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UJI ANTIOKSIDAN EKSTRAK ETANOL DAUN AFRIKA (Vernonia amygdalina), RIMPANG JAHE MERAH (Zingiber officinale var. Rubrum) DAN KELOPAK BUNGA ROSELLA (Hibiscus sabdariffa) DENGAN METODE DPPH (1,1-diphenyl-2-picrylhydrazyl) Yauna, Fadhliyatul; Musman, Musri; Sulastri, Sulastri
Jurnal Ilmiah Mahasiswa Pendidikan Kimia Vol 8, No 2 (2023): JIMPK Juli-Desember 2023
Publisher : Universitas Syiah Kuala

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.82415/jimpk.v8i2.17914

Abstract

Penelitian ini dilaksanakan untuk mempelajari aktivitas antioksidan dari ekstrak etanol daun Afrika, rimpang jahe merah dan kelopak bunga rosella. Ekstrak etanol dari semua bahan alam tersebut diperoleh dengan metode maserasi. Uji antioksidan dilakukan dengan menggunakan metode DPPH (1,1-diphenyl-2-picrylhydrazyl) dan absorbansinya diukur dengan spektrofotometer UV-Vis. Vitamin C digunakan sebagai kontrol positif. Hasil pengujian antioksidan dengan nilai IC50 dari daun Afrika, rimpang jahe merah, kelopak bunga rosella dan pembanding vitamin C diperoleh masing-masing sebagai berikut: 9,473; 7,215; 6,609 dan 5,147 ppm. Berdasarkan pengklasifikasian dari Molyneux dapat dinyatakan bahwa daun Afrika, rimpang jahe merah dan kelopak bunga rosella memiliki aktivitas antioksidan yang sangat kuat. Dengan demikian, ketiga bahan alam tersebut dapat menangkal radikal bebas.
Profile of Student’s Actual Competencies on Atomic Structure Topic using E-Module based on RADEC Model Yauna, Fadhliyatul; Sopandi, Wahyu; Wahyu, Wawan
Journal of World Science Vol. 2 No. 10 (2023): Journal of World Science
Publisher : Riviera Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.58344/jws.v2i10.443

Abstract

Atomic structure material is one of the chemistry topics that is abstract and complex. Learning topics that contain abstract and complex material requires high-level reasoning and thinking. This research aims to describe students' actual abilities in atomic structure material using an e-module based on the RADEC model. This research method is development research that adapts the Borg & Gall design. The subjects of this research were 31 students in the experimental class and 37 students in the control class. This research was conducted at one of the high schools in the city of Bandung. Students' abilities are measured through pretest questions and assignment of pretest questions. The data analysis used in this research is descriptive analysis and n-gain. This research showed that the actual competence of students in the experimental class had an n-gain of 0.58 and was in the medium category. In contrast, the actual competence of students in the control class had an n-gain of 0.29 and was in the low category. Thus, learning using e-modules based on the RADEC model can improve students' competence. The results of the student perception survey show that RADEC-based e-modules are very helpful in independent learning and completing assignments.