Experiment 5
Determination of the Solubility Product Constant of Calcium Hydroxide
Austin Raniel Tan
Institute of Chemistry, College of Science, University of the Philippines, Diliman, Quezon City 1101 Philippines
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Christian Tica, Ryan Tabernilla, Michael Siao, Ron Mabunga, Jaime Olivares, and rest of Team Pogi
Abstract
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By measuring the concentration of the hydroxide ion from a solution saturated with Ca(OH)2 titration analysis against HCl, the experiment’s objective is to determine the solubility constant of calcium hydroxide. But, there are few limitations in solubility constant concept, like the Diverse Ion effect and the Common ion effect. Sources of error probably were the assumptions made throughout the experiment and can be explained further by the limitations of the solubility constant.
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Introduction
In a reaction where a slightly soluble ionic solid is dissolved in water, it ionizes into its respective ions. It signifies that equilibrium between the undissolved and dissolved ions in a saturated solution has been established when a precipitate forms. The solubility of the solid ionic compound Calcium Hydroxide was observed in this experiment. In the equilibrium reaction of Ca(OH)2 Ca(OH)2 (s)⇌Ca(aq)2++ OH(aq)- [1] , the solubility product constant, Ksp, is represented by
Ksp=Ca2+OH- [2]
Ksp is related to Gibb’s free energy change of the dissolution process. Given
∆G° = -RT lnKsp [3]
We can literally say that the solubility constant is affected by temperature. The solubility constant of the system can also be compared to the reaction quotient Qsp like other systems, given by
Qsp=[Ca2+]i[OH-]i [4]
When compared with Qsp, the solubility constant can be used as a basis for the formation of a precipitate. If Qsp
Austin Raniel Tan
Institute of Chemistry, College of Science, University of the Philippines, Diliman, Quezon City 1101 Philippines
-------------------------------------------------
Christian Tica, Ryan Tabernilla, Michael Siao, Ron Mabunga, Jaime Olivares, and rest of Team Pogi
Abstract
-------------------------------------------------
By measuring the concentration of the hydroxide ion from a solution saturated with Ca(OH)2 titration analysis against HCl, the experiment’s objective is to determine the solubility constant of calcium hydroxide. But, there are few limitations in solubility constant concept, like the Diverse Ion effect and the Common ion effect. Sources of error probably were the assumptions made throughout the experiment and can be explained further by the limitations of the solubility constant.
-------------------------------------------------
-------------------------------------------------
Introduction
In a reaction where a slightly soluble ionic solid is dissolved in water, it ionizes into its respective ions. It signifies that equilibrium between the undissolved and dissolved ions in a saturated solution has been established when a precipitate forms. The solubility of the solid ionic compound Calcium Hydroxide was observed in this experiment. In the equilibrium reaction of Ca(OH)2 Ca(OH)2 (s)⇌Ca(aq)2++ OH(aq)- [1] , the solubility product constant, Ksp, is represented by
Ksp=Ca2+OH- [2]
Ksp is related to Gibb’s free energy change of the dissolution process. Given
∆G° = -RT lnKsp [3]
We can literally say that the solubility constant is affected by temperature. The solubility constant of the system can also be compared to the reaction quotient Qsp like other systems, given by
Qsp=[Ca2+]i[OH-]i [4]
When compared with Qsp, the solubility constant can be used as a basis for the formation of a precipitate. If Qsp
References: [2] Petrucci, R.H., Herring, F.G., Madura, J.D., and Bissonnette, C. General Chemistry, Principles and Modern Applications 10th ed. Prentice Hall. New Jersey. 2010 [1] Institute of Chemistry