Experiential learning has proven to be a powerful pedagogical technique to teach students a wide variety of subjects including the sciences. However, due to its very nature, often it becomes challenging to engage all the students equally due to different reasons. To ensure active participation by all the students, students’ presentations were included in the curriculum, following the hands-on activities. Each student presented a sub-topic from the topic “Natural and synthetic materials” and a subsequent interacting session was followed among the students leading to peer learning. The average total scores in the post-test (after the students’ presentations and discussion) were found to be higher than that in the pre-test, which was significantly different (P-value <0.0001). At the same time, the improvement in the scores in the sub-topics the students presented was found to be greater than in the ones the students did not present (1.52 vs 1.21 times, respectively). Statistical analysis also showed that the total scores of individual students correlated positively with their presentation scores. Overall, students’ performances improved after the intervention through the presentations and subsequent interactions among the students. This pedagogy can be implemented for a larger pool of students to ensure efficient learning.
This study aimed to develop and produce a website-based learning media integrated with the Problem-Based Learning (PBL) model on chemical equilibrium topics, to examine the product’s validity, feasibility, and practicality, as well as to evaluate its effectiveness on students learning outcomes. The research employed a Research and Development (R&D) approach using the ADDIE development model integrated with the PBL model and supported by Google Sites. The study involved 34 eleventh-grade students and applied a pre-experimental research method with a one-group pretest–posttest design. The results indicated that the website-based learning media demonstrated a very high level of validity. The feasibility test showed that the product met the feasible criteria, while the practicality test indicated that the media was categorized as very practical. The implementation of the learning media had a positive impact on students’ learning outcomes, as evidenced by an N-gain score of 0.564, classified as a moderate improvement, and an effect size of 1.05, classified as a very large improvement. These findings demonstrate that website-based learning media integrated with the Problem-Based Learning model is effective as an instructional innovation in chemistry education to enhance the quality of both the learning process and students’ learning outcomes, and it has the potential to serve as a reference for the development of digital learning media in other chemistry topics.
This study investigates electronic properties of linear cyanopolyynes (HCnN, with odd n from 3 to 29) by means of electron structure calculations at the DFT/B3LYP/6-311G(3df,3pd) level. Correlations between the chain length, the electric dipole moment and the HOMO-LUMO gap were analyzed. The molecular geometries were optimized and validated by vibrational calculations. The data obtained revealed that the dipole moment increases with the increase in chain length, while the gap decreases in a logarithmic way. The relationship between dipole and gap was described by by a potential model, indicating coherence between molecular structure and electronic properties. These patterns are relevant both for the detection of cyanopolyynes in the interstellar medium, by rotational spectroscopy, and for applications in molecular electronics. The statistical adjustments showed high coefficients of determination (R² > 0.99), confirming the robustness of the models used.
This biographical article honors the life and scientific legacy of Dr. Flávia Vasconcelos de Mello, a Brazilian marine biologist whose research significantly advanced the understanding of environmental contaminants in marine ecosystems. Her work integrated ecotoxicology, analytical chemistry, and trophic ecology, contributing to environmental risk assessment and public health discussions. Beyond her scientific achievements, this article highlights her role as a mentor, collaborator, and passionate advocate for marine conservation.
The Chemister application presents an innovative method for advancing chemistry education, specifically tailored to enhance high school students’ understanding of reaction rates by integrating Artificial Intelligence (AI), Augmented Reality (AR), gamification, and discussion forums. Employing a descriptive analysis within a Research and Development (R&D) framework, this study investigates the app’s effectiveness in improving student engagement and conceptual comprehension. A pilot implementation involving eleven high school students demonstrated promising outcomes. A paired sample t-test conducted on students’ pre-and post-test scores revealed a significant improvement in learning outcomes. The mean pre-test score was 56.5 (SD = 3.69), which increased to 73.1 (SD = 3.93) post-intervention, reflecting an average increase of 29.38%. This difference was statistically significant (t(10) = 9.74, t-critical = 2.10), and the effect size was notably large (Cohen’s d = 4.36), underscoring the app’s meaningful impact on conceptual understanding. The findings indicate that the Chemister application fosters self-directed learning beyond the traditional constraints of time and space while promoting critical thinking through interactive and collaborative features. This study highlights the transformative potential of technology-enhanced learning tools in contemporary chemistry education and advocates for further exploration of their broader applicability in diverse educational contexts.
