An activity is presented in which the thermodynamics of simultaneous, consecutive equilibria are explored. The activity is appropriate for second-year high school or AP chemistry. Students discover that a reactant-favored (entropy-diminishing or endergonic) reaction can be caused to happen if it is coupled with a product-favored reaction of sufficient entropy production or exergonicity. A variety of six product-favoring reactions are individually coupled with the reactant-favored reaction. The experimental results are correlated with the change in the entropies of the universe ([Delta]S[subscript univ]), the change in the standard-state free energies ([Delta][subscript r]G[degree]), and the various equilibrium constants (K). (Contains 3 tables and 4 notes.)