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Hans-Jürgen
SCHMIDT and Cecilia JIGNÉUS
ABSTRACT: Students solving chemistry problems tend to rely on algorithmic methods. However, the problem solving strategy a person applies may depend on the difficulty of the problem. Research on stoichiometric problem solving reports that students working on easy-to-calculate problems created a “non-mathematical” strategy on their own. The aim of the present study was to find out (1) whether Swedish students would behave in a similar manner to that described in literature and (2) how they change the strategies when moving from an easy-to-calculate problem to a more difficult question. Four semistructured interviews were conducted with Swedish senior high school students. The result showed that they reacted as described in literature. In addition to applying mathematical strategies they each developed a non-mathematical strategy. All the students used a non- mathematical strategy to solve an easy question. However, in moving from an easy-to-calculate problem to a more difficult one most students calculated the mass fraction or the percentages of an element in a compound. In this form the strategy comes close to the non-mathematical strategy. It is suggested for introductory chemistry courses to use easy-to-calculate problems and to concentrate on both the non-mathematical and the mass fraction strategy. [Chem. Educ. Res. Pract.: 2003, 4, 305-317] KEY WORDS: stoichiometry; problem solving strategy; problem difficulty; easy problems; semi-structured interview CORRESPONDENCE: Hans-Jürgen SCHMIDT, Karlstads universitet, Institutionen för kemi Universitetsgatan 1, SE- 65 188 Karlstad, Sweden; e-mail: dc2@pop.uni-dortmund.de
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