his study aimed to determine the potential toxicity of the ethanol extract of typical Acehnese plants to shrimp larvae (Artemia salina Leach) using the Brine Shrimp Lethality Test (BSLT) method as indicated by the LC50 value. This study used 1,080 shrimp larvae divided into four groups (three groups of extract concentration series and one negative control group). Each group consists of 15 larvae with three repetitions (triple) of treatment. The four treatment groups were given the suspension of ethanol extract of Cananga flower and leaf extract (Cananga odorata), jeumpa flower and leaf (Michelia alba), and Tanjung flower and leaf (Mimusops elengi) with concentrations of 1000 ppm, 100 ppm, and 10 ppm. The mortality data of shrimp larvae were analyzed by probit analysis to determine the LC50 value. The result of this research is that the ethanol extract of the Cananga flower and leaf (Cananga odorata) has LC50 values of 55.71 ppm and 79.43 ppm, respectively. The ethanol extract of the jeumpa flower and leaf (Michelia alba) had LC50 values of 831.76 ppm and 398.10 ppm, respectively. The ethanol extract of the Tanjung flower and leaf (Mimusops elengi) had LC50 values of 295.12 ppm and 77.67 ppm, respectively.

The electrolytic cell is a chemical material with abstract and concrete concept characteristics. Students often need help learning this material, especially connecting concrete and abstract concepts. Therefore, media is needed that can facilitate students in understanding electrolytic cell material, which is made interesting by utilizing virtual reality technology. The purpose of this research is to produce chemistry learning media based on virtual reality with a feasible and practical MilleaLab platform. The research uses the ADDIE development model (analysis, design, develop, implement, evaluate). The product of this research is virtual reality-based learning media on the MilleaLab platform. The validation assessment from media and material experts with an error rate of 5% based on the Aiken scale obtained Vcount ≥ Vtable (Vtable = 0.87). Each value in the validation of media and material experts is 0.89 and 0.87 with the Valid category. The results of assessing student responses regarding the practicality of this learning media get 88% in the Very Good category. Based on these results, it can be concluded that MilleaLab virtual reality-based learning media on electrolytic cell material is a learning medium that is practical and feasible to use.

Nutritional problems still become a crucial issue in Indonesian public health. Fulfillment of nutritional balance is expected to improve life quality. In humans, one of the nutrients that play a role in the growth of brain and nervous system functions is PUFA, such as omega-6 and omega-3. Besides, fulfillment of nutritional balance can prevent some diseases; especially linoleic acid used to prevent some diseases. Linoleic acid is an omega-6 and essential fatty acid. Linoleic acid is the main essential fatty acid because it is the precursor for GLA, DGLA, and AA. Omega-6 works with omega-3 and some omega-3 benefits are supported or can arise by omega-6 presence. Studies reveal that watermelon contains high linoleic acid. This study aimed to determine the optimum temperature and ratio of fatty acids: urea for the isolation of linoleic acid from watermelon seed oil. The method used was urea inclusion with a variety of temperatures (-6oC, 6oC, 18oC) and the ratio of fatty acid: urea (1:1; 1:3; 1:5). The results showed the optimum watermelon seed oil linoleic acid isolate at 18oC and the ratio of fatty acids: urea 1:5 with linoleic acid purity (%) of 82.53%.

Petroleum is still the primary energy used in the world. Its diminishing production is the trigger to find alternative energy to replace it. Biofuel is an alternative energy that has the potential to replace petroleum because it is renewable, environmentally friendly, and easy raw material. Waste such as used cooking oil can be used as raw material for making biofuels. The low price can reduce the cost of biofuel production. The conversion of oil into biofuel can be done using catalytic cracking with natural zeolite as a catalyst. This study aims to determine the optimum conditions for making biofuel from used cooking oil and determine its physical and chemical properties. The catalytic cracking process is carried out using an autoclave reactor. Used cooking oil and natural zeolite were introduced into the reactor, and the reaction was carried out by varying the time (1, 2, 3 hours), temperature (325, 350, 375 o C), catalyst concentration (3, 5, 7%), and catalyst size. The product is distilled to produce biofuel (liquid), gas, and residue. The optimization results show that 3 hours, a temperature of 375 o C, a catalyst concentration of 7%, and a catalyst size of 180 µm are the optimum conditions for catalytic cracking with 44.94% biofuel yield. The resulting biofuel contains 73.48% hydrocarbons and 26.52% fatty acids. The hydrocarbon composition consists of 19.32% gasoline, 12.82% kerosene, and 35.11% diesel. The density of the biofuel produced is 0.8835g/mL, the flashpoint is 68 o C, and the pourpoint is 27 o C.

This study aims to describe the learning persistence and metacognitive abilities of students through discovery learning models based on blended learning. This research uses a mixed qualitative-quantitative approach with embedded design research. The sample in this study was 50 students of class X MIA, SMA Negeri 4 Jambi City selected by purposive sampling technique. The data collection instruments used were in the form of a study persistence questionnaire, students' metacognitive ability test questions, and interview sheets. The data will be analyzed qualitatively using miles and hubarman and quantitatively analyzed using descriptive statistics and inferential statistics. The inferential statistics performed consisting of assumption tests (normality test, homogeneity test, and linearity test) and hypothesis testing (T test and correlation test). The results of this study indicate that there is a significant difference between learning perseverance and metacognitive ability of students of class XI MIA 1 and class XI MIA 2, with a significance value of 0.011 for student learning persistence and 0.007 for students' metacognitive ability. In addition, it is known that there is a significant correlation between the student's learning persistence variable and the metacognitive ability of class XI MIA students at SMA Negeri 4 Jambi City, which is 0.000.

