Needs Analysis: Development of Web-Based Learning Media on Chemical Bond Concepts

The study aims to explain the need for developing web-based learning media on chemical bonding concepts. This research is descriptive research with a survey method. The sample of this research is the teacher of chemistry subject who teaches chemical bonding concepts at Senior High School in Langsa city. Data collection techniques using questionnaires, interviews, and documentation. The data collected is data on needs on aspects of teacher readiness, student needs, and support. Data analysis uses descriptive qualitative and quantitative descriptive analysis techniques. The results showed that teachers of chemistry subjects at Senior High School in Langsa City had the readiness to use web-based learning media that would be developed. Based on the teacher's response, the development of web-based learning media on chemical bonding material is strongly needed by teachers and students. The support of facilities and human resources at Senior High School in Langsa City on web-based learning media apply is adequate. These results concluded that the development of web-based learning media on chemical bonding material is strongly needed in chemistry lessons at senior high school in Langsa city.

Bond Strength Analysis of Repaired Concrete based on Polymerization of Glycoluril Formaldehyde

Repairing old concrete include the correct choice of material and methodology adopted which may not affect the quality providing monolithic condition for old and new concrete. This study investigates two different parameters such as the impact as well as the optimum usage of new polymer glycoluril-formaldehyde as bonding material. Second one is about to understand the surface preparation for increased bonding strength at the interfacial area of old and new concrete. Five different types of surface textures are used to estimate the bond strength such as plane, lined, waved, grid and chipped. Glycoluril aids as a bonding material in both old and new concrete, and it is introduced at 0%, 1%, 2%, 3%, and 4% into the cement mixture. When the surface preparation creates a rough surface, it helps in repairing the concrete with the help of polymerization of glycoluril formaldehyde which promotes the enhancement of bond strength and slant shear. The bond strength of the specimens was measured by slant shear method in compression as well as tension for a period of 1, 2 and 4 weeks of new concrete. The results indicated that the highest bond strength was achieved in 3 percentage addition of glycoluril and grid patten substrate preparation.

Pengembangan Butir Soal Literasi Kimia pada Materi Ikatan Kimia Menggunakan Model Rasch

This study aims to develop chemical literacy items on chemical bonding material that can be used to measure students literacy skills, help students understand chemical literacy-based questions, understand chemistry, communicate chemistry orally and in writing, and apply their ability to solve problems in daily life. The type of research is development research with Model of Educational Reconstruction (MER) design. The content validity test was carried out by five validators and analysed using the Rasch model with the facets application. Meanwhile, empirical testing of students was analysed using the Rasch model with the winsteps application. The results of the content validity analysis in this study showed the results of the agreement (exact agreements) of 86,8 percent and the estimated results of the approval (expected agreements) of 87,8 percent, and the results of the analysis of chemical literacy instruments had a valid category and had a reliability value of 0,96.

Identifikasi miskonsepsi materi ikatan kovalen pada mahasiswa kimia tahun pertama universitas negeri malang menggunakan tes diagnostik two-tier

