Students misconceptions on the concept of chemical equilibrium

phenomena result from some instructional experience, within or outside of the classroom, but Chemical equilibrium presents particularly unique 12 BİLGİN UZUNTİRYAKİ ve GEBAN opportunities for misconception in both of the categories. In one dislıcartening study (Quilcz and Solaz, 1985), high school teachers showed extensivc nıisıınderstanding of the concepts of Chemical cquilibrium. It has been said that experiential nıisconceptions occur in connectioıı with phenomeııa encountcred in everyday experience. For example, students usııally use the everyday meaııing of the \vord ‘eqııilibrinm’ synonymously with tlıc Chemical meaııing. This leads them to think of Chemical equilibrium as static rather thaıı dyııamic. On the otlıer Iıand, pıior knowledge, language and cogııitive developmeııt can be the cause of misconceptions related to instmctional process. A learner’s prior knoıvledge is the most important variable in success in learning scieııce. If the students’ prior knoıvledge is not cııough to process new information, they will beconıe confused, rcason inaccıırately, and eventually form a misconception. Therefore, teachers need to take into account students’ prior knoıvledge before instruetion takes place and inelude this in Solutions. The other sotırce of misconception related to instructional process is the use of language in teachiııg. This is important bccause the language used by the teachers to communicate concepts may cause students to misinterpret vocabulary, symbols, terıns and analogies. For example, ali of the terms beloıv used for the deseription of equilibriıım Systems can cause great confusion; left, right, stress, slıifl, favor, fonvard, reverse, ete. Kathlen (1994) found that \vhilc inten'ieıving students on tlıeir representatioıı and studies of typical equilibrium problems, some students interpreted the term “favored reactioıı” to mean that the reactants for the favored reactioıı remaiııed as reactants, rather ıhan they \vere “favored” to be converted to produets. Also, “K” is sometimes used to represent the solubility constant, equilibriunı constant and weak acid and bases constant; “m” is ııscd to represent ıııeters and mass; “M” represents both ıııolar mass and molarity; and “n” represents the nunıber of moles, \vhereas “N ” stands for the nunıber of objects in a mole as \vell as nornıality, a term confusing enough in its o\vn right. Therefore, a teacher nıııst elarify frequently and get feedback from students with regard to their understanding of the meaning of various symbols and terms. Anotlıcr cause of nıisconceptions related to the instructional process is students’ cogııitive dcvclopnıent. If teachers use knoıvledge ıvhich is alıeady orgaııized, they are attenıpling to traıısmit a fully orgaııized set of ideas. Hoıvcvcr, the students have not yet created an orgaııization for thenıselves and caıınot receive the information intact. On this point, teachers need to consider students’ cogııitive developmeııt and ıvlıethcr students have understood the concepts or not before doing nıany problem solving activities. Therefore, teachers need to develop ıvays to pronıote students’ coııceptual understanding and to facilitate learning rather thaıı to coııtrol it. There are different methods available to identify students’ misconceptions. The most conımon one is the intervieıv teclıııiquc. Researchers used this technique to study nıisconceptions of students in Chemical equilibriunı (Bergguist and Heikkineıı, 1990; Hackling and Garnct, 1985) in stoichiometry (Mitchell and Gunstone, 1984) and in Solutions (Ebenezer, 1995). The other techniqııe is nıultiple-choice tests. Researchers have developed and administered misconception identification tests related to Chemical equilibriıım (Voska and Heikkinen, 2000; Qııilez and Solaz, 1995; Banerjee and Poıver, 1991; Wheeler and Kass, 1978) and related to covalent boııding and Chemical structtıre (Treagust, 1988). Many researchers have found that Chemical equilibriunı is one of the important and difficult topics in Science content to teach (Bergguist and Fleikkinen, 1990 and Canıacho and Good, 1989). Understanding clıcmical cquilibriunı concepts iııfluence understanding of furtlıer concepts such as acid base behaviour, oxidation/reduction reactioııs and solubility (Bergguist and Heikkinen, 1990). The coııcept of Chemical equilibriuııı iııcludes synthesis of most general chenıistry concepts and principlcs. Misconceptions about the concept of Chemical equilibrium summarized from the literatüre are bclow; 1. The essence of the Chemical equilibriıım concept (Bergguist and Heikkinen, 1990; Hackling and Garııett, 1985; Wheelerand Kass, 1978). 2. The rate of the fonvard reaction inereases \vhen reaction approaches to equilibrium (Niaz, 1998; Hackling and Garnett, 1985). STUDENTS’ MISCONCEPTIONS ON THE CONCEPT OF CHEMICAL EÇUILIBRIUM 13 3. The constancy of equilibriıım constaııt (Voska and Heikkinen, 2000; Wheeler and Kass, 1978). 4. Lcft and right sidedness (Gorodetsky and Gııssarsky, 1986). 5. At equilibriıım, the concentration of reactants are eqııal to the concentration of prodııct (Hackling