The discipline of analytical chemistry involves developing and improving methods to identify, separate, and quantify substances in a sample. This study proposes an experimental methodology for determining the sodium content of nine (9) protein food supplements using flame atomic emission spectrometry after acid decomposition. Analytical validation focused on precision and accuracy through repeatability, intermediate precision, and analyte addition/recovery tests. The procedure showed adequate precision (RSD < 16.6%) and accuracy (recoveries between 78–110%). Comparison with nutritional labels at a 95% confidence level revealed that 78% of the supplements analyzed had sodium levels statistically different from the declared values, with 45% above the stated values, highlighting the risk of excessive intake. In addition, a didactic sequence was developed, structured in four lessons, integrating analytical chemistry with food and nutrition education. Moreover, the proposed didactic sequence establishes a clear learning flow, guiding students from conceptual discussion to experimental practice and data interpretation. This structure enables them to connect precision and accuracy with real-world analytical problems, enhancing critical thinking and promoting meaningful learning. This active methodology enabled students to connect validation concepts (precision and accuracy) to real-world issues, promoting critical thinking and meaningful learning.
Students’ scientific education in basic education has increasingly been examined from two complementary perspectives: the construction of scientific knowledge and chemical literacy. The former focuses on cognitive and formative processes involved in learning scientific concepts and practices while the latter emphasizes the ability to interpret, communicate, and apply chemical knowledge to social, environmental and technological contexts. This paper is a literature review which aimed at exploring interfaces, convergences and pedagogical potential of both perspectives in chemistry education. Eighty-five publications comprise a sample that was identified through searches in academic databases and institutional repositories. After preliminary screening and abstract review, 66 sources were selected for in-depth reading. Out of them, 45 papers were retained for the final analysis, based on their alignment with the theoretical axes of this study. Finally, 25 papers were selected to compose the Results and Discussion section due to their strong conceptual and methodological contributions. The analysis reveals that, although both perspectives have been frequently addressed by the literature, few studies explicitly integrate them. Findings suggest that fostering a more consistent articulation between scientific knowledge construction and chemical literacy may enrich pedagogical practices to make them more meaningful and contextualized and contribute to the development of scientific and critical citizenship in chemistry education.
The Petasis–Boronic multicomponent reaction has emerged as a practical and versatile method for building structurally complex molecules, particularly frameworks bearing newly formed stereocenters. Known for its operational simplicity, mild conditions, and broad functional-group tolerance, it offers an attractive alternative to classical Mannich-type processes. Over time, its scope has expanded through advances that improve stereocontrol, substrate diversity, and reaction efficiency. Over the years, its scope has broadened with developments that enhance stereocontrol, functional group compatibility, and overall efficiency. Recent progress, including asymmetric variants, photoredox-mediated strategies, and continuous-flow adaptations, underscores the flexibility of this transformation. The use of novel boronic acid derivatives and unconventional substrates has further expanded its synthetic potential, enabling the rapid construction of complex molecular frameworks. Collectively, these advances establish the Petasis reaction as a dynamic platform in modern multicomponent chemistry, with wide applicability.
Global agricultural production generates a wide variety of valuable waste. In a world seeking to become increasingly sustainable, it is necessary to take advantage of these resources by establishing processes based on the bioeconomy and the circular economy. Cassava waste and beeswax were used to obtain polylactic acid (PLA). The fermentable sugars were extracted from each residue using a chemical hydrolysis process. Lactic fermentation using a commercial strain and with a multiple factorial design was carried out to evaluate the type of residue (cassava peel, pit, cassava peel-pit mixture), temperature (27 and 45°C), and reaction time (72, 120, 168 hours). The process involved oligomerization and ring-opening polymerization (ROP) to obtain PLA. The highest amount of LA was 2618.81 mg/L when working with a mixture of cassava peel and stone during 120 hours of fermentation at 45°C. During polymerization, 70.05% of the obtained material corresponded to PLA, and through thermal analysis, were determined: Glass transition temperature (Tg = 91.81 °C), melting temperature (Tm = 178.77 °C), and degradation temperature (Td = 286.09 °C). Although the characteristics of the obtained material still differ from those reported for commercial PLA, the study revealed that the selected waste is a potential resource for producing a biopolymer.
