Avaliação do conhecimento sobre periodicidade química em uma turma de química geral do ensino a distância

This work describes the software Quiptabela, suggests a teaching activity, and analyses responses of general chemistry students from the Biological Sciences distance course at the Federal University of Tocantins. The software was described according to its educational potential, featuring the creation of dozens of charts or tables correlating physicochemical properties of the elements, being Brazilian, and free distribution. The teaching activities suggested analyzed students' ability to create and analyze tables and charts correlating the properties of chemical elements. Some 41% of students tested could define the term "periodic", but failed to use the concept to explain and differentiate changes in mass or atomic radius with the atomic number of elements.

O tempo de pega em gelatinas comerciais: uma experiência da disciplina de quimiometria para estudantes de graduação em Química

The aim of this paper is to describe a chemometrics experiment for undergraduate chemistry students using basic concepts of experimental design to determine setting-time of commercial gelatins.

Química Nova Interativa - QNInt - o portal do conhecimento da SBQ: conectando ciência e educação

The Química Nova Interativa (QNInt) portal was launched in 2009 by the Brazilian Chemical Society (SBQ) to offer free quality content for broad audiences. QNInt provides peer-reviewed articles from SBQ journals on science & society, chemical concepts, classroom activities and educational research. With 3,000,000 visits, QNInt also offers a unique library of interactive molecules. In the International Year of Chemistry QNInt served for distributing pH kits and registering data from IUPAC's Global Water Experiment, yielding Brazil the largest share of the global pH data set. The portal performance makes QNInt a valuable resource for connecting science to education.

Visualização no ensino de química: apontamentos para a pesquisa e desenvolvimento de recursos educacionais

Visualization is a fast-growing field in science education. This review covers 171 articles published between 2001 and 2010 in 14 science education journals. Major findings include: i - despite the predominance of English speaking countries, interest in the topic has increased in several countries; ii - qualitative research is increasing, but quantitative methodologies prevail; iii - the role of peer interaction in group activities is little investigated; iv - research on the way students and teachers use visualization tools is increasing, but most publications focus on the tools; v - structure of matter remains the most common subject covered.

A abordagem de questões ambientais: contribuições de formadores de professores de componentes curriculares da área de ensino de química

This paper presents the results of a study involving current teachers of the chemistry teaching curricular components of twelve Chemistry licentiate courses at state universities in the South and South-east of Brazil. The aim was to analyse how these curricular components can work together to address environmental issues in Chemistry teacher-training. From analysis of the interviews, it can be ascertained for example that environmental themes in the curricular components analysed are treated with differing levels of intensity and perspectives, and in some cases, have a more illustrative character regarding chemistry concepts.

Obtenção de biodiesel por transesterificação em dois estágios e sua caracterização por cromatografia gasosa: óleos e gorduras em laboratório de química orgânica

Methanolic transesterification of oils and fats was carried out in a two steps procedure, under basic and acidic catalysis. Palm, soybean, canola, corn, rice, grapeseed, sunflower, peanut, pequi and olive oils, besides tallow and lard were used as feedstock. Specific gravity, relative viscosity, thin layer chromatography and gas chromatography were used to characterize the biodiesel. Biodiesel was obtained in high yield and purity. Results were used to discuss the following key-concepts: 1 - triglycerides, composition and properties; 2 - nucleophilic acyl substitution under basic and acid conditions, 3 - thin layer chromatography, 4 - gas chromatography and its quantitative methods.

Metodologia de ensino jigsaw em disciplina de química medicinal

In this paper, we describe an educational experience involving the use of the jigsaw method on the Medicinal Chemistry course at the University of São Paulo, Brazil. The goal of this proposal was to investigate acceptance and contributions of the method to undergraduate chemistry teaching. Feedback on the jigsaw method collected from the focus groups and questionnaires showed that participants generally acknowledged the advantages of the jigsaw method in helping them learn the Medicinal Chemistry subject. Suggestions for improving the jigsaw method were also received from participants.

