Nonelectrolyte Solutions Research Articles

THE EFFECT OF THE IMPLEMENTATION OF PROJECT BASED LEARNING LEARNING MODEL ON ELECTROLYTE AND NON ELECTROLYTE SOLUTION MATERIALS ON THE LEARNING OUTCOMES OF CLASS X MIPA SMA)

The learning outcomes of class X students at SMA Negeri 1 X Koto Diatas in learning chemistry are still low. One of the methods used to improve student learning outcomes is to apply the Project Based learning model. This study aims to determine the effect of implementing the Project Based Learning model on electrolyte and non-electrolyte solution material on the learning outcomes of students in class X MIPA SMA. This quasi-experimental study used a non-equivalent control group design. The population of this study were all students of class X MIPA even semester of SMAN 1 X Koto Diatas. The sample was taken using a saturated sampling technique, so that class X MIPA 1 was chosen as the experimental class and class X MIPA 2 was the control class. Research data comes from one domain, namely cognitive. The assessment instrument is in the form of a learning outcome test. The data obtained were analyzed using the N-Gain Test, Normality Test, Homogeneity Test and t Test.
 The results of the study in the cognitive domain obtained that the experimental class average was higher than the control class with the t statistical test, obtained tcount = 1.73 and ttable = 0.25. Thus, it can be concluded that the learning outcomes of students in class X MIPA SMA Negeri 1 X Koto Diatas are affected by the application of the Project Based Learning model on electrolyte and non-electrolyte solution materials.

Pengaruh Model Problem Based Learning (PBL) terhadap Hasil Belajar Peserta Didik Kelas X MIPA SMA Negeri 6 Makassar (Studi pada Materi Pokok Larutan Elektrolit dan Nonelektrolit)

This research is quasi-experimental research that aims to know the effect of the problem based learning model (PBL) towards the learning outcomes of the students of class X MIPA SMA Negeri 6 Makassar on the subject matter of electrolyte and nonelectrolyte solution, with posttest only group design. The population is the student of class X MIPA SMA Negeri 6 Makassar consisting of six classes. Sample was randomly selected and X MIPA4 as the experimental class and X MIPA5 class as the control. The experimental class was taught by using the PBL model while the control class was taught with conventional learning model. The learning outcomes data is taken by giving posttest. Learning outcomes data are processed in descriptive statistics and inferential statistics. Descriptive statistical analysis showed that experimental class has higher learning outcomes completeness than control class with 74.29% and 51.52%. The test results for inferential statistical analysis hypotheses using the Mann Whitney test with α = 0.05 obtained Zcount (5.90) > Ztable (1.64). Based on these α values, it shows that there is an effect of the PBL model on the learning outcomes of students of class X MIPA SMA Negeri 6 Makassar on the study of electrolyte and nonelectrolyte solution.

Pengembangan E-Modul Kimia Berbasis Proyek pada Materi Larutan Elektrolit dan Non Elektrolit

This study aims to (1) to determine the results of the analysis of chemistry teaching materials on electrolyte and non-electrolyte solution materials used in schools according to BSNP standards, (2) to develop e-modules for electrolyte and non-electrolyte solution materials according to the BSNP eligibility criteria and have been based on projects, and (3) To determine student learning outcomes after being given project-based e-modules. The population in this study were all students of class X MIA SMA Negeri 1 Deli Tua, totaling 6 classes. The sample in this study was class X MIA 5 who was taught with a project-based chemistry e-module. The instrument used is an e-module feasibility questionnaire according to the BSNP standard, a learning outcome test of 20 questions that have been tested valid. This study uses the method and media development (R&D) with the ADDIE model. The ADDIE model has several stages, namely Analysis, Design, Develop, Implementation, and Evaluation. Where the results of the feasibility analysis of the content feasibility aspect of the e-module are 3.82; language eligibility is 3.83; The feasibility of presenting 3.81 and the feasibility of graphics 3.77 means that the teaching materials from the trial are very valid based on the BSNP. The average student learning outcomes who are taught project-based e-modules in one class are 78.8095. The results of the right-hand t-test with t count = 4.147> t table = 2.086. Thus the criteria for testing the hypothesis t count > t table are met. This means that Ho is rejected, Ha is accepted, so it can be concludedthat the project based chemistry learning e-module developed is better in improving students' chemistry learning outcomes in electrolyte and non-electrolyte solution materials.