This work describes a simple and inexpensive Pb(II) determination by a pencil electrode using the square wave anodic stripping voltammetry (SWASV) method. This research was applied using a batch cell system on 10 mL of 0.1 M acetate buffer pH 4.5. The precision was performed with repeatability and reproducibility in Pb(II) concentrations of 0. 2, 0. 4, 0. 6, and 0.8 µg mL -1 . Two linear ranges were obtained in the concentration of 0.1–1.0 and 2.0–8.0 µg mL -1 . This method offers a detection limit of 0.07 µg mL -1 and a quantification limit of 0.24 µg mL -1 . The technique performed good repeatability (RSD= 7.28–9.53%) and good reproducibility (RSD=7.07–15.10%). The precisions are accepted according to the Association of Official Analytical Chemists (AOAC) standard (RSD repeatability <11% and RSD reproducibility <16% at a concentration of 1 µg mL -1 ). The method offered high operational stability up to 18 measurements (RSD=4.6%). The technique performs acceptable results with low random error in determining Pb(II).

The implementation of the 2013 curriculum, which focuses on the phenomenon of daily life, is part of the government's effort to improve the quality of education in Indonesia. Corrosion is one of the most common problems, so learning how to overcome corrosion is essential. The tannin content of papaya leaves has the potential to be a corrosion inhibitor. As a result, this study aims to investigate papaya leaf extract as a corrosion inhibitor and its potential as a contextual learning aid. The qualitative descriptive method was used in this study, with data collected through literature studies, observations, interviews, and experiments. The results showed that papaya leaf extract could be used as a corrosion inhibitor with a 73 percent efficiency in using a 20% inhibitor. Based on literature reviews, observations, and interviews with educators and students in Yogyakarta, papaya leaf experiments as an inhibitor can be a contextual learning alternative to corrosion material in senior high school in terms of finances, pedagogy, and human resources readiness.

Taro (Colocasia esculenta L. Schott) was potentially a raw material in the fabrication of bioplastic because of its biodegradability properties. Egg shells can be used as a filler in bioplastics because of their rich in calcium carbonate (CaCO3). This study aims to examine eggshell addition to starch-PVA-CT bioplastic properties. Taro tuber and eggshell were extracted first to obtain taro starch and calcium carbonate. Obtained products were incorporated with PVA, glycerol, and citric acid to produce bioplastics. Characteristic tests in this study included functional group analysis, hydrophilicity, mechanical properties, and degradation study in rivers. The taro starch obtained from this study was 4.8% from 900 g of taro tubers. Functional group analysis of bioplastics showed the presence of functional groups O-H, C-H, C-O ester, and C=O carbonyl. The hydrophilicity test showed the best percentage of water resistance in CL PVA/starch bioplastic (50% CT), and the decomposition in the river water environment reached 82%. The test results in this study showed that the best variation was in CL PVA/starch bioplastic (25% CT) with a tensile strength value of 2.05 Mpa and elongation at a break of 4%. These results meet the standards of SNI 7188.7:2016.

concepts of chemicals are generally presented in three chemical representation levels: macroscopic, submicroscopic, and symbolic. This study aims to; (1) evaluate each representation ability; (2) determine how to evaluate the pattern of representational abilities; and (3) evaluate the patterns of each student's macroscopic, submicroscopic, and symbolic representation abilities. Qualitative descriptive has been used as the design of this study. Twenty-one multiple-choice questions based on macroscopic, submicroscopic, and symbolic representations have been designed with validation results from two experts, which are 100% valid, and with the Kuder Richardson formula (K-R 20), the reliability value is 0.84. The subjects in this study were all students of class XI MIPA at SMA Negeri 8 Banda Aceh. The research was conducted online via a google form. The results showed that students with high categories of macroscopic, submicroscopic, and symbolic representation skills were 61, 18, and 51%, respectively. 9.8% of students can master the three levels of representation with high criteria. The pattern of representation ability is mainly owned by 24.4% with high macroscopic and symbolic representation abilities but low submicroscopic representation abilities. Because submicroscopic representation lags macroscopic and symbolic, explanation in chemistry should always involve submicroscopic representations other than macroscopic and symbolic.

Sago pulp is a lignocellulosic waste rich in cellulose, so that it can be used optimally as a source of carbon and cellulose. Fixed carbon can be obtained maximally by determining the carbonization temperature. This research aims to determine the temperature of the cellulose sample starting to decompose and the energy required at the time of decomposition. The process of extracting cellulose from sago fiber waste uses NaOH alkalinization for delignification, bleaching with H2O2, and hydrolysis with HCl. Identification of lignin in sago fiber is known by the appearance of the C=O group in the wave region of 1734.01 cm-1 with strong intensity; after extraction, no peak number was found in the extracted cellulose FTIR spectrum. TGA analysis of cellulose underwent two stages of mass change, the first stage of decomposition of water molecules at a temperature of 47°C-203°C obtained a mass decrease of 5.69%, and the second stage of decomposition at a temperature of 287°C-397°C obtained a mass decrease of 58.95%. DSC analysis obtained two thermal properties of physical changes contained in two endothermic peaks, the first peak of water evaporation which required energy of 28,1120 J/g, and the second peak of decomposition, which required energy of 9.6188 J/g.