In July 2004 the 36th International Chemistry Olympiad was held in Kiel, Germany. Competition for medals included 236 students from 61 countries, accompanied by about 150 teachers and other mentors. During this Olympiad the students performed qualitative and quantitative analyses of a superconductor, based on lanthanum barium cuprate. In the quantitative determination the students assessed the lanthanum and copper content by complexometric and iodometric titration; the alkaline earth metal was identified by qualitative analysis. From these results, the formula of the superconductor could be calculated. New procedures were developed, which in contrast to classical procedures, did not require the use of toxic chemicals. We report on the development and the results of our practical task and the reasons why we chose it for the Olympiad.
Supplement
Detailed instruction of our experiment and of our preparatory tasks, results of the preliminary tests for the quantitative determinations, the formula for the judgement of the results of the quantitative determinations, the results of the qualitative analysis, and a description of the organization of practical exam are available.
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