Pengembangan LKPD Elektronik melalui Model Discovery Learning untuk Meningkatkan Kemampuan Berpikir Kritis Peserta Didik (Studi pada Materi Pokok Larutan Elektrolit dan Non Elektrolit)

This study is a development research that aims to develop electronic LKPD through adiscovery learning model assisted by the 3D PageFlip Professional application on electrolyte and non-electrolyte solution materials that are valid, practical, and effective to be used to improve students' critical thinking abilities. The research procedure employed the ADDIE development model, which consisted of the analysis stage, design stage, development stage, implementation stage, and evaluation stage. The electronic LKPD was validated by two experts. Then it was tested to grade X Aljabar UPT SMAN 11 Pangkep through Google Meet. The results show that the developed electronic LKPD is valid with an average validity value of 3.42. The practicality test includes: (1) the implementation of LKPD learning through discovery learning model is at an average value of M = 1.96 in the value interval (1.5 ≤ M ≤ 2.0) meaning that the aspects and criteria observed are in fully implemented category, (2) the students gave a positive response with a total average percentage of 77.38%, which means the electronic LKPD is in practical category and (3) the teacher gave a positive response with an average total score of 86.18%, it is invery practical category. The electronic LKPD through the discovery learning developed also meets effective criteria with the test results of each indicator of students' critical thinking abilities is in the percentage of 60% - 80% in medium category.

DEVELOPMENT OF BULLETIN AS A LEARNING MEDIA ON ELECTROLYTE AND NON-ELECTROLYTE SOLUTION MATERIALS IN CLASS X MAS DARUL IHSAN ACEH BESAR

This study aims to develop, analyze the feasibility and describe the responses of students and teachers according to the newsletter learning media on electrolyte and non-electrolyte solution material. This type of this research is (Research and Development/ RD). The newsletter learning media developed in this study according to ADDIE model which has five stages: (1) analysis, (2) design,(3) Development (4) Implementation and (5) Evaluation. This research was conducted at the school of MAS Darul Ihsan Aceh Besar with 3 chemistry teachers and 31 students taken from class X. The appropriateness of the newsletter media was assessed by the research supervisor. The percentage of teacher and student responses to the newsletter media that was developed was 97.22% and 83.97% with the very good category. Based on the results of the study, it can be concluded that the developed newsletter media is very suitable for use in the learning process of electrolyte and non-electrolyte solution materials.

Development of Three-Tier Test Instrument Based on Scientific Literacy in Electrolyte and Non-Electrolyte Solution Topics

<p>The scientific literacy is very important for students as a provision to face the challenges of the 21st century. The scientific literacy of students in Indonesia is low. One of the factors which causes students' scientific literacy tend to be low is that students have not been trained in answering questions with typical as on PISA. Efforts to train students to be familiar with scientific literacy include developing test instruments based on scientific literacy. This study aims to examine the feasibility and characteristics of the scientific literacy test instrument for electrolyte and non-electrolyte solutions; besides, examine the profile of students' scientific literacy abilities. The type of this study was Research & Development with a 4D model which includes the stages: define, design, develop, and disseminate. The research subjects were students of class X Science SMAN 1 Sragen. The results of the study show that (1) the scientific literacy test instrument which is developed is feasible and valid to be used with a validity of 34 of 35 questions which is declared valid and reliability of 0.86; (2) the characteristics of the test instrument is that using three aspects of scientific literacy in one question at once and can be used to determine the student's scientific literacy profile well; (3) the profile of students' scientific literacy skills is in a fairly good criterion with a percentage of 59%. The profile of students' scientific literacy abilities from the aspect of scientific competence is obtained as much as 57.21%; 59.72%; and 60.46%.</p>

