Prepare a first derivative plot to determine the volume of hydrochloric acid added at the equivalence point.

Determination of the Ksp of Calcium Hydroxide

Complete the following task:

Purpose

Determination of the Ksp of Calcium Hydroxide

To determine the solubility product expression, Ksp, for calcium hydroxide by titration with an acid versus initial pH and compare the results to the literature value.

Introduction

Calcium hydroxide is an ionic solid that is sparingly soluble in water. A saturated, aqueous solution of calcium hydroxide is represented in equation 1:

Ca(OH)2 (s) Ca2+ (aq) + 2 OH- (aq) (1)

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 constant that illustrates a substance’s solubility in water is represented by Ksp. All compounds, even the highly soluble sodium chloride, have a Ksp. However, the Ksp of a compound is commonly considered only in cases where the compound is very slightly soluble and the amount of dissolved ions is not simple to measure.

In this experiment, you will test the saturated solution of calcium hydroxide and use your observations and measurements to calculate Ksp of the compound. You will do this by titrating the prepared calcium hydroxide solution with a standard hydrochloric acid solution. By determining the molar concentration of dissolved hydroxide ions in the saturated calcium hydroxide solution, you will be able to calculate the Ksp.

General Instructions

The entire report should be word processed (typed), as handwritten portions will NOT be
graded. The report should be submitted to Blackboard before the due date. Organize the report as shown below.

All data in the report must match the data recorded by you in your laboratory notebook. Presenting someone else’s data or changing your data is considered plagiarism (cheating) and will result in a ZERO for this report.

Data and Calculations

Show all work for calculations and report answers using the correct number of significant figures and units.

1. Prepare a first derivative plot to determine the volume of hydrochloric acid added at the equivalence point.

a. Enter your titration pH values in the Excel template and adjust the drop number column if needed.

b. The highest point in the first derivative plot is the volume of HCl added at the equivalence point. Add a descriptive caption and include the plot in your report.

Last Completed Projects