Concept Of Chemical Equilibrium Research Articles

Feasibility of Four-Tier Multiple Choice Diagnostic Test for Identification Conception on Chemical Equilibrium Concept

The purpose of this study was to obtain the feasibility of a four-tier multiple choice (4TMC) diagnostic test instrument for the identification of conceptions on chemical equilibrium material in terms of validity, practicality, and effectiveness criteria. This type of research is ADDIE development research with the Analyze, Design, Development, and Evaluation stages. Validity is obtained from a validation sheet consisting of construct, content, and language validity which gets mode = 4, so that the four-tier multiple choice instrument is said to be valid. Practicality is obtained from a learner response questionnaire supported by a learner activity observation sheet. Practicality in terms of the student's response questionnaire is 84% with a very practical category, while the student activity observation sheet gets mode = 1, so the diagnostic test instrument is said to be practical. Effectiveness is obtained from the diagnostic test instrument reliability test. The Cronbach alpha value obtained in the reliability test was 0.798, so the diagnostic test instrument developed was declared reliable. Based on the results of validity, practicality, and effectiveness, the four-tier multiple choice diagnostic test instrument is declared suitable for use.

Pengembangan Instrumen Tes Diagnostik Five-Tier Multiple Choice untuk Mengidentifikasi Miskonsepsi Siswa pada Materi Kesetimbangan Kimia

This research aims to report the results of identifying the level of misconceptions and the sources causing the misconceptions experienced by class XI IPA students at SMAN 17 Medan regarding the concept of chemical equilibrium. This research is descriptive research using the ADDIE development model. Data collection in this research used tests, interviews and questionnaires. The results of the wide-scale trial showed that the level of misconception of class The largest percentage of misconceptions is the concept of chemical equilibrium in industry at 29%. The lowest percentage of misconceptions experienced by students was understanding the concept of chemical equilibrium at 2%. The highest percentage of categories that cause misconceptions experienced by students is in the MC-PT category or misconceptions caused by individuals at 73% and the lowest category percentage was shown in the MC-B category or misconceptions obtained from books at 34%.

Using Analogies to Dispel Misconceptions about Chemical Equilibrium among Students Studying Agricultural Science

This study examined how analogies influence third-year senior high school students' views of dynamic chemical equilibrium. Six participants willingly shared their understanding of the concepts of chemical equilibrium through semi-structured questionnaires distributed before and after a teaching session. The example aimed to show students how their misconceptions about chemical equilibrium correlate with other logical scenarios. The study's findings demonstrated that a student's capacity to comprehend and relate the analogous events to the target concepts being taught and their ability to handle the computations required by the analogy are crucial factors in determining whether they would succeed. Teachers must help students connect the analogy and the primary concepts to include them in their lesson plans. Teachers should also help students with the calculations needed for the simulation by providing guidance and support. This will help students comprehend and apply the ideas of chemical equilibrium in real-world situations.

Effects of formative assessment with technology on students’ meaningful learning in chemistry equilibrium concepts

This study examines how students’ conceptual and procedural knowledge of chemical equilibrium is affected by technology-supported formative assessment (TSFA) strategies. This study's embedded/nested mixed method research design was used to achieve the study's objective. A random sampling method was used to choose the sample of two intact classes for the treatment group and one intact class for the comparison group. To gather quantitative data, the chemical equilibrium conceptual test and the chemical equilibrium procedural test were adapted from the literature. The qualitative data were also gathered using semi-structured interviews and classroom observations. Descriptive statistics and one-way ANOVA were employed to analyze the quantitative data, and theme analysis was utilized to examine the qualitative data. One-way ANOVA results revealed that, in comparison to students who were taught using conventional methods and formative assessment strategies, students who were taught using technology-supported formative assessment strategies demonstrated improvements in conceptual and procedural knowledge. The results of semi-structured interviews and classroom observations also show that, when compared to students who are taught using conventional methods and formative assessment alone, students who are taught using technology-supported formative assessment strategies have a high improvement in learning outcomes of learning chemical equilibrium concepts. In conclusion, conventional methods and formative assessment alone were shown to be less successful for students’ conceptual and procedural knowledge in learning chemical equilibrium concepts than technology-supported formative assessment strategies. These results led the authors of this research to recommend that TSFA be used by chemistry teachers to enhance their students’ conceptual and procedural understanding of chemical equilibrium concepts.