Management of Energy Conversion Processes in Membrane Systems

The internal energy (U-energy) conversion to free energy (F-energy) and energy dissipation (S-energy) is a basic process that enables the continuity of life on Earth. Here, we present a novel method of evaluating F-energy in a membrane system containing ternary solutions of non-electrolytes based on the Kr version of the Kedem–Katchalsky–Peusner (K–K–P) formalism for concentration polarization conditions. The use of this formalism allows the determination of F-energy based on the production of S-energy and coefficient of the energy conversion efficiency. The K–K–P formalism requires the calculation of the Peusner coefficients Kijr and Kdetr (i, j ∈ {1, 2, 3}, r = A, B), which are necessary to calculate S-energy, the degree of coupling and coefficients of energy conversion efficiency. In turn, the equations for S-energy and coefficients of energy conversion efficiency are used in the F-energy calculations. The Kr form of the Kedem–Katchalsky–Peusner model equations, containing the Peusner coefficients Kijr and Kdetr, enables the analysis of energy conversion in membrane systems and is a useful tool for studying the transport properties of membranes. We showed that osmotic pressure dependences of indicated Peusner coefficients, energy conversion efficiency coefficient, entropy and energy production are nonlinear. These nonlinearities were caused by pseudophase transitions from non-convective to convective states or vice versa. The method presented in the paper can be used to assess F-energy resources. The results can be adapted to various membrane systems used in chemical engineering, environmental engineering or medical applications. It can be used in designing new technologies as a part of process management.

Pengembangan Aplikasi Media Pembelajaran Berbasis Android pada Materi Larutan Elektrolit dan Nonelektrolit

The purpose of this study is to develop the Melonit applications an Android-based learning media on electrolyte and non-electrolyte solutions, and disclose the level of validity of the developed product regarding the validity of the content, construct and media. This type of research is Educational Design Research applying the Plomp development model, which consists of three stages, namely preliminary research, prototyping stage and assessment stage. The research instruments used were in the form of content validity questionnaires, constructs and media and one to one evaluation interview sheets. The results of processing the content and construct validity data were obtained at 0,89 with a valid category. Meanwhile, the validity of the media was obtained at 0,94 with a valid category. Research on android-based learning media applications that have been developed is valid, so that further research can be carried out on the practicality and effectiveness of the applications that have been developed.

Volumetric and acoustic studies of aqueous l-arginine·HCl and l-proline in electrolytic and non-electrolytic solutions at various temperatures

Densities and speed of sound of l-arginine hydrochloride and l-proline within the concentration range (0.03–0.2) mol.kg−1 in water and in aqueous NaCl and Urea are determined between temperatures 288.15 K and 318.15 K and at one atmospheric pressure. Densities and speeds of sound have been used to calculate apparent molar volume of solute (Vφ), isentropic compressibility of solution (κS), apparent molar isentropic compressibility (KS,φ) of solute, limiting apparent molar volume (Vφ0), limiting apparent molar volume of transfer (ΔtrVφ0), limiting apparent molar expansibility (Eφ0), limiting apparent molar isentropic compressibility (KS,φ0) and limiting apparent molar isentropic compressibility of transfer (ΔtrKS,φ0). These results are then interpreted in terms of intermolecular interactions. The concentration dependencies of the calculated quantities, their limiting values and temperature characteristics are discussed in terms of solute - solvent and solute - solute interactions at experimental conditions.

Validity of E-Module Based on Problem Based Learning Integrated Demonstration Video and Science Literacy

The time of mechanical insurgency 4.0 is a period of digitalization in different areas particularly within the field of instruction so it takes educating fabric that can increment understudy movement in learning. This type of research is educational design research using the Plomp model. This model consists of three steps: (1) preliminary research, (2) prototyping, and (3) assessment phase. The research instrument used observation sheets, questionnaires, and learning outcomes tests. The e-module was validated by six construct experts and three content experts. This inquires about points to create an e-module of electrolyte and nonelectrolyte solutions based on problem-based learning integrated demonstration videos and scientific literacy and decide the level of validity of created e-module. This sort of investigation is instructive plan inquire about utilizing the plomp model. The appraisal rebellious utilized were perceptions sheets, surveys, and learning results tests. The e-module was approved by five validators, to be specific the build validator and the substance validator. The comes about of the validity of the e-module develop gotten Aiken’s V normal esteem of 0.85 with a substantial category, and the validity of the e-module substance gotten a normal CVI esteem of 1 with a substantial category. Based on the results of the study, it was concluded that the problem-based learning e-module of electrolyte and nonelectrolyte solutions integrated with demonstration videos and scientific literacy developed was valid.

