利用三段式诊断法探查化学平衡概念的理解

Investigation on Understanding of Chemical Equilibrium Based on Three-Tier Diagnostic Test

采用三段式诊断测试的方法,以浙江省某二级重点中学的高三化学选考生为研究对象,从"化学平衡状态的判定""平衡常数与转化率""平衡移动的影响因素"等3个维度,探查选考生在化学平衡概念理解上的表现。结果显示,选考生化学平衡概念理解的整体水平良好,但对平衡状态的速率判据理解不够全面,相异构想严重;转化率的计算能力和自信表现稍有不足;对催化剂、压强等平衡移动的影响因素存在认知缺陷,特别是压强因素,还未真正掌握压强影响平衡移动的本质机理。

The purpose of this study is to develop a three-tier diagnostic test to assess students’conceptual understanding of chemical equilibrium.The participants come from a secondary key middle school in Zhejiang Province,and all of them select chemistry subject in the college entrance examination.The three-tier diagnostic test are consisted of three dimensions:judgment of chemical equilibrium state;equilibrium constant and reaction conversion rate;influencing factors of equilibrium movement.The results indicate that students’understandings of chemical equilibrium are good in general.But there are lots of alternative conceptions when students use reaction rate to judge the equilibrium state.Students’calculation ability and self-confidence in conversion rate are slightly inadequate.There are also cognitive deficiencies in the influencing factors of equilibrium movement,such as catalyst and pressure.Especially the latter,students have not really understood the mechanism of pressure affecting equilibrium movement.