固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

固相配位化学反应——ⅩⅩⅩ.室温下铁氰化钾的固相反应

本文首次报道了铁氰化钾在室温下与碘化钾、硫化钾的固相氧化还原反应,实验发现在固相下铁氰化钾与碘化钾混合后,生成单质碘和亚铁氰化钾,而在溶液中该反应是反方向进行的.实验还发现,在固相下铁氰化钾与还原剂硼氢化钠不反应,而在溶液中,该反应却能进行.对反应机制进行了初步探讨.     

氯气的制取与性质实验绿色化设计

针对氯气有毒及其与金属反应易于泄露等实验不足,设计了氯气制取、氯气与金属反应和氯水成分探究的全封闭实验。其中,氯气与金属的反应采用原位电加热的方式,加热速度快,金属在氯气中的燃烧现象明显,且能快速识别产物,有效地消除了因加热带来的氯气泄露问题;氯水成分的探究是通过青霉素瓶在封闭条件下进行的。整个实验仪器常规,装置简单,药品用量少,操作容易,现象明显,安全无污染,非常适合课堂演示。     

氯水性质检验的微型实验设计

采用以双通管为主体的复合微型实验装置,4 min 内完成了氯水的制备、氯水颜色的观察、氯水的萃取、氯气与水反应产物H+与Cl-的检验、氯水漂白性的实验。     

汞离子氧化碘离子实验的设计与研究

通过分析硝酸汞与碘化钾混合溶液不发生氧化还原反应的原因,成功地设计了Hg2+氧化I-的实验方法。结果表明,沉淀反应的存在阻止了氧化还原反应的发生,可能是沉淀反应速率快于氧化还原反应速率所致。该方法仪器简单、操作方便,现象明显易观察,成功率高、效果好。     

卤素单质水溶液的颜色研究

在卤素单质间置换反应实验环境下,将氯水、溴水、碘水从有色饱和溶液逐步稀释到无色“溶液”,观察到一系列不同浓度下氯水、溴水、碘水的颜色。指出了卤素单质颜色的变化趋势、主要显色、相互共色等问题。     

基于自封袋和塑料点滴板的氯气性质实验设计

通过运用自封袋和塑料点滴板等微型装置设计实验,并选用浓度较稀的盐酸和次氯酸钠溶液反应来制取氯气,采用滤纸来扩大性质实验中溶液的接触面积,可以很好地完成氯气的氧化性、氯气与碱反应、氯水的漂白性以及氯离子的检验等实验。该微型实验设计绿色环保,操作简便。     

硝酸银溶液与碘化钾溶液反应的实验探究与思考

通过实验探究得出,硝酸银溶液与碘化钾溶液直接混合时,发生生成碘化银沉淀的复分解反应,而通过带盐桥的原电池,阻止离子接触时,则发生氧化还原反应。并从化学热力学和动力学方面对其反应机理进行了分析。     

反应物浓度对化学反应速度的影响

在高等学校中作为溶液中反应物浓度对反应速度的影响的演示实验,常用的是:硫代硫酸钠与硫酸间的反应,碘酸钾与亚硫酸盐在酸性介质中的反应等。这些反应方程式是比较复杂的,而使得在中学里演示上述实验的可能性消失。但氯化高铁FeCl_3与碘化钾KI溶液间的     

自制淀粉碘化钾试纸有关问题的探讨

根据淀粉与碘反应原理,从淀粉的组成、结构以及与碘反应的颜色变化,确定了自制淀粉碘化钾试纸实验中最适宜的淀粉溶液.并通过实验及有关氧化剂的电极电势就"试纸"检验其他物质的适用范围,进行了讨论.     

Interaction of Components in Gel-Forming Potassium Silicate Solution

X-ray phase analysis was applied to study the phase composition of products formed in reaction between components of silicophosphate solutions obtained on the basis of potassium water glass. The temperature ranges of phase transformations of chemical compounds, occurring in thermal treatment of gels of various compositions, were established.     

实验探究电解重铬酸钾溶液

通过实验探究在不同电压、pH、浓度、电极材料等条件下电解重铬酸钾溶液,并从理论上解释现象各异的原因,得到“重铬酸根离子可以在阴极放电”“用石墨电极也可以电解处理含重铬酸根离子的废水”等结论。     

ICP-AES法测定镀金溶液中氯化钾含量

航天部件对表面镀金层有严格的要求。在镀金溶液中加入一定量的导电盐氯化钾,可以提高镀层的导电性,获得结晶细致、化学纯度高、结合力好的镀金层。但氯化钾的浓度必须严格控制在很小的范围内,K^＋浓度过低,会使镀件表面出现针孔、斑点;K^＋浓度过高,又造成镀件表面疏松,附着力减小,严重影响镀件质量。为控制K^＋浓度,传统的方法是采用以火焰作激发光源的仪器,如火焰光度计等,直接测定K^＋浓度,或用化学法间接测定镀液中Cl^-浓度。     

