Yerimadesi Yerimadesi
Laboratorium Penelitian Kimia, Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Negeri Padang, Jl. Prof. Dr.Hamka Padang 25131

Published : 9 Documents
Articles

Found 9 Documents
Search

Studi Inhibisi Korosi Baja oleh Ekstrak Biji Kakao (Theobroma cacao) dalam Medium Udara Muspita, Indah; Mon, Irma; Yerimadesi, Yerimadesi
Periodic Vol 1, No 2 (2012)
Publisher : Jurusan Kimia FMIPA UNP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (71.575 KB)

Abstract

Steel very easily have corrosion in the air (atmosphere corrosion), this led to the decline of quality steel. Therefore, Inhibition of steel Corrosion Study performed by the extract of Cocoa (Theobroma cacao) in the Medium of air which aims to look at the influences of the cocoa seed extract inhibition of corrosion of steel in the medium of air.This research uses a method of reduction of weight (weight loss), identification of compound steel absorbed on the surface of steel using a FTIR spectrometer, analysis of the steel surface and done using stereo microscopes. Of research results obtained that the cacao seed extract may decrease the rate of corrosion of steel in the air with corrosion inhibition efficiency 89,46%. Increased efficiency due to the lack of inhibition adsorption on cocoa extract steel surface that has been evidenced by the results of the FTIR. Surface analysis of steel with a microscope shows the difference of surface state of specimens not coated and coated cocoa extract solution.
Penentuan Kondisi Optimum Proses Degradasi Zat Warna Methylene Blue Pada Reaktor Fotokatalitik TiO2 – PEG Pratama, Rezki; Hardeli, Hardeli; Yerimadesi, Yerimadesi
Periodic Vol 1, No 2 (2012)
Publisher : Jurusan Kimia FMIPA UNP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (12.651 KB)

Abstract

Methylene Blue merupakan zat warna dasar yang penting dalam proses pewarnaan kulit, kain mori, dan kain katun. Pembuangan zat warna ini ke lingkungan perairan menjadi ancaman serius bagi organism aquatik di dalamnya. Proses fotokatalitik dengan semikonduktor TiO2 merupakan teknologi yang potensial dalam memineralisasi zat-zat berbahaya yang sulit dibiodegradasi. Penelitian ini bertujuan menentukan jumlah kolom gelas dan lama penyinaran optimum  reaktor fotokatalitik guna mendegradasi zat warna Methylene Blue 5 ppm. Dalam penelitian ini, digunakan TiO2 Degussa P 25 dengan penambahan zat aditif PEG guna memperbaiki sifat-sifat katalis. Penelitian ini menggunakan dua varibel yaitu varibel pertama adalah  lama penyinaran, dengan 7 variasi waktu. Varibel kedua adalah jumlah kolom gelas dengan 6 variasi kolom gelas. Setelah dilakukan proses degradasi, absorbansi Methylene Blue diukur menggunakan spektrofotometer UV-Vis dan produk degradasi yang terbentuk pada kondisi optimum diidentifikasi menggunakan GC-MS. Dari hasil penelitian didapatkan kondisi optimum  reaktor fotokatalitik yaitu pada jumlah kolom gelas 10 buah dan lama penyinaran selama 6 jam. Pada kondisi ini diperoleh persentase degradasi sebesar 79,49 %. Hasil karakterisasi dengan XRD menunjukkan TiO2 Degussa P-25 merupakan campuran anatase dan rutile dengan ukuran Kristal sebesar 20,571558 nm. Identifikasi dengan GC-MS menunjukkan banyak puncak yang saling tumpang tindih yang menandakan Methylene Blue telah mengalami degradasi.
Analisis Kadar Logam Timbal (Pb) dan Tembaga (Cu) pada Susu Kental Manis Kemasan Kaleng dengan Metoda Spektrofotometri Serapan Atom Dewisartika, Vina; Afkar, Zul; Yerimadesi, Yerimadesi
Periodic Vol 1, No 2 (2012)
Publisher : Jurusan Kimia FMIPA UNP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (12.651 KB)

