JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Social Emotional Learning in Chemistry Learning : Group Investigation dan Contextual Learning Integration to Develop Student’s Social Emotional Competencies
Get PDFThis article presents the results from integrating Social Emotional Learning (SEL) through cooperative learning and contextual approach in chemistry learning. This study was conducted on 10th-grade students in the academic year of 2016/2017. Collaborative learning, as well as the use of real-life scenario, are some of the teaching practices for facilitating Social Emotional Learning (SEL) and promotes students' social-emotional competenciesthat aligned with affective competencies in Indonesia’s 2013 curricula. The proposed teaching practices also answer the challenges faced by the implementation of the 2013 curricula, finding proper teaching practices to integrate to develop student’s character through learning activity. The empirical work of the study is based on a qualitative approach. Six Group Investigation’s stage integrated with the use of real-life scenario was analyzed through various method such as observations, interviews, reflective journals, and student’s worksheets answer. The results found that students showed positive attitudes and perspective’s change towards chemistry learning, establish positive relationship with peers, cooperative skill, tolerance, and responsible decision making by considered himself, others, and community within the learning process
Effectiveness of Rice Husk and Bagasse Fly Ash as Adsorbent of Cr Metal on Batch System
No full textThis study aimed to utilize rice husk and bagasse fly ash as Cr metal adsorbent. In this study, the adsorption used batch system. The steps of research were preparation of materials, activation of materials with HCl and NaOH solutions, characterization test using SEM, FTIR and AAS. Determination of optimum condition of Cr metal adsorption on variation of adsorbent composition, adsorbent mass, adsorbate concentration and isotherm adsorption study. The result showed that the adsorbent of rice husk and bagasse fly ash can be used as adsorbent because there were pores that is based on SEM analysis, based on FTIR results that there were a –OH (hydroxyl) functional group at wavenumber 3424.76 cm-1 and Si-O from Si-O-Si (siloxane) functional group at wavenumber 1048.36 cm-1 in the combination of rice husk and bagasse fly ash adsorbent, based on AAS results it was found that the optimum composition ratio of rice husk and bagasse fly ash adsorbent was 1:2 with the percentage of Cr adsorbed 98.90%, the optimum adsorbent mass at 0.2 g with the percentage of Cr adsorbed 99.77% and the optimum adsorbate concentration at 20.645 mg/L with the percentage of Cr adsorbed 99.63%. The pattern of adsorption isotherm tends followed the Langmuir isotherm which means the adsorption process chemically
Synthesis of Tin(II) Oxide (SnO) Nanoparticle by Hydrothermal Method
Get PDFThis study aims to prepare nanomaterial tin(II) oxide (SnO) by using a simple hydrothermal method at low temperatures. The precursors used were tin(II) chloride dihydrate and sodium hydroxide pellets. Solid tin(II) chloride dihydrate and natrium hydroxide pellets are firstly dissolved in ethanol solvents separately and stirred for 3 h for each solution at a constant temperature 26oC. Characterization in this study were carried out by using X-ray diffraction (XRD) and Scanning Electron Microscopy-Energy Dispersive X-ray Spectroscopy (SEM-EDX). The results of the XRD analysis shows that the sample of SnO nanoparticle is in accordance with the standard JCPDS SnO structure. SnO nanoparticle has tetragonal crystal structures and PSC: tp4 groups. It can be concluded that the tetragonal SnO nanostructure can be produced by a simple hydrothermal method at low temperatures by optimizing several synthesis parameters. The structure of SnO nanostructure has several potential applications i.e the absorption of heavy metals, optics, and as a catalyst for dye photodegradation
Pollutant Concentration and Trajectory Patterns of PM2.5 including Meteo Factors in Jakarta City
Get PDFPM2.5 particulate monitoring has been carried out in South Jakarta. The research objective is to examine the effect of meteorology and pollutant trajectories on PM2.5 conditions based on daily and seasonal patterns from January 2016 to December 2017. The sources of PM2.5 data come from DKI Jakarta BPLHD. The data analysis method uses excel to obtain daily and seasonal PM2.5 patterns (rainy season, transition season and dry season). PM2.5 pollutant trajectory patterns were obtained using a single-Particle Lagrangian Integrated (HYSPLIT) forward trajectory derived from NOAA (National Oceanic and Atmospheric Administration). Then the correlation between PM2.5 with meteorological parameters during 2016-2017 was analyzed. The results showed the maximum concentration of PM2.5 in 2016 occurred in the dry season (June-August) of 57.43 µg/m3 and decreased for 2017 by 50.84 µg/m3. Meanwhile, minimum PM2.5 concentration occurs during the rainy season (December-February) which is equal to 20 µg/m3 in 2016, in 2017 PM2.5 decreases to 15.5 µg/m3. The results of running model (HYSPLIT) forward trajectory of PM2.5 pollutants show when dry season pollutant leads to the western part of Jakarta city while the PM2.5 pollutant in rainy season moved from Jakarta city leads to the eastern region
Optimation of NaOH Catalyst Consentration on 1,3-Diphenyl-2-propen-1-on Synthesis Using Microwave-Assisted Organic Synthesis (MAOS) Method