DEVELOPMENT OF CRITICAL THINKING ABILITY ORIENTED TEXTBOOK ON ELECTROLYTE AND NON-ELECTROLYTE SOLUTION MATERIALS

This study aims to produce electrolyte and non-electrolyte textbooks oriented to critical thinking skills through a problem based learning model that will measure the level of feasibility, response to students and their level of effectiveness. This research refers to the research and development model recommended by Borg & Gal. Data on feasibility rate and response of students are obtained in the form of quantitative data which is converted by the percentage scale of product quality according to the Likert scale. The effectiveness of the book is measured using the average value of N-Gain. The conclusions of this study are textbooks for electrolyte and non-electrolyte solutions with feasibility rate of 95.11% criteria "very high", the response rate of students in the early field test 86.92% and the main field test 87.11% in "very high" category, level book effectiveness with the N-Gain average of 0.62 in "medium" category.

The Effects of E-Module with Guided Discovery Model on Students Learning Outcomes in Electrolyte and Nonelectrolyte Solution

This study aims to analyze the effect of using an e-module electrolyte and nonelectrolyte solution based on guided discovery learning on student learning outcomes. This quasi-experimental study used a randomized control-group pretest-posttest design. The population consisted of grade X student of SMA Negeri 1 Padangpanjang in the 2021/2022 school year and samples were taken using simple random sampling technique. The research instrument was a multiple-choice test and the data were analyzed by n-gain test and hypothesis testing by t-test. Based on data analysis, n-gain experimental class is higher than the control class with a medium category and the hyphothesis is the use of an e-module electrolyte and nonelectrolyte solution based on guided discovery learning is effect in improving student learning outcomes at SMA Negeri 1 Padangpanjang. Keywords: e-module, guided discovery model, learning outcomes. Abstrak: Penelitian ini bertujuan menganalisis pengaruh penggunaan e-modul larutan elektrolit dan nonelektrolit berbasis guided discovery learning terhadap hasil belajar siswa. Penelitian eksperimen semu ini menggunakan desain penelitian randomized control-group pretest-posttest design. Populasi terdiri dari siswa kelas X SMA Negeri 1 Padangpanjang tahun ajaran 2021/2022 dan pemilihan sampel menggunakan teknik simple random sampling. Instrumen penelitian berupa tes dalam bentuk pilihan ganda serta data dianalisis menggunakan uji n-gain dan uji hipotesis menggunakan uji t. Berdasarkan analisa data, diperoleh n-gain kelas eksperimen lebih tinggi dibandingkan kelas kontrol dengan kategori sedang dan uji hipotesis yag diperoleh sig(2-tailed) < 0,05. Dapat disimpulkan bahwa hipotesis diterima yaitu penggunaan e-modul larutan elektrolit dan nonelektrolit berbasis guided discovery learning berpengaruh terhadap peningkatan hasil belajar siswa di SMA Negeri 1 Padangpanjang. Kata kunci: modul elektronik, model inkuiri terbimbing, hasil belajar. DOI: http://dx.doi.org/10.23960/jpmipa/v23i2.pp496-504

STEM-Project Based Learning with Learning Guides on Electrolyte and Non-Electrolyte Solutions to Improve Higher Order Thinking Skills of High School Students

