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对啤酒中反应H2CO3(aq)CO2(g)+H2O(1)的标准自由能变(△rG298θ)和标准平衡常数(Kθ)进行了计算,其值分别是-8.2 kJ/mol和27。汽水中反应HCO3-(aq)+H2Cit-(aq)HCit2-(aq)+CO2(g)+H2O(1)的△rG298θ和Kθ分别是-17.3 kJ/mol和1.07×10-3。介绍了用啤酒和汽水演示化学平衡移动的方法。 相似文献
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第1题1-1.A:Na2WO4;B:H2WO4或WO3·H2O;C:WO3⑴4FeWO4(s)+8NaOH(l)+O2(g)4Na2WO4(l)+2Fe2O3(s)+4H2O(g)2MnWO4(s)+4NaOH(l)+O2(g)2Na2WO4(l)+2MnO2(s)+2H2O(g)(产物写成Mn2O3或Mn3O4也可)⑵Na2WO4(aq)+2HCl(aq)H2WO4(s)+2NaCl(aq)⑶H2WO4(s)WO3(s)+H2O(g)1-2.[1]2WO3(s)+3C(石墨)2W(s)+3CO2(g)[2]反应在298.15K时的标准焓变、标准熵变和标准自由能变化分别为:ΔH=ΣυΔfH m=[2×0+3×(-393.51)-2×(-842.87)-3×0]kJ/mol=505.21 kJ/molΔS=ΣυS=[2×32.64+3×213.64-2×75.90-3×5.74]J·mol-1·K-1=537.… 相似文献
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实验假设水溶液中Ag+和SO42-的浓度非常低时,其活度无论处于同一体系还是在不同体系均相同。依此设计原电池,使该原电池的电池反应为Ag2SO4(s)→2Ag+(aq)+SO42-(aq),采用补偿法测量一定温度下此原电池中AgNO3溶液浓度和K2SO4溶液浓度发生变化时的电池电动势E。依据能斯特方程和Debye-Huckel极限公式,推导出原电池标准电动势E?与电解质的平均活度系数γ±及溶液浓度的关系,用外推法作图得到此电池反应的标准电动势E?。由平衡常数与原电池标准电动势的关系,得到Ag2SO4的溶度积Ksp(Ag2SO4)。 相似文献
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本文介绍一个以溶解度法测定碘在水溶液中热力学数据的实验。1实验目的(1)了解溶解度法测ΔfG m(I2,aq)、Δf Hm(I2,aq)、S m(I2,aq)的原理。(2)了解测量热力学数据的一般方法。2实验原理[1]当1mol I2(s)溶于水达到平衡时,其过程可表示为:I2(s)=I2(c(I2),aq)。K与溶解度关系为:K=r(I2)c(I2)。由于溶解度很小,r(I2)→1,可以通过测量溶解度的办法测量K。由-RTln K=ΔβαG m(1)可以通过测量某温度下的K求出ΔβαG m。根据ΔβαG m=ΔfG m(I2,aq)-ΔfG m(I2,s),ΔfG m(I2,s)=0,可求得ΔfG m(I2,aq)。ΔfG m(I2,aq,298.15K)可以… 相似文献
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1研究背景1.1教材知识Na2 CO3+H2O++CO2≡2NaHCO3[1]1.2经典习题题目:将二氧化碳通人饱和碳酸钠溶液中有大量晶体析出,析出晶体的原因有————.[2]答案:①反应消耗了水,导致了溶剂减少,使碳酸氢钠晶体析出. 相似文献
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①、试题内容:硫酸根离子的检验②实验用品:胶头滴管、试管、Na2CO3溶液(标签为A)、稀盐酸、溶有少量Na2SO4的Na2CO3溶液(标签为B)、BaCl2溶液、稀H2SO4溶液。 相似文献
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以“镁和碳酸氢钠溶液反应”的实验探究过程为例,针对镁和碳酸氢钠溶液反应比镁和水反应速率快这一现象,运用控制变量法和数字化实验,探究了气体产物成分和使速率加快的原因。凸显学生自主生成的实验探究活动在提升学生科学探究与创新意识、证据推理与模型认知等化学核心素养中的重要作用;归纳了解决实验探究问题的一般思维路径;更好地说明化学是一门以实验为基础的科学。 相似文献
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佟琦 《中国无机分析化学》2012,2(4):74-77
采用电位滴定法测定强酸、强碱对NH3-NH4Cl缓冲溶液的滴定曲线,测定了常见的4种NH3-NH4Cl缓冲溶液对强酸、强碱的缓冲容量。通过对滴定曲线和实验数据的分析得到了4种NH3-NH4Cl缓冲溶液缓冲能力的大小比较关系,不仅有助于理解缓冲溶液及缓冲容量的概念而且对分析测试中正确选择缓冲溶液的配制方法及用量具有指导意义。 相似文献
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It was believed that electroosmotic mobility μeo is inversely proportional to the square root of the ionic strength L But the linear relationship for regression analysis was expressed differently in different papers. The paper studied the linear expression of the mathematical relationship between μeo and c (background buffer concentration) by mathematical transform and real experimental data.μeo values of fused silica capillary were determined in four buffer systems. Their experimental conditions were controlled carefully for decreasing temperature difference AT and pH difference ApH in 50 μm ID capillary, in which no double layer overlap existed. The linear relationship between the reciprocal of electroosmotic mobility and the square root of concentration (or ionic strength) was derived by mathematical method. The regression analysis of experimental data was shown to well correspond to the relationship. The constants in regression equation could be well defined and the calculated results were acceptable. 相似文献
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《Analytical letters》2012,45(7):493-517
Abstract The departure from linear response which often occurs at dilute fluoride concentrations of the calibration curve reduces the sensitivity of the electrode. The linear portion of the standard curve may be extended to lower fluoride levels by dilution of the buffer itself. TISAB III M. tri-Ammonium citrate (TAC) is the superior of the eleven buffer systems examined in terms of masking ability. Of the potentially interfering species studied, only Al and Mg pose interference problems. 相似文献
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Dr. Saientan Bag Stefan Rauwolf Dr. Mikhail Suyetin Dr. Sebastian P. Schwaminger Prof. Wolfgang Wenzel Prof. Sonja Berensmeier 《Chemphyschem》2020,21(20):2347-2356
Protein-surface interactions are exploited in various processes in life sciences and biotechnology. Many of such processes are performed in presence of a buffer system, which is generally believed to have an influence on the protein-surface interaction but is rarely investigated systematically. Combining experimental and theoretical methodologies, we herein demonstrate the strong influence of the buffer type on protein-surface interactions. Using state of the art chromatographic experiments, we measure the interaction between individual amino acids and silica, as a reference to understand protein-surface interactions. Among all the 20 proteinogenic amino acids studied, we found that arginine (R) and lysine (K) bind most strongly to silica, a finding validated by free energy calculations. We further measured the binding of R and K at different pH in presence of two different buffers, MOPS (3-(N-morpholino)propanesulfonic acid) and TRIS (tris(hydroxymethyl)aminomethane), and find dramatically different behavior. In presence of TRIS, the binding affinity of R/K increases with pH, whereas we observe an opposite trend for MOPS. These results can be understood using a multiscale modelling framework combining molecular dynamics simulation and Langmuir adsorption model. The modelling approach helps to optimize buffer conditions in various fields like biosensors, drug delivery or bio separation engineering prior to the experiment. 相似文献