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Alotrop Jurnal Pendidikan dan Ilmu Kimia
Published by Universitas Bengkulu
ISSN : 22528075     EISSN : 26152819     DOI : -
Core Subject : Science, Education,
Chemistry Education
Welcome to the Journal Alotrop, is an Open-Acces and peer-reviewed journal aims to publish scientific articles related to chemistry and education :i.e an interaction between natural sciences, educational sciences, technologies and management for both education and sciences and wise use of resources. We particularly encourage manuscripts that discuss contemporary research that can be used directly or inderecly in adressing critical issues and sharing of advanced knowledge and best practices in chemistry and education.
Arjuna Subject : Kimia(semua kategori) - Kimia (Lain-Lain)
Articles 12 Documents
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Search results for , issue "Vol 3, No 2 (2019)" : 12 Documents clear
UPAYA PENINGKATAN SENSITIVITAS NANOPARTIKEL PERAK UNTUK ANALISIS ION MERKURI(II) SECARA CITRA DIGITAL DENGAN PENAMBAHAN NaCl Edo Prasetia; M. Lutfi Firdaus; Elvinawati Elvinawati
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10120

Abstract

The very small concentration of mercury (Hg) in the environment is difficult to detect, so an accurate and sensitive method is needed in order to detect the concentration. Therefore, the purpose of this study was to develop an accurate and sensitive method based on the use of digital imaging methods and silver nanoparticles (AgNPs) as colorimetric sensors for mercury(II) ions (Hg2+) analysis. The process of making AgNPS is done by a bottom up method involving a reduction reaction. The precursor used is 1 mM AgNO3 solution and as bioreductor is an antioxidant compound present in extract of chili pepper (Capsicum frutescens L) with ratio 1: 9. Contact time variation 15, 30, 45, 60 min and 1, 2, 7 days. Addition of NaCl 0.5 and 1 M NaCl were used to increase the sensitivity of AgNPs as colorimetric sensors of Hg2+ ions. Digital Image Method is used to analyze Hg2+ ions at ppb concentration level. The results of the most optimum silver nanoparticles synthesized at the time of solar heating is 60 minutes. The addition of NaCl 0.5 M and 1 M into AgNPs is able to increase the sensitivity of AgNPs. Limit of Detection (LoD) of AgNPs added NaCl 0.5 M and 1 M was able to detect Hg2 + ions by 3.02 ppb and 2.46ppb.
PERBANDINGAN MODEL PEMBELAJARAN KOOPERATIF TIPE THINK TALK WRITE (TTW) DAN CREATIVE PROBLEM SOLVING (CPS) TERHADAP MINAT DAN HASIL BELAJAR KIMIA SISWA Ghea Sefriza Pratiwi; Amrul Bahar; Rina Elvia
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10497

Abstract

The purpose of this study is to describe the comparison of Think Talk Write learning models and Creative Problem Solving learning models to the interests and learning outcomes of chemistry in basic chemical law material. This research was conducted in January-May 2019. The research conducted was a kind of quasi-experimental research. The population of this study was class X MIA, totaling 136 students in SMAN 8 Kota Bengkulu in the academic year 2018/2019. Sampling was carried out after the normality and homogeneity test, so the X MIA 2 class was selected using Think Talk Write and X MIA 3 models that used the Creative Problem Solving model with a total of 68. Analysis of the data used was mean, normality test, test homogeneity, interest questionnaire analysis, N-Gain Score test and hypothesis test (t test). In general, both of these learning models are able to increase students 'interest and learning outcomes of chemistry, where the percentage of students' interest in learning chemistry in the Think Talk Write model is 80.5% and categorized as good, for the class of Creative Problem Solving model the percentage is 76.6% and also categorized as good. For the value of N-Gain score on Think Talk Write (TTW) class is and categorized as high while in the Creative Problem Solving class is 0.62 and is categorized as medium. The t-test results on the affective aspects are sig. (2-tailed) of 0.015 and on the cognitive aspect of 0.001. It states that there are significant differences in the interest and learning outcomes of chemistry that apply the Think Talk Write (TTW) learning model and Creative Problem Solving
PERBANDINGAN HASIL BELAJAR KIMIA SISWA MENGGUNAKAN MODEL PEMBELAJARAN JIGSAW DAN THINK PAIR SHARE (TPS) DENGAN PENDEKATAN SCIENTIFIC PADA KELAS X IPA DI SMAN 3 KOTA BENGKULU TAHUN AJARAN 2018/2019 Pepi Pepi; Hermansyah Amir; Rina Elvia
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10121