Liquid crystals (LCs) are unique materials that combine the fluidity of liquids with the molecular ordering of crystals, making them valuable in optoelectronic and advanced material applications. In this work, new liquid crystalline compounds were synthesized from (Z)-3-(4-butoxyphenyl)-2-(4-hydroxyphenyl) acrylonitrile and alkoxy-substituted vanillic acid derivatives. These structural modifications were introduced to enhance mesophase stability and tailor thermal and optical properties for potential technological applications. The synthesis was achieved via esterification or condensation reactions under controlled conditions. Structures were confirmed using Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy. Differential Scanning Calorimetry (DSC) was employed to determine phase transition temperatures, while Polarized Optical Microscopy (POM) was used to observe mesophase textures. The findings reveal that alkoxy vanillic acid units significantly influence mesophase behavior, yielding compounds with stable mesophases and tunable transition points. This study highlights the relationship between molecular structure and mesomorphic properties, providing a foundation for designing advanced liquid crystal materials for optoelectronic devices.
Student empowerment emphasizes enabling students to become protagonists in their learning process, fostering intellectual autonomy and growth. This approach is particularly crucial for gifted students to prevent academic disengagement. This study aimed to support the academic and scientific development of gifted students by investigating the allelopathic effects of an Eucalyptus globulus Labill aqueous extract on common-bean and radish crops, using a hydrogel as the primary water source. The germination assay was conducted in Petri dishes and evaluated across four different treatments over a period of seven days. The results demonstrated that the hydrogel combined with eucalyptus extract (1:13, gelatin:extract (w/w)) exerted an inhibitory effect on both crops, particularly on radish germination. Furthermore, analysis of key physiological indices revealed that the hydrogel treatment promoted rapid germination but resulted in an unbalanced initial growth pattern (low Dickson Quality Index; high Robustness Index). This research contributes to innovative pedagogical practices by demonstrating how authentic scientific inquiry empowers gifted students, fostering critical thinking and engagement in interdisciplinary areas. The findings highlight the potential of combining allelopathic compounds and hydrogels to promote sustainable agricultural practices, allowing students to actively explore innovative solutions focused on the dual functions of these components in crop management and water conservation.
Analytical Chemistry is about identifying and measuring substances, using careful quantitative reasoning and instruments. This study presents a clear, practical approach to using UV–Vis spectrophotometry to measure caffeine in coffee, using calibration curves and linear regression to connect key analytical concepts to a common product. The method uses liquid–liquid extraction and UV–Vis readings at the absorption maximum, then builds a calibration model for 0–8 mg L⁻¹ with duplicate measurements. The regression equation found was y = 0.0742x − 0.0016, with R² = 0.9987, indicating linear behavior in this range. With this approach, the method had a LOD of 0.36 mg L⁻¹ and a LOQ of 1.09 mg L⁻¹. When applied to commercial coffee, caffeine levels ranged from 0.5641 to 0.7457% (m/m), allowing discussion of sample differences and their relationship to current laws. This paper is Part II of a teaching series in Analytical Chemistry. Part I focused on validation (precision and accuracy) by measuring sodium in dietary supplements, while this work builds on that by highlighting calibration, regression, residual analysis, and quantitative interpretation through a real-food analysis example.
