The Mechanism of Covalent Bonding: Analysis within the Huckel Model of Electronic Structure.

This study explores Turkish chemistry undergraduates' understanding of entropy and identifies and classifies their misunderstandings. For this purpose, a diagnostic questionnaire and semi-structured interviews�before and after teaching�were used. Two diagnostic questionnaires were developed and used as pre-tests and post-tests with 91 students enrolled in a physical chemistry course from two different chemistry education departments in two different universities in Turkey. Just after the administration of the tests, 22 pre-interviews and 7 post-interviews were carried out. The misunderstandings identified were categorized into these five broad headings: (i) Defining entropy as "disorder" and considering visual disorder and entropy as synonymous; (ii) Inaccurate connection of entropy to the number of inter-molecular interactions; (iii) Inaccurate connection of entropy of a system and the accompanying entropy changes in its surroundings; (iv) Entropy of the whole system decreases or does not change when a spontaneous change occurs in an isolated system; and (v) Entropy of carbon dioxide is bigger than that of propane or the same at the same temperature. The findings have implications for tertiary-level teaching, suggesting that a substantial review of teaching strategies is needed.