Earl Krakower
Rochester Institute of Technology Rochester, New York 14623
An Introductory and Terminal Chemistry Course for Engineering Students
A variety of opinions has been expressed in the chemical literature related to the development of suitable curricula for non-chemistrv- maior students who take an introducto" ry course in general chemistry. An effort must he made on the nart of the Instructor to interest the students, clearly inform them of basic concepts and modern developments in chemistry and, at the same time, avoid extensive duplication of material previously taught in high school chemistry. In a large class, the presentation of a first-year chemistry course at a suitably challenging level is complicated by the diverse backgrounds of the students. One added factor to the potential appeal of the course is the use of problems which, in some manner, are relevant to the students' career objectives. At this Institute, the College of Engineering offers three five-year cooperative programs leading to the Bachelor of Science degree with majors in electrical, mechanical, and industrial engineering. Electrical and mechanical freshman students are required to take two quarters (approximately twenty weeks) of general chemistry in the Fall and Winter sessions. No chemistry laboratory course is required. In an attempt to relate chemistry principles with engineering concepts, these two groups of students are combined into one class (approximately 175 students) and given a separate course with the emphasis on physical chemistry, prohlem solving, and instrumental methods of analysis. The class meets three times each week. An additional recitation or tutorial period each week allows for the division of the class into groups of 25 students, maximum. In these sessions, solutions to problems are covered in detail and the students are encouraged to ask questions related to material presented during the week in lectures. These tutorial sessions are taught by members of the Chemistry Faculty, all of whom attend the "main" lectures to keep informed of course developments. Unannounced ten-minute quizzes are given periodically in the tutorial sessions. Although the results of these tests are not formally included in the computation of a student's letter grade for the course, they can he used as leverage to increase a student's grade in a borderline situation. Preliminary letter grades are determined on the basis of two
mid-term hour-examinations. A week before final examinations are scheduled, cut-off points for each letter grade (A,B,C,D,F) are announced to the class based upon the sum of the numerical scores obtained in the mid-terms. The final exam is optional. Students can accept their grade at this point or sit for the final, in an attempt to improve their standing. The incentives given to each student to perform well during the course and not wait for the final examination comhined with the fact that no trailer sections are scheduled ensures a high percentage of student attendance both at the lectures and recitation periods. The academic background of the students is quite diverse. Approximately 15% of the class have taken no previous chemistry course. All students have passed an intermediate algebra course in high school. However the difficultv of usina their knowledge of alaehra to solve chemistry problems-is quite evidentearly into the course. Failure to perform algebraic mani~ulations,the inahilitv to interpret the meaning of an equation and lack of organization in establishing a route for the solution to a problem is commonplace. Perhaps, more attention to problem solving in high school and introductory college mathematics courses would simplify the transition, for the student, of applying mathematical techniques to the solution of chemistry problems. Concurrent with the general chemistry course, the students take engineering calculus-an introduction to differential and integral calculus, general physics-mechanics, heat, sound, electricity, and magnetism and a course in computer techniques.
I'resmred a t t h e m r e t h g uf t h e I)wi$im id Chemical Education in M'nshinptun, I).C., September. 1971.