甘氨酸在氯化钾水溶液中的稀释焓

利用瑞典LKB-2277生物活性检测仪测定了298．15K时甘氨酸在不同浓度的氯化钾水溶液中的稀释焓,根据McMilkm-Mayer理论计算了甘氨酸在不同浓度的氯化钾水溶液中的同系焓相互作用系数．结果表明,甘氨酸在氯化钾水溶液中的焓对相互作用系数h2均为负值,并且随着氯化钾浓度的增加,h2的绝对值逐渐减小。     

Molecular Dynamics Study on Microstructure of Potassium Dihydrogen Phosphates Solution

Molecular dynamics simulations were carried out to study the internal energy and microstruc-ture of potassium dihydrogen phosphates (KDP) solution at different temperatures. The water molecule was treated as a simple-point-charge model, while a seven-site model for the dihydrogen phosphate ion was adopted. The internal energy functions and the radial dis-tribution functions of the solution were studied in detail. An unusually large local particle number density fluctuation was observed in the system at saturation temperature. It has been found that the specific heat of oversaturated solution is higher than that of unsaturated solution, which indicates the solution experiences a crystallization process below saturation temperature. The radial distribution function between the oxygen atom of water and the hydrogen atom of the dihydrogen phosphate ion shows a very strong hydrogen bond struc-ture. There are strong interactions between potassium cation and oxygen atom of dihydrogen phosphate ion in KDP solution, and much more ion pairs were formed in saturated solution.     

高锰酸钾溶液标准物质的研制

介绍高猛酸钾溶液标准物质的研制过程。对研制的溶液标准物质进行了均匀性和稳定性考察。结果表明,该标准物质均匀性良好,定值稳定期为6个月。用称量滴定法定值,定值结果为c(1/5 KMnO4)=0.100 7 mol/kg(k=2)。该标准溶液满足二级标准物质的技术要求,已被批准为国家级二级标准物质。     

如何准确把握和使用教材中的实验资源——以苯能否使酸性高锰酸钾溶液褪色为例

针对新课程教材中实验“苯不能使酸性KMnO4溶液褪色”,通过实验探究和文献分析,指出苯与硫酸（或其他非还原性酸）溶液混合均能使KMnO4溶液褪色的事实,并用“苯的环状活性中间体正离子机理”解释了苯被氧化的原因,提出了新课程背景下如何使用和修订该实验的建议。     

Native Electrospray Mass Spectrometry of DNA G-Quadruplexes in Potassium Solution

A commonly used electrolyte in electrospray mass spectrometry (ESI-MS) of biomolecules is ammonium acetate (NH₄OAc). Although some nucleic acid structures such as duplexes require only proper physiological ionic strength (whatever the monovalent ions) to be properly folded in ESI-MS conditions, the folding of some other nucleic acid structures such as DNA G-quadruplexes also depends on direct binding of specific cations. Here, we developed ESI-MS compatible conditions that allow one to observe DNA G-quaduplexes with K⁺ ions specifically bound between G-quartets. NH₄OAc was replaced with trimethylammonium acetate (TMAA), at concentrations up to 150 mM to provide physiological ionic strength, and the solution was doped with KCl at concentrations up to 1 mM. The trimethylammonium ion is too large to coordinate between G-quartets, where only K⁺ ions bind. Compared with the equivalent NH₄OAc/KCl mixtures, the TMAA/KCl mixtures provide cleaner spectra by suppressing the nonspecific adducts, and favor the formation of similar stacking arrangements as in 100 mM KCl (physiologically relevant cation) for the polymorphic human telomeric DNA G-quadruplexes. This new sample preparation method can be exploited to determine the number of potassium binding sites in new sequences, to screen ligand binding to the structures favored in potassium, and to transfer potassium-bound G-quadruplexes to the mass spectrometer for gas-phase structural probing, as illustrated herein with ion mobility spectrometry experiments.

在缓冲溶液中探究高锰酸钾与草酸的反应

以硫酸氢钠-硫酸钠缓冲溶液为反应介质,研究了温度、溶液pH、高锰酸钾浓度以及草酸浓度等因素对高锰酸钾与草酸反应的反应速率的影响。研究发现,升高温度、降低溶液pH（即增大氢离子浓度）以及增大草酸浓度均能加快反应速率,而高锰酸钾浓度对反应速率的影响规律性不强。     

Kinetics of Formation of Potassium Hydroxyaluminosilicate in Aqueous KOH Solution

The time in which a supersaturated aqueous-alkaline aluminosilicate solution is stable to phasetransformation was studied in relation to the solution composition, temperature. Empirical equations weresuggested describing how the induction period of potassium hydroxyaluminosilicate formation depends on thesolution composition, temperature, and supersaturation factor. These equations allow prediction of the compositions of stable solutions and evaluation of the enthalpy (25.6 kJ mol^{- 1}) and entropy (126.2 J mol^{- 1} K^{- 1}) of solution, the activation energy (19.1 kJ mol^{- 1}) of formation of potassium hydroxyaluminosilicate KAlSiO(OH)₆, and the induction period of formation of the solid phase.