Jurnal Pendidikan Kimia
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Sonochemical Synthesis of Ethyl Cinnamate
Get PDFThis research aimed to determine the yield of ethyl cinnamate synthesized by the sonochemical method and its potency as a sunscreen agent. Ethyl cinnamate was synthesized from cinnamic acid and ethanol with concentrated sulfuric acid as catalysts assisted by ultrasonic waves. The Identification of compounds was carried out by infrared spectrophotometry and gas chromatography-mass spectroscopy. Synthesis of ethyl cinnamate resulted in the form of clear yellow liquid with a fragrant aroma of a cinnamon ester with a 96.61% yield. Identification by an infrared spectrophotometer showed many functional groups of ethyl cinnamate. Identification by GC-MS was given a relative abundance of 98.96%. The product of synthesis had SPF number 4.769 at 10 ppm used Mansur Equation. Based on this research, it concluded that it has potential as a sunscreen agent. The sonochemical method provides an excellent yield of ethyl cinnamate
Designing Calorimeter Made from Various Wastes
Get PDFA research has been conducted which aims to design a waste-based calorimeter as an alternative to measuring heat for chemistry practicum in schools. Research products developed through the steps of design-based research comprising the steps of analysis, design, and development. The resulting product is a waste-based calorimeter equipped with an automatic stirrer. The container to store the reagent solution on the calorimeter is made of Styrofoam, paper, plastic, melamine, PVC and bamboo. Optimization tool was conducted to determine the heat capacity of the calorimeter and the enthalpy of neutralization. The highest accuracy calorimeter value between 78-97%. Bamboo calorimeter has the highest accuracy value (97%). Styrofoam calorimeter has the lowest accuracy values (78%). Based on the results of the validation and feasibility test it can be concluded that the product is declared valid and feasible
Characterization of Biocomposites from Polylactic Acid and Cellulose of Oil Palm Empty Fruit Bunch
Get PDFBiocomposites are polymers reinforced with natural fibers, such as cellulose. This research aims to synthesize cellulose from Oil Palm Empty Fruit Bunch (OPEFB) and biocomposites from PLA and cellulose. In this study, cellulose was obtained through alkalization, hydrolysis, and bleaching of OPEFB. Biocomposites production was carried out by mixing PLA and cellulose using the extrusion method. In the extrusion method, PLA and cellulose of OPEFB were mixed using an extruder above the melting point of PLA of 170°C. The output product of an extruder was then pressed using a compression moulding machine to form biocomposites. The tensile strength of biocomposites had a smaller value than pure PLA, whereas the modulus young of biocomposites with 5% by weight of cellulose had a higher value than pure PLA. The decrease in the mechanical properties of biocomposites was caused by poor adhesion between PLA and cellulose. The water absorption of biocomposites was greater than pure PLA, which was influenced by cellulose's characteristics as hydrophilic and PLA is hydrophobic. Also, the higher water absorption in biocomposites accelerated the weight loss of biodegradability
PENINGKATAN PENGUASAAN KONSEP DAN KETERAMPILAN BERPIKIR KRITIS SISWA MELALUI IMPLEMENTASI MODEL PEMBELAJARAN INKUIRI PADA MATERI POKOK LARUTAN PENYANGGA
