Universitas Negeri Manado, Jurusan Kimia: Open Journal Systems
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Phytochemical and Antioxidant Test of Binahong (Anredera cordifolia (Tenore) Steenis) Leaves Ethanol Extract
Get PDFBinahong Anredera cordifolia (Tenore) Steenis leaves contain chemical compounds that can be used as antioxidants. This study aims to examine the phytochemical and antioxidant activity of the ethanol extract of binahong leaves. Binahong leaves were extracted using the maceration method with an ethanol solvent. The phytochemical test showed that the ethanol extract of binahong leaves contained phenolic compounds, flavonoids, alkaloids, and tannins to have potential antioxidants. The antioxidant activity test was carried out using the DPPH method and absorbance measurement with a UV-Vis spectrophotometer at a wavelength of 517 nm. The results showed that the ethanol extract of binahong leaves had strong antioxidant activity, as evidenced by the IC50 value of 87.423 µg/mL
Penerapan Model Pembelajaran Peer-Led Team Learning Untuk Meningkatkan Hasil Belajar Siswa Pada Materi Larutan Elektrolit Dan Nonelektrolit
Get PDFThis study aims to improve student chemistry learning outcomes by applying the peer-led team learning model. This research design uses Classroom Action Research (CAR) which is divided into two cycles. With four stages, namely planning, action, observation and reflection. This research was carried out at SMA Negeri 1 Tagulandang in class X Science 1, totaling 31 students. This research is only focused on the material of electrolyte and nonelectrolyte solutions. In this study using instruments such as observation sheets, test questions and questionnaires. From the research that has been carried out, it is found that 77.41% of students have successfully met the Minimum Completeness Criteria (KKM) which was continued in the second cycle and obtained an average score of 77.58. From the results of student questionnaires and the results of observations given to students through peer-led team learning, students responded well. This shows that the peer-led team learning model has a positive impact on the learning process.Penelitianaini bertujuan untukameningkatkan hasilabelajar kimia siswaadengan penerapan model peer-led team learning. Desain penelitian ini menggunakan Penelitian Tindakan Kelas (PTK) yang terbagi atas dua siklus. Dengan empat tahapan yaitu perencanaan, tindakan, pengamatan dan refleksi. Penelitian ini dilaksanakan di SMA Negeri 1 Tagulandang pada kelas X Ipa 1 yang berjumlah 31 siswa. Penelitan ini hanya difokuskan pada materi larutan elektrolit dan nonelektrolit. Pada penelitian ini menggunakan instrument seperti lembar observasi, soal tes dan angket. Dari penelitian yang telah dilaksanakan diperoleh 77,41% siswa telah berhasil memenuhi Kriteria Ketuntasan Minimum (KKM) yang dilanjutkan padaasiklus II dan memperoleh nilai rata-rata sebesar 77,58. Dari hasilaangket siswa serta hasilAobservasi yang diberikanApada siswa lewat pembelajaran denganAmodel peer-led team learning siswa menanggapi dengan baik. Hal iniAmenunjukkan bahwa model peer-led team learning menghasilkanAdampak yang positif pada prosespembelajaran
Implementasi Pendekatan Pembelajaran Science Technology Engineering Mathematics Pada Mahasiswa Kimia FMIPA UNIMA
Get PDFThe purpose of this study was to determine the percentage of students' critical thinking skills in the chemical reaction in solution topic by using the STEM approach. This research was conducted in the department of chemistry, FMIPA UNIMA in the 2019/2020 academic year. The descriptive qualitative was using for this research with 29 students from first semester of chemical education department as research samples. Data Collection was carried out by 10 posttest essay that include student critical thinking ability. The result of the test show the ability to answer the critical thinking skills are 17,2% for very critical thinking, 44,83% for critical enough ; and 37% for less critical.Tujuan dari penelitian ini adalah untuk mengetahui persentase kemampuan berpikir kritis mahasiswa pada materi reaksi kimia dalam larutan dengan mengunakan pendekatan STEM. Penelitian ini dilakukan di Jurusan Kimia FMIPA UNIMA pada tahun ajaran 2019/2020. Metode penelitian yang digunakan adalah deskriptif kualitatif. 29 mahasiswa semester 1 dipilih untuk ditetapkan menjadi sampel penelitian. Pengumpulan data dilakukan dengan tes dalam bentuk soal uraian sebanyak 10 butir soal essay tentang materi reaksi kimia dalam larutan yang mencangkup indikator kemampuan berpikir kritis. Dari analisis hasil test diperoleh persentase kemampuan menjawab soal berpikir sangat kritis sebesar 17,24%, cukup kritis sebesar 44,83%, dan kurang kritis sebesar 37,93%
Efektivitas Model Pembelajaran Blended Learning Dalam Meningkatkan Hasil Belajar Siswa Pada Materi Asam Basa Di SMA Negeri 1 Ratahan
