Questões de Concursos Exército Brasileiro

Devido ao intenso calor liberado, reações de termita são bastante utilizadas em aplicações militares como granadas incendiárias ou em atividades civis como solda de trilhos de trem. A reação de termita mais comum é a aluminotérmica, que utiliza como reagentes o alumínio metálico e o óxido de ferro III.

A reação de termita aluminotérmica pode ser representada pela equação química não balanceada:

Al (s) + Fe₂O₃ (s) ? Fe (s) + Al₂O₃ (s) + Calor

Dados: valores arredondados de entalpias padrão de formação das espécies ?H^o _fAl₂O₃ = - 1676 kJ/ mol; ?H^o _f Fe₂O₃ = - 826 kJ/mol

Acerca desse processo, são feitas as seguintes afirmativas:

I – Após correto balanceamento, o coeficiente do reagente alumínio na equação química é 2.
II – Essa é uma reação de oxidorredução e o agente oxidante é o óxido de ferro III.
III – Na condição padrão, o ?H da reação é - 503 kJ para cada mol de óxido de alumínio produzido.
IV – Na condição padrão, para a obtenção de 56 g de ferro metálico, o calor liberado na reação é de 355 kJ.

Teaching English in the Brazilian countryside

      “In Brazil, countryside youth want to learn about new places, new cultures and people. However, they think their everyday lives are an obstacle to that, because they imagine that country life has nothing to do with other parts of the world”, says Rafael Fonseca. Rafael teaches English in a language school in a cooperative coffee cultivation in Paraguaçu. His learners are the children of rural workers.
      Rafael tells us that the objective of the project being developed in the cooperative is to give the young people more opportunities of growth in the countryside, and that includes the ability to communicate with international buyers. “In the future, our project may help overcome the lack of succession in countryside activities because, nowadays, rural workers’ children become lawyers, engineers, teachers, and sometimes even doctors, but those children very rarely want to have a profession related to rural work”, says Rafael.
      “That happens”, he adds, “because their parents understand that life in the countryside can be hard work and they do not want to see their children running the same type of life that they have. Their children also believe that life in the country does not allow them to have contact with other parts of the world, meet other people and improve cultural bounds. The program intends to show them that by means of a second language they can travel, communicate with new people and learn about new cultures as a means of promoting and selling what they produce in the country, and that includes receiving visitors in their workplace from abroad.”
      Rafael’s strategy is to contextualize the English language and keep learners up-to-date with what happens in the global market. “Integrating relevant topics about countryside living can be transformative in the classroom. The local regional and cultural aspects are a great source of inspiration and learning not only for the young, but for us all.”

Adapted from http://www.cambridge.org/elt/blog/2019/01/21/teaching-english-in-the-brazilian-classroom/