The concept of chemistry must be well understood because the concept of chemistry is hierarchical and sequential. In addition, the concept of chemistry is abstract, which can provoke misconceptions. This study aims to identify misconceptions about the covalent bonding material and to determine the percentage of misconceptions about these materials. The results showed that a misconception was observed in 10 concepts of covalent bonding material with the following percentages: 1) 23 percent of the concepts forming elements of covalent compounds, the covalent compounds must be composed of non-metallic elements with non-metallic elements; 2) 69 percent on the Lewis structure concept, the total number of electrons based on the Lewis structure drawing is the number of valence electrons; 3) 54 percent in the concept of double bonds, the breaking energy of the double bonds is twice that of the energy of the single bonds; 4) 35 percent on the concept of covalent coordination bonds, the covalent coordination bonds are shorter than the covalent bonds; 5) 54 percent on the concept of polar covalent bonds and molecular polarity, the pair of binding electrons is located at the same distance between two bonding atoms; 6) 27 percent in the concept of formal charge, the value of the influences of electronegativity in the determination of the formal charge; 7) on the notion of byte rule and the stability of covalent compounds, 27 percent of the stable Lewis structure does not have a free electron pair (PEB) and respects the byte rule; 62 percent chlorine gas will form the Cl2 molecule because it follows the octet rule; and 54 percent of the covalent bonds store chemical energy; 8) 42 percent on the concept of molecular form, the molecular form of a compound is determined by the repulsion of binding electron pairs; 9) on the concept of intermolecular forces and the properties of covalent compounds, 38 percent of the energy required to boil the table salt is superior because the table salt is an ionic bond; and 81 percent of the strongest interactions are hydrogen bonds; and 10) in the concept of valence bond theory, 23 percent of the most important particles in the formation of covalent bonds are valence electrons; and 27 percent electron sharing means sharing one (1) electron with two atoms, as in the case of sharing an apple for two people. Konsep ilmu kimia perlu dipahami dengan baik, karena konsep ilmu kimia berjenjang dan berurutan. Selain itu, konsep ilmu kimia bersifat abstrak, sehingga dapat menyebabkan miskonsepsi. Penelitian ini bertujuan untuk mengidentifikasi miskonsepsi pada materi ikatan kovalen dan mengetahui persentase miskonsepsi pada materi tersebut. Hasil penelitian menunjukkan bahwa miskonsepsi terjadi pada 10 konsep materi ikatan kovalen dengan persentase sebagai berikut: 1) 23 persen pada konsep unsur-unsur pembentuk senyawa kovalen, senyawa kovalen harus tersusun atas unsur non logam dengan unsur non logam; 2) 69 persen pada konsep struktur Lewis, elektron total berdasarkan gambar struktur Lewis adalah jumlah elektron valensi; 3) 54 persen pada konsep ikatan rangkap, energi pemutusan ikatan rangkap dua kali lipat daripada energi pemutusan ikatan tunggal; 4) 35 persen pada konsep ikatan kovalen koordinasi, ikatan kovalen koordinasi lebih pendek daripada ikatan kovalen; 5) 54 persen pada konsep ikatan kovalen polar dan kepolaran molekul, pasangan elektron ikatan terletak pada jarak yang sama diantara dua atom yang berikatan; 6) 27 persen pada konsep muatan formal, nilai elektronegativitas berpengaruh dalam menentukan muatan formal; 7) pada konsep aturan oktet dan kestabilan senyawa kovalen, 27 persen struktur Lewis yang stabil tidak memiliki Pasangan Elektron Bebas (PEB) dan memenuhi aturan oktet; 62 persen gas klorin akan membentuk molekul Cl2 karena memenuhi aturan oktet; dan 54 persen ikatan kovalen menyimpan energi kimia; 8) 42 persen pada konsep bentuk molekul, bentuk molekul suatu senyawa ditentukan tolakan pasangan elektron ikatan; 9) pada konsep gaya antar molekul dan sifat-sifat senyawa kovalen, 38 persen energi yang dibutuhkan untuk mendidihkan garam dapur lebih besar karena garam dapur merupakan ikatan ionik; dan 81 persen interaksi tarik-menarik yang paling kuat adalah ikatan hidrogen; dan 10) pada konsep teori ikatan valensi, 23 persen partikel paling penting dalam pembentukan ikatan kovalen adalah elektron valensi; dan 27 persen sharing electron berarti pemakaian bersama 1 (satu) elektron oleh dua atom, seperti pada kasus berbagi sebuah apel untuk dua orang.

The Development of Advance Organizer Based Distance Learning in Chemistry Bonding Material

The spread of the Covid-19 virus requires the government to take a policy of organizing education online. Learning chemical bonding material is strived to be developed according to the needs of students and learning objectives that are reflected in the curriculum. This study aims to develop advance organizer-based distance learning on chemical bonding material and measure the effectiveness of this product. This study uses the Dick and Carey development model approach. The instruments used included assessment questionnaires, observations, interviews, validation sheets and tests of students' cognitive knowledge. The data obtained were analysed using quantitative descriptive statistics and data on the effectiveness of learning using an n-gain score. The results of this study obtained online learning products with an average validation score of 3.51 on a scale of 4.00 and the student gain value before and after using advance organizer-based online learning was 0.52. The conclusion of this research is that advance organizer-based online learning products on chemical bonding material are very feasible and effective. These findings will be an input for efforts to develop chemical bonding materials and research the development of chemistry learning during a pandemic.

Analysis of Students Understanding of Chemical Bonds Concept Using Three Tier Multiple Choice

Diagnostic tests are needed to determine student weaknesses and can be used as a basis for follow-up with appropriate treatment. One type of diagnostic test is a three tier multiple choice. This study aims to analyze the level of students' understanding of chemical bonding material. The method used is descriptive with the research subjects of chemistry education students totaling 93 people. Data collection with 14 test questions three tier multiple choice and analysis of students' level of understanding using the technique Certainty of Responses Index (CRI). The results showed very low understanding of the chemical bond concept namely 29.50% and 62.77% misconception high category. The use of three tier multiple choice with the CRI technique is able to classify students' conceptual understanding.