氨性硫酸铜溶液离解平衡的探讨

在过量氨水存在下,向[Cu（NH3）4]SO4溶液中加入少量稀NaOH溶液,没有蓝色沉淀;如果向[Cu（NH3）4]SO4溶于水的溶液中加入少量稀NaOH溶液,则有沉淀生成。     

中学化学教材中2种溶液成分的探讨

从理论分析和实验研究2方面,说明了中学化学教材中银氨溶液和铜氨溶液中的主要成分,并给出了证明主要成分为[Ag（NH3）2]OH、[Cu（NH3）4]（OH）2的实验方法。     

经不同浓度FeCl_2溶液处理的γ-Fe_2O_3/Ni_2O_3复合纳米微粒的结构及磁性研究

使用化学共沉淀法制备FeOOH/Ni(OH)_2前躯体,经FeCl_2溶液处理后得到表面包裹2FeCl_3·5H_2O层的γ-Fe_2O_3/Ni_2O_3复合磁性纳米微粒。分别制备了经不同浓度FeCl2溶液处理后的复合磁性纳米微粒,并通过振动样品磁强计(VSM)、X射线衍射仪(XRD)、透射电子显微镜(TEM)和X射线光电子能谱仪(XPS)对样品的结构和磁性能进行分析。实验结果表明,微粒的磁性并不随FeCl_2处理液浓度的增加而单调变化。文中系统分析了FeCl_2溶液浓度对所制备微粒的磁化性质、形态及化学成分的影响。     

五元体系Li^+, Na^+, K^+, Mg^2^+/SO~4^2^- - H~2O 25℃相关 系的研究

用等温溶解平衡法研究了五元体系Li^+,Na^+,K^+,Mg^2^+/SO~4^2^--H~2O25℃溶解度,测得了平衡溶液的密度,获得了该五元体系25℃溶解度相图的十个无变量点和十种平衡固相。十个单盐结晶区分别对应于原始组分K~2SO~4,Li~SO~4.H~2O,MgSO~4.7H~2O,水合物Na~2SO~4.10H~2O,复盐3K~2SO~4.Na~2SO~4,Na~2SO~4.MgSO~4.4H~2O,Li~2SO~4.3Na~2SO~4.12H~2O,2Li~2SO~4.Na~2SO~4.K~2SO~4,Li~2SO~4.K~2SO~4和K~2SO~4.MgSO~4.6H~2O,此外没有产生新的复盐或固溶体。用现代电解质溶液理论---Pitzer模型校验该体系的溶解度测定值,结果令人满意。     

电解质-非电解质混合溶液活度系数的关联及溶解的推算 II:NH3-NaCl-Na2SO4-H2O体系的液固平衡热力学

由于在研究的体系中, Na2SO4是非对称电解质, 且能生成水合盐, 故推导了由非对称型电解质与非电解质所构成的混合溶液的各组分的活度系数关联通式, 并在此基础上讨论了水合盐液固平衡的计算方法.     

NO2在Ag/Pt(110)双金属表面上的吸附和分解

利用俄歇电子能谱(AES)和程序升温脱附谱(TDS)研究了NO₂在Ag/Pt(110)双金属表面的吸附和分解.室温下NO₂ 在Ag/Pt(110)双金属表面发生解离吸附, 生成NO(ads)和O(ads)表面吸附物种. 在升温过程中NO(ads)物种发生脱附或者进一步分解. 500 K时NO₂在Ag/Pt(110)双金属表面发生解离吸附生成O(ads)表面吸附物种. Pt 向Ag传递电子, 从而削弱Pt－O键的强度, 降低O(ads)从Pt 表面的并合脱附温度. 发现能够形成具有稳定组成的Ag/Pt(110)合金结构, 其表现出与Pt(110)-(1×2)相似的解离吸附NO₂能力, 但与O(ads)的结合明显弱于Pt(110)-(1×2). 该AgPt(110)合金结构是可能的低温催化直接分解氮氧化物活性结构.     

