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linxiaogu
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[求助]
英文翻译求助
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The chemical equation is a language of chemistry, one that chemists and chemical educators use constantly. Once chemical equations have been introduced in a course of study, it is often assumed that students understand this representational system. But many of the difficulties in learning chemistry are related to chemical equations (1). If students do not understand the language used by the instructor, how can they be expected to understand what is said? In balancing equations, it is important to understand the difference between a coefficient of a formula and a subscript in a formula. The coefficients in a balanced chemical equation can be interpreted both as the relative number of molecules, moles or formula units involved in the reaction. And subscripts on the other hand indicate the relative number of atoms in a chemical formula. Subscripts should never be changed in balancing an equation, because changing subscript changes the identity of the substance. In contrast, changing a coefficient in a formula changes only the amount and not the identity of the substance and hence can be manipulated in balancing chemical equations. Balancing equation go further than word equation. It gives the formula of the reactants and products and shows the relative number of particles of each of the reactant and the products. Notice that the atoms have been reorganized. It is also important to recognize that in a chemical reaction, atoms are neither created nor destroyed. In other words, there must be the same number of each type of atom on the product side and on the reactant side of the arrow. Thus, a chemical equation should obey the law of conservation of mass. Previous studies (2; 3) have shown that students can produce correct answers to various kinds of problems, including those involving chemical reactions, but their understanding of the underlying chemical concepts was lacking. |
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【答案】应助回帖
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linxiaogu: 金币+8, 翻译EPI+1, ★★★很有帮助, 真的是万分感谢啊，辛苦你了，哈哈，我一个朋友叫我帮忙翻译下，但是我现在上班了很忙就想到找虫友来帮忙了 2012-09-03 19:08:48
linxiaogu: 金币+8, 翻译EPI+1, ★★★很有帮助, 真的是万分感谢啊，辛苦你了，哈哈，我一个朋友叫我帮忙翻译下，但是我现在上班了很忙就想到找虫友来帮忙了 2012-09-03 19:08:48
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化学方程式是化学家及化学教育家经常用的一种化学语言。如果在一系列学习中引进了化学方程式，那前提是学生可以理解化学方程式这一表现方式。如果说学生不知道老师所用的这一化学语言，他们还谈何去明白老师在讲什么呢？ 在平衡化学方程式时，一定要明白方程式两端的系数和下角标所遵循准则的重要性。在一个配平的化学方程式中系数可以通过相对分子数量以及在反应中参与反应的量来进行解释说明，而另一方面下角标则能反应在一化学反应中的相对原子数。但在配平一个化学方程式时千万不能改变下角标，因为改变了下角标那这种物质也就改变了。但相反的是，在配平化学方程式时，化学式前的系数改变却只是改变了这种物质的量，并未改变这种物质的性质。化学方程式比一般的方程要复杂的多，因为它体现了参与反应和生成物之间相对数目和性质之间的转化过程，可以看到反应后元素间发生了重组。还有一个重要的地方需要注意的是化学反应前后既不会有新的元素生成，之前存在的元素也不会消失。换句说法就是说，反应完后，反应物端和生成物端的元素数目和种类都是一样的。这样看来，一个化学方程式是要遵守一定准则的。 以前的研究表明，学生们对于不同的问题也都可以得出正确的答案，这其中也包括了一些化学反应的问题。但是他们对于深于化学概念之下的东西了解还尚且不足。 哥们，您这玩意真够长的。您看翻的还凑合不？  |
2楼2012-09-02 20:48:42
