共查询到18条相似文献,搜索用时 62 毫秒
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葛振新 《新疆教育学院学报》2004,20(2):122-124
本作在教学实践中,通过做“水的硬度的测定”配位滴定等实验,使学生逐步学会分析、探索扣解决化学实验中的问题,培养科学思维的方法。 相似文献
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研究了采用配位滴定法检测菲汀质量的方法,并将用Th(NO3)4作标准溶液与用NH4Fe(SO4)2作标准溶液作了比较.实验证明,钍盐法明显具有操作简便,终点敏锐等特点,有很好的应用价值. 相似文献
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本文将小波变换技术应用于电位曲线的处理,建立了测定酱油中氯化钠含量的方法。 相似文献
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研究了用EDTA配位滴定法,结合反滴定方式测定NaCl-BaCl2混合盐中的BaCl2时的相关问题.对照试验的结果表明,该方法测定BaCl2的结果准确、可靠. 相似文献
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本文研究在PH5.5的六次甲基四胺缓冲体系中,以5-Br-PADAP作为指示剂,用EDTA滴定铅精矿中铅含量。试验结果表明,终点变色敏锐,测定结果变异系数为0.27%(n=5)。 相似文献
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本文研究在PH5.5的六次甲基四胺缓冲体系中,以5-Br-PADAP作为指示剂,用EDTA滴定铅精矿中铅含量。试验结果表明,终点变色敏锐,测定结果变异系数为0.27%(n=5)。 相似文献
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在混合碱的测定中,采用自动电位滴定一阶导数曲线法确定滴定终点,与双指示剂法相比,本法具有终点灵敏、误差小等优点,大大提高了测定结果的准确度和精密度.同时也提高了检测的自动化程度,在生产实际中有应用价值。 相似文献
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分析当前环境污染的现状,强调在大学化学实验中培养学生绿色化学观的必要性。根据绿色化学的理念,探讨如何在滴定分析化学实验教学改进中培养大学生绿色化学观,以增强学生的环保意识。 相似文献
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测定常量铁的重铬酸钾滴定方法存在铬污染,近来各种无汞无铬法测定铁受到关注。本实验针对KMnO4滴定常量铁含量方法终点观察不明显的缺点,采用分步指示的方法,即在接近终点时加入二苯胺磺酸钠为指示剂,极大地敏化了终点观察。改进后的实验用于大学化学实验教学,结果没有显著差别,表明在化学实验教学中有很大推广价值。 相似文献
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利用自制微型化学实验仪器,通过微型滴定法测定自来水中Cl-的含量.实验表明这种微型测定方法具有简便经济,反应灵敏,快速准确的特点.值得在化学实验教学中推广. 相似文献
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用HNO3溶解试样,配制6种元素混合标准系列溶液,用空气-乙炔火焰原子吸收法连续测定Pb,Cd,Fe,Cu,Sb和Mn的含量。建立了优化的仪器测定条件,并进行了相关的干扰实验。方法的回收率为98.9%-102.0%,相对标准偏差为1.8%-2.5%。 相似文献
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ZHANG Ming-kui ZHENG Shun-an 《浙江大学学报(A卷英文版)》2007,8(11):1808-1815
Soils can often be contaminated simultaneously by more than one heavy metal. The sorption-desorption behavior of a metal in a soil will be affected by the presence of other metals. Therefore, selective retention and competitive adsorption of the soils to heavy metals can affect their availability and movement through the soils. In this study, the simultaneous competitive adsorption of four heavy metals (Cd, Cu, Hg, and Pb) on ten agricultural soils collected from the Changjiang and Zhujiang deltas, China was assessed. The results showed that the competition affected the behavior of heavy metal cations in such a way that the soils adsorbed less Cd and Hg, and more Pb and Cu with increasing total metal concentrations, regardless of the molar concen- tration applied. As the applied concentrations increased, Pb and Cu adsorption increased, while Cd and Hg adsorption decreased. The adsorption sequence most found was Pb>Cu>Hg>Cd. The maximum adsorption capacity for the heavy metal cations was calculated, and affected markedly by soil properties. The results suggest that Hg and Cd have higher mobility associated to the lower adsorption and that Pb and Cu present the opposite behavior. Significant correlations were found between the maximum adsorption capacity of the metals and pH value and exchangeable acid, suggesting that soil pH and exchangeable acid were key factors controlling the solubility and mobility of the metals in the agricultural soils. 相似文献
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Nano-particles lanthanum-modified lead titanate (PLT) thin films are grown on Pt/Ti/SiO2/Si substrate by liquid source misted chemical deposition (LSMCD). PLT films are deposited for 4-8 times, and thenannealed at various temperature. XRD and SEM show that the prepared films have good crystallization behavior and perovskite structure. The crystallite is about 60nm. The deposition speed is 3nm/min. This deposition method can exactly control stoichiometry ratios, doping concentration ratio and thickness of PLT thin films. The best annealing process is to bake at 300℃ for 10min and anneal at 600℃ for 1h. 相似文献