The Thermal Decomposition of Basic Copper(l1) Sulfate An Undergraduate Thermal Analysis Experiment Haruhiko Tanaka and Nobuymhi Koga Faculty of School Education, Hiroshima University, Shinonome, Minami-Ku, Hiroshima, 734. Japan The techniques of thermogravimetric analysis (TG), differential thermal analysis (DTA), and differential scanning calorimetry (DSC) have been widely used in the field of solid-state reactions (1,2). Several workers have suggested that the DTA technique is useful in teaching students in undergraduate physical or analytical chemistry laboratory courses (3ii). The relevant thermoanalytical equipment could also he designed and constructed a t a reasonable cost t o universitv or colleee laboratories. to demonstrate the wide applicahiliiy of the& methods ( 3 . 6 , 7).The application of DTA in chemical education has been illustrated with resDect to the thermal decomposition of potassium chlorate'(4). Also. the thermal decom~ositionof urea has been examined by means of TG and DSC. These applications are ideal as introductory undergraduate thermal analysis experiments (5).Thermal analyses of a nickel complex and a mixture of the oxalates of calcium, strontium, and barium have suggested as advanced undergraduate thermal analysis experiments (2). However, it was revealed, at the 8th International Congress on Thermal Analysis (ICTA), that in most countries, verv little thermal analvsis is taueht a t the undereraduate d for example, level. In most universities in the ~ k t e States, there is no special training in this field; only a few schools, known for their research in thermal analysis, have special courses devoted to thermal analysis with small numbers of students enrolled (8). T o cope with the present problem of rather poor student preparation in the field of thermal analysis, teaching material should be extensively prepared for a comprehensive education in this field. The importance of education in thermal analysis was again stressed a t the 9th
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Additional teaching material appropriate for education in thermal analysis is reported here, which has been used successfully in our chemistry course a t Hiroshima University since 1985 (8). We believe that a TG-DTA study of the thermal decomposition of basic copper(I1) sulfate is suitable for such a purpose for the following reasons:
and higher p H due to the introduction of the hydroxide solution, both of which are local and transient. The present article is concerned with the preparation of synthetic hrochantite from solution and a TG-DTA studv of
