Knowing about metal coating (electroplating) is the electrodeposition of coatings or coatings attached to the electrodes to protect the substrate by giving surface properties and dimensions different from the base metal or finishing technique, by coating metal that is easily corroded (corrosion) with metals that are resistant to corrosion with electrical and chemical engineering. Whereas in Indonesian society the technique for metal coating is very familiar with the name of the gilding technique. In ancient times before electroplating and gilding were discovered to avoid corrosion of metals, the incorporation of metals such as copper with tin into bronze, copper with zinc into brass in addition to being resistant to corrosion also added to the beauty of color. Among the alloys above bronze is the oldest alloys that have been used by humans. With the development of the times, more modern gilding techniques were found to be a more practical method, namely electroplating, gilding with electrical and chemical processes that make metals resistant to corrosion. Metal coating is a scientific field which is one of the applications of electro chemical technology. Very closely related to the material science and technology, surface chemistry, physical chemistry, to the engineering. Various metals can be plating. The various metals are classified into five groups: "tumbal" coatings, decorative-protective coatings, engineered metal coatings, rare-use metals, and various types of alloys. All of these have their own characteristics, both advantages and disadvantages.

The discovery of various of new medicinal compounds from various research clarifies the important role of computational studies as the initial basis for finding sources of medicinal raw materials both from natural and synthetic. SARS-coronavirus 2 (SARS-CoV-2) or COVID-19 is the virus which is responsible for the outbreak that affects almost the entire world began in early 2020. This study aim is to determine the interaction between SARS-CoV-2 and quinine derivative compounds by utilizing and developing quinine plants as medicinal ingredients, especially Corona antivirus. The research was conducted in silico with the molecular docking method. The docking software used in this research is AutodockVina. The results showed that from the 10 tested compounds against SARS-CoV-2 virus cells, all of ithas the ability as an antivirus with the binding affinity of around -6 kcal / mol. The native ligands have the best binding affinity among the tested compounds which is around -7.9 kcal / mol. This is also supported by the number of hydrogen bondings and bond lengths as well.

Adsorbent is an adsorption that is used to absorb various pollutants. Adsorbents can be used from natural materials. Natural ingredients that can be used are oil palm empty bunches. Oil palm empty bunches are a carbon-rich material that is getting new research interest in adsorption because of its abundance and properties. Oil palm empty bunches contain carbon, nitrogen, hydrogen, oxygen, sulfur, lignin, hemicellulose, and cellulose. Oil palm empty bunches are used as adsorbent for water saturation.

This research was conducted to design a Problem Based Learning (PBL) based learning module with the ADDIE model. The problems studied are 1) How is the feasibility (validity) and learning effectiveness of the Problem Based Learning (PBL)-based module developed on the buffer solution material to measure students' Higher Order Thinking Skills (HOTS) and 2) What are the students' chemistry learning outcomes using the module-based Problem Based Learning (PBL) is higher than the KKM score. The subjects of this study were 3 expert validators (expert lecturers), and 1 high school chemistry teacher to evaluate the learning to be developed and class XI MIA students of SMA Negeri 1 Purba who were determined by random sampling using an experimental class totaling 30 students. The results of the study showed that 1) the problem-based learning module for chemistry-based learning buffer solution material that was developed was feasible to be used for learning materials to improve students' critical thinking skills. The module is declared effective as seen from the increase in student learning outcomes, namely the average pretest value of 33.5 and posttest 80.13 in the experimental class, 2) The learning outcomes of chemistry using Problem Based Learning (PBL)-based modules developed on buffer solution material are higher than the value KKM (75) with an average score of 80.13.

In this study, activated carbon was prepared from empty oil palm bunches obtained from Padang Bulan, Medan, North Sumatra. The empty oil palm bunches are cleaned, then mashed to obtain a particle size of 200 mesh which is then referred to as the oil palm empty bunches bio-sorbent. This bio-sorbent is then washed with water to remove impurities that may come from fertilizers or insecticides during processing in oil palm plantations such as K, Ca, Mg, Si and P, which are visible from the EDX analysis results of bio-sorbent before washed. From the EDX data after washing, the was observed if there are no peaks of these impurity elements. From the XRD pattern it can also be seen that there are some peaks missing after washing if compared to XRD bio-sorbents. Activated carbon then prepared by heating the bio-sorbent at 500 °C for 1 minute, and the XRD results show an amorphous structure as a characteristic of the formation of activated carbon. SEM images can also be observed that the difference in the surface of the activated carbon is smoother than the surface of the bio-sorbent, besides the activated carbon looks more homogeneous.