论文部分内容阅读
经对制备的钨酸镉、钼酸镉和铬酸镉测定,它们的组成为CdWO_4·H_2O(白色)、CdMoO_4(白色),CdCrO_4·2H_4O(黄色)。应用差热分析法对这些物质的稳定性作了探讨。 本文用离子选择电极法测定了钨酸镉、钼酸镉和铬酸镉的溶度积常数。用镉离子选择电极作指示电极,甘汞电极作参比电极,测得25±1℃(I=0.1)时,K_(SP,CdWO_4)=2.3×10~(-10),K_(SP,CdMoO_4)=2.2×10~(-9),K_(SP,CdCrO_4)=7.6×10~(-5)。并据此计算了钨酸镉和钼酸镉溶解的标准自由能变化△G°以及它们的△G_f°和S°。
The compositions of CdWO 4 · H 2 O (white), CdMoO 4 (white) and CdCrO 4 · 2H 4 O (yellow) were determined by the prepared cadmium tungstate, cadmium molybdate and cadmium chromate. The application of differential thermal analysis of the stability of these substances are discussed. In this paper, the ion-selective electrode method for the determination of the cadmium tungstate, cadmium molybdate and cadmium chromate solubility constant. Using cadmium ion selective electrode as indicator electrode and calomel electrode as reference electrode, K_ (SP, CdWO_4) = 2.3 × 10 ~ (-10) and K_ (SP) were measured at 25 ± 1 ℃ CdMoO_4 = 2.2 × 10 -9, K_ (SP, CdCrO_4) = 7.6 × 10 ~ (-5). Based on this, the standard free energy changes △ G ° of cadmium tungstate and cadmium molybdate and their △ G_f ° and S ° were calculated.