Nuclear chemistry
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Course Outline A topical breakdown of the course contents is given in the table. The treatment of each of these topics is designed to relate to the engineering process. The material that has been selected for the course fulfills a dual role. It must he general enough to be useful to an engineer and at the same time, it must develop the chemistry principles without too many digressions. The historical, sequential approach to general chemistry has, in part, been ahandoned. Rather, an attempt has been made to unify the material by stressing two vital concepts-the equilibrium of a system and the available energy of a system in its environment. Dimensional analysis through gaseous behavior forms a coherent unit of topics which lead the student from simple definitions and statements to more complex manipulations involving substances undergoing physical and chemical changes. For example, applications of the gas laws are illustrated with examples involving the rate of flow of gases. The student is introduced to the concept of a steady-state process in which the properties of a gas (pressure, temperature, composition) and flow rate at a eiven noint in the annaratus do not change - with time. .. This is applied to a prohlem involving an air-cooling unit which is sunnlied with two streams of heated air at different tempe&tures and flow rates. The air must emerge from the unit a t 40°F and 14.7 psia. In order to estimate the size of the exit duct, the flow rate of the exiting gas is calculated. The solution of the prohlem points out the inequality of mass and volume flow rates due to the different temperature and pressure values of the two input streams of gas. In addition, elementary calculus is used to express the ideal gas equation in its differential form. In the course of solving the prohlem, the value of the gas constant, R, is evaluated as 1645 ft-lbs/mole "Rankine, an exercise primarily designed to encourage the students to use the efficient factor conversion method of solving prohlems. Lecture topics in nuclear chemistry are hased upon a description of isotopic species which show potential of being used as nuclear fuels. The operation of the Ginoa nuclear power plant located 20 miles outside of Rochester is descrihed to the class by an invited speaker from Ginna's Science Information Center. In class, an application of nuclear processes is discussed in terms of measuring the wear of piston rings. A discussion of the process whereby a test ring is made radioactive by neutron bombardment and the activity measurement of iron dust in lubricating oil circulating around the ring relates fundamental principles of nuclear chemistry to the engineering process. The students are given an in-depth mathematical treatment of chemical and physical thermodynamic concepts during the second quarter of the course. The lectures present a rigorous account of the first and second laws and their application to gases, liquids, and two-phase mixtures. The topics in the course establish the prerequisite for an advanced thermodynamics course given by the College of Engineering faculty. This junior-level course is taught from the microscopic point of view using the techniques of statistical mechanics. In the freshman chemistry course, although the students hnve nor formnllg covered partlal dlfferenriation and differenr~nlequations, the mnthemat~calapparatus IS descrihed to theG and it is not too long before they are working with transformation formulas. Applications of thermodvnamic orincinles are discussed in terms of fluid flow rates, refrigeration, and phase equilibria. Onlv two lectures are resented for the description and reactions of organic compounds. Rather, famifiarization with organic compounds is acquired in the treatment of instrumental methods of analysis. Structure determina-
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tion is discussed with reference to infrared nuclear magnetic resonance and mass spectroscopy. Gas chromatography is used to describe the separation and purification of organic compounds. Slide showings of each of the instruments and their component parts accompany the lectures. Textbooks and the Use of Media There is evidence today that many universities and two-year colleges have abandoned the traditional, topically-structured courses in general chemistry in favor of a specialized, somewhat more relevant approach. Recent additions (1-3) to the general chemistry textbook market deemphasize the theoretical foundations of chemistry and stress pertinant applications of principles. To date, no textbook specifically addresses itself to a basic chemistry course structured for engineering students. In the course descrihed in this article, the students rely heavily on the instructor to provide adequate lecture notes, additional reference reading and related prohlem sets. Many of the problems presented to the class are taken from chemical engineering textbooks. Television has not been used to replace the classroom lecture. Rather, the students can view prohlem-solving lectures prepared by the Instructor on Institute T.V. These tapes are repeated four times each week (twice in the evening for dormitory viewing) and solutions to prohlems related to the week's class topic are presented at a slow pace and in detail. Chemical concepts are more effectively presented to a large class with the aid of a variety of visual materials. Selected short films are used. The "Lap-Dissolve" slide technique (4-7) has been tested in this course and found to be very effective for instructional purposes. The use of two slide ~roiectorsconnected to a dissolve unit allows the instructor to simulate motion in a visually appealing manner and, a t any time, stop in the middle of a sequence to discuss the concent further or renlv . - to a question from the class. More extensive use of this technique is planned as it allows the Instructor to establish a desirable balance between the presentation of chemical concepts and their application with reference to prohlem solving. Conclusion Prior to the creation of this chemistry course for freshman eneineerine students. our introductorv "service" " course combined engineers, mathematics, physics, medical technology and photoscience majors. Four instructors were assigned to "team-teach" the course. The students found it difficult to adjust to four separate lecturing styles per quarter. The presentation of the lecture material was discontinuous. The colleges that we were servicing, based upon student opinion, expressed their dissatisfaction with the course. Separate chemistry courses were established for interest-related groups of students and team-teaching was eliminated. After two years, solicitation of student opinions regarding course content and teaching techniques indicated that our efforts toward improving the nonchemistw maior curriculum have been rewarding. The majority-of thk students appreciate the relevant chkmical a ~ ~ l i c a t i o nass they are described in terms of fundamen-
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Literature Cited (11 Butler. I. S.. and Grcerar. A. E., "Mevsnt Pmhlems oi Chemical Prineipln."
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