Post-secondary Science Students' Understanding on Mole Concept and Solution Concentration (original) (raw)
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Thai Grade 10 and 11 Students’ Understanding of Stoichiometry and Related Concepts
International Journal of Science and Mathematics Education, 2007
The research reported in this case study explores the understanding of stoichiometry and related concepts of Thai science students in grades 10 and 11 after major national curriculum reforms. Students_ conceptions and alternative conceptions were investigated using a questionnaire-the Stoichiometry Concept Questionnaire (SCQ) (N = 97), which consists of 16 multiple-choice items, the choices for which respondents are required to provide reasons. The findings suggest that less than half of the students surveyed hold what is considered by a panel of experts to be a scientifically acceptable understanding for the conceptions investigated. The main student alternative conceptions are that one mole of all substances has a volume of 22.4 L at STP, that a solution that contains a greater mass of solute has the higher molar concentration, and that the limiting reagent is the reagent for which the lowest mass of reactant is present. Examination of students_ reasons suggests that they resort to the use of algorithms with little understanding of the underlying concepts. It thus seems the national educational reforms have not resulted in a sound understanding of some science concepts. It is recommended that curriculum developers should specify a need for conceptual understanding along with capability in numerical problem-solving in their learning objectives, and link this to assessment regimes that reward conceptual understanding. A need for ongoing professional development seems essential if the intentions of the Thai curriculum reforms are to be realized.
Chem. Educ. Res. Pract., 2012
This paper reports on students' understanding of sugar concentration in aqueous solutions presented in two different modes: a visual submicroscopic mode for particles and a verbal mode referring to macroscopic amounts of sugar. One hundred and forty-five tertiary college students studying some form of first-year chemistry participated in the study. For problems of a similar nature, students were much more successful in solving solution concentration problems that were presented verbally than were presented using a submicroscopic representation of particles. The implications of this for chemistry education are outlined in the paper. One contributing factor to the poor success rate with submicroscopic representations (SMR) was possibly the fact that the SMR were presented in multiple-choice format whereas the verbal representations required a short-answer response. While the multiple-choice format may prove deceptive, on account of the way students interpret alternatives containing visual images, students agreed it also proved instructive in highlighting the importance of accounting for volume change in concentration calculations.
2014
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...
STUDENTS’ MISCONCEPTIONS IN STOICHIOMETRY
STUDENTS’ MISCONCEPTIONS IN STOICHIOMETRY Suandi Sidauruk Palangkaraya University Abstract: Misconceptions in stoichiometry of 1096 senior high school students in grade 2nd and 3rd class were studied through the use of paper-pencil test and clinical interview. Some stoichiometry misconceptions identified supported some results of former research. Therefore, the developed SDT can be used to trace misconceptions in stoichiometry. The concentration analysis resulted in the identification of 30 stoichiometry misconceptions held by students, they are 12 chemical equation misconceptions, one relative of atomic mass misconception, and 16 mol misconceptions. The misconceptions were caused by: (1) the habit of using a chemical term verbally, (2) new theories of chemistry were still related to "old terms" that had a shifted meaning, (3) a number of atoms containing in a molecule was calculated by using wrong strategy such as (molecular mass/molar mass) x N, (4) the mole was more related to volume or mass than to amount of particles, (5) the formula: v = n x 22,4 liters/mole was applied to determine solid, liquid, or gas volume, (6) the terms of molecule, atom, and mole were used interchangeably, (7) chemical concepts were explained by using algorithmic-dependent, specially in explaining mole, mass, and volume intercorrelations, (8) if its name was given, students used strategy of memorization to determine molecule formula of a substance, and (9) the Mr was used to replace molar mass in calculating the mass of a substance by using the formula mass = mol x Mr. Key words: misconceptions - stoichiometry – chemical equation – relative of atomic mass – mol.
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...
Electronic Journal of Science Education, 2003
Stoichiometry is one of the most basic, central, yet abstract topics in chemistry. It is essential for understanding quantitative and qualitative aspects of chemical reactions as well as for solving many types of problems in high school chemistry. Moreover, one body of research findings highlight the importance of conceptual understanding for successful problem solving and qualitative thinking in chemistry and suggest that students' inadequate and incorrect conceptual knowledge impede successful problem solving in stoichiometry , while other studies have demonstrated an over -reliance on using algorithms to solve problems ). As a result, since teaching stoichiometric calculations is a difficult task , new instructional approaches and methodologies should be used in implementing curricula meant to prepare meaningful learners in chemistry; a situation which requires an understanding of students' problem solving strategies in chemistry in general and more specifically in stoichiometry.
Exploring Students " Conceptions on Stoichiometry Using SCQS and VCQS
This study describes the prevalent conceptions held by third year high school students (n=204) on stoichiometry enrolled in one National High School in the Philippines. The Visual Conceptual Questionnaire in Stoichiometry (VCQS) and Symbolic Conceptual Questionnaire in Stoichiometry (SCQS) were used as the main instruments utilized in the study, which has a reliability coefficient of 0.66 and 0.65, respectively. Analysis of the conceptual test using VCQS and SCQS showed that biggest number of the students (57.11% & 59.07%) has incomplete understanding of balancing chemical equations. This implies that students did not fully understand the concepts on stoichiometry. Comparing students' performance on both the VCQS and SCQS, results revealed that there is significant difference on the performance of the students in the two tests. This indicates that students performed better in SCQS than VCQS. The findings of this study have potential in translating research insights into practical advice for teachers regarding tactical moves on how to diagnose students' conceptions on stoichiometry. This can also help the teacher to decide on what way/ways to be employed in teaching stoichiometry considering the use of particulate drawing and symbolic notation.
2018
This study determined the most common alternative conceptions of students in stoichiometry using mental models and illstructured problems. Qualitative and quantitative research methods were used in the study with conceptual understanding test as the main data gathering instruments. Respondents were third year Bachelor of Secondary Education, Biological Science students. Frequency and percentage were the statistical tools applied to answer the question presented in the study. Results showed that students manifested alternative conception in illustrating model of certain chemical reactions, particularly the reactants of the reaction. Moreover there were inconsistency in the reasoning of the students on how chemical reactions takes place. There was an indication of misconception between atom and molecule among students. Students‟ conceptions of atom and molecule were ambiguous, for the students, the two concepts could be used interchangeably. Participants also manifested alternative co...