Visões de meio ambiente e suas implicações pedagógicas no ensino de química na escola média

This study was realized with high school Chemistry teachers from the region of and around Florianópolis (SC). It examines the pedagogical implications of these teachers' views on environmental issues, and discusses the possibilities and difficulties of bringing these issues into the Chemistry classroom. The semi-structured interviews were analyzed using Textual Discourse Analysis principles. The dominance of content-based teaching and traditional pedagogical approaches appears to hinder curricular changes. Most subjects pay little heed to environmental issues and their relation to Chemistry, and endorse a view of science as neutral, and the environment as anthropocentric - views far from Green Chemistry principles.

A linguagem química e o ensino da química orgânica

The importance of chemical language and specifically of molecular models and their representations in the development of chemistry is discussed. Structural formulas are projections of molecular models used as a specific language by chemists. The meaningful learning of chemistry requires knowledge of this language. The use of these analogical symbols without the necessary understanding engenders difficulties for the learning of chemistry.

Cloração do anisol, tolueno e nitrobenzeno com ácido tricloroisocianúrico (ATCI): aspectos computacionais sobre a reatividade e regiosseletividade

We present in this educational article a theoretical analysis based on DFT/B3LYP 6-311++G (d,p) and ab initio MP2/6-311++G(d,p) computational calculation about the reactivity and the regioselectivity on the chlorination reaction of anisole, toluene and nitrobenzene, using trichloroisocyanuric acid (TICA) as donor of Cl+. The H.O.M.O. / L.U.M.O. energy and N.B.O. atomic charges of various aromatic systems were calculated in ab initio level. The energies of the reagents and intermediaries were calculated using D.F.T.. These results have been presented as a quantitative example for the S E A mechanism, in the undergraduate organic chemistry disciplines.

A Química Quântica na compreensão de teorias de Química Orgânica

Quantum chemical calculations were performed in order to obtain molecular properties such as electronic density, dipole moment, atomic charges, and bond lengths, which were compared to qualitative results based on the theories of the organic chemistry. The quantum chemistry computational can be a useful tool to support the main theories of the organic chemistry.

Adsorção e propriedades de volume de misturas binárias água álcool: um experimento didático com base em medidas de tensão superficial

An undergraduate physical chemistry experiment based on the drop counting method for surface tension measurements is proposed to demonstrate adsorption isotherms of binary aqueous solutions of ethanol, n-propanol, and n-butanol. Excess surface is obtained by the derivative of surface tension taken with respect to alcohol activity, after this activity calculation using van Laar equation. Laboratory class contents are surface tension, excess surface, percolation of hydrogen bonds, micelle, activity, and ideal solution.

Aspectos históricos dos cursos de licenciatura em química no Brasil nas décadas de 1930 a 1980

This article describes some historical moments in the establishment and development of chemistry teacher's training courses since 1930, with the creation of universities in Brazil, until 1980. Correlations between educational and political questions that influenced the directions taken for the formation of chemistry teachers in Brazil are discussed. From a review of the bibliographical sources available, we revisited stances of discussions on public policies related to science teacher's formation in general and in chemistry, particularly, in order to provoke a reflection on what challenges and prospects exist in the current scenario of undergraduate chemistry education in Brazilian universities and colleges.

Artigos da revista Ciência Hoje como recurso didático no ensino de química

This paper presents the results from the selection and analysis of Ciência Hoje articles published from 2004 to 2009 with the aim to discuss some of their features which can assist teachers in chemistry teaching. Therefore, the articles were analyzed according to their content and format based on an analytical tool proposed by Kawamura and colleagues. The results indicate that this magazine offers a reasonable collection of articles related to chemistry with a variety of contents and approaches.

Formação docente no ensino superior de Química: contribuições dos programas de aperfeiçoamento de ensino

The literature on the challenges of teacher education in undergraduate chemistry teaching is limited. In the present study, the application of didactic proposals elaborated by two authors of this paper, graduate students and teaching assistants of the teaching improvement program at University of São Paulo, was investigated in terms of their contribution to the teaching assistants' education and undergraduate students' receptivity toward them. Such proposals were based on the jigsaw cooperative learning strategy and applied in two undergraduate courses. The results indicate students' good receptivity and suggest their importance to teaching assistants' education.