Transformations of Glycerol into High-Value-Added Chemical Products: Ketalization and Esterification Reactions

Biomass allows us to obtain energy and high-value-added compounds through the use of different physical and chemical processes. The glycerol obtained as a by-product in the synthesis of biodiesel is considered a biomass compound that has the potential to be used as a raw material to obtain different chemical products for industry. The development and growth of the biodiesel industry allows for the projection of glycerol biorefineries around these plants that efficiently and sustainably integrate the biodiesel production process together with the glycerol transformation processes. This work presents a review of the ketalization and esterification of glycerol to obtain solketal and acetylglycerols, which are considered products of high added value for the chemical and fuel industry. First, the general aspects and mechanisms of both reactions are presented, as well as the related chemical equilibrium concepts. Subsequently, the catalysts employed are described, classifying them according to their catalytic nature (zeolites, carbons, exchange resins, etc.). The reaction conditions used are also described, and the best results for each catalytic system are presented. In addition, stability studies and the main deactivation mechanisms are discussed. Finally, the work presents the kinetic models that have been formulated to date for some of these systems. It is expected that this review work will serve as a tool for the advancement of studies on the ketalization and esterification reactions that allow for the projection of biorefineries based on glycerol as a raw material.

THE INFLUENCE OF THE 6-PHASE LEARNING CYCLE - THINK PAIR SHARE LEARNING MODEL ON LEARNING OUTCOMES AND STUDENT RETENTION ON CHEMICAL EQUILIBRIUM MATERIALS

This study aims to decide the influence of the Learning Cycle 6 Phase - Think Pair Share learning model on knowledge results and student retention on chemical equilibrium material. The research design was a quasi-experimental research design without a pretest (posttest-only control group design). All students of class XI MAN 1 Kota Malang were used as the population in this study. The sample selection was carried out using the cluster random sampling technique and 2 research groups were acquired. Class XI MIPA 6 was selected as the experimental class using the Learning Cycle 6 Phase - Think Pair Share learning model while class XI MIPA 5 was selected as the control class using the Learning Cycle 6 Phase. The number of students in class XI MIPA 5 was 36 students, while the amount of students in class XI MIPA 6 was 34 students. The measurement instrument used is a test. The test was carried out after being given treatment to measure students' skills to recognize the concept of chemical equilibrium. In addition, there is a retention test that is held 1 week and 1 month after students study chemical equilibrium material without prior notification. Test the hypothesis to determine whether there was a substantial difference in education outcomes and retention between schoolchildren taught by the 6-Phase Learning Cycle - Think Pair Share learning model and students taught with the 6-Phase Learning Cycle model in chemical equilibrium material with the Independent Sample T-Test. The data analysis technique used consisted of preliminary analysis consisting of a normality test and homogeneity test and analysis of results consisting of hypothesis testing. The outcomes of the Independent Sample T Test showed a likelihood worth of fewer than 0.05 which indicated that there was a substantial difference between the knowledge outcomes of the experimental group and the control group. The probability values of retention tests I and II are also smaller than 0.05. This shows that there is a substantial difference amongst the retention test of the experimental group and the control group on retention tests I and II. The outcomes of this research show that the midpoint knowledge outcomes in the experimental group are higher than the midpoint knowledge outcomes in the control group, namely 77 in the experimental class and 71 in the control class. This proves that the Learning Cycle 6 Phase - Think Pair Share learning model has an effect on student learning outcomes of MAN 1 Kota Malang on chemical equilibrium material. This model also affects student retention.

