chemical terminology hut who has not had a course in physical chemistry." To this end the author believes two methods, the "valence change" and the "ion-electron" methods t o he necessary. The basis for each of these methods is given; and numerous
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examples, which illustrate the effect of the conditions maintained during the reactions, are discussed. The preface statement indicates that the hook is designed for students in courses more advanced than the usual first-year college course; and familiarity with the equilihtiprinciple and the theory of electrolytic dissociation is presupposed. The "valence change" method, developed in the first part of the hook, presents no new materials; but gives the author's scheme for representing the detivation of equations by this method, which he considers applicable only t o non-ionic reactions, such as those between gases and solids a t high temperatures. It may he noted that the form given here is somewhat less simple than some of the other schemes which have appeared in t h e literature from time t o time. The major portion of the hook is devoted t o a discnssion of the "ion-electron" method. "The basis of the method is found in the fact that practically all of these reactions can be carried out so as t o secure an electric current from them." According t o this method, partial equations are written for the oxidizing agent and for the reducing agent, showing in ionic form the gain and loss of electrons for each. The final ionic equation is balanced by equalizing the numbers of electrons concerned. The balancing of a typical equation, represented on pages 38 and 39, requires six steps for securing the ionic equation (seven if a molecular equation is desired). The applicability of this method in balancing equations for reactions involving hydrogen peroxide, sodium thiosulfate, thiocyanates, and other less commonly used substances, in addition t o the common oxidizing and reducing agents, is pointed out. The discussion of atomic structure, valence, and the theoretical aspects of the subject including the effect of attendant conditions should he valuable for the students in the field for which the book is intended. The method of balancing equations,
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while theoretically sound, is more bersome than some of the other methods which have been described in THIS JOURNAL, particularly for thosensers who prefer t o express reactions in the form of molecular equations. Certain inconsistencies are noted in that the author writes on page 31: "Unless we are able t o state (and prove such statements) that an atom has lost seven electrons, we cannot state that the valence of that atom is +7." Nevertheless, in the work on pages 13 and 18 such assumptions have been made and the table on page 11 contains additional examples of this. One notes also a few careless expressions such as that on page 76: "The various states of oxidation given on page 67 can react with each other." I n the opinion of the reviewer, this monograph will not prove valuable for use in elementary courses in chemistry. The student in such courses cannot understand the logical development of the method a t the time he begins t o encounter o x i d a t i o n - r e d u c t i o n reactions. T h e method itself is somewhat more cumbersome than others which involve the application of electronic steps. Many teachers will object to the exclusive use of ionic instead of molecular equations, particularly during the early stages of the work. If the method presented hy Professor Jette is to be followed, it would appear t o be necessary for the student first to learn some other method of handlimg the equations for common ouidatianreduction reactions; and then in his mare advanced work t o take up such phases of this method as may prove ureful far considering the less common cases.
New Type Questions in Chemism. CHARLESG. COOK,Ph.D., Globe Book Co., New York. 1927. First edition. vi 91 pp. 12.5 X 19 cm. Cloth, 60 cents.
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This little book sets as its task to
"make chemistry teaching more efficient and more interesting." Types of tests used are: , com"The old type . . , true-false , statements for pletion . . , evidence correction, and home tests." Advantages of use of new-type tests are that "a greater number of topics may be covered in short tests" and "the answer paper may he corrected rapidly." The hook contains in the neighhorhwd of a thousand requirements covering individual requirements for eleven elements, requirements for fifteen others grouped after the periodic arrangement with special test groups upon a number of typical compounds such as water, hydrogen peroxide, hydrochloric acid, oxides of sulfur, etc. Theories, atoms, molecules, nomenclature, Avogadra's hypothesis, molecular weights and formulas, electrolytic dissociation theory; reversible reactions and the periodic law come in also for individual test requirements. Five specimen sheets of examinations, presumably from the Regents' sets, though not so stated, are given as an appendix "to familiarize the student with the type of questions he is elmected t o he able t o answer." Criticisms that are likely to come t o the booklet are: too much space devoted t o equations; not enough numerical problems; acids, bases, and salts not recognized; oxidation and reduction not treated separately, and an undue use of true-false requirements. The book will undoubtedly be welcomed by a host of teachers, especially those teaching in high schools. While i t is hardly the last word in the field of testing it is a creditable pioneer offering from the hands of a teacher of experience. This is undoubtedly a field which the future will see more fully cultivated.
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Essays on the Art and Principles of Chemistry. HENRY E. ARMSTRONG.The Macmillan Company, New York, 1927. 276 pp. 22 X 15 cm. $4.50. xvxi
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