Chimestry mole (original) (raw)
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The mole is not an ordinary measurement unit
Accreditation and Quality Assurance, 2011
In this paper, it is argued that the SI system has not carefully enough taken into account the differences that exist between stoichiometry and physics, and because of this neglect forced the kind-of-quantity amount of substance into a false form. The mole is not a unit such as the metre, the kilogram, and the second. It is a “unit” only
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...
Modeling the Mole Understanding with Mathematical Reasoning
2019
The amount of substance, expressed in the units of moles is an essential concept in chemistry and physics. Students entering physics courses usually possess a chemistry background. However, this study showed that their understanding of units of matter on the microscopic level is fragile, and needs improvement. Research shows that the complexity of interpretations of quantities expressed as ratios; molar mass or atomic mass makes formulating a dimensional analysis or proportion of these ratios unclear to students. Based on these findings, this study proposes applying equations of fundamental constants and proportional reasoning, instead of ratios, as the main building blocks to formulate conversion algorithms. In the line of that, a deductively designed lecture was delivered to a group (N=25) freshman college physics students. While on the pretest, only (N=4, 16%) correctly converted a mass of a substance expressed in kilograms to a number of moles, on the posttest the percentage of ...
Post-secondary Science Students' Understanding on Mole Concept and Solution Concentration
Universal Journal of Educational Research, 2019
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.
Wither the Concepts of Mole and Concentration: Conceptual Confusion in applying M1V1 = M2V2
Universal Journal of Educational Research, 2016
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.
The first step to knowiedge is to know that we are ignorant.