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All Journal Fullerene Journal of Chemistry Oxygenius Journal Of Chemistry Education
Djefri Tani
Universitas Negeri Manado
Chemistry Education

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Penerapan metode praktikum berbasis bahan alam dalam pembelajaran kimia untuk meningkatkan hasil belajar siswa pada materi reaksi redoks Loriana Tiak; Djefri Tani; Joice Dorsila Susana Caroles
Oxygenius Journal Of Chemistry Education Vol 1 No 1 (2019): Oxygenius : Journal of Chemistry Education
Publisher : Chemistry Department, Universitas Negeri Manado

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (235.046 KB) | DOI: 10.37033/ojce.v1i1.95

Abstract

The purpose of this study was to determine the improvement in learning outcomes of class X students in East Halmahera 9 High School on redox reaction topic by using natural product praticum methods in chemistry learning. This research is a preexperimental study with a One Group Pretest-Posttest Design. The population and sample are taken all students of class X with a total number of students of 20 people. The collected data is processed from the results of the pretes-posttest. Data were analyzed using the formula t-test the research hypothesis and obtained tcount> t table (19.49> 2.10). The results show that the average posttest value was greater than the average value of the pretest, so it can be concluded that student learning outcomes provided with natural product practicum methods influence student learning outcomes.
Separation and Characterization of Silica from Rice Husk with Varying Heating Times Caroles, Joice; Sahabang, Neybi; Tani, Djefri; Rumengan, Stefan Marco
Jurnal Kimia Fullerene Vol 9 No 2 (2024): Fullerene Journal Of Chemistry
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37033/fjc.v9i2.647

Abstract

Rice husk is a by-product of rice processing that has many uses but is rarely used by most people. Rice husk has abundant silica content which can be used as an adsorbent. This research was conducted to separate silica from rice husk by using the alkali fusion method with varying heating times (30, 60, 120, and 180 minutes) and to characterize silica using FTIR, XRD, and SEM-EDS. the maximum silica yield achieved was 50.75% after heating 60 minutes. The results of XRD characterization showed the presence of a spectrum in the 22o region at an angle of 2θ with a non-sharp spectral shape which is an amorphous nature of silica. In the FTIR test, there is a typical absorption of the silanol group in the absorption area of 1099.48 cm-1, while the results of the SEM-EDS analysis show the percentage of silica mass is 34.39%.
OPTIMASI KONSENTRASI LARUTAN KAPUR SIRIH UNTUK MENETRALKAN ASAM LEMAK BEBAS (ALB) PADA MINYAK GORENG Sinaba, Berry; Tani, Djefri; Tuerah, Jeanne
Oxygenius: Journal Of Chemistry Education Vol 7 No 2 (2025): Oxygenius : Journal Of Chemistry Education
Publisher : Chemistry Department, Universitas Negeri Manado

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Oil is a triglyceride compound that is liquid at room temperature. Oil can experience changes in aroma and taste during storage. To overcome the damage to the oil, neutralization is carried out. Neutralization is a process to break free fatty acids from oil or fat, by reacting free fatty acids with bases or other reagents, thus forming soap (soap stock) with the aim of purifying oil, reducing residual gum, improving taste, and reducing darkness from the oil. Neutralization can be done in various ways, namely by using alkali, sodium carbonate, ammonia, or by using steam. This study aims to determine the optimum concentration of whiting solution in neutralizing free fatty acids. Neutralization was carried out with several concentrations, namely 10%, 12%, 14%, 16%, 18%, 20%. The test parameters in this study were free fatty acid content, acid number, peroxide value and water content. Based on the results obtained the optimum concentration was 16% with free fatty acids 0.1781, acid number 0.25, peroxide number 4.39, water content 0.39.
Co-Authors Jeanne M. Tuerah Joice Dorsila Susana Caroles Loriana Tiak Sahabang, Neybi Sinaba, Berry Stefan Marco Rumengan