电解水演示实验的探究

电解水实验为中学化学的一个经典演示实验,然而在实验中很难得到氢气和氧气的体积比为2∶1的结果。文章从离子电迁移率、超电势、溶液的酸碱度等影响电解水反应的主要因素入手,研究了电解水实验的科学原理,并运用这些原理结合改进后的实验装置进行了电解水实验过程的探究,获得了电解水实验的满意效果,很适合在课堂中进行演示。     

电解水中电极材料与电解条件的选择

义务教育初中化学电解水的实验（实验3～1）是为了给学生学习水的组成提供感性认识。因此,做好该演示实验,特别是使实验结果接近H2和Q2的体积比为2：1的理论值,成为讲好这节课的关键。本文从分析实验结果产生误差的原因及减少误差所采取的措施出发,通过自制的电解水装置,选择容易找到的电极材料及与之相匹配的电解质及溶液浓度、电压等条件的对比实验结果说明使实验结果更接近理论值的条件,为做好本实验提供参考。一、电解水时氢氧体积比产生误差的原因电解水的化学原理是：阴极：2H+＋22—HZ十阳极：4OH－－4e、ZH。O＋OZt“”…     

铝作阳极电解氢氧化钠溶液的实验研究

铝是活泼金属,作为阳极电解氢氧化钠溶液理论上应该是铝失去电子成为铝离子溶解于氢氧化钠溶液。通过实验研究,可以得出铝作阳极电解氢氧化钠溶液实质是电解水。电解产生的氧气可以在铝电极表面形成一层不致密的氧化铝,所生成的氧化铝不溶于氢氧化钠溶液。     

中学爆鸣气实验的改进

爆鸣气实验是中学生开始学习化学后,继制氧气、氢气、电解水等实验之后的一个重要的演示实验。传统的作法是:取一只集气瓶,用排水取气法通入1/3体积的氧气,再通入2/3体积的氢气,用玻璃片盖好瓶口,从水槽中将集气瓶取出,瓶口朝下。     

基于STEM理念的中学化学创新实验研究——以“自制电解水芯片实验室”为例

介绍了基于STEM理念下让学生自制电解水芯片的实验探究。学生观察芯片上的电解水现象,负极产生的氢气和正极产生的氧气体积比为2:1。本实验简单、安全、环境友好,适宜于学生独立实验操作。此研究通过设置科学问题、强调学生探究、体验科研的全过程,激发了学生兴趣,培养了学生的创新能力。     

O-掺杂石墨电极VO2+/VO2+电对反应活性研究

采用氧气等离子体处理石墨电极表面,实现氧及含氧官能团的掺杂,以改善VO2+/VO2+电对的反应活性.FT-IR和EDS测试结果表明,氧气等离子体处理石墨表面引入了含氧官能团,从而提高了VO2+/VO2+电对的电化学活性.在本文实验条件下20 min等离子体处理的电极活性最好,8 mA.cm-2电流密度恒流充放电,石墨电极VO2+/VO2+电对库仑效率达到91%,比未处理电极的库仑效率提高了19%.     

钙熔盐电解石墨阳极破损机理及防护研究

通过扫描电镜和电子探针分析钙熔盐电解中破损石墨阳极的结构和杂质,探索了其破损机理,认为主要是由于孔隙存在导致氧化和孔隙吸附电解质,电解质因水解、脱水等过程使其周围的石墨阳极颗粒受应力不平衡而发生破损.通过实验研制出适合于钙熔盐电解过程用的石墨阳极具有抗氧化性能的涂层,并对涂层进行了XRD,SEM分析和氧化失重实验.实验表明该涂层在680～750℃下成硼玻璃态,能渗透到石墨阳极孔隙中,涂层表面致密无裂纹且附着力强,因而具有较好的抗氧化能力.该涂层是一种适合钙熔盐电解的、性能优良的石墨阳极涂层.     