Abstract

This study aims to compare the Think Pair Share (TPS) and Jigsaw learning models with the Scientific approach to the results and interest in learning chemistry in the mole concept material in class X MIPA SMAN 3 Kota Bengkulu. This research was carried out in January-April 2019. This type of research was a quasi-experimental study with a population of all classes of X MIPA totaling 180 students. How to obtain samples through normality and homogeneity tests through cluster random sampling technique, where two classes of research samples were obtained, namely Experiment 1 class which applied Think Pair Share (TPS) learning model and experimental class 2 which applied the Jigsaw learning model. Based on the results of the study it was concluded that the two learning models proved to be able to increase students' learning outcomes and interest in chemistry and reach KKM, namely 76 with the acquisition of the N-Gain Score in the Think Pair Share (TPS) learning model of 0.71 and in the Jigsaw learning model of 0, 79 where both values of N-Gain Score have a high category. The results of students' interest in learning chemistry in the experimental class 1 were 75.93% with good categories and the results of the learning interest in the experimental class 2 were 82.01% with very good categories. The results of hypothesis testing through t test on the cognitive aspect sig. (2-tailed) of 0.002 and in the affective aspect of 0,000. It states that there are significant differences in the results and interest in learning chemistry that apply Think Pair Share (TPS) and Jigsaw learning models with the Scientific approach.
SINTESIS METIL ESTER DARI LIMBAH KELAPA SAWIT DENGAN SONOCHEMISTRY DAN CRACKING MENJADI BIOFUEL DENGAN KATALIS CrMo/HZ Jertadi Putri Dhani; Agus Sundaryono; Dewi Handayani
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10498

Abstract

This study aims to calculate the percentage methyl ester converted to biofuel through catalytic cracking reaction,analyzes component and determine characteristics using catalyst CrMo/HZ. This research begins with impregnation sample preparation which includes heating oil,degumming,bleaching and determination free fatty acid (FFA). Methyl ester obtained from liquid waste conversion crude palm oil through an esterification and transesterification reaction with H2SO4 and NaOH catalyst with sonochemistry methode is a method that utilizes ultrasonic waves origanating from a device is ultrasonic cleaner for one hour at temperature 60oC. The methyl ester obtained was cracked with a CrMo/HZ catalyst which was carried out for 2 hours at temperatur 380oC. To find out the components of compounds formed in methyl ester, an analysis was performed using GCMS then characteristics of biofuel are determined from the result of catalytic cracking obtained through acid number testing,density,viscosity,pour point and fog point. The result obtained from the conversion of methyl ester to biofuel with Crmo/HZ Catalyst Is 60,17% And For Testing The Physical Characteristics Of Biofuel Namely The Acid Number 1,87 Mg KOH/G, density 0,804 g/cm3, viscosity 1,162 Cst, pour point 0oC and fog point 1,4oC. The result of cracking produce a consituent component of biofuel namely gasoline 33,67%, kerosene 16,26%, gas oil 10,24% beside that, there are still methyl ester as much as21,89%.
PENERAPAN MODEL PEMBELAJARAN AUDITORY, INTELLECTUALY DAN REPETITION (AIR) DENGAN MENGGUNAKAN MEDIA PEMBELAJARAN KARTU ARISAN UNTUK MENINGKATKAN AKTIVITAS DAN HASIL BELAJAR SISWA KELAS X MIA 1 SMAN 8 KOTA BENGKULU Diana Sumiati; Amrul Bahar; Dewi Handayani
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.9873

Abstract

This study aimed to improve learning activities and learning outcomes of students in class X MIA 1 of Senior High School (SMAN) 8 Bengkulu on the subject of chemical bonds through the application of Auditory, Intellectualy, and Repetition (AIR) learning models by using learning media with lottery card. This study is a classroom action research consisting of three cycles, each cycle consisting of four stages, planning, action, observation and reflection. In collection of data was done by non-test and test methods, teacher observation sheets, student observation sheets and post-test. The data was processed by using simple quantitative data analysis techniques, the total value of each student, the average value, the percentage of absorptive power, learning completeness and the average observation score.The results of the study in the 2018/2019 school year showed that the application of the Auditory Intellectualy Repitition learning model using learning media with lottery  cards in class X MIA 1 of SMA Negeri 8 Kota Bengkulu could improve teacher activities, student activities and student chemistry learning outcomes. This can be seen from the average score of teacher activities in the first cycle to the third cycle in a row : 23, 27.5 and 31.5. Student activity also showed improvement in each cycle. The average score of student activity in cycle I to cycle III was sequentially 20, 25 29.5. Learning outcomes also increase in each cycle. This can be seen from the average value of the test results in each cycle, in the first cycle of 61.82, in the second cycle of 67.88, in the third cycle of 79.09. Classical absorption in cycle I, cycle II, cycle III are 61.82%, 67.88%, 79.09%, with the percentage of completeness learning in each cycle of 42%, 73%, and 87.8 %.
UJI AKTIVITAS ANTIBAKTERI DAUN JERUK KALAMANSI (Citrofortunella microcarpa) TERHADAP BAKTERI Staphylococcus aureus DAN Escherichia coli Deza Oktasila; Nurhamidah Nurhamidah; Dewi Handayani
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10122

