J o h n J. A l e x a n d e r and J o h n G. D o r s e y University of Cincinnati Cincinnati, Ohio 45221
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The Synthesis and Reactions of a Cobalt A project for freshman laboratory
T h e design of suitable experiments for t h e general chemistry l a h o r . & y presents a challenging prnblem. Appn~priate activities a t the freshman level ought t o introduce students to needed lat~oratorytechniques and hasic chemical principles. At the same time the experimenrs should capture students' interest. An important factor in maintaining this interest i s t h e opportunity for successful completion of t h e laboratory work. Students t e n d to become rather discouraged if their efforts seem t o produce few results. Added to these reauirements in manv institutions are other pressures resulting from the large sizes nf freshman laboratory sections and the artenrlant loeistical vroblems. T h e work must fit conveniently into three-hour modules. Chemicals must not b e inordinately expensive. Required equipment m u s t b e readily available. T h e principles of t h e experiment m u s t b e grasped b y t h e teaching assistantships who staff t h e laboratories and have the most direct contact with students. Finally, t h e results should b e amenable t o "objective" grading preferably involving unknowns andlor product yields to h e handed in. Results of this kind encourage useful discussions among students b u t prevent excessive cooperation i n writing laboratory reports. With so manv criteria to b e satisfied i t is little wonder t h a t large numbers of freshman experiments d o n o t also offer nossibilities for interestine discussions with briehter students, ?or extending t h e work inGolved and for conveying some of the excitement of a developing research problem ( 1 ) . Description of t h e Experiment and Student Results At the University of Cincinnati we have had considerable success with a project-type experiment lasting far three laboratory periods during the first quarter of the freshman laboratory. During the first week students prepare a sample of [Co(NH&COd(NOd.0.6 H.0 (21.. (uide infral. ~ ~ . . ,., ' . ~ . I'reparation of the reIraamin? rarbonato mmplex from 1Og of Co(NO,