Get PDFwith a variation of NaOH catalyst concentration has been done. The purpose of this study was to determine the concentration of NaOH catalyst in the synthesis of 1,3-diphenyl-2-propen-1-on using MAOS method which produced optimal yield. The synthesis of 1,3-diphenyl-2-propen-1-on using benzaldehyde and acetophenone was carried out using the MAOS method with NaOH catalyst. The variation of NaOH catalyst concentration was 10%, 20%, 30%, and 40%. Microwave radiation was carried out at 140 watts for 20 seconds. The purity of the synthesized 1,3-diphenyl-2-propen-1-on was tested by melting point, TLC, and gas chromatography. The structure of the synthesized 1,3-diphenyl-2-propen-1-on was characterized by FTIR, GC-MS and NMR. The results showed that the compound 1,3-diphenyl-2-propen-1-on can be synthesized from benzaldehyde and acetophenone using MAOS method. The obtained yield at varying catalyst concentrations of 10, 20, 30 and 40% were (50.58±1.84%, (69.20±1.58)%, (84.55±1.50)% and (90.60±0.96)%, respectively. The concentration of 40% NaOH catalyst produces the most optimal yield of synthesis products.Â
Decoction as an Alternative to Producing Indigo Tarum Areuy (Marsdenia tinctoria) Dyes and Its Role on Fiber Coloration from Cellulose
Get PDFIndigo natural dyes are generally made by maceration-fermentation for 24 - 72 hours impacting on productivity. A faster extraction method is needed by decoction methods. The faster production of indigo tarum areuy dyes is done by decoction at temperatures of 60ºC, 70ºC and 80ºC for 5 minutes, 10 minutes and 15 minutes. The extract was adjusted to reach pH 11. Aeration was carried out 30 minutes and then deposited for 24 hours. Indigo dyes are determined yield, purity of indigo, and evaluation of the quality of the staining results using spectrophotometric methods and color fastness testing of washing. Increased yield of indigo dyes occurs at temperatures of 60ºC and 70ºC. At 80ºC, the yield decreases with increasing decoction time. The best temperature and decoction time for pure indigo yield and the quality of the dyeing results in cotton were at 70ºC for 15 minutes with a yield of 3.625 grams per 500 grams of leaves. The dyeing color of the cotton fabric has increased along with the increase in yield and the purity of the dye. The highest color determination is achieved by a cloth dyed by indigo dyes from the decoction process at 70ºC for 15 minutes, with a K / S value of 3.8754. The extraction time and temperature did not affect the washing fastness
Preparation and Characterization of Chitosan-Avocado Seed Starch (KIT-PBA) Edible Film
Get PDFChitosan is a biopolymer that has the advantage of being able to form films that are non-toxic which has great potential to form edible films. To improve the properties of edible films in the form of antioxidants, it is necessary to add other materials such as avocado seed starch. This study aims to determine the effect of the use of avocado seed starch on mechanical properties, degree of swelling and solubility of edible film chitosan-Avocado Seed Starch (Kit-PBA). This study uses a laboratory experimental method. Steps in this study are (1) extraction of avocado seed starch; (2) Making edible film Kit-PBA (mixing chitosan and avocado seed starch), heating and neutralizing) with a ratio between chitosan: avocado seed starch are at 50:50; 60:40; 70:30; 80:20; 90:10; 100: 0; (3) Characterization of Kit-PBA are (tensile strength and elongation) edible film mechanical properties, swelling test and solubility test. The results showed that the higher the concentration of chitosan in the Kit-PBA edible film, the tensile and elongation strength values would increase while the degree of swelling and solubility would decrease
Au Extraction from Mineral Rocks with Aeration-Cyanidation Hydrometallurgy and Comparative Study of Its Effectiveness in Various Methods and Solvents
Get PDFIndonesia is a country with abundant mining potential, one of it is gold (Au) which has a high economic value. Separation of gold metal from mineral rock consists of several methods, such as extraction, hydrometallurgy, and membrane emulsifier technology. These three methods produce different effectiveness of percentage recovery (%recovery), depend on the optimum conditions of each method and type of solvent. This study aims to separate the gold metal from mineral rocks through the hydrometallurgical method with an aeration-cyanidation solvent combination. Hidrometallurgy method is liquid extraction from ores. The test used is a qualitative test of SnCl2 solution and characterization test with XRF. The results showed that the percentage of recovery (%recovery) of Au with aeration and cyanidation process for 24 hours was 92.8%. Aeration and cyanidation better than emulsifier membrane method and hydrometallurgy with sodium bisulphite, hydrogen peroxide, Cyanex 272 and NH4Cl 0.9 M
Development of Computerized Testlet to Measure Science Process Skill on Stoichiometry
Get PDFThis research aims to develop a computerized testlet assessment to measure science process skills on stoichiometry material in terms of validity, reliability, difficulty level, distinguishing features and deception indexes that meet the criteria as good assessment instruments, and can display individual profiles of science process skills students. The subject of the research trial was a grade X student of Senior High School in Boyolali. Validity test is done by content validity, criteria, and expert validation. Reliability test is done by finding the price of the reliability coefficient r. Characteristics test is done by determining the level of difficulty, distinguishing features and deception index. The profile of science process skills is determined by measuring students' mastery of the science process. The results of the research and development was declared feasible and met the criteria as a good question with a validity of questions more than 0.79 (valid), has a test reliability on the main field trials of 0.643 and 0.610 on the trial the implementation of the field is relatively high, has a distinguishing power with a percentage of 10% bad, 66.7% is sufficient, and 23.3% is good, has a difficulty level with a percentage of 20% difficult, 53.3% moderate and 26.7% easy