Efektivitas Pembelajaran Stereokimia Berbasis Visualisasi 3d Molekul untuk Meningkatkan Kemampuan Spasial

Penelitian ini bertujuan menyelidiki keefektifan program pembelajaran stereokimia berbasis visualisasi 3D molekul menggunakan salah satu chemical drawing software berbasis open source yakni Avogadro, dan animasi kekiralan melalui komputer untuk meningkatkan kemampuan spasial mahasiswa calon guru. Studi menggunakan quasi experimental control group pretest-posttest design. Instrumen penelitian terdiri dari 25 soal pilihan ganda disertai alasan, disusun berdasarkan indikator tiga dimensi utama kemampuan spasial. Penelitian dilaksanakan di satu LPTK di Provinsi Lampung, semester ganjil Th. Akademik 2014/2015. Subjek penelitian terdiri dari kelas kontrol dan kelas eksperimen, masing-masing ada sebanyak 30 mahasiswa. Hasil penelitian menunjukkan bahwa rata-rata skor post test kemampuan spasial kelompok mahasiswa dengan pembelajaran stereokimia berbasis visualisasi 3D molekul secara signifikan lebih tinggi dibandingkan kelompok mahasiswa yang media pembelajarannya menggunakan molymod. Keefektifan program ditunjukkan oleh peningkatan N-gain dalam kategori sedang dan efek size (d) dalam kategori tinggi untuk ketiga dimensi utama kemampuan spasial

Synthesis of fructone from ethyl acetoacetate and ethylene glycol using phosphotungstic acid catalyst

Fructone is a perfume compound with the aroma of apples. Fructone can be synthesized through the acetalization reaction of ethyl acetoacetate and ethylene glycol using an acid catalyst. This study aims to determine the effect of the cyclohexane-water azeotropic method and to determine the optimum conditions for the synthesis of fructone using phosphotungstic acid as a catalyst. Fructone synthesis using reflux equipped with Dean-Stark apparatus. Determination of the optimum conditions includes temperature variations of 75, 78, and 81°C; mol ratio of ethyl acetoacetate and ethylene glycol 1:1.5; 1:2; and 1:3; the number of mol of catalyst 2; 1; 0.5; 0.25; and 0.125 mmol. The reaction time is 30, 60, 90, 120, 150, 180, 210, and 240 min. The synthesis products were analyzed by GC and GCMS. The optimum conditions for the synthesis of fructone were found at a temperature of 78C, the ratio of mol of ethyl acetoacetate and ethylene glycol 1: 3, the amount of catalyst was 1 mmol and the reaction time was 3 hours. Fructone produced is 93.42%

Growth Process Of Organic Vetiver Root With Potato AS Intercropping Plant

Vetiver oil (Vetiveria zizanoides) is one of Indonesia main export commodities. Vetiver root is perennial plant and generally planted with vegetables as intercropping plant. Increasing the selling price of vetiver oil can be done by transferring the production of conventional vetiver oil (non-organic) to organic vetiver oil. Demonstration of land used was one hectare, which 2,000 m2 for planting vetiver root with potato (Solanum tuberosum) as inter-cropping plant and 8,000 m2 for vetiver root without intercropping, in Sukakarya-Samarang, Garut. The planting used goat and cow dung as manure, distillate water of vetiver oil and liquid bio-pesticide as pesticide. Variables studied included plant height, number of leaf and crotch. In the first quarter of the years, the number of leaf and crotch of vetiver root with intercropping was better than vetiver root without inter-cropping. However, there was not significant difference for plant height of vetiver root, both with and without intercropping. Products of organic potato as intercropping plant of vetiver root were less than those of non-organic potato, but the latter had a better texture and durability

Green Synthesis of Some Calix[4]Resorcinarene Under Microwave Irradiation

AbstractA green synthetic procedure for the preparation of some calix[4]resorcinarenes using a household microwave oven has been carried out. This method represents a very rapid heating alternative to the conventional method that involves very long time of reactions (from 20-24h in conventional heating to 5-8min in microwave irradiation). C-4-hydroxy–3-methoxycalix[4]resorcinarene (CHMPCR), C-4-methoxyphenylcalix[4]resorcinarene (CMPCR) and C-2–phenylethenilcalix[4]resorcinarene (CPECR) was achieved by placed of resorcinol, an aldehyde, HCl and ethanol inside a household microwave oven. The product was recrystallized by methanol and analyzed by spectral analysis (FTIR, H-NMR and MS). Optimization of reaction was carried out in variation of microwave power, reaction times and reactant composition. The result shows that optimum condition of synthesis of C-4-hydroxy-3–methoxycalix[4]resorcinarene (CHMPCR) with microwave irradiation were at microwave power 332W, reaction time 8min and the mole ratio of resorcinol and 4-hydroxy-3-methoxyphenylbenzaldehyde 1:1. This parameter gave product in 97.8% (53.7% after recrystallization). The CPECR synthesis using resorcinol and cynnamaldehyde (1:1) at microwave power 332W for 5min afforded the product in 97.3% (44.5% after recrystallization). Whereas the reaction of resorcinol and 4-methoxyphenylbenzaldehyde (1:1.2) at microwave power 264W for 5min gave CMPCR in 99.5% (68.6% after recrystallization)

The Effects of Using Predict-Observe-Explain Strategy Assisted by Conceptual Change Text Towards the Conceptual Mastery of Prospective Primary School Teachers on the Matter and Its Changes

This research aims at determining the differences in the increase of conceptual mastery of the matter and its changes between students who study with the Predict-Observe-Explain Strategy assisted by Conceptual Change Text (POE-ACCT) and students who study with the Expository Strategy. This study involved 63 students who were divided into 2 groups, a control group (33 students) and an experiment (30 students). The research instrument is in the form of a five-tier diagnostic test. The instrument has gone through an expert and empirical validation process. The data obtained were analyzed with descriptive and inferential statistics. The results showed a significant increase in the conceptual mastery of the experimental group (N-gain = 0.26) and in the control group (N-gain = 0.06), which were significant (p < .05). The POE-ACCT strategy was found more beneficial compared to the Expository Strategy in increasing the conceptual mastery of the prospective elementary school teachers. Although the POE-ACCT strategy provided an increase in the conceptual mastery, an increase of 0.26 was categorized in a low category and this indicated the need for improvement of the strategy