This work presents a comprehensive systematic review of the potential of Norbornadiene/Quadricyclane (NBD/QC) as a promising molecular system for solar thermal energy storage (MOST). Utilizing the Methodi Ordinatio methodology, this study aims to identify, classify, and rank the most impactful research articles based on a weighted combination of their citation count, impact factor, and year of publication. A complete literature search was performed across the Scopus, ScienceDirect, and Web of Science databases using targeted keywords such as "Norbornadiene," "Quadricyclane," and "solar thermal energy storage." A complete literature search across Scopus, ScienceDirect, and Web of Science using targeted keywords initially identified 567 studies; after applying relevance criteria, 341 articles published between 2014 and 2024 were selected for detailed analysis. The saved studies were then ranked using the InOrdinatio index, ensuring a data-driven prioritization of the most relevant contributions to the field. The analysis highlights recent technological advancements in NBD/QC-based solar energy systems, focusing on photoconversion efficiencies exceeding 90%, energy densities reaching up to 966 kJ/kg, improvements in isomerization kinetics, and enhanced thermodynamic stability of their metastable states. This systematic review not only contributes to the growing body of knowledge on molecular solar thermal systems but also offers strategic reflections for advancing sustainable and efficient solar energy technologies.
Wastewater producing from different sources like textile industry, rubber industry, paper industry, leather industry, cosmetic industry etc. contains a large amount of organic and inorganic chemicals such as dyes, dye intermediates, heavy metal ions etc. This review article is about the removal of dyes from wastewater using plant materials. Among different methods used so far, adsorption by plant materials is inexpensive and easy alternative method for the removal of dyes from wastewater. Dyes have very harmful impact on the environment especially on aquatic life which in turn has adverse effect on human beings. Therefore, it is essential to classify these dyes and find some suitable, easy and inexpensive method for their removal. Utilization of adsorption has gained great importance for the protection of environment by removing dyes from wastewater. Some adsorbents are effective but expensive, harmful and nonbiodegradable while as some are ineffective. That is why, new effective adsorbents are needed which should be least expensive, energy efficient, biodegradable and easily available. Plant material is mainly composed of lignin and cellulose and has good adsorbent property, easily available, cheap, biodegradable and nontoxic. From the survey of research papers, it was found that agricultural wastes have outstanding capabilities for adsorption. In this article we have mentioned the key study during adsorption process and reviewed the suitability and efficiency of both raw and chemically modified agricultural products in the removal of dyes from wastewater.
Firearm-related homicides are a global concern, and determining the cause of death in highly decomposed remains a challenge in forensic investigations. This study explores the potential of gunshot residue (GSR) analysis in blowfly (Chrysomya albiceps) puparia as a forensic tool, correlating residue levels with firing distance and time since death. Three pork samples were subjected to different shooting conditions: close-range shots, contact shots, and a control (no shots). C. albiceps larvae were reared on these samples, and puparia were collected at intervals from 15 to 135 days post-shooting. Inductively coupled plasma mass spectrometry (ICP-MS) analysis revealed significantly higher levels (p < 0.05) of lead (Pb), barium (Ba), and antimony (Sb) in puparia from shot samples compared to the control, with contact shots showing the highest concentrations. Additionally, a time-dependent decrease in GSR levels was observed. These findings support the use of forensic entomotoxicology in shooting cases, demonstrating that puparial GSR analysis can help estimate shooting conditions and postmortem interval. [GRAPHICS]
The nonsteroidal anti-inflammatory drugs (NSAID) are excreted unchanged in the environment that can have toxic effects on living organisms. Among these drugs, naproxen and ketoprone are widely used. Thus, a study was proposed to evaluate the interaction between different concentrations (mmol L-1) of the variables naproxen [NPX] and ketoprone [KET] against the acute toxicity of the Artemia salina (A. salina) and Allium cepa (A. cepa) applying the 22 factorial design. Responses were used: percent A. salina mortality (% mortality) and A. cepa root growth (% root growth). For A. salina, after 72 h of exposure with ([NPX] and [KET] = 0.15 mmol L−1) caused an 80% mortality. While A. cepa root growth was higher with ([NPX] and [KET] = 0.03 mmol L−1) exhibiting 133.58% root growth. However, genotoxicity was shown by the highest frequency of the values of chromosomal alterations (CA) with 46.8% CA±9.16, when compared with the negative control equal 12.6% CA±6.39. Thus, from the test (p<0.05) with the p-values of 0.0302. The lower concentrations showed necrosis and micronuclei with 1.82%±1.66 apoptotic index and 5.4%±1.40 micronuclei for 5025 cells counted. Therefore, drugs demonstrated high A. salina acute toxicity and potential genotoxic and mutagenic effect for A. cepa based.
