edited by JAMES0.SCHRECK University of Northem Colorado Greeley,CO 60639
filtrates e residues Enhancing Interest in Organic Chemistry The following two manuscripts introduce novel ideas to help you involve your students in organic chemistry. New lectures and laboratory experiments and directions in teaching chemistry through the use of the laboratory are provided in this feature. Experiments will be fully detailed and will be field-tested before they are published.
Part I. Relating Redolence in Organic Chemistry Class Terrill D. Smith University of Central Oklahoma Edmond, OK 73034
To pique the interest of the students in my organic chemi s t lecture. ~ I often pass around samples for them to smell of s"ubstanc& from the representati;e functional organic classes. I ask them to guess the odor or its origin. Of course, care must be exercised to select only substances that will not give off a toxic vapor. The samples consist of 2-3 drops of a liquid or about the same volume of a solid, dispersed on a small wad of cotton in the bottom of a 2-02 screwcap jar that is identified by a Compounds Used in Relating Odor and Functional class
Functional Groups ketone alkene, ketone aromatic ether ester ester alkene, ester alkene alcohol alcohol aldehyde, ether, phenol alkene, aldehyde cinnamaldehyde alkene, ether, phenol eugenol ester, phenol methyl salicylate aldehyde benzaldehyde piperonal aldehyde, ether methyl anthranilate amine, ester thymol phenol ester benzyl acetate 2,3-butanedione ketone 6-methylhept-5-ene- alkene, ketone 2-one ester ethyl isovalerate alkene pinene alkene. ketone L-carvone Compounds camphor a-ionone anethole isoamyl acetate ally1 caproate linalyl acetate limonene menthol 2-phenylethanol vanillin
Odor medicine violets licorice banana pineapple lavender lemonlorange cough drops roses vanilla cinnamon cloves wintergreen almond heliotrope grape Listerine mouthwash jasmine butter, caramel pear flavor ripe apple pine, turpentine wearmint
code number or letter. The samples were chosen to represent a variety of common flavors and framances. The students are also shown the stru%ures of the compounds that .yield these odors. Althouzh no attempt is made to relate odor with structure, the students often recognize that esters are often associated with fruity aromas. The samples are usually passed around when the functional classes are studied. The structures may also be used in nomenclature exercises. While most ofthe samples have pleasant odors that are reminiscent of food flavors, some of the substances used, like tbymol and pinene, are more utilitarian and often challenging. The table lists some compounds that I have founduseful. I have included neither simple amines nor carboxylic acids because thev usuallv have offensive odors and mav be toxic. Several sources ( 1 3 )provide information on common odoriferous comrmunds. manv of which can be found in a typical organic chemical stockroom. Students seem to enjoy the experience of trying to associate these "chemical odors" with something "familiar", such a s a food flavor or perfume fragrance. Colleagues often borrow the "smelly bottles" for use in general or introductom chemistrv. The samples have also been used to entertainvisitors s&h a s junidr high and high school students during Chemistry Day activities. Literature Cited 1. The Memk In&, 9th ed.; Windholz M., Ed.: Menk:Rahway, 1976. AUyn and Bacon: Boston. 2. Lehman, J. W Oprotioml Organre Chemistry, 2nd 1988. 3. Pavia, D. L.; Lampman, 0. M.; Knz, 0. S. Orgonle Lobomlory Tpehnlgupa, 3rd Saunden: Philadelphia, 19R8.
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Part II. Organic Chemistry Squares: A Game for Reviewing Organic Chemistry James 0. Schreck University of Northern Colorado Greeley, CO 80639
I often use a popular television game show to review organic chemistry concepts, but the concept could be applied to other courses a s well.' The came show that I have found to be most useful is ~ollywooYdSquares. The students are alreadv familiar with the game stratew-a auiz version of the classic tic-tac-toe in which two players take turns marking either their X's or 0's in an open block of nine squares. Aplayer wins the game by placing three identical marks in a vertical, horizontal, or diagonal row. I n the television version of the game, nine celebrities, who are usuallv " ~.o.o u l a rmovie and television stars or sports personalities, occupy a desk a t one of nine squares in a life-sized 3 x 3 frame on the studio staee. Two lavers attempt to win squares for their mark i n a proce'ss that
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'See Scarpetl, D. J. Chern. Educ. 1991, 68, 1027for "Chemical Jeopardy, an alternative to conventional forms of group meetings. Volume 69 Number 3 March 1992
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begins when one of them selects a square. The emcee then asks a question to be answered by the celebrity who occupies that square. The answer may be right or wrong, and the player must agree or disagree with the celebrity. If the player correctly judges the veracity of the celebrity's answer, the player wins the sauare., which will now bear that olaver's . " mark. If the player is wrong, the square is marked for the opposing player. An exception to this rule of forfeiture occurs if it would end the game; the players must win outright, not by error of the other nlaver. A winner is declared when three marks appear vertically, horizontally, or diagonally. Prizes are given to the winner. In my organic chemistry class I play the role of the emcee. Two students, who are usually confident about their knowledge of a given chapter, volunteer to be the players. They sit a t the front of the classroom facing the other students. Nine other students are chosen (sometimes with reluctance) to be the individuals in the sauares. These nine students remain in their seats, but thk 3 x 3 sauare is written on the chalkboard with the names of the &dents in the square. Acoin flip determines which player goes first.
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The player then chooses a student in the square to answer the question, and I begin the game by asking the auestion. For examnle. ifwe are reviewim the chanter on alkenes, my questik'might include %it is theAtypical reaction of an alkene?", "What is the name of the intermediate formed when a proton adds to propene?", or "Would the alkene shown be designated as E, Z, or neither?" Then X's and 0's fill the large square on the chalkboard, and the questioning continues until one of the players wins the game. I have found that this exercise builds confidence, generates camaraderie, heightens students' interest in the renew process, and helps them learn organic chemistry. In our game, prizes are not given (not even points for the upcoming exam). Players and the nine squares are changed after every win so that all students get involved. Even though some students are reluctant to participate, I tell them that it is really the player who must earn the mark in the square. Hopefully, the more reluctant student will have done some outside preparation for the review. The students like to play the game, and when the next exam is announced, someone always inquires about playing Organic Chemistry Squares!