Abstract

Telah dilakukan penelitian tentang Analisis Kadar Logam Timbal (Pb) dan Tembaga (Cu) pada Susu Kental Manis Kemasan Kaleng dengan Metoda Spektrofotometri Serapan Atom. Penelitian ini bertujuan untuk mengetahui pengaruh pelarut terhadap kadar logam timbal (Pb) dan tembaga (Cu) dalam susu kental manis kemasan kaleng, mengetahui pengaruh masa kadaluarsa dan keutuhan kemasan terhadap kadar logam timbal (Pb) dan tembaga (Cu), serta mengetahui kadar logam timbal (Pb) dan tembaga (Cu) dalam salah satu susu kental manis kemasan kaleng yang beredar di pasaran. Analisis kadar timbal (Pb) dan tembaga (Cu) dilakukan dengan menggunakan metoda destruksi basah dan dilakukan beberapa variasi yaitu variasi pelarut, variasi masa kadaluarsa serta variasi keutuhan kemasan kaleng. Hasil penelitian menunjukkan bahwa semua sampel mengandung timbal (Pb) dan tembaga (Cu). Kadar timbal (Pb) tertinggi didapatkan dengan menggunakan pelarut aquaregia, dengan keadaan kaleng rusak dan masa kadaluarsa satu bulan setelah kadaluarsa yaitu 4,548 mg/L. Kadar tembaga (Cu) tertinggi didapatkan dengan menggunakan pelarut aquaregia, dengan keadaan kaleng rusak dan masa kadaluarsa satu bulan setelah kadaluarsa yaitu 4,491 mg/L.
Inhibisi Korosi Baja oleh Ekstrak Serbuk Gergaji Kayu dalam Medium Air Laut Hartika, Putri; Yerimadesi, Yerimadesi; Hardeli, Hardeli
Periodic Vol 2, No 2 (2013)
Publisher : Jurusan Kimia FMIPA UNP

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (12.651 KB) | DOI: 10.24036/p.v2i2.3004

Abstract

The using of steel support building system in some productions in Indonesia, such us oil refineries, cooling systems production, shipbuilding and marine equipment. The sea is a corrosive environment so the metals which stay in the sea easy to corrosion. One of all effort to reduce the rate of corrosion of steel is the use of organic inhibitors such as tannins, nicotine and lignin. Wood sawdust is one natural ingredient that contains lignin. These compounds can complex with iron. This study aims to utilize wood sawdust extract as corrosion inhibitor of steel in medium of sea. Wood sawdust was extracted by using alkali method. The rate of corrosion and steel corrosion inhibition efficiency with wood sawdust extracts were determined by using the gravimetric method (the reduction of steel weight before and after corrosion). Based on the results of the study showed that the extract of wood sawdust can reduce the corrosion rate of steel in the medium of the sea with corrosion inhibition efficiency of 38.8% on 30 ppm the extract concentration. The analysis of steel surfaces using a stereo microscope with a magnification 40 times. It can seen the difference surfaces between coated steel and uncoated with wood sawdust extract in medium of the sea. Coated steel less rusty than uncoated.
Validitas Dan Praktikalitas Modul Reaksi Redoks dan Sel Elektrokimia Berbasis Guided Discovery Learning untuk SMA Yerimadesi, Yerimadesi; Bayharti, Bayharti; Oktavirayanti, Risa
JURNAL EKSAKTA PENDIDIKAN (JEP) Vol 2 No 1 (2018): JEP : Jurnal Eksakta Pendidikan
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (951.846 KB) | DOI: 10.24036/jep/vol2-iss1/143

Abstract

Module based on guided discovery learning can be used as an alternative to improve student’s activeness and understanding the concept. This research aims to develop redox reaction and electrochemical cell module based on guided discovery learning and reveals its validity and practicability. The type of this research is a development research using 4-D development model. The research instrument used was a questionnaire in the form of validity and practicality sheet. This module was validated by 3 UNP chemistry lecturers and 2 chemistry teachers of SMAN 10 Padang. Practicality test were conducted on 2 chemistry teachers and 32 twelfth grade students of SMAN 10 Padang. Data were analyzed by Cohen’s Kappa formula. The results of the validity test showed that the module has a very high validity category (k=0.83). Practicality test results by teachers and students showed that the module has high practicality category (k=0.79 and 0.80). Based on the results of this research, it can be concluded that the module developed was valid, practical.
Pengembangan Lembaran Kerja Siswa (LKS) Ekperimen Berbasis Guided-Inquiry Materi Laju Reaksi Untuk Siswa SMA / MA Andromeda, Andromeda; Yerimadesi, Yerimadesi; Iwefriani, Iwefriani
JURNAL EKSAKTA PENDIDIKAN (JEP) Vol 1 No 1 (2017): JEP : Jurnal Eksakta Pendidikan
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (554.89 KB) | DOI: 10.24036/jep/vol1-iss1/47

