Mathematical Treatment to Understanding the Concentration Terms (original) (raw)
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Due to their abstract nature, the mole concept and solution concentration are difficult for students to understand and apply to stoichiometric calculations. This study was designed to investigate students' perceptions and difficulties in solving problems related to the mole concept and solution concentration. Thirty-eight students (18-19 years old) who were pursuing science related programmes from a private university college in Malaysia participated in the study. Students were asked to answer twenty-five open-ended questions on the mole concept and solution concentration. Analysis of students' responses revealed that they were not able to connect the mole concept with mass and number of particles. Students were also grappling to answer problems regarding concentration and dilution. This study suggests that it is important to determine whether students' difficulties to master the concepts are due to lack of knowledge or the presence of alternative frameworks so that so that pedagogical instruction can be modified. This study was part of a larger research project where students' responses on this open-ended test will be used to get a greater generalizability in order to construct the alternatives to the four-tier multiple choice (4TMC) instrument to identify students' alternative frameworks on these concepts.
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In this paper, we investigated and classified the answers of college freshmen when asked about “the final concentration value of a mixture of solutions ”. Prior to the explanation of the topic in class, a diagnostic questionnaire on “solutions” was presented to 532 first year students in the chemistry course at the University of Buenos Aires. The questionnaire consisted of three questions assessing the same concept: the calculation of the final concentration of a solution obtained mixing a concentrated and a dilute solution of the same solute. The format of the three questions was multiple choice answer with justification, but they differed in their chemical language style: chemical formulas, verbal-procedural, and visual languages were used. It was noted a trend to apply mathematical calculations, when chemical problems are addressed, even when such calculations are not necessary. Thus, obtaining a numerical result would be considered appropriate by the students, with no analysis o...
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Concentration of solutions problems are among the most important and at the same time one of the most challenging topics in chemistry. The aim of this study was to determine the sources of the difficulty that students often face when performing calculations related to concentration. The study involved 153 tertiary college students (food science, chemistry and biology majors) who have learned the concepts of mole and concentration of solutions prior to the study. Students' written working steps in answering two concentration questions in the semester summative examination were analyzed. The results showed that 52 % of students answered Question 1 correctly whereas only 28 % of students solved Question 2 successfully with a clear display of conceptual understanding. Analysis of students' answers led to the identification of common errors, in conceptual understanding of the topics. It was revealed that one contributing factor to the poor success rate in solving problems related to the concentration was the superficial understanding of the mole concept. Mastery of the mole concept is foundational to understanding concentration of solutions. Difficulties with the former may inhibit learning of the latter. However, the results of this study implied that inappropriate application of the formula M 1 V 1 = M 2 V 2 was the main problem students faced in solving the questions. Specifically, students faced difficulties understanding the use and the meaning of M 1 V 1 = M 2 V 2. A lack of conceptual understanding of the mole concept appeared to lead students to rely on the use of memorized formulae and steps to solve the questions. Implications for assessment, research and instruction are also included.
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Students’ success in stoichiometry problem solving depends mainly on their understanding of the concept of mole and conceptual understanding of the problems. The challenge of enhancing students’ performance in solving stoichiometry problems remain a daunting task as many resort to just teaching how solve stoichiometry problems algorithmically. Two purposes of this study are: first, identifying the major factors influencing students’ performance in stoichiometry problem solving and second, investigating problems faced by students and teachers in stoichiometry learning and teaching in the classroom. A mixed method research design was employed in this study which involved a test and interview protocols. To conclude, students’ understanding of the concept of mole and their problem representation ability are significant predictors, however mathematical ability is not a significant factor in determining students’ success in solving the problems. Students have difficulties in ‘making sense...
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This paper is a concept paper reflecting on the conceptualization of the concept of a 'mole' in the literature. The focus of this paper is to problematize the conceptualization of the mole concept in the literature and argues for a refined conception. The mole concept and reaction stoichiometry are two domains within chemistry, taught at secondary school level that learners generally tend to find problematic (Huddle & Pillay, 1996). Learners that move on to study chemistry at a tertiary level tend to lack the necessary proficiency and basis for success and generally perform poorly despite these topics being covered in the secondary school curriculum. This could possibly be attributed to a poor subject knowledge base and pedagogical content knowledge. Some indicators in teaching practice of teachers with low levels of content knowledge include expressing the same alternative conceptions as those held by learners. Teachers' content knowledge is important for developing con...
Calculations in Chemistry: Permanent Problem of Students and Their Teachers
Gamtamokslinis ugdymas, 2009
Problems requiring calculation at chemistry lessons cause a peculiar difficulty to students. The bibliography concerning the methods of solving calculus problems is very extensive. Several propositions ((visualisation of an algorithm, teamwork with students-experts and addition of context to text of exercises) verified in practice are described there. They can make easier the teacher work in developing students' skills in solving calculus assignments in chemistry, particularly in classes where chemistry is taught at basic level. But the most important issue is to reflect not "how" but "why" a teacher includes calculus problem in her/his own chemistry lessons.