Students’ misconceptions chemical equilibrium

Ozkaya (76) studied conceptual difficulties experienced by prospective teachers in a number of electrochemical concepts, namely half-cell potential, cell potential, and chemical and electrochemical equilibrium in galvanic cells. The study identified common misconceptions among student teachers from different countries and different levels of electrochemistry. Misconceptions were also identified in relation to chemical equilibrium, electrochemical equilibrium, and the instrumental requirements for die measurement of cell potentials. Learning difficulties were attributed mainly to failure of students to acquire adequate conceptual understanding, and the insufficient explanation of the relevant... 

Unfortunately, it seems to be difficult to teach this topic. Finley, Stewart and Yarroch [2] studied the level of difficulty of various themes in chemistry and reported the results of 100 randomly chosen teachers of chemistry from Wisconsin who chose chemical equilibrium as being clearly the most difficult theme overall. Berquist and Heikkinen [1] noted in addition Equilibrium, considered one of the more difficult chemical concepts to teach, involves a high level of students misunderstanding . One can therefore expect a large variety of misconceptions because of the difficulties in teaching this subject as well as for understanding it. 

Berquist and Heikkinen [1] have summarized students misconceptions concerning chemical equilibrium in many areas as follows ... 

In 1992-1994, Kienast [7] carried out tests on chemical equilibrium with over 12,000 students in four test cycles. The following misconceptions, which were also described by the above-mentioned authors, were observed with particular regularity In equilibrium the sum of the amount of matter (concentration) of reactants is equal to the sum of the amount of matter (concentration) of the products (...) in equilibrium the amounts (concentrations) of all substances which are involved in equilibrium are the same (...) the sum of the amounts of matter (concentrations) remain the same during a reaction (...) data which has been supplied on the amount of matter (concentration data) should be multiplied with stoichiometric coefficients from the reaction equation, in order to find the true amount of matter concentration [7]. 

Because misconceptions about chemical equilibrium have been related in literature to student s lack of comprehension in basics of mathematics, they were also asked for their last grade in that subject. This way it was possible to gain an idea of whether there are correlations between students misconceptions relating to chemical equilibrium and the quality of their grades in mathematics. 

The answers and explanations contain misconceptions as already discussed. The following problems convey a connection to chemical equilibrium and -without giving any choice of answers - students were requested to supply answers, if possible detailed explanations. 

Banerjee, A. Misconceptions of students and teachers in chemical equilibrium. International Journal of Science Education 12 (1991), 355... 

Wheeler, A.E., Kass, H. Student misconceptions in chemical equilibrium. Science Education... 

Many studies have documented students conceptual difficulties in the area of chemical equilibrium (e.g., Gussarksy Gorodetsky, 1990 Hackling Garnett, 1985 Maskill Cachapuz, 1989 Wheeler Kass, 1978 Johnstone, MacDonald Webb, 1977). Most of these studies concern students in upper secondary educabon. Some studies, however, have focused on university students of chemistry in the context of thermodynamic courses (e.g., Thomas Schwenz, 1998), or on chemistry teachers (Banerjee, 1991). Remarkably similar misconceptions were found across groups of students at different levels and from various countries. In particular ... 

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