Abstract

This study aims to produce teaching materials based material reaction rate guided inquiry (learning cycle: the phase of exploration, discovery / establishment of the concept and application) in the form of a valid experiment worksheets and practical use in learning chemistry in SMA / MA. This type of research included in Research and Development (R & D). The development model used in this study is the four-D (4-D). The research instrument is the validation sheet and questionnaire. Data from the study consists of three aspects, namely, the validity, the practicalities and effectiveness of teaching materials. Data validity and practicalities processed using Cohens Kappa formula, and the effectiveness of data using a percentage In this study is limited to the validity and practicalities. Validation of teaching materials from the aspect of content, language and graffiti and feasibility of construction. Data from the validator obtained an average score moment kappa was 0.87, and the results of practical analysis conducted with a limited test in MAN 3 Padang obtained an average score of 0.84 practicality value of 0.78 of teachers and students. From the analysis worksheets that showed 86 % of students working on critical questions and exercises contained in LKS experiments that have been made can be answered students. These results indicate that LKS guided inquiry-based experiments developed extremely valid and practical use in learning chemistry
Efektivitas Penggunaan Modul Larutan Penyangga Berbasis Discovery Learning terhadap Hasil Belajar Siswa Kelas XI MIA SMAN 7 Padang Yerimadesi, Yerimadesi; Putra, Ananda; Ririanti, Ririanti
JURNAL EKSAKTA PENDIDIKAN (JEP) Vol 1 No 1 (2017): JEP : Jurnal Eksakta Pendidikan
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (467.225 KB) | DOI: 10.24036/jep/vol1-iss1/29

Abstract

Quasi experiment research with randomized control posttest group only design was carried out to determine the effectiveness of using a discovery learning based module on students learning outcome. Grade XI MIA-1 to MIA-4 students academic year 2015/2016 in SMAN 7 Padang became population of this study. Through cluster sampling technique, grade XI MIA-1 and grade XI MIA-4 were chosen as experiment and control classes respectively. The experiment class was taught using discovery learning based module in buffer solution topic while the control class was taught the same topic conventionally without the module. Research instrument used was cognitive learning outcome test with multiple choice form. Data showed that the mean test score of experiement class (78.84) was higher than that of control class (71.09). Normality and homogenity test proved that both classes were homogeneous and normally distributed. T-test, as data analysis taken, showed that t-count (3,51) is bigger than t-table (1.67). Thus, it could be concluded that students’ cognitive learning outcome in experiment class is significantly higher than that in control class. The use of discovery learning-based module in buffer solution topic was effective in increasing learning outcome of grade XI MIA students in SMAN 7 Padang.
Pembuatan Media Animasi untuk Topik Hibridisasi dengan Program Macromedia Flash Wijayanti, Fitria; S, Syukri; Yerimadesi, Yerimadesi
ALKIMIA Vol 2 No 1 (2018): ALKIMIA
Publisher : SCIENCE AND TECHNOLOGY FACULTY OF UNIVERSITAS ISLAM NEGERI RADEN FATAH PALEMBANG

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (578.545 KB) | DOI: 10.19109/alkimia.v2i1.2255

Abstract

Computer-based learning media can be one alternative in the learning of chemistry, especially hybridization concepts. This media will visualize abstract concepts into animations, drawings and help students understand concepts with interactive questions. The purpose of this research is to produce learning media on hybridization materials using macromedia flash program that can help the process of chemical learning. The type of research conducted is Research and Develompment (R & D). The instrument used is a questionnaire with Likert scale. The result of this research is hybridization learning media with macromedia flash program suitable to be used for science students at school.
Efforts to Improve Competency of Teacher MGMP Chemistry, Padang City Through Training For Development of Teaching Materials Based on Guided Discovery Learning Yerimadesi, Yerimadesi
Pelita Eksakta Vol 2 No 2 (2019): Pengabdian Masyarakat
Publisher : Fakultas MIPA Universitas Negeri Padang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24036/pelitaeksakta/vol2-iss2/45

Abstract

This article is compiled based on the results of community service activities through the community partnership program of Padang State University in 2018 year. This activity aims to improve the competence of chemistry teachers in Padang City chemistry group  through training based on guided discovery learning materials. The way to implement these activities can be done through training and workshops to 53 Padang chemistry group teachers. The instruments used were questionnaires for teacher and student responses. The product trial was carried out on 27 students of class X at Padang 1 Public High School in the 2018/2019 academic year. Data analysis was performed using percentage techniques and moment Cappa Cohen's. From the results of the questionnaire analysis of the chemistry teacher's response to the implementation and presentation of the material by the resource persons in succession, the average percentage percentage was 88% and 91% with the second category of aspects  that being assessed very high. From the questionnaire analysis of teacher and student responses to learning using chemical modules based on guided discovery learning (GDL), the mean value of the kappa moment was 0.85 for the teacher's questionnaire responses with very high categories and 0.70 for the responses questionnaire of students with high categories. It was concluded that training in the preparation of teaching materials based on guided discovery learning could improve the competence of chemistry group teachers.