This study explores the synthesis of rhenium complexes using two novel ligands; N(SO2(Iodobenz))dpa (L1) and N(SO2(tfm)py)dpa (L2). The formation of these ligands and their corresponding rhenium complexes, [Re(CO)3(L1)]⁺ (C1) and [Re(CO)3(L2)]⁺ (C2), was meticulously confirmed through 1H and 13C NMR spectroscopic analysis. Interestingly, the singlet peak associated with the methylene hydrogens in the ligands (4.54 ppm for L1 and 4.66 ppm for L2) transformed into two doublets in the complexes, indicating distinct magnetic environments upon complexation with rhenium. Structural verification via single-crystal diffraction confirmed the successful synthesis of L1, L2, C1 and C2. UV-Visible spectroscopic analysis aided in the identification of π−π* transitions within the 200-265 nm range for ligands, and MLCT (metal-to-ligand charge transfer) transitions around 310 nm for the complexes. FTIR spectra exhibited significant changes in the S-N stretching bands of L1 (916 cm-1) and L2 (919 cm-1) upon coordinating to Re (C1 (832 cm-1) and C2 (830 cm-1). While both ligands displayed considerable fluorescence, both complexes showed quenched fluorescence. Swiss TargetPrediction analysis indicated the potential of these compounds as Serine/Threonine protein kinase inhibitors. Molecular docking studies of L1, L2, C1 and C2 with human Serine/Threonine protein kinase Aurora A and PIM2 revealed favorable binding affinities and emphasize their potential as lead compounds in the cancer drug development.
Many students struggle to understand chemistry due to the complexity of the content and abstract concepts. Teachers’ mediation based on technological, pedagogical, content knowledge (TPACK) and the contextualization of the content with everyday life may help in this process. In this study, molecular modeling was used as a tool to help teach chemistry integrated with biology. An observational, qualitative and quantitative study was conducted with 136 high school students and 167 undergraduate students. We carried out a mini course named “Is there chemistry in food” and some of the examples approached were water, sodium chloride, sucrose, lactose, oleic acid, collagen, capsaicin receptor and others. An increase in correct answers was observed by comparing the answers after the two-hour mini-course and the correct answers before the activity, reaching 46.30% in some questions. When asked about the efficiency of the method, most of the students answered positively and detached the contributions to learning, the innovative, fun, interactive or dynamic character, the visualization of the molecules, and the practice itself. Thus, molecular modeling tools can be an interesting strategy to be explored in chemistry and biology classes, especially in high school.
Practical laboratory experiments are essential to connecting theory to practical application and providing important support for academic training; however, many curricula still lack effective practical activities. This work proposes a didactic laboratory experiment highlighting the organic synthesis of a heterocyclic perimidine, providing an integrative approach to concepts such as carbonyl group addition and substitution (imine formation), thin-layer chromatography (TLC), liquid-liquid extraction, recrystallization, and yield calculations. Furthermore, a comparison was made between water and glycerol as environmentally friendly (green) solvents. Characterization techniques such as melting point, spectroscopy NMR 1H and 13C, vibrational spectroscopy (FTIR) and UV-Vis were also used for product identification and discussion. The experiment was designed for undergraduate students and offered an opportunity to explore a variety of concepts in organic chemistry while integrating sustainable practices with fundamental techniques, demonstrating its potential as an effective and engaging educational tool.
Datura stramonium, commonly known as thorn apple, jimson weed, devil's snare, or devil's trumpet is an important medicinal plant. It belongs to Kingdom: Plantae, Order Solanales, Family: Solanaceae, Genus Datura, and Species: D. stramonium. It is used in traditional medicine to treat many ailments, including skin eruptions, abscesses, inflammation, boils and acne. Leishmaniasis is an important parasitic problem and is in focus for development of new drugs for it all over the world. Anti-leishmanial activity was performed against Leishmania tropica KWH23 promastigote......
