![]() How the concept of concentration is learned was investigated in some studies in the context of the general characteristics of solutions ( e.g. This is particularly marked at university level therefore, this study seeks to contribute to our knowledge of this process. Given the importance of these concepts, in comparison with other subjects dealt with in the area of research into chemistry teaching, very few studies centre on the learning process associated with the concept of concentration in general, and molar concentration in particular. Difficulties with the concepts of concentration ( Pinarbasi and Canpolat, 2003 de Berg, 2012) and molarity ( Niaz, 1995 Ryan, 2012) persist even in university students. ![]() (2005) did not include the concept of concentration.ĭifficulties encountered when learning the concept of concentration have been discussed, together with secondary pupils, in many studies ( Calik, 2005 Devetak et al., 2009 Adadan and Savasci, 2012), but few articles have focused specifically on molar concentration ( Duncan and Johnstone, 1973 Gabel and Samuel, 1986 Heyworth, 1999). For example, in their bibliographical review article on learning about chemical solutions, Calik et al. However, most research has focused on students’ ideas about the nature of solutions and the process of dissolution rather than quantitative aspects. The review carried out by Gabel and Bunce (1994) showed this lack of comprehension on the part of secondary pupils. The preparation of a solution with a specific concentration constitutes a primary goal in many general chemistry laboratories notwithstanding, the procedure is poorly understood ( Dunnivant et al., 2002). ![]() However, this concept is not easily understood by the majority of secondary school ( Adadan and Savasci, 2012) and university students ( de Berg, 2012), which is problematic considering that it constitutes such a basic operational concept in experimental chemistry. Specifically, the concept of concentration is a prerequisite applied to areas of chemistry such as stoichiometry, acids and bases, kinetic chemistry, equilibrium chemistry and electrochemistry ( Calik et al., 2010), to name but a few. ![]() The subject of concentration of solutions is very important, since it is a basic, central concept in the chemistry curriculum both at secondary school and university levels. Their study requires consideration not only of the qualitative, but also the quantitative aspects of solutions associated with the concept of concentration. Introduction Most biological processes and many chemical reactions occur between substances dissolved to form homogeneous mixtures or solutions. It was also established that much conceptual confusion, such as the lack of differentiation between n and M, lies behind the algorithmic, numerical solution strategy carried out exclusively by many students. The main difficulty arises in inverse proportionality tasks where the number of moles (extensive) and M (intensive) should be related qualitatively to determine which solution occupies the smallest volume. These results reveal that approximately half the first-year university students have no clear conceptual understanding of molarity. Results obtained from think-aloud interviews related to this questionnaire, which were performed with 18 students, are also analysed. A “Reasoning with molarity” questionnaire, which explores the logical–mathematical relationships between the variables n, V and M, was administered to 303 Argentine first-year university students. The specific problems underlying learning of this concept have not yet been focused on in sufficient detail or depth. This article presents and discusses the results of a study that investigates university students’ comprehension of the concept of molar concentration, following teaching and evaluation of the subject.
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