Abstract

This study aims to examine the antibacterial activity of ethanol extract and essential oil of Kalamansi citrus leaves (Citrofortunella microcarpa) against Staphylococcus aureus and Escherichia coli bacteria. The raw material of Kalamansi citrus leaves is obtained from the Village of Pondok Kubang, Bengkulu Tengah (3.70060S, 102.35780E). Ethanol extract from Kalamansi citrus leaves was obtained by maceration using ethanol 96%, then ethanol extract was made dilution concentration 40 ; 20; , 10; and 5%. The essential oil of Kalamansi citrus leaves is obtained by water-vapor distillation, then made variations of concentration 20;, 15;, 10;  and 5%. The method used to test the antibacterial activity is the paper disc diffusion method , the antibacterial activity is shown by the diameter of the inhibiting  zone formed. The data of antibacterial test result were analyzed by using One Way Anova test which showed the effect of treatment on the growth of test bacteria seen from the value (P <0,01) and continued by Duncan test to know the effect of the treatment. The results showed that ethanol extract of Kalamansi citrus leaves had antibacterial activity against S. aureus and E. coli bacteria with moderate inhibitory diameter is  7.20 and 5.73 mm at concentration 40%, while antibacterial activity on essential oil of Kalamansi citrus leaves is categorized as strong with inhibition zone diameter is 14.83 and 13.00 mm at concentration 20%.
IMPLEMENTASI MODEL PEMBELAJARAN LEARNING CYCLE 5E PADA MATERI HIDROLISIS GARAM DI KELAS XI MIPA SMAN 1 BENGKULU TENGAH TAHUN AJARAN 2018/2019 Isnaini Safitri; Dewi Handayani; Salastri Rohiat
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10507

Abstract

This study aims to determine the effect of the implementation of the 5E Learning Cycle learning model on increasing mastery of concepts in the subject matter of salt hydrolysis. This research was conducted at SMAN 1 Bengkulu Tengah in the 2018/2019 class XI MIP academic year in one meeting. The trial implementation of the 5E Learning Cycle model uses a pre-experimental research design with the form of one-group pretest-posttest design. The study was  conducted in February 2019 at SMAN 1 Bengkulu Tengah. The population in this study were students of class XI MIPA in SMA Negeri 1 Bengkulu Tengah academic year 2018/2019 which amounted to 126 people. Determination of the study sample was carried out by testing the normality of the population. The study sample was taken using simple random sampling technique obtained by students of class XI MIPA 1, the number of students was 31 people. The instruments used consisted of student response questionnaire sheets and concept mastery assessment sheets. Student response data, mastery of concepts were analyzed descriptively and their improvement was analyzed by analysis of gain scores. The results showed that students gave a positive response to the 5E learning cycle model with an average value of 4.2 from a maximum value of 5 which indicated that students felt greatly helped by learning with the 5E Learning Cycle model. This is also supported by a high score increase on mastery of concepts which obtained an average value of 76.97 which is in the effective category. Based on the results of the study, it was concluded that the implementation of the 5E learning cycle model in the subject matter of effective salt hydrolysis to improve mastery of concepts in class XI MIPA SMAN 1 Bengkulu Tengah Academic Year 2018/2019.
STUDY ON Hibiscus tiliaceus LEAVES AS ANTIBACTERIAL AND ANTIOXIDANT AGENTS Mohamad Syahmie Samsudin; Yosie Andriani; Purbowatiningrum Ria Sarjono; Desy Fitrya Syamsumir
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.9874