初中新课程微型化学实验的设计研究

根据初中化学新课程实验内容进行微型化学实验设计,其中包括空气中氧气含量的测定、氧气的制取与性质、电解水实验、氢气的制取与性质、二氧化碳的制取与性质、一氧化碳的制取与性质等实验。     

提高大分子Fullerene含量的有效方法

通过用掺有异相物质的石墨电极进行电弧反应，所得的混合物中大分子Ｆｕｌｌｅｒｅｎｅ的含量在１０％以上，为进一步分离，提纯以及深入研究大分子Ｆｕｌｌｅｒｅｎｅ打下了基础。研究发现，阳极材料中完整石墨结构的存在是生成Ｆｕｌｌｅｒｅｎｅ的必要条件，异相物质的存在为Ｆｕｌｌｅｒｅｎｅ的生长提供了热的载体，从而使产物中大分子Ｆｕｌｌｅｒｅｎｅ的含量增加。     

TiO2纳米管修饰镍电极及其光催化辅助电解水制氢性能研究

本文通过水热法制备二氧化钛纳米管(TiO2NT),并用制备的TiO2NT对碱性电解水制氢装置的镍片阳极进行修饰,在电解水的基础上,通过光催化与电解过程的耦合,提出并实现了光催化辅助电解水制氢过程。通过XRD、UV-Vis、FE-SEM、AFM和光催化辅助电解水制氢等方法对试样的结构和性能进行了表征和测试。结果表明,在紫外光照条件下,用TiO2NT修饰镍片阳极的光催化辅助电解水过程的产氢速率比单纯电解水提高了61%。     

Dichroism of absorption and polarization of phosphorescence of molecules of the closed form of nitrobenzospirothiopyran

The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997.     

非那雄胺合成工艺改进

非那雄胺能抑制5α-还原酶的活性,明显降低二氢睾酮水平,是一种治疗良性前列腺增生的有效药品。该合成工艺以甾烯酮酸为原料,将其与氯化亚砜反应,无须分离即与叔丁胺反应得17β-酰胺化合物,再氧化开环,环合,氢化,脱氢合成了非那雄胺。经元素分析、IR、1HNMR、13CNMR、MS分析表征了其结构。该法无须使用昂贵的2,2-二吡啶二硫化物和剧毒药品苯亚硒酸酐,且以乙酸铵代替氨气,降低了对设备的要求和腐蚀,更适用于工业生产。     

Determination of heats of detonation and influence of components of composite explosives on heats of detonation of high explosives

The heats of detonation of 20 simple high explosives and explosive mixtures were determined by means of an adiabatic detonation calorimeter designed by the authors. The results indicated that the performance of the instrument was reliable and the experimental data were very accurate. For explosive mixtures, there was a linear accumulative relationship between the heats of detonation of the explosive mixture and its components. Accordingly, the heats of detonation of explosive mixtures could be calculated directly from the heats of detonation of simple explosives and the characteristic heats of other components. The experiments showed that the gold or brass shell of the cylindrical charge could be substituted by a thick-walled porcelain shell, which had the advantage of cheapness.

     

Synthesis of phenolic components of Grains of Paradise

Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared.     

Summary of development of the theory of stability of colloids and thin films

In this review, the research of the author in the field of colloidal systems is summarized. The factors influencing colloidal stability are systematized and analyzed. Examples are presented to illustrate the practical utilization of the theory of stability of colloids and thin films.This review was prepared on the basis of the works of the author, which were awarded the State Premium for 1991 in the field of science and technology, chemistry section.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 8, pp. 1708–1717, August, 1992.     

Study of hydration of two cements of different strengths

Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, M_o, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700^oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date.     

氯氧化镁生成热的研究

用氧化镁氯化镁水溶液制备了8水合氯氧化镁[nMg(OH)2·MgCl2·8H2O], 并测定了其在盐酸中的溶解热, 实验结果表明, 氯氧化镁溶解热与n值呈线性关系, 根据溶解热求出5Mg(OH)2·MgCl2·8H2O和3Mg(OH)2·MgCl2·8H2O的生成热分别为-7727.1和5888.1kJ·mol^1^-。     

Thermodynamics of the formation of oxosulfides of rare-earth elements

The enthalpies of solution of several oxosulfides of rare-earth elements and the high-temperature enthalpies of oxosulfides and oxosulfates of lanthanum and yttrium were measured using solution calorimetry and high-temperature microcalorimetry techniques. Standard enthalpies of formation and some thermodynamic properties of oxosulfides and oxosulfates were calculated. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2 pp. 294–297, February, 1997.     

恶臭嗅辨实验室建设探讨

针对恶臭测试的环境影响问题,提出了解决的实例方案,并对方案的要点及优缺点进行讨论,此方案在实际操作中具有较好的效果。