A PROPOSITION FOR TEACHING LABORATORY OF QUALITATIVE ANALYTICAL CHEMISTRY. Teaching laboratory of qualitative analytical chemistry is still a controversial issue in chemistry courses. However, important researchers and educators in chemistry recognized and highlighted the importance that the contents of this discipline represent in the formation of chemists, once it can provide handling and understanding of microscopic phenomena based on the observation of their macroscopic effects, once such reactions and phenomena are the basis of important instrumental methods of analysis. Thus, a proposal based on a bottom-up approach has been developed, starting with the observation of different reactions of cations in laboratory, followed by a search for the reaction responsible for each resulting phenomenon observed during the experimental step. Then these reactions are related with the separation procedures of each group of cations. Eventually the separation of these groups can also be performed depending on the time available. The proposal has been applied in teaching laboratory of qualitative analytical chemistry at Instituto de Química de São Carlos/USP since 2015, where the discipline is offered duirng 4 hours/week, and a positive feedback regarding the evolution of the methodology and its acceptance by students. Good results were also obtained concerning the appropriation of the contents by the students, using the proposal.
Graphite powder was mixed with polyurethane in order to prepare composite materials in different proportions, such as 50, 60 and 70% (graphite w/w) intended to be used in voltammetric analysis. Results of thermogravimetry, differential scanning calorimetry and dynamical mechanical analysis were used in the characterization of the composites. Thermal and visco-elastic behaviors of pressed and non-pressed graphite-polyurethane composites used as electrode materials were investigated regarding the graphite content. TG curves revealed that thermal stability increases with the graphite content. DSC presented that the composites are completely cured after 24 h and DMA was used in the determination of glass transition of the composites, varying between approximately 56 -59°C and 70 -83°C for pressed at 4000 psi and nonpressed composites, respectively, showing that the pressing during the cure resulted in lower mobility of polymeric chains inside the composites.
Dedico este trabalho, Aos meus pais, Carlos e Tereza, pelo amor, incentivo. À minha irmã Ana Paula, pela amizade e apoio. Ao meu irmão Paulo Sérgio, minha cunhada Paula e à pequena Isis. iii Agradecimentos A Deus por tudo que tenho e sou. Ao Prof. Dr. Éder Tadeu Gomes Cavalheiro pela amizade, respeito, confiança, incentivo, pela orientação e discussões. Ao Prof. Dr. Gilberto O. Chierice pelo respeito, incentivo e amizade. À Dra. Priscila Cervini Assumpção pelo apoio, pelas discussões e pelo incentivo. Às amigas que sempre estiveram do meu lado em todos os momentos, Amanda, Gra, Ju (Barbie), Rita e Grace. Agradeço à Andressa (Braba), Aline e Claudio pela amizade, carinho e estadia no Aloja, fundamentais para a realização desse trabalho.
<p>O presente trabalho pretende discutir as contribuições da pesquisa na formação por meio da análise dos temas privilegiados por trabalhos de Iniciação Científica da área de ensino de química apresentados nas Jornadas Nacionais de Iniciação Científica (JNIC). O trabalho é de cunho qualitativo e está baseado na pesquisa documental. Para a coleta dos dados recorremos aos Anais das Jornadas Nacionais de Iniciação Científica publicados na página da Sociedade e acessamos os resumos dos trabalhos apresentados, no período de 2005 a 2017. A análise dos trabalhos se deu por meio de análise de conteúdo dos resumos simples e classificação dos trabalhos pelos eixos temáticos: i) Formação Inicial e Continuada, ii) Ensino-Aprendizagem, iii) Materiais-didáticos, iv) Experimentação e v) Educação Inclusiva. A discussão tecida proporcionou um mapeamento das tendências das pesquisas de Iniciação Científica (IC) desenvolvidas naquele evento, identificando as temáticas de investigação que estão sendo abordadas.</p>
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