JKPK (Jurnal Kimia dan Pendidikan Kimia)
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Synthesis and Characterization Nanosilica from Rice Husk Ash Using Sol-Gel Method with Addition Of PEG-6000 and PVA
Full text linkNano-silica (NS) from rice husk ash was successfully synthesized using a sol-gel process with the addition of polyethylene glycol (PEG) 6000 and polyvinyl alcohol (PVA) as a template. The purpose of this study is to investigate the properties of NS functional groups and the effect of PEG6000 and PVA concentrations (5%, 10%, and 15% (b / v)) on the size, morphology, and distribution of nanosilica. The functional groups of NS are characterized by Fourier transform infrared (FTIR), the size and morphology of NS are characterized by scanning electron microscopy (SEM). In contrast the size analyzer characterizes the particle size distributionof particulate matter (PSA). The results indicated that the addition of PEG-6000 and PVA affected the size and morphology of NS. The FTIR spectra showed the presence of silanol (Si-OH) and siloxane (Si-O-Si) groups. According to the SEM results, the morphology of NS -PEG is round and relatively more uniform than the amorphous morphology of NS-Control and NS-PVA. Instead of PEG-6000, Sol-gel PVA can be obtained with a narrow particle size distribution
Effect of Chitosan Concentration on Macroporous Chitosan-TPP Beads toward Turbidity, Dye Content, and COD of Sasirangan Wastewater
Full text linkThis research was carried out to determine the effect of chitosan concentration in synthesising crosslinked tripolyphosphate (TPP) macropore beads on turbidity, dye content, and Chemical of Demand (COD) Sasirangan wastewater. Macroporous chitosan-TPP beads were synthesised from chitosan solution with various concentrations of 2%, 3%, 4%, and 5% and added NaHCO3 as a porogen, then dripped into 0.75% tripolyphosphate solution. It was further interacted with Sasirangan wastewater by adsorption method with its effect analysed by using the turbidity value, dye content, and COD. The results showed that beads with a 3% chitosan concentration were the most effective in reducing the turbidity, dye content, and COD value. Furthermore, using a more than 3% chitosan concentration indicates reduced effectiveness. Macroporous Chitosan-TPP beads were able to produce a decrease in turbidity, dye content and COD by 81.21%, 55.44%, and 59.37%.Â
The Development of Android-Based Learning Media (Chemdroid) on The Topic Thermochemistry to Improve The Students’ Achievement
Full text linkThe application of technology in learning is currently increasingly sophisticated. The development of learning media is widely applied to make learning more flexible. in this article will discuss the development (R&D) of Chemistry on Android (Chemdroid). This study aims to determine the media's quality based on the chemistry teacher's assessment, determine the readability of the media based on the assessment of students who have received this material, and determine the impact of this media trial in chemistry learning. The development design used is ADDIE (Analysis, Design, Development, Implementation, and Evaluation). At the implementation stage, the posttest control group design was used by involving two classes as the control and experimental class. The variable measure is students achievement. The results obtained are that the Chemdroid learning media has been developed and declared valid by four experts. The assessment results by five high school chemistry teachers were Very Good, with a mean value of 3.31. The results of this assessment state that the Chemdroid learning media is suitable for use as a learning media for thermochemistry. In comparison, the readability test results by 16 students from 4 various senior high schools resulted in Good criteria with a mean of 3.24, which means that this media is legible and useful for students in various groups. The analysis of the implementation results states that the two classes have a significant difference
The Development of Structured Inquiry with three-Level Representation Module
Full text linkMole concepts are essential parts of chemistry learning and have become preliminaries to learn other chemistry concepts. However, the learning resource used has not incorporated three representations, resulting in students' learning outcomes. This study aimed to develop a structured inquiry module in terms of validity and practicality. The method used in this study is research development through the use of the Plomp model. There were 141 senior high school students in Padang participating in the study. The instruments of this study included cognitive tests. The result of the study indicated that the structured inquiry module had high validity (V=0.98), practicality based on teachers' response (P=0.36) and students' response (P=0.36)Furthermore, the result of the t-test toward hypotheses of the learning outcome of the mole concept showed that the learning outcome of the mole concept in experimental groups was higher than that of control groups at both schools. Hence, the structured inquiry module has high validity and practicality. It is also effective to be used in chemistry learning at school. The module developed is a module with three levels of representation (macroscopic level, submicroscopic level and symbolic level). The module contains structured inquiry activities. The module also includes several components such as teacher guidelines, student activity sheets, worksheets, worksheet keys, test sheets, test sheet keys.