稀溶液中溶剂的化学势及其在依数性上的应用

长期以来,稀溶液中溶剂A的化学势为μA（1）=μ^＊A（1）＋RTlnxA,溶质B的化学势为μB（溶质）=μ^ΞB（溶质）＋RTln（bB／b^Ξ）,两式使用了不同的组成变量：溶剂的摩尔分数xA,溶质的质量摩尔浓度bB。按规定,溶液的组成变量应选用bB,故本文介绍了导出理想稀溶液中μA（1）=μ^＊A（1）-RTMA∑BbB的方法,并从此式出发推导出稀溶液的依数性。     

金前驱液pH值对Au-Pd/SiO2催化剂上噻吩加氢脱硫活性的影响

考察了金前驱液的pH值对Au-Pd/SiO2双金属催化剂用于噻吩加氢脱硫反应活性的影响,应用N2吸附,X-光粉末衍射(XRD)、程序升温还原(TPR)等技术对该催化剂的物性与结构进行了表征.发现当金前驱液的pH值为7时制得的双金属催化剂具有较好的加氢脱硫活性,并具有最小的孔径,该催化剂以PdO相与Au0相共存.与Pd/SiO2催化剂相比,Au-Pd/SiO2催化剂的稳定性明显提高.虽然AuxPdy合金相的生成对提高双金属催化剂的脱硫活性不利,但能明显改善催化剂的抗硫中毒能力.     

不同吸附模式对As(V)在TiO2颗粒上亚稳态吸附的影响

通过对比As(V)在TiO2颗粒上的柱(column)吸附和静态(batch)吸附行为,研究了柱吸附和静态吸附两种反应模式对该体系亚稳态吸附的影响.在相同热力学条件下,将总量一定的As(V)溶液分别加入柱吸附和静态吸附体系中.结果表明,随着吸附模式的改变,静态吸附体系比柱吸附体系更快达到吸附平衡,静态吸附体系平衡吸附量(0.42 mg·g-1)明显高于柱吸附体系平衡吸附量(0.25 mg·g-1),且静态吸附体系的吸附不可逆性弱于柱吸附体系的吸附不可逆性.说明溶质吸附模式(动力学条件)的改变使得相同热力学条件下的吸附反应达到了不同的平衡状态.柱吸附和静态吸附实验中,As(V)在TiO2颗粒上的液膜扩散系数、总传质系数及吸附平衡后形成的微观吸附状态均不同,共同导致了两种反应宏观吸附行为上的差异.     

Nitrosonium Nitrate,an Isomer of N2O4 in IF5

N₂O₄ dissolves in IF₅ as NO⁺NO₃^–, as established by n.m.r spectroscopy, and in the solid state the solvate complex NO⁺NO₃^– · IF₅ is formed. This contains a double chain of alternating NO⁺ cations and NO₃^– anions. (a = 483.4(2), b = 773.9(1), c = 932.6(3) pm, (α = 70.18(2)°, β = 80.90(3)°, (γ = 87.34(2)°, space group P1, Z = 2).     

InGaAs探测器中的双孔法非线性校正技术

探测器的非线性误差是影响光谱仪器精度的主要因素,采用双孔法解决InGaAs探测器的非线性校正问题,消除了InGaAs探测器非线性误差对水红外分析仪吸光度示值的影响。实验结果表明,水红外分析仪经非线性校正后的吸光度偏差明显小于校正前的吸光度偏差,提高了仪器测定结果的准确度。     

Enthalpies of solution and crystallization of ammonium aluminum sulphate dodecahydrate in water at 25°C

Enthalpies of crystallization of NH₄Al(SO₄)₂·12H₂O from aqueous solutions at 25°C, measured using a calorimetric method and determined from previously published data on the concentration dependence of the enthalpy of solution, are reported. The results are compared with the values obtained from the temperature dependence of solubility and from vapor pressure data by using the Williamson equation. The integral and partial molar enthalpies of solution in concentrated and diluted solutions are given.     

