Chem 182: Experiment 8 Determining the Ksp of Calcium Hydroxide Calcium hydroxid

Question

Chem 182: Experiment 8 Determining the Ksp of Calcium Hydroxide Calcium hydroxide is an ionic solid that is sparingly soluble in water solution of Ca(OH)2 is represented in equation form lution of Ca(On s nronic solid that is sparingly soluble in water. A saturated, aqueous, as shown below. Ca(OH)2 (s)- Ca2+ (aq) + 20H' (aq) The solubility product expression describes, in mathematical terms, the equilibrium that is established between the solid substance and its dissolved ions in an aqueous system. The equilibrium expression for calcium hydroxide is shown below The constant that illustrates a substance's solubility in water is called the Kap. All compounds, even the highly soluble sodium chloride, have a K However, the Kp of a compound is nd is comimonly considered only in cases where the compound is very slightly soluble and the amount of dissolved ions is not simple to measure. Your primary objective in this experiment is to test a saturated solution of calcium hydroxide and use your observations and measurements use your observations and measurements to calculate the Ksp of the compound. You will do this by titrating the prepared Ca(OH)2 solution with a standard hydrochloric acid solution. By determining the molar concentration of dissolved hydroxide ions in the saturated Ca(OH)2 solution, you will have the necessary information to calculate the Kp to calculate the Kp of the compound. You will do this OBJECTIVES In this experiment, you will Titrate a saturated Ca(OH): solution with a standard HCl solution. Determine the [OH ] for the saturated Ca(OH): solution Calculate the Ksp of Ca(OH)2 Figure 1 67

Explanation / Answer

Mean volume of HCl         = (11 +12.5)cm3 /2

                                                = 11.75 cm3

           No. of moles of HCl = CV

=11.75 * 10-3 *0.05 M

=0.5875 * 10-3 mol

OH concentration = n/V

                                    = 0.5875 * 10-3 mol/15* 10-3

                                    = 0.0391 M

Ca2+ + 2OH-                           Ca(OH)2

So ( Ca2+) = 0.0391 M/2

                = 0.0185M

K sp       =      (Ca2+ )( OH-)2

= 0.0185M * ( 0.0391 M)2

= 2.828* 10-4 mol3 dm-9

Theoretical Ksp      = 5.02 *10-6

% ERROR                   =( 2.828* 10-4/5.02 *10-6) *100

                                                = 56.33%

Related Questions

Navigate

• Browse (All)
• Browse C
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.