Rash Model Approach for Analysis of Misconception on Chemistry Learning with Distractor Analysis
No full textMultiple-choice questions can be used to identify misconceptions through distractor analysis. Distractor analysis for identifying misconceptions using Rasch modelling to find out how students choose options and whether they have any misconceptions. The test instrument uses questions from the teacher association in Indonesia to assess students’ ability to master chemical contexts. The number of question items used is 35 and has been validated and tested for reliability to be feasible to use. Questions were given to 462 first-year high school students. The fit item analysis results show that there are several questions related to clothing that indicate misconceptions. This is supported by the distractor analysis value, which found that misconceptions indicate questions related to electrolysis, the incidence of colligative properties in daily life and the factors that affect corrosion. The distractor’s value and the option probability curve are used to see how students know the ideas offered. The analysis results found that the material in the form of concepts and their application showed a large misconception, in which students would find it difficult to combine concepts and their applications
Phytochemical Screening of Honey Pineapple Peel Extract and Its Application as an Antibacterial Additive in Dish Soap Formulation
Full text linkThis research aims to scientifically develop bioactive compounds from honey pineapple peel and develop a dish soap formulation with extract additives of honey pineapple peel that can be antibacterial. The research was conducted in stages, namely process of extracting honey pineapple peel was carried out by the maceration method using 96% ethanol as a solvent, phytochemical screening of the ethanol extract of honey pineapple peel was done to determine the class of compounds contained in the extract, and application of honey pineapple peel extract in dish soap formulation was to obtain a dish soap formulation with optimal antibacterial activity. Testing the ability of dish soap products to inhibit S. aureus bacteria was performed by the method of filter paper disc diffusion. The results revealed that the ethanol extract of honey pineapple peel contained alkaloids, flavonoids, tannins, and saponins. The ethanol extract of honey pineapple peel has been applied in a dish soap formulation and tested for the antibacterial activity of S. aureus. Antibacterial test results showed that the dish soap formulation with the addition of 5% pineapple peel extract provided strong antibacterial activity, indicated by a precise zone formation of 12.60 m
Implementation of The Video Project with Distance Learning on The Basic Chemistry Course
Full text linkEducation in the 4.0 era encourages the use of digital technology in a sustainable learning process. This article tries to analyze student responses to implementing a video project in a basic chemistry course. This research is qualitative research with a survey method. The participants were 74 students of the Chemistry Education Study Program and Mathematics Study Program consisting of 8 male students and 66 female students. Data collection techniques using online questionnaires by google form application. The steps in this study are  Search for instrument literature to be compiled on the google form, compile a google form student response to the implementation of the video project, distribute the google form questionnaire link to students, and analyze the data obtained. The results showed that students positively responded to the implementation of the video project in terms of autonomy, teamwork, and technology used. The implementation of video projects improves learning skills, collaboration, and digital literacy independently, although students experience problems in video editing because they are not used to using these
The bioactive of Pinus merkusii needle and bark extract as antioxidantand anti-aging
Full text linkPinus merkusii is a native pine species to Southeast Asia and has used as an oleoresins source and raw material for pulp and paper industries. This plant also possesses several biological activities, such as anti-inflammatory and larvicidal activity. This study aims to evaluate the antioxidant and antiaging activity of P. merkusii needle and bark. The qualitative phytochemical screening was used to evaluate the presence of secondary metabolites compounds. DPPH (2,2-diphenyl-1-picryl-hydrazyl) methods evaluated the antioxidant activity, and an anti-tyrosinase assay was used to evaluate the antiaging activity. Phytochemical analysis showed flavonoids, phenols, alkaloids, tannins, and terpenoids in both extracts. Bark extract showed the presence of saponins and triterpenoids, while needle extract possesses steroids. The antioxidant activity (IC50) of P. merkusii bark extract was 59.32 ± 1.74 µg/mL, stronger than needle extract (68.67 ± 1.47 µg/mL). Also, the bark extract showed higher inhibitory activity of tyrosinase (IC50) 74.97 ± 1.54 µg/mL than needle extract (96.08 ± 1.77 µg/mL). From this investigation, P. merkusii bark extracts appeared to have more potential as a natural source of antioxidants and antiaging and might be beneficial in these subjects
Leaching Basalt Rock using Averrhoa Bilimbi Extract
Full text linkThis research was conducted to determine the effect of solid/liquid ratio (s/v), temperature, and stirring Speed on per cent extraction of iron using oxalic acid from Averrhoa bilimbi. The variation of the solid/liquid (s/v) is 10%, 15% and 20 (%), the temperature variations used are 30, 60 and 90 oC, while the variation of the stirring Speed uses 200, 400 and 600 rpm. Some basalt rock samples are put into the reactor and leached using an oxalic acid solution from Averrhoa bilimbi. Within a certain period of time, the filtrate was taken and analyzed for Fe content using Atomic Absorption Spectroscopy. The residue was analyzed using XRF and XRD. The results showed that the highest percentage of iron extraction for basalt rock leaching experiments using oxalic acid from Averrhoa bilimbi was achieved at a temperature of 90oC, 10% of solid/liquid ratio, 400 rpm stirring speed and 120 minutes of leaching time with a percent iron extraction of 65.90%. XRD analysis results showed that the compounds formed in the residual leaching were Anorthite, Ferrosilite, Cristobalite and quart low
Nitrate Adsorption capacity of Activated Gamalama Volcanic Ash
Full text linkThe adsorption process of nitrate from an aqueous solution by using activated Gamalama volcanic ash was investigated. Gamalama volcanic ash (VA) was activated with HNO3 2M. The effect of adsorbent mass and initial nitrate concentration on nitrate adsorption were observed in this study. The adsorption process was conducted using a various mass of adsorbent (1 g, 2 g, 4 g, 6 g, and 8 g), various initial concentrations of nitrate (20 mg/L, 30 mg/L,40 mg/L, 50 mg/L, and 60 mg/L). The increasing of adsorbent mass decreased the adsorption capacity was observed. It was also found that the increase in initial concentration increased the adsorption capacity. The highest nitrate adsorption capacity showed by 1 gram adsorbent for 0.167 mg/g, and at nitrate initial concentration 80 mg/L, for 1.831 mg/g. Adsorption isotherm of nitrate on activated VA was determined and figured. These isotherms were modelled according to Freundlich and Langmuir adsorption isotherm