PREFACE The fact is borne out by the experience of every teacher who has classes to prepare for college examinations, that tlle contents of the prevailing textbooks fail to furnish adequate , scientific material and drill to pass the entrance examins tions. The subject is so broad and the theories involved are so complex, that the student often finds hiinself on the thresh- old of the examination room completely bewildered by the many facts, theories, laws, and details, ailcl is entirely unable to make a scientific application of his knowledge. This book has been prepared as a review of the theories and la vso f elementary chemistry, and there has been added to each topic a sufficient nunlber of p1-oblems to make a thorough application of the students knowledge. It presumes on tl es tudents part a thorough acquaiiltance with physical mixtures, laws of densities and specific gravity, laws of heat and electricity, the metric systenl, and an adequate training in some good textbook in elementary chemistry. These questions and problems have been taken from the most recent college, College Board, and Regents of the State of New York examinations, and from the latest and most huthoritative textbooks, and will be found from the authors experience more than sufficient to prepare a student for the kntrance examinations for any college, or for the College Board examinations. The questions and problems are classified so that a chapter or parts of one may be taken up, in connection with the textbook used in thc class, for clinching the principles studied, or the book may be used as a preexainination review. It is REVIE r QUESTIOSS AND PROBLEIIS not necessary that the student should solve all the problems, but such selection should be made as will assure the instructor that he is adequately prepared. It must be observed in the use of the book that the student must seek much necessary information from his text, and there should be accessible several good textbooks for handy reference. . Reference to the appendixes will be found helpful in solving inany of the problems. Acknowledgment is hereby made to the authors and publishers of the following textbooks, for the material obtained from their publications Lees Experimental Chemistry, P. 1 lakistons Son Co. Linebargers Chemistry, JXancl, hIcNally Company Newells Inorganic Chemistry and Baskerville and Estabrookes Problems in Chernistry, D. C. Heath Co. Brownlee and Others tt First Principles of Chernistry, Ally11 and I3acon hIorgan and IJym, ziis Chemistry, The JLacmillan Company hlcPherson and Hendersons Elerner tary Chernistry and the pul licntions of the College Entrance Examination Board, Gin11 and Coinpally a. nd to the authorities of the various universities, and to the ltoard of Regents of the State of New York, whose entrance examinatioil questions have beell used. 11. S. 11. UNGER CONTENTS CHAPTER I I . PHYSICA D L E F I I NITIONS . . . . . . . . . PA G 1 E I I . CIIRJIICALD EFINITIONS . . . . . . . . . 2 111 . IIYSICAL L AWS AND TIIEOI . Y . . . . . 4 I. CIIE IICALLA WS . . . . . . . . . . . 5 V . CHEI ICX T L I IEOI Y . . . . . . . . . . 7 VI . CHEAIICADL IVISION . . . . . . . . . . . 8 V11 . ELECTROLYTIDCI SSOCIATION . . . . . . . 14 V111 . VALENCY . . . . . . . . . . . . . . 17 IS . PEI IOD C I L C A SSIFICATIO . N . . . . . . . 18 X . IYDI OG A E N N D WATER . . . . . . . . 10 XI . TIIE N ITROGENG ROUP A SD AIIC . . . . . 24 S11 . THE O SY EN-SUI PIIUGIR O UP . . . . . . 20 XI 11 . IIIE CAKIION-SILICONG I OU . P . . . . . . 34 S I V ...