The purpose of this study was to examine the effect of STEM-Project Based Learning with learning guides on the Concept of Electrolyte and Non-Electrolyte Solutions on the ability to think of high order students of class X SMA Negeri 3 Palangka Raya. The study used a quasi-experimental method with a nonequivalent control group design. The research sample was 35 students of Class X MIPA 1 as a control class and 36 students of Class X MIPA 5 as an experimental class. STEM-Project Based Learning with learning guides is done using the help of study guides. Data collection of higher order thinking skills is carried out using tests (pretest and posttest) specifically designed to measure higher order thinking skills. The data obtained were statistically analyzed using the t test to compare the increased thinking ability of the kontrol class and the experimental class. The statistical test results obtained that t count is greater than t table , that is t count = 21.74 greater than t table = 2.032, which shows that the average increase in high order thinking skills of experimental class students is better than the average increase in the ability of thinking of control class students. Thus, it can be concluded that STEM-Project Based Learning with learning guides on the Concept of Electrolyte and Non-Electrolyte Solutions can improve higher order thinking skills. Keywords: electrolyte and non-electrolyte solutions, STEM-Project Based Learning, high order thinking. Abstrak: Tujuan penelitian adalah menelaah pengaruh pembelajaran STEM-Project Based Learning with learning guides pada Konsep Larutan Elektrolit dan Non Elektrolit terhadap kemampuan berpikir tingkat tinggi siswa kelas X SMA Negeri 3 Palangka Raya. Penelitian menggunakan model kuasi eksperimen dengan desain nonequivalent kontrol group. Sampel penelitian adalah 35 siswa Kelas X MIPA 1 sebagai kelas kontrol dan 36 siswa kelas X MIPA 5 sebagai kelas eskperimen. Pembelajaran STEM -Project Based Learning dilakukan dengan menggunakan bantuan panduan belajar. Pengumpulan data kemampuan berpikir tingkat tinggi dilakukan menggunakan tes (pretes dan postes) yang dirancang khusus untuk mengukur kemampuan berpikir tingkat tinggi. Data yang diperoleh dianalisis secara statistik menggunakan uji t untuk membandingkan peningkatan kemampuan berpikir kelas kontrol dan kelas ekperimen. Hasil uji statistik diperoleh thitung lebih besar dari t tabel yaitu t hitung = 21,74 lebih besar dari t tabel = 2,032 yang menunjukkan bahwa rata-rata peningkatan kemampuan berpikir tingkat tinggi siswa kelas eksperimen lebih baik dari rata-rata peningkatan kemampun berpikir siswa kelas kontrol. Dengan demikian dapat disimpulkan bahwa pembelajaran STEM -Project Based Learning pada Konsep Larutan Elektrolit dan Non Elektrolit dapat meningkatkan kemampuan berpikir tingkat tinggi. Kata kunci: Larutan elektrolit dan non -elektrolit, STEM -Project Based Learning, berpikir tingkat tinggi. DOI: http://dx.doi.org/10.23960/jpmipa/v23i3.pp1214-1223

Pengembangan Lembar Kerja Peserta Didik Berbasis Keterampilan Proses Sains pada Materi Larutan Eleketrolit dan Nonelektrolit

This study aims to develop student worksheet based on science process skills and to determine the level of feasibility and teacher response to the developed student worksheet. The form of this research model is research and development (R&amp;D) with reference to the ADDIE development model modified into ADD, namely Analysis, Design and Development. The subjects of this study were student worksheet and the responses of 3 chemistry teachers at SMA Kubu Raya. The data collection instrument used was the assessment sheet. the feasibility of the material, language, and graphics as well as the teacher's response questionnaire. The results of data processing show that the developed student worksheet is very suitable for use in learning electrolyte and non-electrolyte solutions in terms of the feasibility of material, language, and graphics with a percentage of 98.2% with a very feasible category. Based on the calculation of the teacher response questionnaire to the science process skills based student worksheet, it shows that the teacher response is very good with a percentage of 93%. Thus, science process skills based student worksheet is very suitable to be used in the learning process.

The Development of E-Instrument to Test Students Mental Models on Electrolyte and Non-Electrolyte Solutions

The purpose of this study is to design an instrument that can be used to determine students mental models in electrolyte and non-electrolyte solutions. Students do not have complete understanding of electrolyte and non-electrolyte solutions topic. It takes an instrument that can measure students mental models, which can then be used to find out why students do not have complete understanding of electrolyte and non-electrolyte solutions topic. The research method used is the RnD method with a 4D model. The research steps consist of define, design and development. The results of this study are e-instruments that can be used to measure students mental models on electrolyte and non-electrolyte solutions. The average results of the instrument feasibility from material experts and teacher experts were 89 percent and 83 percent, namely worthy with very good predicate and good predicate. These results indicate that the designed instrument is feasible to use. The instrument designed only reached the validation stage due to lack of time in research.