Topic-Specific Pedagogical Content Knowledge-Based Instruction and Level of Conceptual Understanding of Chemical Kinetics and Equilibrium concepts on Grade 11 Students

The goal of this study was to assess students’ level of conceptual understanding of chemical kinetics and equilibrium using topic-specific pedagogical content knowledge (TSPCK)-based instruction in chemistry grade 11 students. The research was a mixed approach that involved 159 grade 11 chemistry class students from Addis Ababa administrative city, Ethiopia, and employed a mixture of qualitative and quantitative methodologies. Purposive sampling was used for the sample procedure and four intact classes were selected as three intervention groups and one control group: curricular saliency-based, representation-based, conceptual teaching strategy-based instruction, and comparison groups. The level of conceptual understanding was assessed using reasoned questions, specifically a two-tiered multiple-choice pretest, and posttest. The findings revealed that students’ conceptual understanding of chemical kinetics was higher than that of chemical equilibrium concepts. According to the findings of the students’ pretest and posttest, the level of conceptual understanding increased from 27.08% to 32.21% in chemical kinetics and from 15.91% to 23.68% in chemical equilibrium. Overall, representation-based instruction and conceptual teaching tactics boosted students’ conceptual knowledge and accomplishment in chemical kinetics and equilibrium concepts. This study proposes that the level of conceptual understanding of grade 11 students in chemical kinetics should take into account the horizontal relationship between mathematics and the chemical kinetics concepts, which should be taught using technology-assisted teaching strategies such as conceptual teaching strategies and three-fold mental representations.

Development of an assessment instrument to evaluate the concepts of chemical equilibrium at macroscopic, sub-microscopic, and symbolic representation levels using the rasch model

This study aims to develop a test instrument that can be used to evaluate the concept of chemical equilibrium at the macroscopic, submicroscopic, and symbolic levels of high school students who are declared valid, reliable, have a difficulty index, and have good item discrimination. This study was designed using the Rasch development model, which Wei has modified with ten research stages. The results of the research to test content validity were analyzed through the minifacets program with five validators consisting of four chemistry lecturers at Padang State University and one teacher at high school SMAN 3 Padang, obtaining fit analysis results seen from the exact agreement value of 89.1%, which is very close to the expected agreement value of 89.7%. The test results on 30 students of SMAN 3 Padang who were analyzed through the ministep program showed valid results for all items because they met the criteria for the MNSQ, ZSTD, and Pt Mean Corr outfit scores. The reliability value obtained for the item is 0.74, which meets the sufficient criteria, and Cronbach's alpha reliability value is 0.74, which meets the good criteria. All question items also do not have DIF based on gender. The analyzed index of difficulty and discriminating power fulfilled the good criteria with the classification of easy, medium, and difficult items.

Revealing Preservice Teachers’ Conceptions, Troublesome Knowledge and Threshold Concept of Chemical Equilibrium through Predict Observe Explain Mental Model Diagnostic Test (POE-MMDT)

The purpose of this study is to reveal preservice teacher’ conception of chemical equilibrium concepts which then were further analysed to identify the troublesome knowledge and threshold concept of chemical equilibrium. The participants of this study were 68 preservice chemistry teachers from one of the Teacher Education Institutions in Bandung, Indonesia. Using the descriptive-qualitative design, this research uses a predict-observe-explain mental model diagnostic test consisting of four main questions related to the phenomenon equilibrium process of the decomposition of N2O4 to become NO2. The findings show that most of the preservice teachers’ conceptions about chemical equilibrium are at the level of partial understanding, with five misconceptions has been identified in this study: (1) the reaction in chemical equilibrium is the same as an irreversible reaction; (2) the concentration of reactant and products are the same at equilibrium state; (3) gas with a greater concentration at equilibrium state can be determined from the gas that was first inserted to the container; (4) the concentration ratio at equilibrium is equal with the ratio of the coefficient reaction, and (5) the reactant is the gas which fills the container first. Further analysis shows that there are eight concepts in chemical equilibrium with troublesome knowledge characteristics, namely (1) the concentration of reactants and products in a state of equilibrium; (2) changes in the concentration of reactants and products to a state of equilibrium when starting from any side; (3) reactions that occur in an equilibrium state, (4) chemical equations for equilibrium reaction; (5) the rate of reactions in equilibrium state; (6) the change of reaction rate to reach an equilibrium state; (7) the relationship between Q and K; and (8) the calculation of reactants and products concentration at an equilibrium state. In addition, chemical equilibrium has two threshold concepts: the dynamic characteristic of equilibrium reaction and equilibrium constant. These findings show that the predict-observe-explain instrument has the potential to disclose PSTs’ mental model since it requires the participants to explain the prediction and its corresponding observation result. Besides, this instrument also guides the participants in explaining the macroscopic phenomena, which generates information about their understanding at the submicroscopic and symbolic levels. should be recognised as encompassed by and a form or part of “for all.”

