Educacion Quimica最新文献

Complex crude oil refining processes involve several organic reactions whose mechanisms, kinetic and thermodynamic phenomena determine the product distributions, therefore, these reactions constitute an important reference for setting operating conditions of many processes in the industry. Under the integral vision of the chemical engineering teaching, 3 hydrocarbon conversion processes are analyzed (combustion, alkylation and cracking) taking into account the organic reactions involved in each process and its influence to determine the type and quality of the products obtained.

This article reflects on the notion of context and its importance in the teaching and learning of science in general and chemistry in particular. A brief review of the various ways of understanding science education in context and problems associated with its application in the classroom is done. From this analysis a proposal of criteria for the development of contextualized learning units is presented, and its goal is to construct a model with the key ideas to be applied. As an example of this, the design of a teaching unit is shown for an atomic model that takes into account a possible scenario of progression in their learning

Tin dioxide semiconductor gas sensors represent an alternative for gas detection in air because its simplicity and low cost. This coupled with the need for a computer based interface, makes them ideal for developing multidisciplinary projects with students from areas such as Chemistry, Electrical Engineering, Electronics and Computer Science. This document shows the construction of a low cost system for evaluation of semiconductor gas sensors. This system consists of an exposure chamber, an electronic interface to manipulate the sensor and to transfer data to the computer and a methane generator for use in the laboratory.

Esters consist in one of the classes of chemical substances widely found in nature. Some esters of low molecular weight tend to have a pleasant flavor and therefore are widely used by food and drinks industries. The esters can be synthesized by the reaction between a carboxylate anion and an alkyl halide, or by Fischer esterification reaction. Industrially, this last reaction is one of the main procedures for the esters synthesis, and according this work, a simple experiment about this specific obtaining method is described and proposed for undergraduate discipline of organic analysis. The preparation of alkyl levulinate and lactate, from levulinic acid and/or lactic acid, is carried out in laboratory, easily, requiring three periods of four hours and is useful for chemistry teaching.

To Charles Hatchett (1765–1847), a self-educated scientist and first class analytical chemist, we owe the discovery of niobium, the analysis of a series of important minerals and animal substances such as shells, bones, dental enamel, a detailed study of bitumens, the separation of an artificial tanning material from mineral and animal sources.

The development of ecological awareness in different layers and sectors of society in Latin America involving Education, which may contribute to the formation of a creative economy, related to experimental practices with concern for environmental issues. The objective of this research was to develop an experimental low cost and easy implementation which was used biomass babassu (babassu mesocarp) as biosorbent in the removal of methylene blue dye from aqueous solutions. The babassu mesocarp showed good sorption capacity were used since small amounts of biosorbents in the removal of dye. It was found that there is a proportional relation between the amount of the biosorbent and dye concentration, at least in dilute solutions. We could realize the importance of washing step during the preparation of biosorbent. It is at this stage that are removed water soluble substances which can enhance the effluents of organic matter. The experiment also promote the concept of environmental sustainability and reuse of waste, as well as enrich the practical and settings chemical sorption, bioremediation, sorbent, biomass, intermolecular forces, solubility, polarity and biosorbent. Also, be keen curiosity of students, awakening them to the importance of research in chemistry

This article presents the concept of geographical and cultural border as an analogy to construct a different perspective on a historical fact and its main contribution to the origins of Chemistry as one of the sciences of nature. It is thought up on the origin of the model of the Phlogiston and of the reasons English and German chemists had to admit and accept it during the 18th century. It is also demonstrated that the G. E. Stahl proposal was a conceptual and methodological construction, which cannot be abandoned by the simple “entelequia” for the oxygen. An analysis of A. L. Lavoisier work was done in order to discuss the category of “scientific Revolution” of T. S. Kuhn, and conclude, that this step cannot be assumed from the above mentioned perspective.

This second part of the paper describes the techniques that were developed after platinum treatment, its associated elements, applications and its addition to the periodic table. The discussion is around how the scientific research of a particular chemical element involves social, economic and political factors applicable to other metals as well.

A conceptual and methodological proposal arises here based on scientific controversy, as an option for student teachers to develop ownership and argumentative skills. This assumes appropriation of school science knowledge as constructor evidence to develop scientific controversies in the classroom enhancing argumentation, conviction and commitment, which are key to improving teaching and educational quality in school.