Solutions, in Particular Dilute Solutions of Nonelectrolytes: A Review

The liquid state is one of the three principal states of matter and arguably the most important one; and liquid mixtures represent a large research field of profound theoretical and practical interest. This topic is of importance in many areas of the applied sciences, such as in chemical engineering, geochemistry, the environmental sciences, biophysics and biomedical technology. First, I will concisely present a review of important concepts from classical thermodynamics of nonelectrolyte solutions; this will be followed by a survey of (semi-)empirical approaches to representing the composition and temperature dependence of selected thermodynamic mixture properties, and finally the focus will be on dilute binary nonelectrolyte solutions where one component, a supercritical solute, is present in much smaller quantity than the other component, called the solvent. Partial molar properties in the limit of infinite dilution (indicated by a superscript ∞) are of particular interest. For instance, activity coefficients (Lewis–Randall (LR) convention) are customarily used to characterize mixing behavior, and infinite-dilution values gamma_{i}^{{{text{LR,}}infty }}provide a convenient route for obtaining binary parameters for several popular solution models. When discussing solute (j)—solvent (i) interactions in solutions where the solute is supercritical, the Henry fugacity h_{j,i} left( {T,P} right), also known as Henry’s law (HL) constant, is a measurable thermodynamic key quantity. Its temperature dependence yields information on the partial molar enthalpy change on solution Delta H_{j}^{infty } left( {T,P} right), while its pressure dependence yields information on the partial molar volume V_{j}^{{{text{L,}}infty }} left( {T,P} right) of solute j in the liquid phase (superscript L). I will clarify issues frequently overlooked, touch upon solubility data reduction and correlation, report a few recent high-precision experimental results on dilute aqueous solutions of supercritical nonelectrolytes, and show the equivalency of results for caloric quantities (e.g. Delta H_{j}^{infty }) obtained via van ’t Hoff analysis of high-precision solubility data with directly measured calorimetric data.

Pengembangan Modul Elektronik Terintegrasi Problem Based Learning (PBL) Pada Materi Larutan Elektrolit dan Non Elektrolit

This study uses Research and Development (R&amp;D) research methods, namely developing problem-based chemistry teaching materials on electrolyte and non-electrolyte solutions. Aims to determine the feasibility standard of chemistry teaching materials in accordance with the eligibility criteria for content, language, presentation, and graphics and see student responses to the developed teaching materials. The stages that were passed in the research started from syllabus analysis with 13 revised curriculum, book analysis, design and development of teaching materials, validation of expert teaching materials, and student responses to teaching materials resulting from the development so that problem-based teaching materials were composed of electrolyte and non-electrolyte solution materials that appropriate and in accordance with BSNP criteria.Based on the validation results of teaching materials using a modified BSNP questionnaire, in this questionnaire the aspects assessed include aspects of content feasibility, language feasibility aspects, presentation feasibility aspects, and graphic feasibility aspects. Based on the results of standardization of problem-based modules on electrolyte and nonelectrolyte solution materials by Unimed chemistry lecturers and Chemistry Teachers, overall the average content feasibility obtained a result of 3.48 with valid criteria and no need for revision, for language eligibility the results obtained 3.59 with criteria valid and does not need revision, for the feasibility of the presentation, the result is 3.73 with valid criteria and does not need revision, and for the feasibility of the graphic, the result is 3.60 with valid criteria and does not need revision. This means that the average result is 3.60. Problem-based Modules on electrolyte and nonelectrolyte solutions are valid and do not need to be revised. After the teaching materials are valid, it is recommended to conduct an assessment of students with the aim of seeing the percentage of students' satisfaction level with problem-based teaching materials developed based on aspects of appearance, material aspects, and benefits aspects. The results obtained from 30 respondents, namely the display aspect of 92.67%, the material aspect of 90.5%, and the benefit aspect of 88.17%. So that the average percentage level of student satisfaction with problem-based teaching materials that have been developed is 90.44%. This proves that students like problem-based teaching materials so that teaching materials can be used in chemistry learning as well as reading references for students.

