Ksp Of Reaction Lab Report

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Introduction Although, in general, salts are known for their solubility, not all types of salts completely dissociate in water. Some of them partially dissociates and creates a dynamic equilibrium due to the instances when their ions recombine to form the original salts. An example of this is potassium hydrogen tartrate (KHC4H4O6 or KHT). When KHT is placed in water, it partially dissolves and forms K+ and HC4H4O6- ions. This reaction is shown below:
KHC_4 H_4 O_6 (s)⇄ K^+ (aq)+HC_4 H_4 O_6^- (aq)
(1)
The equilibrium constant of reaction (1) is written as Ksp or solubility product constant. The Ksp of reaction (1) is shown in the equation:
K_sp=[K^+ ][HC_4 H_4 O_6^-] (1) One of the purposes of the experiment is to determine the Ksp value
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In the second part of the experiment, KHT was added to solutions of different potassium ion concentrations. Similar to the first part, the concentration of HC4H4O6- was calculated through titrations of 0.05 M KCl and 0.1 M KCl solutions with known NaOH concentrations. The total concentration of K+ for the solutions with the common ion is equal to the K+ concentrations from the KCl solutions and the K+ concentration from the KHT itself, which is equal to the concentration of HC4H4O6-. A scatter plot graph that compares the concentrations of K+ and HC4H4O6- for this part of the experiment is shown in the data below. Another purpose of the experiment is to determine the Ksp value of calcium hydroxide (Ca(OH)2). When Ca(OH)2 is placed in water, it partially dissociates to form Ca2+ and two OH- ions. This is evident in the reaction:
Ca(OH)_2 (s)⇄Ca^(2+) (aq)+2OH^- (aq)
(3)
The Ksp expression for reaction (3) is shown
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One of the possible causes of this inaccuracy is the scale. In the experiment, the scale was used to measure the mass of KHP used in the standardization of NaOH. Since NaOH was used to standardize the HCl solution and to titrate the KHT in water, KHT in 0.05 M KCl, and KHT in 0.1 M KCl solutions, a slight inaccuracy in the measurement of the scale would cause a lot of errors in the whole experiment. In order to improve this, it is important that the scale used in the experiment is accurately calibrated. Aside from this, it is also necessary to perform the experiment in a more controlled environment, where external factors like the wind cannot affect the measurements of the scale. Besides the scale, the buret could have also caused some inaccuracies in the experiment. Most of the procedure in the experiment involves titration. Since the buret was used in the titration, it is important that the valves of the buret are tight enough throughout the experiment. This is because the valves are important in controlling the amount of NaOH or HCl being added to the solution being titrated. Any problems in the buret would cause inaccuracies in the volume recorded during the equivalence point. In order to improve this, it is important to utilize a more accurate buret with tight valves so the release of titrant is more controlled. Another possible source of error in the experiment is the filter

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