Get PDFThis study aims to determine the efectiveness of the Blended Learning learning model on student learning outcomes on acid-base material. This research was conducted at SMA Negeri 1 Ratahan in the 2020/2021 academic year. The research method used is descriptive qualitative. A total of 18 student of class XI MIA 1 were selected to be set as research samples. The research data was obtained from the final evaluation in the form of multiple choice questions and student response questionnaires. Based on the data analysis, the percentage of student learning completeness was 83.3% with a very good category. The responses given by students to the Blended Learning learning questionnaire were 92.2% and the results of the N-Gain Test showed that the effectiveness of using the learning model was 0.744 with a high category. Based on the resuts of this study, it can be concluded that blended learning model is effective in improving student learning outcomes on acid-base material.Penelitian ini bertujuan untuk mengetahui efektivitas model pembelajaran Blended Learning terhadap hasil belajar siswa pada materi asam basa. Penelitian ini dilakukan di SMA Negeri 1 Ratahan pada tahun ajaran 2020/2021. Metode penelitian yang digunakan adalah deskriptif kualitatif. Sebanyak 18 orang siswa kelas XI MIA 1 dipilih untuk ditetapkan menjadi sampel penelitian. Data penelitian diperoleh dari evaluasi akhir berupa soal pilihan ganda dan angket tanggapan siswa. Berdasarkan analisis data diperoleh persentasi ketuntasan belajar siswa sebesar 83,3% dengan kategori sangat baik. Siswa memberikan tanggapan positif terhadap pembelajaran Blended Learning dengan persentasi sebesar 92,2% dan hasil Uji N-Gain menunjukan bahwa efektivitas penggunaan model pembelajaran sebesar 0,744 dengan kategori tinggi. Berdasarkan hasil penelitian ini maka dapat disimpulkan bahwa model pembelajarn Blended Learning efektif dalam meningkatkan hasil belajar siswa pada materi asam basa.
Penelitian ini bertujuan untuk mengetahui efektivitas model pembelajaran Blended Learning terhadap hasil belajar siswa pada materi asam basa. Penelitian ini dilakukan di SMA Negeri 1 Ratahan pada tahun ajaran 2020/2021. Metode penelitian yang digunakan adalah deskriptif kualitatif. Sebanyak 18 orang siswa kelas XI MIA 1 dipilih untuk ditetapkan menjadi sampel penelitian. Data penelitian diperoleh dari evaluasi akhir berupa soal pilihan ganda dan angket tanggapan siswa. Berdasarkan analisis data diperoleh persentasi ketuntasan belajar siswa sebesar 83,3% dengan kategori sangat baik. Siswa memberikan tanggapan positif terhadap pembelajaran Blended Learning dengan persentasi sebesar 92,2% dan hasil Uji N-Gain menunjukan bahwa efektivitas penggunaan model pembelajaran sebesar 0,744 dengan kategori tinggi. Berdasarkan hasil penelitian ini maka dapat disimpulkan bahwa model pembelajarn Blended Learning efektif dalam meningkatkan hasil belajar siswa pada materi asam basa
Determination of Vitamin C (Ascorbic Acid) Contents in Two Varieties of Melon Fruits (Cucumis melo L.) by Iodometric Titration
Get PDFVitamin C, also known as ascorbic acid, is a water-soluble vitamin that is regarded as one of the safest and most effective nutrients. Vitamin C can be found in most fruits, and one of the fruits that contain vitamin C is melon fruit. The objective of the study is to determine vitamin C content in two varieties of melon fruits (Sky Rocket and Rock Melon) through the iodometric titration method. The method of determination was cheap, accurate, and can be used for routine analysis. The samples were collected from different markets in Yogyakarta. The results recorded the concentrations of ascorbic acids in Sky Rocket melon (30.84±0.3066 mg/100 g), and Rock Melon (33.77±0.2237 mg/100 g). The color of the fruit flesh affects the difference in vitamin C content between two varieties of melon fruit. The vitamin C content of orange-colored flesh (Rock Melon) is greater than that of greenish-yellow flesh (Sky Rocket)
Treatment of Dye Wastewater from Batik Industry by Coconut Shell Activated Carbon Adsorption
No full textBatik is a characteristic Indonesian textile product. The color of batik is one component that affects the quality of batik. Various types of batik dyes, one of which is remazol dyes. Remazol dyes are synthetic dyes that have strong chemical bonds. This is what underlies the process of production of the household batik industry in the village of Purwosekar, District of Tajinan, Malang Regency, with remazol coloring will produce liquid waste that is difficult to be deciphered naturally. This study aims to provide a water treatment solution using the coconut shell activated carbon adsorption method with chemical activation and the ability to adsorb remazol dyes. Adsorption experiments were carried out in batches with a mesh size of 8 with coconut shell carbon activated with 1 M HCl solution for 24 hours. The absorption of remazol dyes by coconut shell activated charcoal is carried out with a stirring speed variation for 60 minutes and the mass of activated charcoal to find the optimum adsorption conditions. Stirring speed variations are 30 rpm, 60 rpm, and 90 rpm, resulting in the highest efficiency at a speed of 90 rpm. While the variations in mass are 200 grams and 300 grams, the highest efficiency is obtained with a mass of 300 grams. Thus, the efficiency of the coconut shell activated carbon is proportional to the stirring speed and mass of the coconut shell activated carbon use
