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1998年高考化学试题第27题实验题在考生和化学教师中引起强烈的反响.全国2919份化学抽样卷统计难度为0.18(属于难题),区分度为0.279(低于0.3,不够理想).我们就以此题为例,进行解题思路分析,力求收到举一反三的效果.27题.(11分)测量一定质量的铝锌合金与强酸溶液反应产生的氢气的体积,可以求得合金中铝和锌的质量分数.现有下列实验用品:中学化学实验常用仪器、800 mL 烧杯、100 mL 量筒、短颈玻璃漏斗、铜网、铝锌合金样品、浓盐酸(密度1.19 g·cm~(-3))、水.按图示装置进
In 1998, the 27th item of chemistry test questions in the college entrance examination caused a strong response among the examinees and chemistry teachers. The difficulty of statistical analysis of 2919 chemical sampling volumes across the country was 0.18 (which is a difficult problem), and the discrimination degree was 0.279 (less than 0.3, not ideal). Take this problem as an example, to analyze the problem-solving ideas, and strive to receive the effect of the other way round. 27 questions. (11 points) The volume of hydrogen produced by the reaction of a certain quality of aluminum-zinc alloy and strong acid solution can be obtained in the alloy And the mass fraction of zinc. The following experimental supplies are available: commonly used instruments for middle school chemistry experiments, 800 mL beakers, 100 mL graduated cylinders, short neck glass funnels, copper mesh, aluminum zinc alloy samples, concentrated hydrochloric acid (density 1.19 g·cm~(- 3)) Water, enter the device as shown