JKPK (Jurnal Kimia dan Pendidikan Kimia)
Not a member yet
222 research outputs found
Sort by
APLIKASI LIGNOSELULOSA SULFONAT AMPAS TEBU UNTUK ADSORPSI ZAT WARNA TEKSTIL KATIONIK BASIC VIOLET 10
Get PDFTelah dilakukan penelitian aplikasi lignoselulosa sulfonat ampas tebu untuk adsorpsi zat warna tekstil kationik basic violet 10. Lignoselulosa sulfonat disintesis dari limbah ampas tebu melalui proses ekstraksi dan sulfonasi menggunakan larutan induk yang terbuat dari 168 g Na2SO3 dan 1 g NaHCO3. Penelitian ini menggunakan metode eksperimen di laboratorium. Prosedur kerja yang dilakukan adalah dengan membuat adsorben alami, bebas ekstrak, dan lignoselulosa sulfonat kemudian mengidentifikasi gugus fungsi dengan metode spektrofotometri menggunakan spektrometer infra merah. Uji adsorpsi dilakukan pada berbagai variasi waktu interaksi 5, 10, 20, 40, 80, dan 160 menit pada pH 6,0. Untuk analisa kuantitatif dilakukan dengan metode spektrofotometri menggunakan spektrofotometer UV-Vis pada panjang gelombang 542,75 nm.Kandungan komponen ekstraktif total (total extractive content) dari ampas tebu yang diteliti adalah 15,2 %. Adsorben lignoselulosa sulfonat memiliki daya adsorpsi paling tinggi terhadap zat warna tekstil kationik basic violet 10 yaitu sebesar 87,42 %, sedangkan adsorben alami 66,3% dan adsorben bebas ekstrak 82,64%. Waktu optimum adsorpsi oleh adsorben alami adalah 40 menit, sedangkan untuk adsorben bebas ekstrak dan lignoselulosa sulfonat adalah 80 menit
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
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
Digital Literacy Analysis of Chemistry Education Students in Using the ChemDraw Application
Get PDFStudents digital competence abilities can be measured using the individual competence framework. There are five indicators used: information, communication, content creation, safety, and problem-solving. This study analyses students digital literacy profile with high, medium, and low ChemDraw skills. This research is a qualitative descriptive study. The trial was conducted on 25 Chemistry Education Students at UIN Walisongo Semarang with high, medium and low ChemDraw skills. Data were obtained using ChemDraw test instruments, observation and questionnaires. The data obtained were analysed based on digital literacy indicators to obtain student digital literacy profiles. The results showed that the digital literacy level of students with high ChemDraw skills had a moderate level of digital competence. Students with medium ChemDraw skills have a moderate level of digital competence. Meanwhile, students with low ChemDraw skills have a low level of digital competenc
Influence Comparison of Precursors on LiFePO4/C Cathode Structure for Lithium Ion Batteries
Get PDFElectricity is the most energy demanded in this era. Energy storage devices must be able to store long-term and portable. A lithium ion battery is a type of battery that has been occupied in a secondary battery market. Lithium iron phosphate / LiFePO4 is a type of cathode material in ion lithium batteries that is very well known for its environmental friendliness and low prices. LiFePO4/C powder can be obtained from the solid state method. In this study the variables used were the types of precursors : iron sulfate (FeSO4), iron oxalate (FeC2O4) and FeSO4+charcoal. Synthesis of LiFePO4/C powder using Li:Fe:P at 1:1:1 %mol. Based on the XRD results, LiFePO4/C from FeSO4+charcoal shows the LiFePO4/C peaks according to the JCPDS Card with slight impurities when compared to other precursors. XRD results of LiFePO4/C with precursors of FeSO4 or FeC2O4 shows more impurities peaks. This LiFePO4/C cathode is paired with lithium metal anode, activated by a separator, LiPF6 as electrolyte. Then this arrangement is assembled become a coin cell battery. Based on the electrochemical results, Initial discharge capacity of LiFePO4/C from the FeSO4 precursor is 19.72 mAh/g, while LiFePO4/C with the FeC2O4 precursor can obtain initial discharge capacity of 17.99 mAh/g, and LiFePO4/C with FeSO4+charcoal exhibit initial discharge capacity of 21.36 mAh/g. This means that the presence of charcoal helps glucose and nitrogen gas as reducing agents
Using Think-Pair-Share to Develop Students' Social and Emotional Competencies in Chemistry Learning
Get PDFThe aim of this study was to analyze students' social and emotional competencies through the integration of Think Pair Share (TPS) and a Social and Emotional Learning (SEL) approach to topics related to AcÂids and Bases. Social and emotional learning (SEL) is the process through which children and adults underÂstand and manage emotions, set and achieve positive goals, feel and show empathy for others, establish and maintain positive relationships, and make responsible decisions.. The study involved thirty-five 11th grade students in one of private school in Jakarta and was conducted between January and April, 2017. A qualitative methodology was employed to analyze students’ social and emotional competencies using interÂviews, classroom observations, reflective journals, and student worksheets. The application of a SEL apÂproach was carried out by integrating it with a TPS strategy. In the Think stage students were given the opportunity to explore their understanding of acids and bases and to solve problems individually. In the Pair stage they could communicate their insights to the group, and in the Share stage they had occasion to present their group perspectives and respond to others. The five social and emotional competences found in this study were; self awareness, self management, social awareness, relationship management, and reÂsponsible decision making. Self awareness was demonstrated by