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Ⅳ、克原子和克分子在化学计算中的应用(一)胡国华同志说张海若同志的“全文中似乎强调了做计算题一定要用克分子,这对发展学生的思维能力来说似乎还值得商榷。”该不该强调呢?我觉得是应该强调的。强调用克分子做化学计算题不但不会阻碍学生的思维能力的发展,相反地会培养学生的逻辑思维,会使学生的思维能力获得恰当地提高。因应用克原子、克分子来解答计算问题有一定的优越性,能使学生正确地计算和掌握应用问题。这些优越性已为张海若同志所缕述,不再赘。更重要的是:根据分子式或化学方程式来计算化学应用问题时引用了克原子、克分子,不但简化了计算,而且还把原子分子的概念引入重量(克数)的计算。如不经过这个步骤,学生是很难捉摸题目中的道理的,即使学生能照样地解答题目,也必然是机械的生搬硬套。胡国华同志说:“如果 FeS_2中的硫全部生成 H_2SO_4的话,则一个 FeS_2分子应当可以生成二个 H_2SO_4,因此可以找出119.9克 FeS_2能生成2×98克 H_2SO4_。”这里一个 FeS_2分子和119.9克FeS_2有什么关系?知道了一个 FeS_2分子能生成二个H_2SO_4,是怎样找出119.9克 FeS_2生成2×98克 H_2SO_4的呢?学生不懂的地方就在这里,胡国华同志用“因此”二字就轻轻地带过去了。我以为这里必须引用克分子的概念来作为桥樑,概念才够清楚,思维才合乎逻辑,计算才更简单。我们可以教学生这样想:
Ⅳ. The Application of Gram-Atoms and Molecules in Stoichiometry 1. Comrade Hu Guohua said Comrade Zhang Hai-ruo’s “full text seems to emphasize the need to use numerators in making computational questions. This seems to be still debatable in developing students’ thinking abilities ”Should not stress? I think it should be emphasized. Emphasizing that using numerator to do stoichiometry not only will not hinder the development of students’ thinking ability, on the contrary, it will train students’ logical thinking and make students’ thinking ability properly improve. Due to the application of gram atoms, molecules to solve the calculation of the problem has some advantages, enabling students to correctly calculate and master the application of the problem. These superiority have been described by Comrade Zhang Haoruo, no longer redundant. More importantly, the use of grams of atoms, grams, to calculate chemical applications based on formulas or chemical equations not only simplifies the calculation, but also introduces the concept of atomic molecules into the calculation of weight (grams). If you do not pass this step, students are hard to catch the truth in the subject, even if the students can still answer the question, it must be mechanical mechanically. Comrade Hu Guohua said: “If all the sulfur in FeS_2 is H_2SO_4, then one FeS_2 molecule should be able to generate two H_2SO_4, so 119.9 g FeS_2 can be found to produce 2 × 98 g H_2SO4_.” Here one FeS_2 molecule and 119.9 g FeS_2 What does it matter? Knowing that one FeS 2 molecule can generate two H 2 SO 4, how can one find 119.9 grams of FeS 2 to generate 2 × 98 grams of H 2 SO 4? Where students do not understand, Comrade Hu Guohua uses the word “therefore” The light strip passed. I think it is necessary to quote here the concept of the Armenian as a bridge. The concept is clear enough that thinking is logical and the calculation is simpler. We can teach students to think so: