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JOURNAL OF CHEMICAL EDUCATION
MAY,1929
THE FRESHMAN CHEMISTRY COURSE WITH PARTICULAR REFERENCE TO THE LABORATORY WORK* G . ALBERT HILL.WBSLEYAN UNIVERSITY, MIDDLETOWN, CONNECTICUT
The proper correlation of secondary school and college chemistry courses has never been a simple matter. Many secondary school teachers feel that the colleges expect, perhaps require, far too much of the entering student, while, on the other hand, some college instructors pay so little attention to secondary school courses that they put beginners and students presenting chemistry for admission to college in the same class. Most educators are agreed that unless the secondary chemistry student is given credit for his earlier work in some way or other he is subjected to an injustice. If the college course for those presenting chemistry presupposes a knowledge equivalent to that called for by the college examination board syllabus and students are demoted to a simpler course if they cannot maintain the pace, the well-prepared student will he enabled to profit by his training and the handicap of deadwood be removed from the course. If two freshman courses are to be given, some scheme for dividing the class must be arrived at. At Wesleyan two courses are offered-B, for those who presenting chemistry expect to take more, A, for all others. A is a modified pandemic course, not too difficult for beginners, yet with enough new features to make it a real course for those who already have some acquaintance with chemistry. The laboratory work is so arranged that those who have already had a courserin chemistry will not he called upon to repeat experiments previously carried out. Considerable stress is laid on lecture demonstrations in this course, and visual educational means are extensively employed. A member of this course who decides to take more chemistry must take a semester course in the second half year devoted to theoretical topics. If the decision to go on with the subject is not made prior to the mid-year period, the student is penalized in point of time and must take B or the course in theory the next year, unless he can show, by examination, his fitness for qualitative analysis or organic chemistry. Students not infrequently fail to appreciate that they are subject to the general rule that failure to arrive a t a decision involves a penalty, here exacted in an expenditure of time or energy in preparing for an examination to demonstrate ability to proceed with advanced courses in chemistry. This paper deals especially with section B, previously mentioned. In this course lectures, recitations, and laboratory work are the main features. Relatively little attention is paid to lecture demonstrations, though a few experiments, which are particularly helpful in clarifying some of the theoR e a d before the Division of Chemical Education at the 76th Meeting of the American Chemical Society, September 12, 1928. at Swampscott, Mass
retical material, are introduced. A textbook is utilized. This fact deserves more than a word. A perusal of recently published books shows that they fall into two classes. The one is much like the older descriptive texts and general chemistry books, while the other class of "modern" texts stresses principles and is based on the assumption that the student is already acquainted with chemistry. Hence it emphasizes chemical relationships and really teaches inorganic chemistry. To my mind this is quite different from teaching descriptive chemistry or the old encyclopedic, general chemistry, so called. Failure to teach inorganic chemistry is the worst sin to be laid to the door of many freshman chemistry courses. The students may know what a blast furnace looks like and recall the number of gallons of gasoline used in one year, but they will rarely evidence a real grasp of the broad relationships which indicate a thorough appreciation of the study of metals and non-metals. A sad lack of a knowledge of inorganic chemistry is evidenced by those enrolled in every course for which freshman chemistry is a prerequisite. Six students out of thirty in a summer course in organic chemistry, which I recently conducted, did not recognize that the white precipitate, caused by passing the products of combustion of sugar into lime water, was calcium carbonate. They could not write oxidation and reduction equations with anything approximating facility. The calculation of theoretical and percentage yields of products, involving only simple equations, they found difficult. .~olecularweight and formula problems seemed mysteries to many. All of fhese subjects, any teacher of freshman chemistry would expect his students to be familiar with. The facts were the more striking since the class to which I refer happened to be made up of students representing a broad geographical distribution of colleges, not less than seven, wherein their freshman courses had been taken. As a rule, students find elementary organic chemistry a difficult course, and this, in my opinion, is largely due to lack of familiarity with straight inorganic chemistry. The chemistry of the amines, as taught in the elementary course, should be relatively simple for students familiar with the chemistry of ammonia. A knowledge of the essential differences in the behavior of the halogen in halides and the halogen in hypohalites would make simpler the action of halogens in alkaline solution on amides, and the addition reactions of hypochlorous acid. A more ready understanding of the phenomenon of hydrolysis would be of great help in appreciating the behavior of mordants, processes such as the saponification of esters, and in general the behavior of amphoteric compounds. A knowledge of the chemistry of urea really depends upon a thorough grasp of the chemistry of carbon dioxide and the existence of carbonates and carbamates. Incidentally, it may be pointed out that most students in elementary organic
