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1.
通过建构模型探讨了多反应物平衡体系中增加反应物浓度对转化率的影响,并用曲线进行表征。模型表明,转化率的变化与反应物和生成物化学计量数相对大小关联紧密。文中结论澄清了某些错误认知,对中学化学教学有一定的指导意义。 相似文献
2.
《Physics and Chemistry of Liquids》2012,50(5):607-613
Abstract Equilibria in aqueous solutions in the system leucine + VO2 + has been studied by a combination of potentiometric and spectrophotometric methods, in the pH range 3–4.4 with high ligand-to-metal ratios. An equilibrium model, MY, is assumed, where M and Y represent the metal ion and fully dissociated amino acid anion, respectively. The results showed that formation and stability constants of complex system increased with decrease of dielectric constants. Linear relationships were observed when log KP was plotted vs. 1/D, where KP and D represent stability and dielectric constants of the system, respectively. 相似文献
3.
A UV spectrometric method was developed to determine the molar absorptivity (C) and formation constant (Kc) of the association complex of unsubstituted chalcone in cyclohexane, in the concentration range from 4.00·10−4 to 2.00·10−2 mol dm−3. The thermodynamic and spectroscopic magnitudes such as Kc and C contribute to the understanding of the physicochemical behavior of several ,β-unsaturated carbonylic compounds, of low solubility in water, as it is the case of numerous flavonoids of chemical and biological importance. The studied association complex, formed by two chalcone molecules, is characterized by the constants C (300.8 nm)=4.98·104 dm3 mol−1 cm−1 and Kc=5.58·103. The method proposed is convenient for the study of solute–solute molecular associations particularly those due to dipole–dipole interactions. 相似文献
4.
“测定I3-=I-+I2平衡常数”是大学无机化学实验课的实验之一,该实验中使用了较多的碘,分散振荡时间较长,导致残留的碘挥发到空气中给环境和人体带来危害。为此对该实验进行了改进,利用超声波辅助分散减少分散时间,用微量代替常量减少试剂用量。经过多次重复实验,在超声波辅助分散5 min,降低试剂用量90%的情况下,测得平衡常数为1.54×10-3,相对误差为2.67%,证明该方法完全可以替代现有的实验方法。 相似文献
5.
The stability constantK
1of the equilibrium NH
3
+H+NH
4
+
was determined by potentiometric titration in synthetic seawaters of 5 to 40 (per mille) salinity and sodium chloride solutions between 0.2 and 0.7M ionic strength at temperatures of 5, 15 and 25°C. Moreover,K
1was determined in sulfate-free seawater of 35 salinity and 25°C. The dependence of logK
1on salinity (or ionic strength) and temperature can be reasonably well described by linear relations. TheK
1obtained for sulfate-free seawater agrees very well with earlier experimental results and theoretical predictions. From the measuredK
1and literature data on the equilibrium NH
3
(atm)NH
3
(aq., NaCl), the atmospheric concentration of ammonia at equilibrium with seawater was estimated. 相似文献
6.
二溴对甲基偶氮羧质子化及其离解 总被引:1,自引:0,他引:1
用萃取法对二溴对甲基偶氮羧进行了纯化,并用分光光度法研究了二溴对甲基偶氮羧的质子化和五级离解作用,测定了其质子化常数和逐级离解常数,获得满意的效果。 相似文献
7.
8.
The universal gas constant R is an important constant in physics, and one of the vital fundamental constant throughout the teaching of general chemistry. This article aims to present a general review about the universal gas constant to the science and engineering majored students, including its history, determination, physical meaning and applications in chemical education. The choice of R values under various conditions is also provided to help students better understand and master basic concepts. 相似文献
9.
Synthesis and characterization of non-peripherally (4,5) and peripherally (6,7) substituted metal free and Pd octapentylthiophthalocyanine and coordination of palladium ions to these Pcs are reported. The unmetalated complexes (4 and 6) show Pd coordination at the central metal and at the ring. The number of Pd ions bound to complex 4 were found to be five and to complex 6 were three. The equilibrium constant for the binding of Pd to complexes 4 was lower (K = 1.2 × 109 dm3 mol−1) than for complex 6 (K = 5.7 × 1010 dm3 mol−1). 相似文献