HOW MUCH ORGANIC CHEMISTRY SHOULD BE INCLUDED IN THE GENERAL CHEMISTRY COURSE?* FRANKC. WHITMORE, NORT~STER UNIYERS~Y, N EVANSTON, ILLINOIS
Of course, many answers could be given to this question varying from none to the amount of organic chemistry included in some of the larger freshman texts. M y particular way of answering it may be introduced by another question-What is the purpose of the course in general chemistry? For perhaps ninety per cent of the students this purpose has very little to do with professional chemistry, either as applied in chemistry or in pursuits such as engineering and medicine, which use chemistry as a tool. Most of the students are preparing for some life activity which can be carried on rather successfully without any chemistry but which will be more interesting with a slight knowledge of chemistry. For this class of students it is important to give in the general course a few of the fundamental conceptions of organic chemistry. I would consider these to be the conception of structural formulas as distinct from the ordinary formulas used in the rest of the course, the existence of homologous series and the existence of isomers. Of course, the fact that the compounds of carbon outnumber the compounds of all other elements by about five to one should be brought out. This will naturally impress the student with the complexity and consequently almost limitless possibilities of organic chemistry. The existence of homologous series will serve as a simplifying influence in what would otherwise appear chaotic. I usually start with methane and show structurally that the addition of a carbon atom also involves the addition of two extra hydrogens and thus build up the methane series. Starting with ethane I show that the two carbons can be held together by two valences from each, thus leaving room for only two hydrogens on each carbon. The ethylene series is built up from this first member. The acetylene series follows in logical order. When I have finished this phase of the subject, I have on the blackboard three columns containing empirical formulas of the three simple series of hydrocarbons. Going down each column there is a constant difference of CH2. Going across there is a constant diierence of two hydrogen atoms. To keep up the interest in the practical or applied, I give very little about the occurrence of the methane hydrocarbons in petroleum, etc., a little on the ethylene series in cracked gasoline, and a few words about acetylene. *Paper delivered at the joint session of the Divisions of Organic Chernistty and Chemical Education of the A. C. 3.at Richmond, Va.,April 14,1927. In the absence of the author, this paper was read by R . A. Baker.
IN GENERAL CHEMISTRY COURSE? VOL.4, No. 8 ORGANICCHEMISTRY
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In giving the conception of isomerism I give a list of facts about the number of hydrocarbons of a given formula, emphasizing just what we mean by saying that there are two diierent butanes, considering briefly the analyses, molecular weights, boiling points, etc. I then have the students attack the problem of arranging four carbons and ten hydrogens in all possible ways consistent with the quadrivalence of carbon and the univalence of hydrogen. They then attack this problem with the isomeric pentanes. At the present time it is possible to give an added touch of reality to this little game by telling them of the work of the Ethyl Gasoline Corporation in synthesizing all nine of the isomeric heptanes a t a cost of many thousands of dollars for the purpose of studying the effect of isomerism on knocking of gasoline. The fact that some of these heptaues create a worse knock than rather high boiling kerosene and that others are very good anti-knocks impresses the student with a practical difference between isomers. I next take up a series illustrating the theoretical stages of the oxidation of methane. This series, of course, includes methyl alcohol, formaldehyde, formic acid, and carbonic acid. A few important members of each homologous series which is started by these substances are given. Certain variations of these type substances are given, such as glycerol, glucose, and sucrose. The combination of an alcohol and an acid to form an ester is considered, and the fats are taken up briefly. The formula of a simple polypeptide is given and the proteins are mentioned. I usually finish by giving the structural formula of indigo, with a little talk on how chemists work out their formulas, which are really their working blue prints, and then build up the materials from these blue prints, and finally introduce all sorts of variations and improvements on the original substances. In connection with indigo I show some of the modifications such as thioindigo red and Tyrian purple. Obviously, the student cannot be expected to master all this material, but the exposure to it broadens his conception of man's power over matter in a very worthwhile way. I have not considered here the amount of organic chemistry as applied to foods and similar materials which may be taken up in the general course. BY W. M. BLANCHARD D~SCUSS~OU-LED BY RALPH V. MCGREW) (REPORTED
W. M . Blanchard, De Pauw University. I thought the meeting this morning was to consider the introductory course in organic chemistry, whereas Dr. Whitmore seems to have talked about the little organic chemistry that we can give in the introductory
course in general chemistry. The remarks I had intended to make would not, therefore, be appropriate to open the discussion on this paper.
J. S. Guy, Emory Uninersity. Why not make the first course in chemistry a course in elementary organic instead of inorganic? Inorganic chemistry is coming to contain so much physical chemistry and other complicated things that i t is beyond the understanding of the freshman. Elementary organic is not quite hard enough for him yet. I think I shall try such a system next year. Also, why not put quantitative analysis before qualitative? When the student takes qualitative first he develops careless habits of technic which he has to overcome before he can do good quantitative work. If he took quantitative first he would develop accuracy from the beginning and the theoretical side of analytical chemistry could be started just as well in the quantitative course as in the qualitative.
A. J. Clark, Michigan Agricultural College. For the past ten years we have been giving a large amount of organic chemistry in our first-year course for students who will probably take only one year of chemistry. This seems to be a sensible thing to do because really organic chemistry covers a larger field than inorganic and i t is a t least as important that the student know something about it. The inclusion of a large amount of organic chemistry makes an interesting and valuable course for students who do not have time to take separate courses in inorganic and organic.
E. E. Reid, Johns Hopkins University. We give two courses in introductory chemistry: one is a fundamental course in inorganic for students who expect to take more chemistry; the other is a course for the other kind of students and is similar to that described by Professor Clark. The former is a prerequisite to all subsequent courses in chemistry, so if a student who has taken the more general course decides later to go on in chemistry he must take the iuorganic course before he can proceed any further. He thus loses time, but the first two courses are different enough that he can learn something from each. However, cases of this kind are very rare, as the students nearly always decide definitely in advance whether they want to take more than one year of chemistry.
The greatest and noblest pleasure which men can have in this world is to discover new truths; and the next is to shake off old prejudices.-FREDERICKTHE GREAT
