【摘要】 本文从化学平衡的角度讨论了开放体系中二氧化碳的分压（Pco₂）对CaCO₃溶解量的影响。根据定量计算的结果,CaCO₃的溶解量之所以随着Pco₂的升高而增大,主要是由于以下三方面的原因所造成的:首先,随着Pco₂的升高,水溶液的pH将会降低,从而使水溶液中CO₃^2-的含量减小,因此溶液中CaCO₃的浓度积将会减小,结果便导致了CaCo₃的溶解;其次,随着Pco₂的升高,水溶液中HCO₃^-的含量将会增大,这样便使得以CaHCO₃⁺的形式结的Ca²⁺的含量增多,这也导致了CaCO₃溶解量增的大;第三,CaCO₃解量增大的结果,使溶液的离子强度增加,这又导致了各离子活度系数的减小,从而也促进了CaCO₃的溶解。文章最后还讨论了应该怎样去定性地解释Pco₂对CaCO₃溶解量的影响,并认为使用反应; CaCO₃+H₂O + C₂OCa²⁺+2HCO₃^-来定性地解释Pco₂对CaCO₃溶解量的影响,存在有以下两个方面的问题:第一,该反应没有反映出Pco₂升高或降低过程中水溶液中最重要的因素之一的〔H⁺〕的变化;第二,对于与CaCO₃相平衡的水溶液,当Pco₂升高时,用该反应来解释会导致矛盾的结果。更多还原

【Abstract】 From the viewpoint of the chemical equilibrium, the author discusses the effect of the partial pressure of carbondioxide ( Pco2 ) on the dissolved amount of CaCO3 in the open system in this paper. According to the results of quantitative calculation, there are three reasons resulting in the increase of the dissolved amount of CaCO3 with the increase of Pco2. Firstly, with the increase of Pco2, the PH value of the solution will decrease, so the concentration of CO2-3 in the solution will decrease, too. This results in the dissolution of CaCO3. Secondly with the increase of Pco2, the concentration of HCO3- in the solution will in crease. This also causes the content of Ca2+ to be increased in the form of CaHCO3+ in the solution. For this reason,the dissolved amount of CaCO3 will increase, too. Thirdly, the increase of the dissolved amount of CaCO3 leads to the increase of the ionic strength of the solution. This results in the decrease of activity coefficients of various ions, which also helps to dissolve CaCO3. At last, this paper discusses how to exlpain the effect of Pco2 on the dissolved amount of CaCO3 qualitatively, He considers that there are two problems in explaining the effect of Pco2 on the dissolved amount of CaCO3 by using the following reaction;CaCO3 + H2O + CO2-Ca2+ + HCO-3Firstly, this reaction does not reflect the variation of [H+], one of the most important factors in the aqueous solution in the increasing or decreasing processes of Pco2. Secontly, for the aqueous solution that is in equilibrium with CaCO3, the explanation of this reaction will lead to contrary results when Pco2 increases.更多还原