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 $$\gamma_{i}^{{{\text{LR,}}\infty }}$$ γ i LR, ∞ 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 $$h_{j,i} \left( {T,P} \right)$$ h j , i T , P , 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 $$\Delta H_{j}^{\infty } \left( {T,P} \right)$$ Δ H j ∞ T , P , while its pressure dependence yields information on the partial molar volume $$V_{j}^{{{\text{L,}}\infty }} \left( {T,P} \right)$$ V j L, ∞ T , P 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. $$\Delta H_{j}^{\infty }$$ Δ H j ∞ ) obtained via van ’t Hoff analysis of high-precision solubility data with directly measured calorimetric data.

Pengembangan Media Pembelajaran PowerPoint Interaktif Berbasis Inkuiri Terbimbing pada Materi Larutan Elektrolit dan Nonelektrolit Kelas X SMA/MA

Electrolyte and nonelectrolyte solutions are one of the materials in SMA/MA class X chemistry. The materials of electrolyte and nonelectrolyte solutions can be understood well through their macroscopic, submicroscopic, and symbolic representations. This study aims to develop interactive PowerPoint learning media based on guided inquiry on electrolyte and nonelectrolyte solution material for class X SMA/MA which is in accordance with the characteristics of the material and the demands of the 2013 curriculum. (define, design, develop, and disseminate). This research is limited to the develop stage. Testing the validity and practicality of interactive PowerPoint learning media based on guided inquiry on electrolyte and nonelectrolyte solution material using an instrument in the form of a questionnaire. The subjects of the validity test of this interactive PowerPoint learning media were three chemistry department lecturers and two MAN chemistry teachers. The practicality test subjects of this interactive PowerPoint learning media were two MAN 5 chemistry teachers and twenty MAN 5 Mandailing Natal students. The data obtained from the questionnaire were processed using the kappa moment to obtain the k value of each validity and practicality test item. The interactive learning media of electrolyte and nonelectrolyte solutions produced in this study had a validity k value of 0.86 and practicality by teachers and students obtaining k values of 0.895 and 0.89, with very high criteria of validity and practicality. Larutan elektrolit dan nonelektrolit merupakan salah satu materi dalam kimia SMA/MA kelas X. Materi larutan elektrolit dan nonelektrolit dapat dimengerti dengan baik melalui representasi makroskopik, submikroskopik, dan simboliknya. Penelitian ini bertujuan untuk mengembangkan media pembelajaran PowerPoint interaktif berbasis inkuiri terbimbing pada materi larutan elektrolit dan nonelektrolit kelas X SMA/MA yang sesuai dengan karakteristik materi dan tuntutan kurikulum 2013. Penelitian yang dilakukan termasuk jenis penelitian pengembangan (research and development) dengan model 4-D (define, design, develop, dan disseminate). Penelitian ini dibatasi sampai tahap develop. Pengujian validitas dan praktikalitas media pembelajaran PowerPoint interaktif berbasis inkuiri terbimbing pada materi larutan elektrolit dan nonelektrolit menggunakan instrumen berupa angket. Subjek uji validitas media pembelajara PowerPoint interaktif ini adalah tiga orang dosen jurusan kimia dan dua orang guru kimia MAN. Subjek uji praktikalitas media pembelajaran PowerPoint interaktif ini adalah dua orang guru kimia MAN 5 dan dua puluh orang siswa MAN 5 Mandailing Natal. Data yang dihasilakan dari angket diolah memakai momen kappa untuk memperoleh nilai k setiap item uji validitas dan praktikalitas. Media pembelajaran interaktif larutan elektrolit dan nonelektrolit yang dihasilkan pada penelitian ini memiliki nilai k kevalidan 0,86 dan kepraktisan oleh guru dan siswa memperoleh nilai k 0.895 dan 0.89, dengan kriteria kevalidan dan kepraktisan sangat tinggi.

PENGEMBANGAN PENUNTUN PRAKTIKUM LARUTAN ELEKTROLIT DAN NONELEKTROLIT DI SMA NEGERI 1 RASAU JAYA

A practical guide is an important role in conducting an effective practicum class. It helps students to take part in the activities in accordance with the learning goals. Therefore, this study aimed to develop a practical guide of electrolyte and nonelectrolyte solutions for students of SMA Negeri 1 Rasau Jaya. Using an R & D model of Borg and Gall, seven out of eleven stages of material design were employed. The stages used in this study were research and data collection, planning, draft development, initial product trial, initial product revision, main field trial, and revision of operational products. The data collection technique used were observation, questionnaire, and measurement. The instruments were observation and questionnaire sheet, and posttest question. The study revealed that the practically gathered from the teacher questionnaire was 91,0% and from the student’s response was 83,1%. The effectiveness of the practical guide was 91,8%. Hence, the practical guide of electrolyte and nonelectrolyte solutions for students of SMA Negeri 1 Rasau Jaya is effective and valid. Therefore, it can be concluded that a practical guide is highly recommended to be used in the practicum class.

Penerapan Strategi Pembelajaran TGT Dibandingkan dengan TSTS Dalam Meningkatkan Hasil Belajar Kimia Siswa

Penelitian ini bertujuan untuk mengetahui perbedaan peningkatan hasil belajar kimia siswa yang diajarkan dengan Strategi Pembelajaran Two Stay Two Stray dibandingkan Teams Games Tournament dengan media Power Point, pada pokok bahasan Larutan Elektrolit dan Nonelektrolit. Populasi dalam penelitian ini adalah seluruh kelas X MAN 2 Model Medan, yang berjumlah11 kelas dan setiap kelas terdiri dari 36 siswa. Sampel dalam penelitian ini sebanyak 2 kelas yang diambil secara acak. Instrumen yang digunakan dalam penelitian ini adalah tes hasil belajar dalam bentuk pilihan berganda dengan jumlah soal sebanyak 22 soal yang telah dinyatakan valid dan reliabel serta lembar observasi tanggung jawab. Hasil penelitian menunjukkan bahwa Tidak terdapat perbedaan yang signifikan Hasil belajar siswa yang diajarkan dengan strategi pembelajaran TSTS dengan media Power Point dibandingkan siswa yang diajar dengan kooperatif tipe TGT dengan media Power Point (sig. 0,480 > 0,05). This study aimed to determine the differences of the increase in student chemistry learning outcomes taught with the Two Stay Two Stray Learning Strategy compared to the Teams Games Tournament with PowerPoint media on Electrolyte and Nonelectrolyte Solutions subjects. The population in this study was all the first grade students in MAN 2 Medan with 11 classes and each class consisted of 36 students. The samples in this study were 2 classes taken randomly. The instrument used in this study was a test of learning outcomes in the form of multiple choices with 22 questions that have been declared valid and reliable as well as the observation sheet of responsibility. The results showed that there were no significant differences of student learning outcomes taught with TSTS learning strategies with PowerPoint media compared to students taugh with a cooperative TGT type with PowerPoint media (sig. 0.480> 0.05).