共查询到19条相似文献,搜索用时 109 毫秒
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准确滴定的判据是分析化学滴定分析教学过程中的重点和难点,因为它是进行滴定分析方法建立与评价的依据。笔者依据学科发展趋势和知识点的前后衔接性,将络合滴定和质子酸碱滴定均作为酸碱滴定来处理,抓住化学定量分析的允许误差要求不大于0.1%,依据滴定终点溶液各组分的浓度特性要求,引导学生推导准确滴定与分步滴定的判据,让学生易于接受和掌握。 相似文献
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设计出一全面正确处理酸碱滴定过程一系列问题的综合程序,该程序能计算混合酸碱溶液的pH值、化学计量点的pH值、滴定突跃范围以及滴定误差等数据,并能绘制滴定曲线,自动选择指示剂,还可为实际滴定分析提供多种信息。 相似文献
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设计出一全面正确处理酸碱滴定过程一系列问题的综合程序,该程序能计算混合酸碱溶液的pH值、化学计量点的pH值、滴定突跃范围以及滴定误差等数据,并能绘制滴定曲线,自动选择指示剂,还可为实际滴定分析提供多种信息。 相似文献
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在酸碱中和滴定的教学中,利用pH传感器与数据采集技术绘制pH曲线,让学生体会酸碱中和滴定过程中的pH突跃,使学生通过四重表征来理解酸碱中和反应的过程。 相似文献
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本文介绍了从突路范围推导滴定分析的可行性条件的方法。文中讨论了酸碱滴定,配位滴定,氧化还原滴定,沉淀滴定的突跃范围及其相应的滴定分析可行性条件。 相似文献
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中和滴定的滴定终点 ,要借助指示剂的颜色变化来确定。那么是否任何一种指示剂都可作为某一中和滴定的指示剂来确定滴定终点呢 ?事实并非如此。也就是说中和滴定指示剂的选择是有一定原则的。下面以0 .10 0 0 mol· L- 1Na O H标准溶液滴定 2 0 .0 0 m L ,0 .10 0 0 mol· L- 1的 H Cl为例来加以说明。这一滴定的基本反应为 : Na OH HCl Na Cl H2 O在这一滴定过程中锥形瓶中溶液 p H值的变化可分以下四个阶段来考虑。一、滴定前 (消耗 Na OH标准溶液的体积为 0 )这时锥形瓶中只盛有 2 0 .0 0 m L0 .10 0 0 mol· L- 1HCl,故溶… 相似文献
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丙氨酸尾式卟啉及其锌配合物的电化学性质 总被引:1,自引:0,他引:1
本文采用循环伏安法研究了 5 -邻 [N - (L -丙氨酸 ) -乙氧基 ]苯基 - 10 ,15 ,2 0 -三苯基卟啉及其锌配合物在CH2 Cl2 为溶剂和TBPA为电解质条件下的电化学性质 .在循环伏安图中 ,两种物质都呈现 4对可逆的氧化还原峰 ,其氧化还原过程仅发生在卟啉的π电子体系上 .同时对其电化学反应机理作了推测 相似文献
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利用琼脂糖(agarose)将过氧化氢酶(Cat)固定在热裂解石墨电极表面,制备Cat—agarose膜修饰电极.包埋在琼脂糖中妁过氧化氢酶与电极直接传递电子,在pH6.0的缓冲溶液中可得一对可逆的氧化还原峰,式电势为-0.343V(vs SCE),这是过氧化氢酶辅基血红素Fe(Ⅲ)/Fe(Ⅱ)电对的氧化还原.其式电势随溶液的pH值增加而负移且成线性关系,直线斜率为-36.8mV/pH,说明过氧化氢酶的电子传递过程伴随有质子的转移.过氧化氢酶修饰电极.在16.5—278μmol/L的范围内,催化电流与过氧化氢浓度成线性关系. 相似文献
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Illustrative practical work is commonly used in chemistry education to enrich students?? understandings of chemical phenomena. However, it is possible that such practical work may not serve to foster understanding but rather cause further confusion. This paper reports the struggles experienced by a group of senior (Year 12) secondary chemistry students as they sought to understand redox chemical concepts involved in the reactions occurring when steel wool is added to copper sulfate solution. The results showed that the students lacked the skills required to make accurate observations during the practical work. Nor were they able to link the observed phenomena with previously taught redox concepts. The paper also presents possible ways to overcome the difficulties encountered by students as they move between macroscopic and submicroscopic levels of representation of redox reactions. 相似文献
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Yi Xingwang Yang Yuexi Xu Dawei Tian Ye Song Song Cao Chunmei Li Xingang 《天津大学学报(英文版)》2022,28(3):174-185
Transactions of Tianjin University - Tuning metal–support interactions (MSIs) is an important strategy in heterogeneous catalysis to realize the desirable metal dispersion and redox ability... 相似文献
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ABSTRACTThe study that is the subject of this paper tested the effects of EDI (explanation-driven inquiry) on students’ redox conceptual understanding and their misconceptions. Two classes of 119 10th grade high school students were involved. Two groups of students in the same school were chosen. One class that was taught by EDI teaching was set as the treatment group and another class that received conventional teaching was set as the control group. Students’ conceptual understanding was measured by a standardised instrument, and the students’ misconceptions were compared. The analysis of covariance showed that EDI teaching had significant effects on students’ redox conceptual understanding, and the results of the chi-square test demonstrated that students’ conceptual understanding level was improved by using EDI teaching. Also, after comparing the two groups of students’ misconceptions of redox, the results indicated that the students’ misconceptions changed toward deeper conceptual understanding in the treatment group that used EDI. Finally, some suggestions were made on how to implement EDI in the classroom. 相似文献
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从理论上讲,任何氧化还原反应都可安排成原电池反应.但要将很多常见的氧化-还原反应安排成原电池反应(如:氢氧燃料电池等)予以演示,却不是一件容易的事.本文介绍一种自制的新型电极,利用这种电极可将大部分的氧化—还原反应方便地做成原电池向学生予以演示. 相似文献