Abstract

This study aimed to evaluate antioxidant and antibacterial activities of methanol, hexane, dichloromethane, ethyl acetate, and water crude sample fractions of H. tiliaceus leaves. Various type of samples play an important role to determining which compound that will give the positive results in antioxidant test (inhibiting free radical scavenging activity) which they probably have potency for preventing the cancer disease. Furthermore, those types of samples were also tested to the antibacterial test as their possibilities to be created as new antibiotics in the future. This research also focused on what compound groups that actually present in H. tiliaceus leaves by using the phytochemistry test. Antioxidant potency of H. tiliaceus leaves extracts for the radical scavenging activity for quantitative assay was measured by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. The antibacterial potency was measured by the Muller Hinton Agar (MHA) by applied the sample chemical crude in the plate. The result showed that all chemical crude of H. tiliaceus leaves has high antioxidant property as methanol crude (MC) 308.416%; hexane crude (HC) 232.837%; dichloromethane crude (DC) 150.837%; ethyl acetate crude (EC) 73.623% and water crude (WC) 71.777% with respected to the readings of  100% from quercetin (Q) as a positive control. From antibacterial result, entire samples had shown the positive results towards both gram positive (Staphylococcus aureus and Bacillus subtilis) and gram negative bacteria (Klebsiella pneumonia and Escherichia coli). The ranges of the inhibition zone were both at 7-10 mm and 10-15 mm. The phytochemistry test determine that the samples actually contained a lot of compounds which were proteins, carbohydrates, phenols/tannins, flavonoid, terpenoids, glycosides and also steroid. It is clearly indicated that H. tiliaceus leaves have potential to be used against the antioxidant and also as new antibacterial agents
PERBANDINGAN MODEL PEMBELAJARAN KOOPERATIF TIPE STUDENT TEAMS ACHIEVEMENT DIVISION DAN TEAM GAMES TOURNAMENT BERBANTUAN MEDIA KARTU KATION ANION TERHADAP HASIL BELAJAR KIMIA Anisa Rosmalara; Rina Elvia; Salastri Rohiat
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10495

Abstract

This study aims to determine the differences in student chemistry learning outcomes between classes that apply the Student Teams Achievement Division (STAD) learning model with a class that applies the Team Games Tournament (TGT) learning model to chemical compounds. This type of research is quasi-experimental with a population of class X IPA Academic Year 2018/2019 which amounts to 204 students. Samples were obtained from the results of the normality test and homogeneity test, namely class X IPA 4 which applied the STAD learning model with cation anion media and class X IPA 6 which applied the TGT learning model with anion cation card media. This study was conducted in January-March 2019. Analysis of the data used is the average (mean), normality test, homogeneity test, and hypothesis testing (u test). In general, the two models were able to improve learning outcomes, where the STAD learning model obtained higher results, namely 79.723. Data on students' chemistry learning outcomes were obtained from the pretest and posttest values where the average value of the increase in cognitive learning outcomes for the STAD class and the TGT class was 57,222 and 46,944. Through a series of statistical tests hypotheses were tested using the u test with a significant level (? <0.05) indicating the value (Sig. 2-tailed) of 0,000. This shows that there are significant differences in learning outcomes between classes applying the STAD learning model assisted by anion cation cards with classes that apply the TGT learning model assisted by anion cation cards.
PERBANDINGAN SENSITIVITAS NANOPARTIKEL PERAK DENGAN REDUKTOR ALBUMIN DARI TELUR AYAM DAN BEBEK UNTUK ANALISIS MERKURI Fikri Fadillah Azhar; Elvinawati Elvinawati; Nurhamidah Nurhamidah
ALOTROP Vol 3, No 2 (2019)
Publisher : University of Bengkulu

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33369/atp.v3i2.10508

Abstract

The aims of this study were determine the protein level of chicken egg albumin (Gallus Sp.) And duck egg albumin (Anas domestica) also optimum conditions, sensitivity, and LOD values of silver nanoparticles (NPP) synthesized using bioreductors of chicken (Gallus Sp.) egg albumin and duck (Anas domestica) egg albumin for analysis of mercury ions (II). This research was conducted at the Laboratory of Chemistry FKIP UNIB on April - July 2019. Protein levels of chicken egg albumin and duck egg albumin were obtained in the amount of 0.210 gr / 100 ml and 0.234 gr / 100ml, respectively. The NPP synthesized in this study was carried out by mixing silver precursors derived from 10 mM AgNO3 solution and 1% albumin solution as bioreductors of each chicken egg albumin solution and duck egg albumin. The optimum condition of NPP synthesized using chicken egg albumin bioreductor and duck egg albumin was the same, with the number of comparisons between AgNO3 and albumin solutions namely 1: 2 and stirring time of 30 minutes. The results showed that NPP synthesized using chicken egg albumin and egg albumin ducks had good sensitivity to Hg metal with the addition of Hg metal concentrations above 50 ppm that be marked with significant color changes from brownish yellow to clear. LOD values in each NPP synthesized using bioreductors of chicken egg albumin and duck egg albumin were 3334 ppm and 2,238 ppm, so that NPP synthesized using bioreductor of duck egg albumin was more sensitive than NPP synthesized using bioreductor of chicken egg albumin for mercury metal analysis. This is influenced by the differences of protein levels of chicken egg albumin and duck egg albumin where the protein level of duck egg was higher than the protein level of chicken egg.

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