Vicente Seabra Telles e a criação da nomenclatura em português para a Química 'Nova' de Lavoisier

In 1787, Lavoisier and coworkers published a 314-page book entitled Méthode de nomenclature chimique in which a novel system for the naming of compounds and elements was presented. The Brazilian chemist Vicente Coelho de Seabra Telles (1764-1804) was responsible for translating it into Portuguese. Telles proposed the adoption not only of the Latin etymology, but decided to use Latin suffixes as well, because of the similarity between Latin and the Portuguese language. In doing so, he made the names of the compounds in Portuguese bear a closer resemblance to the names in Latin than to those in French or Spanish.

Produção de casos para o ensino de Química: uma experiência na formação inicial de professores

The Method of Case Studies has often been employed in higher education, but few initiatives have focused on basic education. This work addressed the production of cases by students from a chemistry teacher training course. The proposal was applied in the discipline of Basic Inorganic Chemistry and aimed to familiarize students with the Method from the preparation of cases focused on basic education. We believe the proposal was efficient in showing future teachers the need to develop teaching strategies that, beyond learning concepts, stimulate students in training skills such as teamwork, critical thinking and decision making.

Polímeros impressos com íons: fundamentos, estratégias de preparo e aplicações em química analítica

Chemical imprinting technology has been widely used as a valuable tool in selective recognition of a given target analyte (molecule or metal ion), yielding a notable advance in the development of new analytical protocols. Since their discovery, molecularly imprinted polymers (MIPs) have been extensively studied with excellent reviews published. However, studies involving ion imprinted polymers (IIPs), in which metal ions are recognized in the presence of closely related inorganic ions, remain scarce. Thus, this review involved a survey of different synthetic approaches for preparing ion imprinted adsorbents and their application for the development of solid phase extraction methods, metal ion sensors (electrodes and optodes) and selective membranes.

Explorando as percepções de professores em serviço sobre as visualizações no ensino de química

Taking into account the requirements for the teaching of chemistry, several visualization resources (software, videos, animations, molecular models, among others) are available. These visual aids are used in order to enhance the understanding of chemical phenomena in the classroom. However, many teachers make scant use of these resources, limiting macroscopic understanding of chemical science. Thus, this article discusses chemistry teachers' views on several aspects such as using visual aids in teaching chemistry, a resource most widely used in classes on atomic models, isomerism and spatial geometry.

Química e filosofia: rumo a uma frutífera colaboração

This review seeks to present a brief history of the philosophy of chemistry and the major issues discussed in the framework of this emerging discipline of philosophy of science, such as the question of physicalist reductionism and physical and chemical causality. In this vein, it also addresses the current debate over relevant issues of chemical world such as atomic orbitals, molecular structure, chemical bonding, models and explanations, as well as the foundations of the periodic table. Finally, the importance of the link between the philosophy of chemistry and chemistry education is analyzed, especially in relation to teacher training.

Composição química e atividade anticolinesterásica de uma fração ativa do extrato de folhas de Citrus limon (L.) Burm

This paper describes the chemical composition and acetylcholinesterase inhibition of an active chromatographic fraction of the EtOAc extract of Citrus limon leaves. The composition of the active fraction presented a mixture of two coumarins, 5,8-dimethoxy-psoralen and 5,7- dimethoxycoumarin, identified by ¹H and ¹³C NMR data analysis, including DEPT, COSY, HMBC and HSQC experiments. It was also demonstrated that this mixture presents qualitative and quantitative AChE inhibition. In vitro studies indicated a CE50 value of 340 µg/mL with 95% of confidence. In vivo studies (10 and 25 mg/kg) revealed inhibition of 30.09 and 30.06% of AChE activity in relation to neostigmine, respectively.

Físico-química experimental: uma proposta para abordar equilíbrio de fases em sistemas ternários

On undergraduate courses, practical classes represent periods in which students can verify the concepts presented in theoretical classes. Conversely, the teaching internship in graduate programs allows these students to incorporate pedagogical practices into their experience, predominantly involving observation and reproduction of methods adopted by supervisors. We propose internship teaching as a period for reflection on our pedagogical practice and present a methodology for an experimental physical chemistry classroom. The students can interact with the experiment and instructor, furthering the study of ternary systems while developing their skills for investigative work.