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All Journal Fullerene Journal of Chemistry Oxygenius Journal Of Chemistry Education
Djefry Tani
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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.
Penerapan Media Pembelajaran Laboratorium Virtual Berbasis PhET Pada Materi Larutan Asam Basa di SMA N 1 Likupang Gracesela Tangka; Djefry Tani
Oxygenius Journal Of Chemistry Education Vol 4 No 1 (2022): Oxygenius : Journal of Chemistry Education
Publisher : Chemistry Department, Universitas Negeri Manado

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.37033/ojce.v4i1.348

Abstract

The..purpose of this study was..to determine the..improvement..of student learning outcomes in..class XI MIA 1 at SMA N 1 Likupang on acid-base solution using a PhET-based virtual laboratory. This...research..is a..quantitative research using experimental..method using a one-group pretest-posttest design. The sample in this study was class XI MIA 1 as an experimental class..with a total of 30..students. Data collection was done by giving..a pretest before the learning process was carried out and a posttest after the learning process. The research..data obtained in the form of the difference between the..average..pretest..and..posttest values ​​in the experimental class is 45.3. The average pretest value is 40.7 while the average posttest value is 86. Before the one sample t test was..carried out, the normality test was first carried out and it was found that the data were normally distributed. then tested by t-test, the results obtained are tcount = 17.14 > ttable = 2.001. Thus, it..can be concluded that there is an..increase in student learning outcomes in the..application of PhET-based virtual laboratory learning media on acid-base solution material at SMA Negeri 1 Likupang.
PEMBUATAN DAN KARAKTERISASI KARBON AKTIF DARI ARANG TEMPURUNG KELAPA DENGAN KOMBINASI AKTIVASI KIMIA DAN FISIKA Djefry Tani; Sonny Lumingkewas
Jurnal Kimia Fullerene Vol 7 No 2 (2022): 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.v7i2.515

Abstract

Kajian pembuatan karbon aktif dari tempurung kelapa telah dilakukan dengan perlakuan kimia dan fisika menggunakan aktivator HNO3 dan zat pengaktif gas CO2. Pembuatan karbon aktif dilakukan dengan pirolisis tempurung kelapa, kemudian diaktivasi secara kimia melalui proses perendaman dalam larutan HNO3 pada variasi konsentrasi 0,5; 1,0; 1,5; dan 2,0 M selama 12 jam. Karbon aktif dengan kualitas terbaik dihasilkan dari karbon aktif dengan konsentrasi HNO3 1,5 M pada temperatur 8000C . Hasil karakterisasi pada konsentrasi ini menghasilkan rendemen karbon aktif sebesar 73,41%%, kadar air 3,25%, kadar zat mudah menguap 19,20%, kadar abu 1,18%, karbon terikat 78,29% dan daya serap terhadap iodium sebesar 294,60 mg.g. Angka daya serap iodium ini memenuhi Standar Industri Indonesia no.0258-79
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 Gracesela Tangka Jeanne M. Tuerah Joice Dorsila Susana Caroles Loriana Tiak Sahabang, Neybi Sinaba, Berry Sonny Lumingkewas Stefan Marco Rumengan