Chemistry
Mostrando 25-36 de 2733 artigos, teses e dissertações.
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25. Chemical composition of Andropogon gayanus cv. planaltina predicted through nirs and analyzed through wet chemistry
RESUMO Objetivou-se comparar os teores dos nutrientes do capim Andropogon gayanus obtidos no equipamento NIRS com os valores obtidos por análises de via úmida, para identificar se os modelos globais de calibração do equipamento NIRS são adequados para predizer a composição químico-bromatológica. As análises de via seca no NIRS foram executadas no L
Arquivo Brasileiro de Medicina Veterinária e Zootecnia. Publicado em: 2022
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26. Synthesis of Triazoles by Electro-Assisted Click Reaction Using a Copper Foil Electrode
This paper presents an innovative pathway for the synthesis of triazoles using the well-known “click chemistry” assisted by the electrochemical oxidation of metallic Cu0. The click reaction is used to couple a wide range of biological interest compounds. In this case, faster and less polluting methods for a biological environment was achived by in situ C
J. Braz. Chem. Soc.. Publicado em: 2021-07
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27. Dificuldades no ensino e na aprendizagem de química orgânica do ensino superior - estudo de caso em duas Universidades Federais
This research investigates difficulties associated to the curricular component Organic Chemistry I based on a study case of Chemistry undergraduate courses (Bachelor and Teachers education) in two Federal Universities in the Brazilian South region. The analytical process integrated official documents of the courses (pedagogic projects, students’ grades), q
Quím. Nova. Publicado em: 2021-06
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28. Dificuldades de ingressantes de um curso de licenciatura em química sobre conceitos da eletroquímica: um desafio para o ensino superior
The present work discusses some of the difficulties that chemistry undergraduates have with electrochemistry and possible impacts on higher education. They responded to a questionnaire about their insights and experiences regarding electrochemistry teaching, as well as their knowledge about it. The responses were categorized according to their difficulties,
Quím. Nova. Publicado em: 2021-06
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29. Lignin-modified road marking paint: weathering aging studies
Abstract The accelerated artificial aging with ultraviolet radiation, viscosity, density, no-pick-up time, flexibility, and abrasion resistance of lignin-modified road marking paint were evaluated. The addition of lignin did not cause significant changes in the physical chemistry, flexibility and no-pick-time test compared to the precursor paint. The additio
REM, Int. Eng. J.. Publicado em: 2021-06
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30. A Catalysis Guide Focusing on C–H Activation Processes
From the recent development of catalytically controlled C-H activation with amenable synthetic routes obviating many challenges, the demand for this strategy has raised significantly to perform complex organic transformations. The impact of the achieved results in both homogeneous and heterogeneous catalysis reflects its efficacy in modern synthetic chemistr
J. Braz. Chem. Soc.. Publicado em: 2021-05
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31. CLASSIFICAÇÃO DAS SUBSTÂNCIAS QUÍMICAS: UM CONCEITO POUCO EXPLORADO NA EDUCAÇÃO QUÍMICA
The classification of chemical substances is a concept little explored in Chemistry teaching literature and in Chemistry textbooks at higher and secondary levels. The aim of this paper is to discuss theoretically the importance and contributions of this concept for teaching and learning Chemistry. The History of Chemistry reveals that the chemical criteria f
Quím. Nova. Publicado em: 2021-04
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32. UMA PROPOSTA PARA O ENSINO DE LABORATÓRIO DE QUÍMICA ANALÍTICA QUALITATIVA
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 ba
Quím. Nova. Publicado em: 2021-04
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33. DESENVOLVIMENTO NOS MÉTODOS DE GLICOSILAÇÃO: UMA CHAVE PARA ACESSAR SUAS APLICAÇÕES NA SÍNTESE DE MOLÉCULAS BIOATIVAS
Glycosylation reaction is an important class of reactions in organic chemistry, and the development of the method contributes to the synthesis of many biologically active compounds containing various glycoside bonds. Is arguably the most important, albeit challenging, reaction in the field of carbohydrate chemistry. Examples of the products of glycosylation
Quím. Nova. Publicado em: 2021-04
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34. A VISITA DE FRITZ HABER AO BRASIL
Fritz Haber was awarded with the Nobel Prize in Chemistry in 1918 for the ammonia synthesis from its gaseous components. This work was fundamental to stop starvation around the world. On the opposite, his engagement to produce chemical weapons during the First World War is also an important fact in the life of this scientist. This polemic scientist visited B
Quím. Nova. Publicado em: 2021-04
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35. SALA DE AULA INVERTIDA NO ENSINO DA QUÍMICA ORGÂNICA: UM ESTUDO DE CASO
The flipped classroom is one of the types of rotation model strategies that aim of increasing interaction and personalized contact time between students and teachers in the classroom setting. In this study, we investigated the application of the flipped classroom strategy in two classes of the different semesters in the discipline of Organic Chemistry. The t
Quím. Nova. Publicado em: 2021-04
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36. EFEITO DO HG2+ E DOS ÍONS CU2+, FE2+, NI2+, SN2+ E ZN2+ NA ESTABILIDADE DE NANOPARTÍCULAS DE PRATA: UMA PRÁTICA INTERDISCIPLINAR DE NANOTECNOLOGIA EXPERIMENTAL
The growing predominance of nanoscience and nanotechnology makes it increasingly important that these topics become an integral part of all scientific education. For this reason, in the present work, an interdisciplinary experiment of nanotechnology is introduced. As silver nanoparticles (AgNPs) are the most applied nanomaterial in consumer products, the cur
Quím. Nova. Publicado em: 2021-04