Jurnal Akademika Kimia
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Analysis of the Levels of Ethanol Extract Flavonoid Compounds in Cocor Bebek (Kalanchoe Pinnata) Leaves using UV - Vis Spectrophotometer
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Cocor bebek is a plant that is easy to cultivate in Indonesia. This cocor bebek contains chemical compounds such as steroids, alkaloids, glycosides, tannins, and flavonoids which have antioxidant properties. Research on the analysis of flavonoid levels in the leaves of cocor bebek (kalanchoe pinnata) has been carried out using the UV-Vis spectrophotometric method. This research aims to determine the levels of flavonoids in the ethanol extract of cocor bebek leaves. The extract of chemical content in cocor bebek leaves was carried out by maceration method using 70 % ethanol. The flavonoid content of the sample extract was measured by measuring the absorption at wavelengths of 510 nm and 700 nm. The results obtained in the qualitative test showed that the cocor bebek leaf extract was positive for flavonoids which were characterized by a change in color from brownish red to green. The results of the quantitative test showed that the flavonoid content in the cocor bebek leaf extract was 0.321 mg/100 g
Cross-Sectional Survey : The Influence of Various Teacher Backgrounds on West Kalimantan Chemistry TPACK Teachers
No full textThis study aims to examine teachers' perceptions of their Technological Pedagogical and Content Knowledge (TPACK) about age, gender, length of teaching, work location, teacher status, teacher education, and certification programs. This study used a cross-sectional survey method used in non-experimental quantitative research. The population in this study were all chemistry teachers in West Kalimantan using a purposive sampling technique obtain 70 to respondents from 14 districts. The survey consisted of 28 statement items and distributed questionnaires via Google form to chemistry teachers. Chemistry teachers rated themselves on a 5-point scale. All domains of the TPACK framework demonstrated valid and reliable instruments on Pearson's correlation values and Cronbach's Alpha Kruskal Wallis non-parametric test, Pearson's correlation was performed to analyze the data. Significant differences can be seen in the CK domain when viewed from gender differences with a p for CK of 0.044, so there is a significant difference between the gender of women (Mean = 4.08 SD = 0.416) and men (Mean = 4.32 SD = 0.470). Location of work affects the teacher's TCK and TPACK because there is a significant difference when viewed from the p namely the TCK and TPACK of 0.036 and 0.025. Perceptions of teachers' TPACK abilities were greater for teachers in cities than in villages in both the TCK domain (Mean = 3.58; 3.82 SD = 0.430; 0.466) and TPACK (Mean = 3.63; 3.91 SD = 0.483; 0.554)
Development of a Flipbook on Functional Groups of Organic Compounds: SATLOC Approach Oriented to Science Literacy
Get PDFThe development of flipbooks for learning functional groups of organic compounds is needed to enable students to learn independently more easily and interactively. The functional groups of organic compounds have characteristics that should be realised through a systematic approach, namely SATLOC (Systematic Approach to Teaching and Learning Organic Chemistry). Based on the independent learning curriculum, the implementation of learning should emphasise the development of literacy and numeracy skills. Therefore, this research aimed to develop and assess the feasibility of a flipbook on the functional groups of organic compounds using a SATLOC approach oriented toward scientific literacy. The flipbook's development used the ADDIE (Analysis, Design, Development, Implementation, Evaluation) model. The level of product feasibility is obtained through a content validity test, including materials and media, and limited trials. The average percentage of scores for the content validity test results for materials, media, and limited trials was 88%, 85%, and 85%, respectively. These results indicate that the product is high-quality and feasible for use
The Utilization of Avocado Seed Powder (Persea americana Mill) as a Metal Adsorbent of Cu(II)
No full textAvocado is a fruit that has a high nutritional value are beneficial for human health. In the fruit of the avocado are seeds of avocado that are still less utilization thus discarded and become waste. The content in avocado seeds can be used as an adsorbent. This research utilizes avocado seed powder (Persea americana Mill). As Metal Cu(II) Adsorbent. This study aims to determine the water content, ash content, and optimum pH of the adsorption of Cu(II) metal using avocado seed powder. Determining the concentration of Metal Cu(II) using the tool spectrophotometry Atomic Absorption (AAS). Determination of the optimum pH is done by varying the pH 2, pH 3, and pH 4. This research results show that the water content is 4.88% and the ash content is 1.94%. The results of the analysis of the optimum pH to adsorb Cu(II) metal is pH 4 with a percentage of metal that is absorbed by 65.515%. Based on the results of the study showed that avocado seeds can be used as adsorbents
Activation of Durian Skin Biomass with H2SO4 Activator on the Absorption of Lead from its Solution
No full textResearch has been carried out on the bioabsorption of lead (Pb) using durian skin biomass (Durio zibethinus) which has been activated using an H2SO4 activator. The durian skin sample used was durian skin from Central Sulawesi. The processing technique to remove lead (Pb) from liquid waste was carried out by an adsorption process. The adsorption process is an effective purification and separation technique used in industry because it is more economical and simple in treating wastewater and is a technique that is often used to reduce metal ions in wastewater. This study aims to determine the mass and contact time of the adsorption of Pb by durian skin biomass. Determination of the adsorbed metal used atomic absorption spectrophotometry (AAS). The results obtained showed that the optimal Pb ion adsorption occurred at a weight of 2.5 grams with an absorption capacity of 99.94 %. While the optimal Pb ion adsorption occurred at a contact time of 40 minutes with an absorption capacity of 99.94 %
Learning Difficulties and Students' Ability Level During Pandemic Covid-19 on the Subject of Thermochemistry
