JKPK (Jurnal Kimia dan Pendidikan Kimia)
Not a member yet
222 research outputs found
Sort by
Practicality Analysis of Developing the Student Worksheet Oriented Blended Learning in Acid Base Material
Get PDFThis study aims to produce a Student Worksheet (LKPD) in an integrated manner with blended learning oriented, the learning was carried out based on 1) the online and offline activities of students; and 2) student responses. The design of this study was using the stages of defining, designing, and developing, followed by testing. Data collection had been conducted by using instruments for measuring student activity and responses. The results of this study indicate that 1) the online and offline activities of students were 97.03 and 98.33%, respectively and 2) the results of the questionnaire responses of students were 93.33%. Based on the results of the response and online and offline activities it can be indicated that the development of LKPD is very practical to be use in acid-base subject learning.Â
Synthesis and Determination Level of Calcium-Phosphate Hydroxyapatite (HAp) from Chicken Eggshell
Get PDFThe purpose of this study was to synthesize bio-ceramics hydroxyapatite (HAp) from local chicken eggshell and broiler chicken eggshell. The synthesis was done by using precipitation method with sintering temperature 1000ºC. In addition, to determine the levels of calcium-phosphate contained in HAp bioceramics AAS and Spectrophotometer UV-Vis were used. The results show that of 10 grams of each eggshell powder can produce 8.8-9.8 g of HAp powder. Determination of calcium level in HAp by AAS was about ± 71.23% from local chicken eggshell and ± 78.62% from broiler chicken eggshell. Whereas determination of phosphate level in HAp using Spectrophotometer UV-Vis was about ± 67.22% from local chicken and ± 73.75% from broiler chicken eggshell
Antioxidant Activity of Methanol Extract of the Purun Tikus (Eleocharis dulcis) Leaves
Get PDFPurun tikus (Eleocharis dulcis) is a kind of swamp plant, can be found in open water areas, both in swamps and rice fields. Purun tikus is an indicator vegetation of acidic sulfate soil. Chemically, plants that able to adapt to special or extreme conditions, usually produce a compound that are unique and have unique bioactivity as well. This paper reports a phytochemical screening of Purun tikus methanol extract and its antioxidant activity. The results showed that the methanol extract of Purun tikus leaves contained phenolic compounds, flavonoids, tannins and terpenoids. By using DPPH method as an antioxidant test, the methanol extract of purun tikus leaves showed a strong activity, with IC50 value was 58.58 ppm while vitamin C had an IC50 value of 4.50 ppm
Analysis of a Quantitative Relationship Between the Structure and Analgesic Activity of Meperidin Derivatives Using Semi-Empirical AM1 Method
Get PDFThis research aims were to analize a quantitative relationship between the structure and analgesic activity of meperidine derivatives and to determine the Hansch equation between meperidine derivatives and their analgesic activity. The study was done by computer calculation (in sillico) using semiempirical method of AM1. The first stage was molecules modelling of meperidine derivative compounds, followed with performing the process of geometric optimization. The second step was to determine the descriptor value in the form of electronic, steric, and hydrophobic descriptors. The last stage was done by statistics analysis using multiple regressions with backward model. The results showed that analgesic activity was significantly influenced by variation of descriptors, especially electronic descriptor which has more dominant influence than steric and hydrophobic descriptors. The most influential descriptor is the charge on N atoms, since N atoms are an important component in analgesic compounds
Phytochemical Test and Antibacterial Test of Rhizopora apiculata Mangrove-Root against Escherichia coli and Staphylococcus aureus Bacteria
Get PDFIndonesia has many kinds of mangrove but they have not been widely utilized as health food and medicinal products because of the limited information and research on the content of bioactive compounds in the mangroves. One of the mangrove species that are found in the Bontang mangrove forest, East Kalimantan is R. apiculata. It is used as fuel, building materials, shipbuilding, and as traditional medicine. This study aims to determine the class of secondary metabolites compounds and the antibacterial activity of methanol extract of R. apiculata mangrove roots. The extraction was performed by maceration method using methanol solvent. Secondary metabolites compounds class in the mangrove sample was determined qualitatively by using several phytochemical reagents. Antibacterial test against E. coli and S. aureus were performed using diffusion method with various concentration of the roots-mangrove methanol extract of 500, 250, and 125 ug/well. Incubation was performed in various time of 12, 24, 48 and 72 hours. Phytochemical test results showed that the roots-mangrove methanol extract of R. apiculata contained secondary metabolites classes of alkaloids, flavonoids and triterpenoids. The extract does not inhibit the growth of E. coli, but it could inhibit the growth of S. aureus at 500 ug / well with incubation time of 12, 24, 48 and 72 hours and have inhibition zones of 7.95 mm, 8.3 mm, 8.0 mm, and 7.0 mm, respectively. At a concentration of 250 ug/ well with an incubation time of 48 hours has a 7.5 mm of inhibition zone. Those inhibitions are relatively weak category