Analysis of Students Misconception using Two-Tier Multiple Choice Diagnostic Test on Electrolyte and Nonelectrolyte Topic in SMAN 2 Padang

This research aims to (1) knowing whether there are misconceptions of 10 th grade students at SMAN 2 Padang on the topic electrolyte and nonelectrolyte solutions and (2) the percentage of 10 th grade students at SMAN 2 Padang who have misconceptions about the topic electrolyte and nonelectrolyte solutions. This research uses a two-tier multiple choice diagnostic test instrument consisting of 14 item questions. The method used in this research is a quantitative descriptive approach. The sampling technique was taken using a simple random sampling technique. Data collection techniques were carried out through tests given to students of class X MIPA 6 which were attended by 40 people. In this research, the population was all of 10 th grade students at SMAN 2 Padang, while the sample was students of class X MIPA 6. The results of data processing in this research indicate that in general students of class X MIPA 6 have misconceptions with an average percentage of misconceptions of 36.94%. Students experience misconceptions on the sub-concept of the properties of the electrolyte solution by 22.5%, the sub-concept of chemical bonds and electrolyte properties of 43.75%, and the sub-concept of the electrical conductivity of the solution has the highest percentage of misconceptions, which is 44.58%.

Peningkatan Aktivitas dan Hasil Belajar Siswa dalam Pembelajaran Kimia Menggunakan Model Pembelajaran Discovery Learning di SMA Negeri 1 Praya Barat

This study aims to increase the activeness and learning outcomes of students' chemistry by applying the Discovery Learning learning model to electrolyte and non-electrolyte solutions at SMA Negeri 1 Praya Barat. This research is a classroom action research which is conducted in two cycles. The research subjects were all students of class X-MIPA-1 for the academic year 2019/2020, totaling 31 students. In this study, student learning activities were obtained through observation while learning outcomes were obtained through formative tests. The results of this study indicate; 1) Students' chemistry learning activities increase by applying the Discovery Learning learning model to the electrolyte and non-electrolyte solution material according to the two observations in Cycle I of writing and reading activities 50%, doing worksheets 20%, asking friends 10%, asking teachers 5%, and which are not relevant to teaching and learning activities 5% while according to the observations of Cycle II writing and reading activities are 21%, doing LKS 50%, asking friends 13%, asking teachers 16%, and those not relevant to teaching and learning activities 1%; 2) Students' chemistry learning outcomes increase by applying the Discovery Learning learning model to the electrolyte and non-electrolyte solution material in Formative I, showing 18 students completed individually, while the class was incomplete while in Cycle II, 28 students completed individually and the class completed with the average of cycle I and cycle II were 69 and 88 and the percentage of classical completeness was 58% in cycle I and 90% in cycle II.

Water Activity Prediction in Sugar and Polyol Systems Using Theoretical Molecular Descriptors.

Water activity is a key factor in the development of pharmaceutical, cosmetic, and food products. In aqueous solutions of nonelectrolytes, the Norrish model provides a simple and effective way to evaluate this quantity. However, it contains a parameter, known as the Norrish constant, that must be estimated from experimental data. In this study, a new strategy is proposed for the prediction of water activity in the absence of experimental information, based on the use of theoretical molecular descriptors for characterizing the effects of a solute. This approach was applied to the evaluation of water activity in the presence of sugars (glucose, fructose, xylose, sucrose) and polyols (sorbitol, xylitol, glycerol, erythritol). The use of two descriptors related to the constitutional and connectivity properties of the solutes was first investigated. Subsequently, a new theoretical descriptor, named the global information index (G), was developed. By using this index, the water activity curves in the binary systems were reconstructed. The positive results obtained support the proposed strategy, as well as the possibility of including, in a single information index, the main molecular features of a solute that determine its effects on water activity.