No full textThis study aims to identify learning difficulties learning experienced by students on the subject thermochemistry in class XI IPA SMA Negeri 8 Palu during the Covid-19 pandemic for the 2021 / 2022 school year. The instruments used in this study are thermochemistry tests, questionnaires, and interviews. The result showed students’ difficulties in the subject thermochemistry in class XI IPA was 60 %, the highest difficulty of students is found in the thermochemistry test of calculating the heat of the type of compound, calculating enthalpy changes, and formulating steps and hypotheses of an experiment. The difficulty is indicated by the low level of student comprehension of 54 %, medium 43 %, and high 3 % with an average of 30%. Furthermore, the difficulty of students in participating in chemistry learning during the Covid-19 pandemic is technical difficulties with a percentage of 65.92 %, difficulties in implementing learning with a percentage 0f 65.44 %, and external difficulties (environment and parents) with a percentage of 52.92 %. based on these results, the learning difficulties experienced by students during chemistry learning thermochemistry subjects during the Covid-19 pandemic include students often being constrained by signals and quotas to access materials on the internet and do not have student handbooks to study at home, difficulty understanding chemistry concepts because teacher explanations are elusive, students are not active in participating in learning because chemistry learning during the pandemic is not interesting, can’t afford chemistry books and quotas also parents don’t provide motivation and students are often lazy to do assignments because no one helps with doing. The result of this study indicates that the level of students' difficulties learning about thermochemistry is a quite high category with a low level of student ability and students agree that it is difficult to study chemistry during the pandemic Covid-19
Analysis of the Critical Thinking Skills of Students in Senior High School in Solving the Reaction Rate Problem
Get PDFThis study aimed to obtain a description of the critical thinking skills of SMA Negeri 3 Palu students in solving reaction rate problems. The type of research used is descriptive-quantitative, with the research design in the form of case studies. The research sample consisted of students of class XI IPA 1 to XI IPA 4 SMA Negeri 3 Palu, with 108 students. The research instrument used is a critical thinking skill test in the form of 6 questions, validated with a value obtained for expert validation of 3.72 and an average empirical validation value of 0.72. Data analysis is done by calculating the grades students get for each indicator of critical thinking skills, then grouping them by essential categories of thinking. According to Ennis, the indicators of critical thinking skills used in this study are to provide simple explanations, build basic skills, draw conclusions, provide further explanations, and set strategies and tactics. Based on the results of the research data analysis, the highest percentage of critical thinking skills for the five indicators used in a row, namely 37.04, 51.85, 61.11, 53.70, and 42.59 %. These results show that each student has different critical thinking skills. The percentage obtained is, on average, in the medium to high category. The results of this study show that the essential thinking skills of high school students of SMA Negeri 3 Palu, grade XI IPA, are in a good category
Effect of Avocado Leaves Extract on Creatinin and Urea Levels in Rats Induced NaCl and Prednison
No full textCreatinine and urea are metabolic waste substances excreted by the kidneys. Kidneys excrete metabolic waste substances. Renal dysfunction is associated with the increased level of creatinine and urea in the blood. The ethanolic extract of avocado leaves (Persea americana Mill.) contains flavonoid compounds, alkaloids, tannins, saponins, and steroids which act as antioxidants and antihypertensive. It is known to reduce creatinine and urea levels in the blood. The animal model was divided into five groups: normal control, negative control (CMC - Na 0.5 %), and avocado leaves ethanolic extract group with doses of 75, 150, and 250 mg/kg BW rats. All groups except the normal control group were induced by oral administration of NaCl solution 2 % and prednisone suspension 1.5 mg/kg BW rats for 21 days and following treatment by oral administration for 7 days based on its group. Flavonoid compounds of avocado leave ethanolic extract identified as 5,7-di-OH-dihydroflavonol. Results show Kruskal - Wallis test between groups (p < 0.05) is significantly different. Concluded that administration of avocado leaves ethanol extract at doses of 75, 150, and 250 mg/kg BW rats might reduce creatinine levels, while avocado leaves ethanol extract at a dose of 250 mg/kg BW rats could reduce urea levels
Analysis of the Characteristics of Chemical Compounds in Palm Flour (Arenga pinnata) from the Poso District
Get PDFAren (Arenga pinnata) is a palm family with the potential to develop high economic value in tropical regions such as Indonesia. This study aims to determine the levels of each chemical compound contained in palm flour (protein, fat, carbohydrate, potassium, and calcium levels). Determination of protein, fat, and carbohydrate levels in this study using a UV - VIS spectrophotometry tool. Determination of potassium (K) and calcium (Ca) levels using a flame photometer. The results showed that the analysis of protein content obtained 1.5765 %, fat content obtained 1.465 %, and carbohydrate content obtained 55.88 %. The analysis of potassium content obtained 1.76 %, and calcium levels obtained 1.495 %. The results of this study are expected to be foodstuffs that can be processed into food to meet the needs of protein, carbohydrates, fat, potassium, and calcium in the body
Analysis of Water-Soluble Vitamin Change in Tomato (S.lycopersicum) Due to Ozonolysis of Imidacloprid Degradation Treatment by Using Spectrometry and HPLC Method
No full textIn this study, the effect of imidacloprid degradation on the reduction of water-soluble vitamins in tomatoes was observed, such as ascorbic acid, pyridoxine, niacin, and thiamine. Analysis was carried out using a spectrophotometer and high-performance liquid chromatography. The degradation method with ozone water for 15 minutes showed a better result than the ozonolysis method because the decrease in levels of water-soluble vitamins is smaller. The percentage decrease of each water-soluble vitamin in the ozone water method is ascorbic acid by 17.103 %, pyridoxine by 6.723 %, niacin by 2.781 %, and thiamine by 0.333 %. Ozone water methods also produce a high percentage of degradation which is 90.56 %