An Optimization of Functional Monomer, A Preliminary Study of Meropenem Imprinted Polymer as Selective Sorbent
Get PDFMolecularly imprinted polymer is a polymer that synthesized together with targeted molecule (analyte) through polymerization process. When the polymerization has completed, extraction is taken to pull the analyte out of the polymer, and it will give a specific “frame†of targeted molecule which leave cavities and further is used to give specific recognition of the analyte. Functional monomer, template molecule, crosslinker agent, porogenic solvent and initiator are the main components involved in the synthesis of this kind of polymer. The right functional monomer is needed to make polymer building block with high selectivity when used as sorbent. The selection of suitable and precise functional monomer has been elaborated in this study. methacrylate acid, itaconic acid and acrylamide is then studies as functional monomer that will be chosen to give the best polymer performance as sorbent. From IR spectrum results, it can be concluded that polymer has been synthesized successfully. Peak at 1157 cm-1 which is a peak of C-N bond from β-lactam ring support this statement. Finally, it can be concluded that methacrylate acid is the best functional monomer for making polymer as sorbent for meropene
Conceptual Understanding Analysis Through Two-Tier Model Diagnostic Tests on Acid-Base Materials
Get PDFThis research aims to organize instrument of computer-based two-tier multiple choices diagnostic test. The research method used was quantitative and qualitative method. This research was conducted in class XI MIPA 3 and XI MIPA 4, Senior High School 1 Ungaran. The research procedure was designed starting from selecting the difficult subjects, arranging test plan, designing two-tier model of diagnostic test, designing web, tryout, analysis of tryout data, diagnostic test, interview, and analysis of concept understanding. The finding of the research that the instrument was valid and reliable. The result of students’ concept understanding of acid-base on implementation class showed that 9 of 35 students (26.86%) understood the concept thoroughly, 4 of 35 students (8.43%) got misconception, 1 of 35 students (3.71%) kept guessing, 12 of 35 students (34.86%) grasped less understanding while 9 of 35 students (26.14%) did not understand the concept of Acid-Base. The inference drawn of this recent study is that computer-based two-tier diagnostic test instrument can be used to analyze students’ concept understanding about acid-base by combined interpretation of students’ answers with several categories of concept understanding, misconception, guessing, less understanding of the concept, and failure to understand the concept. Â
Study of Solvent Mixture of Aqua destillata–Acetone in the Making of Cellulose Propionate Membrane
Get PDFIn this article we will discuss the solubility test of cellulose propionate on various ratio variations of aqua destillata–acetone. Previously cellulose propionate was dispersed into a solvent mixture of aqua destillata-acetone. Variation in volume ratio of aqua destillata–acetone was 4: 1; 3: 1; 2: 1; 1: 2; 1: 3, and 1: 4. The mixture is stirred for 48 h and filtered. The solid was then put into a mold with a sintering technique at a temperature of 100oC for 5-10 minutes. Membrane characterization includes solubility parameters (δmix), density using picno meter and calculation of sample dimensions, and swelling index. The results of the calculation of solubility parameters (δmix) solvent mixture of aqua destillata–acetone (1: 4) close to δ cellulose acetate (12.47). Differences in membrane density using picno meter and calculations in dimensions indicate the presence of cavities or pores in the membrane. Difference in density value of both calculations occurs in the membrane with a mixture of aqua destillata–acetone (1: 3). The highest hydrophobicity properties were obtained in the ratio of solvents of destillata–acetone (1: 4) with the smallest swelling index (48.14%)
Synthesis of Natural Ni/Zeolite Activated by Acid as Catalyst for Synthesis Biodiesel from Ketapang Seeds Oil
Get PDFThe purpose of this research are to know the effect of addition Ni on the acidity value of Ni/zeolite catalyst and to know the best combination nickel and Zeolit activated by acid as a catalyst ofthe cracking process during synthesis biodiesel from ketapang seed oil. The Ni/Zeolite catalysts were prepared by immersing the zeolite activated by HCl 4 M into Ni(NO3)2 solution with concentration variation of0%, 5%, and 10%. The catalysts were characterized using XRD, SEM and FTIR. The results showed that the more Ni the more acidity value of the catalyst. The best quality of biodiesel was synthesized using combination catalysts of 5% Ni/Zeolite activated by acid