Analisa Sifat Kemagnetan Polimer Poliethylen Glycol (PEG-4000)-coated Nanopartikel Magnetite Fe3O4 Menggunakan Vibrating Sample Magnetometer (VSM)
Get PDFIron oxide (Fe3O4) nanoparticles have been synthesized using coprecipitation method. Characterization of the magnetic properties of iron oxide (Fe3O4) nanoparticles using Transmission Electron Microscopy (TEM) shows a loop hysteresis curve on Fe3O4 magnetite nanoparticles with a value of Mr 7.7 emu/g at 0 kOe field, Ms 68.2 emu/g at an external field 14 ,61 kOe. A low Mr value or close to zero indicates that the Fe3O4 nanoparticle material is softmagnetic. Fe3O4 nanoparticles that had been modified with PEG-4000 polymer showed a Ms value of 55.7 emu/g in a 14 kOe field, an Hc coercivity field of about 60 Oe, and a Mr. 6.3 emu/g value in a 0 kOe field. The smaller the particle size, the more likely the material has a single magnetic domain. The smaller the sample particle size, the smaller the remanent magnetization value. The smaller the value of remanent magnetization, the residual magnetization that is still possessed by a material/sample when it is not affected by an external magnetic field is also greater
Pengaruh Model Pembelajaran Problem Based Learning Pada Materi Sistem Koloid Terhadap Hasil Belajar Kimia Siswa Kelas XI MIA di SMA Negeri 1 Lirung
Get PDFProblem based lerning is a learning model that involves students to solve a problem through the stages of the scientific method so that students can learn knowledge related to the problem and at the same time have the skills to solve the problem. This research aims to determine the effect of the Problem based lerning learning model. on student learning outcomes. The research was conducted at SMA Negeri 1 Lirung in the 2018/2019 academic year. The population was all classes in SMA Negeri 1 Lirung with a sample of class XI MIA 2 and class XI MIA 3 as an experimental class of 20 students. With the research design Posttest Only Control Design with the True Experimental method. The results of the calculation of the test (t) the mean similarity of the two parties obtained tcount (4.406) and ttable 2.002 at the level of α = 5%. This shows that the value of t is greater than t table, so the hypothesis Ho is rejected and Ha is accepted, so it can be concluded that there is a significant influence on the problem-based lerning learning model on student learning outcomes of Chemistry at SMA Negeri 1 Lirung.
 
Perbandingan Efektivitas Ampas Teh Hitam dan Ampas Teh Hijau sebagai Adsorben Ion Logam Cr (VI)
Get PDFIndustrial waste contains various hazardous chemical compounds, such as heavy metals, one of which is chromium hexavalent ion, Cr (VI). Cr (VI) ion is carcinogenic and has toxic effects on humans. A study to treat Cr (VI) ion waste by adsorption using tea dregs has been carried out. Two types of tea dregs, black tea and green tea dregs are used as adsorbents, to compare their adsorption effectiveness. Adsorption effectiveness was determined using the visible-spectrophotometer. Parameters such as pH, adsorbent mass and concentration of Cr (VI) ions were optimized. Study determination of the adsorption isotherm model for each tea dregs included. The results showed that black tea dregs produced greater effectiveness than green tea dregs, with optimum adsorption conditions at pH 2, adsorbent mass of 0,8 grams and Cr (VI) ion concentration of 100 ppm with 99,50% removal efficiency. Meanwhile, green tea dregs produced the optimum adsorption conditions at pH 2, adsorbent mass of 0,4 grams and Cr (VI) ion concentration of 50 ppm with 87,49% removal efficiency. Langmuir adsorption isotherm model is fit for adsorption process by black tea dregs, meanwhile, green tea dregs fit with Freundlich and Langmuir isotherm model
Sintesis dan Karakterisasi Nanopartikel Perak – Ekstrak Daun Pelawan (Tristaniopsis Merguensis Griff) Termodifikasi PVA
Get PDFSynthesis and characterization of silver nanoparticles have been carried out by reacting pelawan leaf extract (Tristaniopsis Merguensis Griff) with a solution of 0.05 M silver nitrate (AgNO3) and PVA through a stirring process for 24 hours. UV-VIS, and XRD analyzed the characteristics of silver nanoparticles. Gray and accompanied by a precipitate. The results of UV-VIS analysis showed absorption at a wavelength of 420 at a concentration of 0.75% and 460 nm at a concentration of 3%. XRD diffractogram of PVA modified silver nanoparticles showed a diffraction pattern of %) and 2 = 38.25o, 44.43o, 64.43o, 77.43o (3% PVA) with Miller indices (111), (200), (220), and (311). Based on the results of an (International Center For Diffaction Data) No. 01- 071-4613, namely at 2 38.11, 44.2, 64.37 and 77.42 (PVA 0.75), silver nanoparticles with a cubic crystal system were formed. In addition, the results of the XRD analysis are also used to determine the average nanosilver particle size using the Debye-Scherr equation