Determination of Ksp, ΔG°, ΔH°, and ΔS° for the Dissolution of Calcium Hydroxide in Water: A General Chemistry Experiment
William B. Euler, Louis J. Kirschenbaum, Ben Ruekberg, Journal of Chemical Education, 2000, 77, 1039 – 1040
Introduction
Most first-year college chemistry courses include the conscepts of equilibrium, free energy, enthalpy, and entropy and the relationship between them. All are incorporated in one titrimetric experiment presented here. The chemicals used are sufficiently low in toxicity that waste disposal is simple. The chemical operations are straightforward. In this exercise, saturated solutions of calcium hydroxide at two (or more) temperatures are prepared and titrated with standardized hydrochloric acid solution. Using these titration data, the Ksp and ΔG° for the dissolution of calcium hydroxide are determined. ΔG°, ΔS°, and ΔH° for the reaction are determined from the temperature dependence.