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(上接本刊中旬第124页)四、经常进行对照比较,揭示相关对象的异同比较是一种揭示不同事物的共同点和差异点的重要的逻辑方法和思维过程,在学习有机化学时尤其应经常运用。(1)需要明确事物的差异性时要用。如,了解有机物和无机物反应速率差异,了解“基”与“根”、分子结构简式的不同,苯与其同系物比较,能与Na反应产生H2的物质及它们羟基H原子的活泼性比较。(2)需要了解事物间的相似性时要用。如,通过比较物理性质可发现所有烃、卤代烃、酯都不溶于水,而低级的醇、酚、醛、羧酸可溶,其中
(Continued from the mid-page 124) Fourth, often comparison and comparison, revealing the similarities and differences between related objects Comparison is a reveal different things commonalities and differences in important logical methods and thinking process, in the study of organic chemistry, especially Should be used frequently. (1) need to be clear when the difference between things to use. For example, to understand the difference between organic and inorganic reaction rates and to understand the difference between the simple structure of “base ” and “root ”. Compared with their homologues, benzene can react with Na to produce H2 and their hydroxyl H atoms Lively comparison. (2) Need to understand the similarities between things to use. For example, all hydrocarbons, halocarbons and esters are found to be insoluble in water by comparison of physical properties, while lower alcohols, phenols, aldehydes and carboxylic acids are soluble, with