understanding a student’s abilities, their needs, and their self- confidence. Self management was indicated by a student’s ability to manage pressure, plan strategies, and seek help. Social awareness competencies were analyzed through the development of students' attitudes to diversity and how they demonstrated care for friends. Relationship management comÂpetencies were identified by observing a student’s ability to manage friendships, how they overcame differÂences, and whether they provided assistance to each other. The responsible decision making competency was determined by observing how students made decisions when trying to solve a problem and whether they were able to plan a strategy when facing pressure. Whilst integrating SEL the researchers were chalÂlenged by the need to empower students, encourage teachers to stimulate students’ social and emotional competencies, and to manage time constraints. Integrating SEL into chemistry learning provided opportuniÂties for students to develop their social and emotional competencies through independent thinking activities, group discussions, and presentations to their peers
Hydroxiapatite (HAp) Bioceramics Made from The Caletaiya presclupta Snail Shells from Poso Lake
Get PDFBioceramic Hydroxyapatite (HAp) was a derivated chemical synthetic compound from calcium phosphate commonly used to care for hard tissue damage. Bioceramic Hydroxyapatite can be synthesized from the compounds rich with calcium contains. This study treated the synthesis and physicochemical Characterization of the HAp made from Celetaiya persclupta snail shells obtained from Poso lake. From the characterization of the sample C. presclupta shells obtained the water contains 0.50±0.00%; ash contains 0.9913±0.0017g/g; potassium 0.0005±0.00007g/g; calcium 0.0391±0.0059g/g; phosphate 0.0221±0.0009g/g; phosphorus 0.0111±0.0005 and the ratio of Ca/P 1.7382±0.1994%. The synthesis of HAp by base precipitation method showed the yield of synthesis 85.2891±4.2496% with the level of material reduction during synthesis 18.0442±1.1684%. The result of characterization of the HAp showed that the potassium contains 0.0002±0.00003g/g; calcium 0.0121±0.0031g/g; phosphate 0.0167±0.0013g/g; phosphorus 0.0084±0.0007g/g; ratio of Ca/P 1.3724±0.2736%; porosity 9.9929±0.7626%; swelling ability 24.8416±1.4989%; and biodegradability 10.8958±1.1781%. The overall results concluded that the C. presclupta snail shells could become a source of Bioceramic Hydroxyapatite (HAp).Â
The Effect of Bilimbi Juice Levels and Soaking Time on The Growth of Aspergillus flavus, L. in Corn Kernels
Get PDFproduces aflatoxin compounds that are hepatocarcinogenic. The study intends to analyze the effect of concentration and soaking time of corn kernels in bilimbi (Averrhoa bilimbi) juice on the growth of Aspergillus flavus. The experimental research, corn kernels soaked in star fruit juice concentrations of 5, 10, and 15% v/v, for 10, 20, and 30 minutes. Corn kernels are taken and planted in AFPA media. Microscopic observations every hour to observe the growth of Aspergillus flavus from planting to growth. Data were analyzed using two-way ANOVA, followed by LSD test with 95% CI. Research shows there is a decrease in pH caused by increased levels of star fruit juice. Concentrations of bilimbi fruit and soaking time can inhibit the growth of Aspergillus flavus in corn kernels. The optimal inhibitory potential was found at 15% v/v with a soaking time of 30 minutes
Students' Cognitive Analysis using Rasch Modeling as an Assessment for Planning of Strategies in Chemistry Learning
Get PDFRasch modelling based on assessment can help teachers analyze the students' cognitive knowledge level and development. However, teachers are considered unsuccessful in teaching where the achievement of indicators in learning science, such as chemistry, is not holistically actualized. This study aimed to analyze High School students' knowledge in Banjarmasin City, especially on students' knowledge (cognitive aspect), using the Rasch modelling data analysis technique and exploring how chemical learning strategies are planned based on the symptoms of the data obtained. The data collection technique used a dichotomous format test technique (multiple choices). The research method used was descriptive with a quantitative approach to examine Rasch's various data, which was then interpreted qualitatively to describe the issues raised. The study results show that person reliability (students) based on Rasch modelling analÂysis is +0.79, and item reliability is +0.98, where the value indicates that the consistency of the participant response pattern is "sufficient." Then, the mean person measure is -0.07, while the mean item is 0.00. It means that the participants' "mean value" is below the "mean value" of the item that the students' ability is below the item's ability. The Rasch data's recapitulation value showed that the response patterns of various data symptoms and those data were interpreted. It showed students' knowledge of atomic structure material was still considered low based on the Rasch model criteria. This is a reference for making appropriate chemical learning strategy plans to improve their knowledge. In conclusion, Rasch modelling-based assessment is effectively used in analyzing students' (cognitive) ability on atomic structure material. These results produce a strategic plan like what in chemistry learning such as the importance of conducting further diagÂnoses using misconception tests, identifying students' learning styles, constructing stuÂdents' knowledge through the concept of chemical representation, and developing appropriate learning media according to their needs (students)