Get PDFPenelitian ini ditujukan untuk mendeskripsikan pengaruh penerapan model pembelajaran inkuiri terhadap penguasaan konsep dan keterampilan berpikir kritis siswa, serta mendeskripsikan hubungan antara keterampilan berpikir kritis dengan penguasaan konsep siswa. Penelitian ini merupakan gabungan dari penelitian pra-eksperimen jenis one group pre test-post test design dan penelitian korelasional, yang diawali dengan pengembangan perangkat pembelajaran menggunakan model Dick & Carey. Penelitian ini dilaksanakan di SMAN 1 Gresik dengan sampel siswa kelas XI IPA-3. Data tentang penguasaan konsep dan keterampilan berpikir kritis siswa dianalisis secara deskriptif, sedangkan hubungan antara keterampilan berpikir kritis dan penguasaan konsep dianalisis dengan teknik korelasi product moment. Berdasarkan hasil analisis data dapat disimpulkan bahwa (1) Pembelajaran kimia pada materi pokok larutan penyangga dengan model inkuiri dapat meningkatkan penguasaan konsep dan keterampilan berpikir kritis siswa (2) Ada hubungan yang kuat dan signifikan antara keterampilan berpikir kritis dengan penguasaan konsep siswa
PEMBELAJARAN KIMIA MENGGUNAKAN MODEL STUDENT TEAMS ACHIEVEMENT DIVISION (STAD) DAN TEAM GAMES TOURNAMENT (TGT) DITINJAU DARI KEMAMPUAN AWAL DAN GAYA BELAJAR
Get PDFTujuan penelitian ini adalah untuk mengetahui pengaruh penggunaan metode Student Teams Achievement Division (STAD) dan Team Games Tournament (TGT), kemampuan awal, gaya belajar dan interaksinya terhadap prestasi belajar kognitif dan afektif siswa. Penelitian ini menggunakan metode eksperimen. Populasi adalah mahasiswa D-3 dan D-4 jurusan analis kesehatan tahun akademik 2012/2013 Fakultas Ilmu Kesehatan Universitas Setia Budi Surakarta. Sampel diperoleh melalui random sampling. Eksperimen dilakukan pada mahasiswa D-3 jurusan Analis Kesehatan menggunakan model STAD, mahasiswa D-4 jurusan Analis Kesehatan menggunakan model TGT, dan campuran kelas D-3 dan D-4 jurusan Analis Kesehatan sebagai kelas uji coba dengan identifikasi dan penyimpanan bahan kimia. Teknik pengumpulan data dengan menggunakan tes dan angket. Teknik analisis data menggunakan uji Kruskal-Wallis dengan taraf signifikansi 5%. Hasil analisis data menunjukkan bahwa, (1) ada pengaruh yang signifikan penggunaan model STAD dan TGT terhadap nilai kognitif (sig.=0,000),tetapi tidak pada nilai afektif (sg.=0,103), (2) ada pengaruh yang signifikan antara kemampuan awal dengan nilai belajar mahasiswa, (3) ada pengaruh yang signifikan antara gaya belajar terhadap nilai belajar kognitif (sig.=0,017), tetapi tidak pada nilai afektif mahasiswa (sig.=0,795), (4) ada interaksi yang signifikan antara penggunaan model STAD dan TGT dengan kemampuan awal terhadap nilai belajar mahasiswa, (5) ada interaksi yang signifikan antara penggunaan model STAD dan TGT dengan kemampuan awal terhadap nilai belajar mahasiswa, (6) ada interaksi yang signifikan antara kemampuan awal dengan gaya belajar terhadap nilai belajar kognitif (sig.=0,000) tetapi tidak pada nilai afektif mahasiswa (0,057), (7) ada interaksi yang signifikan antara penggunaan model STAD dan TGT dengan kemampuan awal dan gaya belajar terhadap nilai belajar mahasiswa
Application of Nanocomposit Of Al2O3/Activated Carbon Prepared by Hydrothermal Process for Phenol Removal
Get PDFNancomposite of Al2O3/activated carbon was prepared from the mixture of alumina oxide (Al2O3) and activated carbon from palm oil shell under the mixture of aquabidest and ethanol (1:1). The mixture was treated by hydrothermal process at 250 oC for 3 h. Resulted Al2O3/ activated carbon was characterized using SEM/EDX for studying the morphology structure of activated carbon and composite showing a like flower structure attached on the surface. The chemical compositions were 73.18%, oxygen 23.72%, aluminium 2.30%, dan silica 2.00%. The efficiency of composite was investigated for removal of phenol in aqueous solution. The maximum adsorption of phenol was obtained at pH 2, adsorbent weight 2 g, contact time 60 min and phenol concentration 100 ppm
Misconception Profile of High School Student on Electrolyte and Non-Electrolyte Solution Using Pictorial-Based Two-Tier Multiple Choices Diagnostic Test