Effects of Technology-Integrated Formative Assessment on Students' Retention of Conceptual and Procedural Knowledge in Chemical Equilibrium Concepts

The main objective of this study was to evaluate the impact of technology-integrated formative assessment strategies on students’ retention of conceptual and procedural knowledge in chemical equilibrium concepts. A quasi-experimental control group interrupted time series design was employed. Data was collected from 132 students, who were selected using a random sampling technique from three governmental secondary schools. Two experimental groups and one comparison group were involved in the study. A series of chemical equilibrium conceptual and procedural tests were used to collect data. A mixed model ANOVA was used to analyze the test scores. The three groups had varied mean gain scores in conceptual and procedural exam scores as repeated measurements of time, as can be observed from the descriptive statistics. The two-way mixed ANOVA findings revealed that there was a significant main effect between groups on conceptual test scores. Furthermore, on conceptual knowledge test scores, there was a significant interaction between time point and intervention groups. On procedural exam scores, there was also a significant difference between the three time points and intervention groups. A significant interaction between time points and groups was also observed. Given that there was a significant difference between the pre-test, post-test, and follow-up post-test scores in the experimental group, with the difference favoring the post-test scores, it can be concluded that the technology-integrated formative assessment strategy is successful in raising secondary school students' conceptual and procedural test scores.

Enhancing Students’ Academic Interest Using Two Instructional Models in Chemical Equilibrium In Benue State, Nigeria

The study investigated the effects of 4As and 5Es instructional models on senior secondary II students’ interest in chemical equilibrium in Benue State. Two research questions guided the study, while two hypotheses were formulated and tested. The study adopted quasi-experimental, non-randomized control group pretest and posttest design. The population of the study comprised 8,864 SSII Chemistry students. Samples of 194 SSII students from six Government grant aided secondary schools in Benue Education Zone C were selected using multistage sampling techniques. Instrument for the study was Chemical Equilibrium Students’ Interest Rating Questionnaire (CESIRQ) with reliability coefficient of 0.70. Analysis using mean, standard deviation and mean gain scores were used to answer the research questions while Analysis of Covariance (ANCOVA) was used to test the hypotheses at 0.05 level of significance. The findings of the study revealed that there was a significant difference in the mean interest rating of students taught chemical equilibrium using 4As, 5Es instructional models and modified lecture method [ F 2,193 = 89.995; P = 0.000< 0.05]. There is no significant difference in the mean interest rating of male and female students taught chemical equilibrium using 4As instructional model [ F 1,62 = 2.339; P = 0131< 0.05]. There is no significant difference in the mean interest rating of male and female students taught chemical equilibrium using 4As instructional model [ F 1,63 = 3.173; P = 0.080< 0.05].There is no significant interaction effects between instructional models and gender on students interest [F2, 193 = .262; P = .769 > 0.05] when taught chemical equilibrium concepts. The study concludes that 5Es and 4As instructional models have greater effects on students’ academic interest in Chemical Equilibrium than Modified Lecture Method on SS II students in Benue Education Zone C. Based on the findings, it was recommended among others that Ministry of Education through Chemistry teachers should emphases the use of 5Es and 4As instructional models in teaching to enhance the academic interest of students in Chemistry.