A problematização das atividades experimentais na educação superior em química: uma pesquisa com produções textuais docentes

Through the analysis of articles with proposals for experimental activities and with current pedagogical, epistemological and environmental discussion on experimentation by Chemistry professors, this paper investigates ways of highlighting relevant methodological characteristics that can be incorporated in experiments. Based on analysis of the suggestions for experiments it appears that of particular importance are: a concern for students' physical welfare and for the effects of residues; the need to confront an impoverished infrastructure that hinders experimentation; and the valorisation of clarifying student knowledge. It argues in favour of the need to set out the problems of experimentation in educators' professional development.

Investigando a presença da história da ciência em livros didáticos de Química Geral para o ensino superior

This paper aims at analyzing the history of science content of three general chemistry textbooks used in Brazilian universities: the translations of Kotz and Treichel's Chemistry & Chemical Reactivity, Atkins and Jones's Chemical Principles, and Garritz and Chamizo's Química. Results revealed different trends for the inclusion of history of science in chemistry teaching. Kotz & Treichel and Atkins & Jones used history mainly as curiosity and ornament. Garritz & Chamizo adopted the historical approach as one of the organizing axis of their textbook. Nevertheless, the historical content of the three textbooks may be criticized from current historiographical standpoint.

O trabalho experimental no ensino de Química

This article deals with conceptions of the experimental work in the Chemistry teaching, developed among teachers and students. The research was carried out using qualitative methodology, based on Gaston Bachelard's thoughts. The results showed dispersion of conceptions among both students and teachers. This dispersion, interpreted as a profile of conceptions, was discussed based on the notions of Bachelard's epistemological profile and Mortimer's conceptual profile. This work points out the need to rethinking and finding new directions for experimental activities in the training courses for Chemistry teachers, in order to meet Chemistry educators' social goals.

A problematização das atividades experimentais na educação superior em Química: uma pesquisa com produções textuais docentes - parte II

Through the analysis of articles with proposals for experimental activities and with current pedagogical, epistemological and environmental discussion on experimentation by Chemistry professors, this paper investigates ways of highlighting relevant methodological characteristics that can be incorporated in experiments. 102 articles from national periodicals were analysed, all of which suggested experiments for use in Chemistry higher education. Based on analysis of the suggestions for experiments it appears that of particular importance are: visions, such as those that explain a belief that experimentation incentivizes motivation and conceptual learning; awareness of observation influenced by empiricism; and "errors" of students, which enrich their knowledge.

Miniprojeto para ensino de química geral experimental baseado na fermentação do caldo de cana-de-açúcar

This paper describes a five-week mini-project for a general chemistry laboratory course. Activities are included preparations of ethanol and sucrose solutions, calculation of concentrations, determination of densities with densimeters, sugarcane juice fermentation with CO2 capture in alkaline solution, distillation, and determination of amounts of ethanol and CO2 formed. Abilities and concepts normally present in practical general chemistry courses are covered: use of balances, volumetric glassware and densimeters, preparation of solutions, performing of dilutions, determination of solution densities, observation of chemical reactions, stoichiometric calculations, separation of mixtures, and titration.

Preparação de nanopartículas de prata e ouro: um método simples para a introdução da nanociência em laboratório de ensino

A new practical experiment involving silver and gold nanoparticle syntheses was introduced in an inorganic chemistry laboratory course for undergraduate students at the Institute of Chemistry, UNICAMP. The nanoparticles were synthesized by the reduction of silver nitrate and tetrachloroauric acid with sodium borohydride and sodium citrate in an aqueous medium. Stabilities of the suspensions were tested using several different reactants including sodium chloride, polyvinylpyrrolidone, polyvinyl alcohol and cistamine. Changes in optical properties were observed by electronic spectra and also by transmission electronic microscopy, which also yielded data for estimating particle size.

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.