<span lang="EN-US">Organic Chemistry of Natural Materials (KOBA) is a course that requires students to define, classify, and isolate compounds of natural materials. However, there are some students who still have difficulty understanding the application of material in everyday life. So that learning materials are needed that can make students active and independent in solving problems related to real life, namely by making E-Modules combined with the POE learning model. This study aims to obtain the validity of E-Module Based on POE products and to obtain questionnaire data on the responses of chemistry education students after using E-Module Based on POE. This type of research is Research and Development (R&amp;D) with the Thiagarajan learning development model which consists of 4D (define, design, develop, and disseminate) which involves one group of subjects. The results showed that the E-Module Based on POE utilizing the Flip PDF Professional application produced a valid E-Module with an average CVR value of one. And the student response questionnaire data to the E-Module developed was 98.04% with the very good category. Means that the E-Module Based on POE developed can be a supplement to KOBA teaching materials.</span>

<em>Aquilaria malaccensis</em> is a plant species from the Thymeleaceae family. <em>A. malaccensis</em> contains secondary metabolites of phenolic groups, namely benzophenone, chromone, coumarin, xanthone, and flavonoids with various biological activities such as antioxidants and anticancer. This study aims to determine the potential of <em>A. malaccensis</em> stem bark extract as an anticancer and to determine the characteristics of secondary metabolite compounds contained in <em>A. malaccensis</em> stem bark extract. Extraction of the stem bark of <em>A. malaccensis</em> by maceration method in stages using <em>n</em>-hexane, ethyl acetate and methanol as solvents. The anticancer activity test used the microculture tetrazolium (MTT) assay against Murine Leukemia P-388 cells. Compound separation using thin layer chromatograph (TLC) and gravity column chromatography (CC) methods. Determination of chemical compounds using liquid chromatography mass spectroscopy/mass spectroscopy (LCMS/MS). The extracts of <em>n</em>-hexane, ethyl acetate, and methanol each had anticancer activity which was classified as active with an IC₅₀ value of 20.64, 26.61, and 14.49 µg/mL. Based on the results of separation and identification of compounds in methanol extract with TLC, CC, and LCMS/MS, methanol extract contains acetaminophen, aminosamptothesin, isophorone, diethyl phthalate, 3-hydroxy-6H-benzochromen-6-one, isolongifolenic, 2-(2-phenethyl) chromone, 4′,7-dihydroxy-2′,5-dimethoxyisoflavone, 4-hydroxy-3-(1-phenylpropyl)-2H-chromone-2-one; 6-methylchromone-2-carboxylic acid; 3,4-dimethyl-2- phenylmorpholine; and β-calacoren compounds.

Soursop plant parts that are often used by the community, namely the fruit and leaves. Ripe soursop fruit is usually developed to produce juice and lunkhead products. Ripe soursop fruit contains vitamin C which is known to have a wrong function, namely to increase immunity, so that it can protect the body from pathogens. Soursop leaves are often used by the community in the form of a decoction of the leaves for traditional medicine. The research about antioxidant test on ethanol extract of soursop leaves ( Annona muricata Linn) had been conducted using DPPH method (1,1-diphenyl-2-picrylhdirazyl). This research aims to indicate the antioxidant activity of soursop leaves. Samples were collected from Lambaro Skep, a region of Banda Aceh. Then, the sample was dried by air before macerated using ethanol 96%. After that, the filtrate is evaporated using rotary evaporator and concentrated again using a hairdryer. The concentrated extract is then tested for antioxidant activity using DPPH method at maximum wavelength of 517 nm. The result shows young soursop leaves extract has 14.462 ppm of IC 50 value, while old soursop leaves extract has IC 50 value of 9.626 ppm.

<p class="Abstract"><span lang="IN">Preparation of highly ordered TiO₂ nanotube arrays (HOTNAs) by anodization of Ti foil industrial grade in ethylene glycol electrolyte containing 0.3% of ammonium fluoride and 2% of water at 30 V for 90 minutes was conducted. The morphology structure, chemical composition, functional group, crystal phase, and optical properties of HOTNAs were characterized by field emission scanning electron microscope (FE-SEM), Energy Dispersive X-Ray (EDX),Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), and ultraviolet visible diffuse reflectance spectroscopy (UV/Vis-DRS). The well-ordered nanotube with vertically oriented structure was formed in the HOTNAs having size in diameter, length, and wall thickness of 48,0 nm, 1,8 µm, and 26,7 nm, respectively. The fabricated HOTNAs were evaluated for their sensing properties for CO detection. The results show that the fabricated HOTNAs were able to detect 2500 ppm of CO gas with response about 93,429 at operation temperature 150 </span><span lang="IN">°</span><span lang="IN">C. This preliminary study of sensing performance demonstrates that the prepared HOTNAs under this study is potential and promising as a material sensor for CO detection.</span>

Hydrocarbon material is one of the organic chemical materials which is the basic concept for studying the next organic chemistry concept. Based on the result of observation, the average score of students in Organic Chemistry I course is 67.89. The result of this study indicates that students have difficulty of understanding in organic compounds. The objective of this research is to analyze the understanding on chemistry education students of hydrocarbon compounds in Organic Chemistry II course. The research design in this research is descriptive quantitative. The research subjects are students of the 2017 Chemical Education study program. There are 3 stages in the research, including pretest, implementation of learning, and posttest. The pretest aims to obtain data on students' initial knowledge of the material to be studied. Implementation of learning aims to improve students' understanding of hydrocarbon compound material, while posttest aims to measure the level of understanding of students after being given treatment. The conclusion of thisstudy is the students have highest difficulty in the topic hydrocarbon reactions (67.75%).

Used cooking oil is oil from frying which is an unused material. The processing of used cooking oil into biodiesel is expected to reduce household waste and become a new and renewable energy source. The first step in making biodiesel is the esterification process by measuring the value of free fatty acids. The purpose of this study was to determine the optimum time used during the esterification process and to compare the volume of using sulfuric acid (H 2 SO 4 ) catalyst using the Anova method. The research was conducted using an experimental method. The variables used in this study were the deposition time of 12 hours to 25 hours and the volume of catalyst compared was 2 ml and 4 ml for every 200 ml of used cooking oil. Based on the results of the analysis, it was found that the optimum conditions that can be used in the deposition process are at 18 hours using 4 ml of catalyst. Based on the results of ANOVA analysis, it can be concluded that the calculated F value (0.002) &lt;F table (94.196), it means that the FFA value of the 2 and 4 ml catalyst variations does not have a significant difference. faster process.

This study aims to develop recitation-based teaching materials for learning qualitative analysis of cations. The procedure for developing teaching materials adopts the 4-D development model (Define, Design, Develop, Dissemination) from Thiagarajan. The development results were tested theoretically and empirically. The theoretical feasibility test was carried out using expert judgment, including chemist expert, pedagogic expert, and learning media. Empirical feasibility was tested through legibility tests and limited implementation tests. Based on the expert assessment, the recitation method based teaching materials developed in this study is content valid with individual readability of 87,86% and group readability of 89,32%. The results of testing the implementation of teaching materials in the learning process showed that recitation-based teaching materials were effective, in guiding students to do independent learning activities with an effectiveness of 84,16%. The use of Cation Qualitative Analysis teaching materials based on the recitation method in online learning is effective in increasing student understanding of qualitative analysis of cations with an N-gain value of 0,81. The students' ability to complete study assignments with the help of worksheets on teaching materials has a positive correlation, with an increase in concept understanding (r = 0,91) with a contribution value of 88,43%.