Pre-Service Science Teachers' Images and Misconceptions About Chemical Equilibrium

Determining pre-service teachers’ images and removing their misconceptions with scientifically true ones are very important so that these teachers could bring up students without misconceptions. In the current study, it was aimed to highlight pre-service science teachers’ images and misconceptions about chemical equilibrium together and in detail. For this purpose, qualitative research was employed. The research was conducted on 20 pre-service science teachers educating at a university in middle Anatolia region. Worksheets were utilized as data collecting tools. In worksheets there was a question about making pre-service teachers draw four different scenarios for a given chemical equilibrium reaction at different times; at the beginning of the reaction, before the chemical equilibrium, at the chemical equilibrium, after the chemical equilibrium, but at a common temperature and then making them explain their drawings. Data was analysed through content analysis. The results lightened that pre-service science teachers’ chemical equilibrium concept images were inadequate since their mental images about the concept were scientifically wrong. On the other hand, the pre-service science teachers had different misconceptions. The most common misconceptions of pre-service science teachers were as “Diatomic molecules form atoms and then these atoms form new chemicals (f:10).”, “There are only products or activated complexes in the tank during and/or afterwards of the chemical equilibrium (f:15).”, “Atoms could disappear and/or reappear (f:14).”, and “Products are formed at the chemical equilibrium (f:17).”

Potency to overcome misconceptions by using multiple representations on the concept of chemical equilibrium

This study aims to analyze the potential of some representations in overcoming misconceptions about the concept of chemical equilibrium. In this study using research and information gathering, the first stage conducted is related to articles relating to misconceptions that exist on the concept of chemical equilibrium, obtained in chemical equilibrium, then carried out an analysis of 14 articles, which cite misconceptions on chemical equilibrium, from this article a misconception that is often found is that the rate of the forward reaction is not the same as the rate of back reaction. From this collection of articles, 5 general chemistry textbooks were then reviewed, which presented the concept of chemical equilibrium for multiple representations, to overcome the misconceptions associated with the articles that were analyzed previously. The results obtained from general chemistry textbooks with several representations are able to overcome misconceptions derived from article analysis and can help students visualize the observed concept changes.

Molecular Simulation Assisted Discovery Learning to Improve Higher Order Thinking Skills in Chemical Equilibrium Concepts

Molecular Simulation Assisted Discovery Learning to Improve Higher Order Thinking Skills in Chemical Equilibrium Concepts

Analysis of misconceptions in chemical equilibrium among senior secondary school students in Ilesa Metropolis in Osun State, Niger

Physical chemistry has been an aspect of chemistry which students find difficult at the secondary and tertiary levels of education. In the past, the effort of researchers has been focused on the research that will identify various causal factors which can be attributed to the performance of the learners in this aspect of chemistry. Also, very few experimental studies, has been carried out to improve students’ performance. In order to find the right bases for all research that will improve students’ achievement, there is a need to profile the misconceptions in the aspect of physical chemistry which is chemical equilibrium. The purpose of this study is to determine students’ misconceptions regarding the concepts of chemical equilibrium. To diagnose students' misconceptions in this area, a two-tier multiple-choice question on chemical equilibrium test was administered to 300 high school students in Ilesa Metropolis of Osun- state, Nigeria. Descriptive analysis was used in analyzing the data, students’ responses in a Chemical Equilibrium Misconception Test (CEMT) were categorized. The results revealed widespread misconceptions among students in the areas related to (1) equilibrium constant (2) heterogeneous Equilibrium (3) Approach to chemical equilibrium, (4) Application of Le-Chatelier Principle and (5) adding a catalyst.

Analysis of misconceptions in chemical equilibrium among senior secondary school students in Ilesa Metropolis in Osun State, Niger

Physical chemistry has been an aspect of chemistry which students find difficult at the secondary and tertiary levels of education. In the past, the effort of researchers has been focused on the research that will identify various causal factors which can be attributed to the performance of the learners in this aspect of chemistry. Also, very few experimental studies, has been carried out to improve students’ performance. In order to find the right bases for all research that will improve students’ achievement, there is a need to profile the misconceptions in the aspect of physical chemistry which is chemical equilibrium. The purpose of this study is to determine students’ misconceptions regarding the concepts of chemical equilibrium. To diagnose students' misconceptions in this area, a two-tier multiple-choice question on chemical equilibrium test was administered to 300 high school students in Ilesa Metropolis of Osun- state, Nigeria. Descriptive analysis was used in analyzing the data, students’ responses in a Chemical Equilibrium Misconception Test (CEMT) were categorized. The results revealed widespread misconceptions among students in the areas related to (1) equilibrium constant (2) heterogeneous Equilibrium (3) Approach to chemical equilibrium, (4) Application of Le-Chatelier Principle and (5) adding a catalyst.