courses usually regard this word as a misprint. The halides of phosphorus, phosgene, chromyl, and sulfuryl chlorides are substances which appear quite anomalous and mysterious to most students who enter an organic course after having completed a standard course in inorganic chemistry The general behavior of acid halides, if once learned in inorganic chemistry, makes clear a considerable section of organic chemistry, where compounds of this class, organic and inorganic, are manifestly important. As far as laboratory work is concerned, many college courses do not sufficiently recognize the experience gained in the secondary schools. This frequently results in a lack of interest and a feeling of over-confidence on the part of the student. Laboratory tendencies evident today are, first, to make the work largely like, in fact frequently a repetition of, the better secondary school laboratory exercises. The law of constant proportion, chemical equivalents, the amount of water in crystalline copper sulfate or barium chloride are expressions having to do with experiments conducted in many of the up-to-date secondary schools, yet the same experiments are found in college chemistry manuals and frequently carried out in college even by students who have already done them. A second tendency is to make the course savor too strongly of analytical chemistry, either qualitative or quantitative. It is generally believed that most students learn most of their inorganic chemistry in their college qualitative courses. With this opinion I am inclined to agree. However, freshmen, I believe, concentrate too mffch on getting unknowns right, on having reports accepted, or too closely rely on the table of separations, and miss the really important facts of chemistry with which they are dealing. The courses dealing with quantitative are little less than farcical unless they pennit students to utilize the more delicate balances, which, because of the students' inexperience and the impossibility generally of providing adequate supervision, leads to a cultivation of lack of respect for balances and other delicate instruments. The third tendency is to elaborate physical chemistry too fully. I am in complete accord with the desire to have the students begin to think along physical chemical lines from the very outset of their careers. I do feel that most freshmen, students approximately 18 years of age, are not sufficiently mature mentally to really appreciate physical chemistry. Parrot-like, they can learn the laws presented, and may finally solve certain problems, but I have a very firm conviction that they really have little notion of just where they are going, and the important applications of their experiments are all too infrequently matters not even brought to their attention. Some one has aptly said that physical chemistry is a state of mind, and I feel that it is unjusbto freshmen to expect them to have acquired or to acquire such a state to a very marked degree.
In order to teach the students inorganic chemistry, I believe that advantage should be taken of a young person's natural desire to make something. In my opinion the popularity of the extremely well-known book, "Creative Chemistry," is in no small measure due to the splendid way the creative side of this science is presented. Hence, I feel that experiments in the freshman year, certainly for those who have presented chemistry, should be of a preparative character. If an experiment requires more than one laboratory period, so much the better. This gives the individual a chance to concentrate for a considerable period of time on one important topic, and this is a great advantage over the so familiar test-tube type of experiment which students rush through in one period, usually without understanding it, and then forget. The dictionary is .a good book, but not the best reading because, as has been said, the subject changes so often. Preparative experiments (we run 16 in an ordinary college year) give the students continuity of subject and do not spatter the attention over too large a section of the science in a short space of time. The preparative experiments may be so varied as to permit teaching a great deal of laboratory technic, apparatus may be simple or complicated, purifications may be carried out to any desired extent. A reasonable amount of elementary analytical work, such as testing the purity of the sample either qualitatively or quantitatively, if desired, may be introduced to give the student an idea of the paths which he will subsequently follow. By calculating the amounts of reagents 'necessary and the cost of the chemicals used, also theoretical and percentageryields, the student will be shown that problems are not mere mathematical exercises, seemingly thrown into a course in an otherwise attractive subject to make i t tedious and difficult, but have a very real and practical use. There are available a few laboratory manuals, very few old ones and a somewhat larger number of new ones, which include preparative experiments. It is perhaps worthwhile to mention that the laboratory manuals, which accompany what I have termed "modem texts," include preparative work. Courses presenting laboratory work of the nature here recommended are already being given in a few institutions, and to my mind indicate the way the freshman course in college is developing.