Electrochemical behavior of tartaric acid at solid electrodes in aqueous and mixed solutions

Electrochemical behavior of D-tartaric acid at the Pt-, Cu-, Ta-, Cu-Hg-electrodes and the Cd-alloys with Sn, Ni, Hg, and In in aqueous and mixed solutions (water mixtures with acetone, ethanol, dimethylformamide, and pyridine) is studied by voltammetry. It is shown that the tartaric acid voltammograms always show waves related to the hydrogen ion discharge. A method recently suggested by authors allowed calculating the dissociation degrees at different stages, the concentrations of ionized and not ionized forms in dilute solutions of stereoisomers: DL-tartaric, L-tartaric, D-tartaric, and meso-tartaric acids. Simple empiric equations are suggested for the approximate calculating of some dissociation parameters for these acids.     

高中化学教科书课后习题难度预估方法研究

在文献研究的基础上,提出14个影响高中化学教科书课后习题难度的假设因素,并对这14个因素进行检验分析,最终剔除无效因素,确定对高中化学教科书课后习题难度有显著影响的因素是:运算要求、知识量、题型和行为目标层次。结合实测难度及14个影响因素的赋值标准,建立难度预估方程。并用实测难度检验预估方程的准确性,期望为今后化学试题难度预估研究提供基础。     

On dissociation of weak dibasic and tribasic organic acids participating in Krebs cycle

The method suggested earlier by the authors was used to analyze the regularities of electrolytic dissociation processes for weak dibasic and tribasic organic acids participating in the tricarboxylic acid cycle (Krebs cycle), most important biochemical process that completes the oxidation of main intermediates of degradation of hydrocarbons, fats, and proteins in a living body. The dissociation degrees, concentrations of ionized and nonionized forms in dilute (0.1–10 mM) solutions of oxaloacetic, citric, isocitric, α-keto-glutaric, succinic, L-malic, and fumaric acids were calculated.     

传感器在氯化铜溶液颜色探究中的应用

利用传感器通过数字化技术分析了离子浓度、温度、离子络合等因素对氯化铜溶液颜色的影响。让学生看到溶液中离子的变化,同时培养了学生的探究能力。     

Solubility of Tris-(hydroxymethyl)-aminomethane in water-2-methoxyethanol solvent mixtures and the solvent effect on the dissociation of the protonated base

Solvent effects are discussed in terms of the free energies of transfer G_t ⁰ from water to aqueous 2-methoxyethanol (MCS) solvents, of the uncharged base (B) evaluated from the measured solubilities, of HCl evaluated earlier, and of Tris hydrochloride (B.HCl). The characteristic minimum at 25°C is attributed to selective solvation of the individual species involved in the equilibrium process. The results indicate that the primary solvation either of H⁺ or BH⁺ ions arising from specific ion-dipole interactions outweigh the electrostatic or the secondary solvation effect.     

Simultaneous measurement of the solubility of nitrogen and carbon dioxide in polystyrene and of the associated polymer swelling

New experimental results for the solubility of nitrogen and carbon dioxide in polystyrene are reported, accompanied by data on the change in volume of the polymer caused by the sorption process. The two phenomena were measured simultaneously with a combined technique, in which the quantity of penetrating fluid introduced into the system was evaluated by pressure‐decay measurements in a calibrated volume, whereas a vibrating‐wire force sensor was employed for weighing the polymer sample during sorption inside of the high‐pressure equilibrium cell. The use of the two techniques was necessary because the effects of swelling and solubility could not be decoupled in a single gravimetric or pressure‐decay measurement. The sorption of nitrogen in polystyrene was studied along three isotherms from 313 to 353 K at pressures up to 70 MPa. The sorption of carbon dioxide was measured along four isotherms from 338 to 402 K up to 45 MPa. The results are compared with values from the literature when possible, although our data extend significantly the pressure ranges of the latter. The uncertainties affecting our measurements with nitrogen are 1 mg of N₂/g of polystyrene in solubility and 0.1% of the volume of the polymer. For carbon dioxide, the uncertainties are 5 mg of N₂/g of polystyrene and 0.5% respectively, carbon dioxide being about 1 order of magnitude more soluble than nitrogen. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2063–2070, 2001     

Origin软件在计算氢离子平衡浓度方面的应用

在Origin 7.5(或以上版本)的运行环境下,通过运行Find_Roots.opj求根附件,可实现各种类型酸碱溶液氢离子平衡浓度的快速、准确计算。介绍了这种计算方法的详细流程。