In this general chemistry laboratory exercise, the absorbance of [CoCl([superscript i]PrOH)[subscript 3]][superscript +], where [superscript i]PrOH is isopropyl alcohol, is used to determine the equilibrium constants for its reaction with methanol to form [CoCl([superscript i]PrOH)[subscript 2](MeOH)[subscript 3]][superscript +] in the temperature range of approximately 10 to 20 degrees C. The absorbance versus concentration calibration plot is determined by sequential additions of a concentrated [CoCl([superscript i]PrOH)[subscript 3]]Cl standard to [superscript i]PrOH. The equilibrium mixture is cooled in a CaCl[subscript 2]-ice bath, and measurements of temperature and absorbance are made at various time intervals as the solution warms to room temperature. The variation in the equilibrium constant as a function of temperature is used to determine the Gibbs energy, enthalpy, and entropy. (Contains 1 table and 3 figures.)