Get PDFThe development and study had been done to determine misconceptions profile of class X high school students in Kuningan West Java on electrolyte and non-electrolyte solutions using descriptive methods. The instrument used was a pictorial-based two-tier multiple choices diagnostic test consisted 18 questions. The instrument had been tested for its feasibility with the CVR and CVI values was one, and the Cronbach's Alpha (reliability) value for the whole item was 0.706. The items were applied to class X students in schools with high, medium and low category. Based on the results of the application, the most common misconceptions of students on electrolyte and non-electrolyte solutions was that when dissolved in water, ionic compounds would be ionized into ions, oxygen atom in water molecule interacted with anions and hydrogen atoms in water molecule interacted with cations (37.78%). The misconceptions of class X high school students on electrolyte and non-electrolyte solution in high and low category schools in Kuningan had a significant difference. Based on the one-way ANAVA test, the significance level < 0.05, there was 0.045. The misconception of class X high school students in Kuningan on electrolyte and non-electrolyte solutions based on gender differences did not have a significant difference. Based on results of t test, the significance level > 0.05, there was 0.755
Synthesis of Core-Shell Fe3O4/C18/SiO2/[3 (2-Aminoethyl amino) propyl] Trimethoxy Silane and The Study of The Adsorption Kinetics Model of Cu2+ and Cr6+ Ions
Get PDFSynthesis of Core-Shell Fe3O4/C18/SiO2/[3 (2-Aminoetil amino) propyl] Trimethoxy silane has been conducted to study its adsorption kinetics of Cu2+ and Cr6+ ions. Fe3O4 synthesis was carried out to form cores that have magnetic properties. The aim of the coating C18/SiO2/[3(2-Aminoetilamino) propyl] trimethoxy silane was to protect these cores from physical degradation due to acids and bases, as well as the application of synthetic materials. The sono-coprecipitation method showed good results under N2 gas flow with the results of black crystals. The success of SiO2 and [3(2-Aminoethylamino) propyl coatings the transformation of the color showed Trimethoxy silane into brown and weight gain of the synthesis result. Analysis of XRD data showed that little Fe2O3 impurities were clarified by FTIR data showing the presence of amine groups from the starting material. The SEM-EDX and TEM showed a spherical shape with a core-shell system. The adsorption kinetics model was studied using two kinetics models for Cu2+ and Cr6+ ions. The results were demonstrated by the suitability of Cu adsorption to the pseudo order 1, with an adsorption rate of 0.0333 min-1, whereas for Cr corresponded to pseudo order 2 with an adsorption rate of 0.00536 gmM-1min-1
ISOLASI, AMPLIFIKASI DAN SEKUENSING FRAGMEN 1,9 KILOBASA GEN HEAT SHOCK PROTEIN 70 SALMONELLA ENTERICA SEROVAR TYPHI
Get PDFSalmonella enterica serovar Typhi merupakan penyebab demam tifoid atau penyakit tifus pada manusia. Mekanisme molekuler patogenesitas Salmonella merupakan sistem yang kompleks dan diatur oleh sejumlah gen dan faktor-faktor virulen. Salah satu gen tersebut adalah dnaK yang mengatur sintesis Heat Shock Protein 70 (HSP70). Penelitian ini bertujuanuntuk memperoleh gen HSP70 yang berukuran 1,9 kilobasa dari bakteri Salmonella enterica serovar Typhi. Gen tersebut dapat digunakan untuk pengembangan vaksin tifus maupun diteliti lebih lanjut untuk mengungkap fungsi lainnya. Gen HSP70 berhasil diamplifikasi dari genom S. Typhi dengan reaksi polimerisasi DNA (PCR) menggunakan pasangan primer spesifik HSP70. Hasil elektroforesis menunjukkan bahwa produk amplifikasi tersebut berukuran 1900 pasang basa.Produk PCR dimurnikan sebelum urutan nukleotidanya ditentukan melalui sekuensing. Analisis hasil sekuensing menunjukkan produk PCR tersebut memiliki homologi sebesar 99% dengan dnaK (gen HSP70) S.enterica serovar Typhi strain CT18 yang terdapat pada gene database NCBI