Differential Gibbs and Helmholtz reactor models for ideal and non-ideal gases: Applications to the SMR and methanol processes

This work unifies the concepts of chemical reaction equilibrium and transport phenomena applied to fluid flow of reactive gas mixtures over solid catalysts. Different from accurate modeling of reactions, which in the outset relies on reaction kinetics, the current approach is rather based on calculation of thermodynamic equilibrium thus requiring far fewer model parameters. Here, minimization of Gibbs or Helmholtz energy is solved in an inner loop inside the transport equations for heat, mass, and momentum. In addition to ideal gas, the non-ideal virial expansion and Soave-Redlich-Kwong equations of state have been used to model the gas mixture. The use of thermodynamic energy potentials ensures that all the derived properties like e.g. heat capacity, density, reaction enthalpy and equilibrium composition are derived from one fundamental relation only. The complete model framework is exemplified using the steam methane reforming and methanol synthesis processes. Herein, different combinations of energy potential (Gibbs versus Helmholtz) and numerical solution method for solving the transport equations (finite volume versus orthogonal collocation) have been studied with focus on model complexity, and efficiency and robustness of the solver. Orthogonal collocation is shown to be more efficient than finite volume, and Gibbs energy is shown to be more efficient than Helmholtz energy. The last statement depends on both flow conditions and implementation details and is therefore not a general result. The proposed model framework is a novel tool for calculating industrial reactors which operate quite close to equilibrium and might as such be useful for process design studies, albeit not for accurate simulation.

Effectiveness of Dual Situated Learning Model in Improving High School Students’ Conceptions of Chemistry Equilibrium and Preventing Their misconceptions

This study aims to compare the impact of the Dual Situated Learning Model (DSLM) and conventional instructions in improving High School Students’ understanding of chemical equilibrium concepts and the prevention of possible misconceptions. The study utilized a quasi-pretest-posttest control and experimental group design with two classes of XI SMAN as the research sample (N=60 students). Pre-posttests consisting of 12 two-tier questions (r = 0.691) used to assess the learners’ understanding of the chemical equilibrium. The results showed a significant difference in favor of the learners who taught using the DSLM model in comparison to those in the conventional approaches (Fount = 4.149; p = 0.003). Students in the experimental class had a better understanding and fewer misconceptions about the concept of chemical equilibrium. Implications for science educators suggest that learning that is designed by considering students' misconceptions or preconceptions and anticipating them through appropriate learning steps will have a positive influence on the learners’ conceptual understanding.

Exploring Chemical Equilibrium for Alcohol-Based Cobalt Complexation through Visualization of Color Change and UV–vis Spectroscopy

Introducing chemical equilibrium concepts in undergraduate general chemistry promotes improved understanding of chemical reactions. We have developed an engaging laboratory experiment exploring the...

Distinct roles of salt cations and anions upon the salting-out of electro-positive albumin

Precipitation experiments of electro-positive albumin by the action of a wide number of salts, and at different concentrations, were performed at a constant temperature (25 °C). The pH range studied covered extreme acidic conditions up to hydronium concentrations where the dissociation of the protein carboxyl groups becomes noticeable. The time required for the clouding phenomenon to occur and the quantity of salted-out protein were also ascertained. The results here reported show that the salt anion is the main salting-out species for the positively charged protein, where their efficacy in salting-out albumin from aqueous solution increases in the order: F− < Cl− < Br− < NO3− < I− < SCN− ~ ClO4− < SO42−. Although at extreme pH conditions the salt cation has no significant influence on the protein salting-out, experiments performed at higher pH values, where the carboxyl groups starts to dissociate, revealed a non-monotonic effect of the salt upon protein precipitation. We interpret this observation as a result of the presence of different protein forms, with which the salt cation participates in chemical equilibrium. Overall, the proteins salting-out phenomenon induced by salt can be rationalized by a general mechanism driven by electrostatic interactions and chemical equilibrium concepts.