Final answer:
A Keq greater than 1 indicates an exergonic reaction that releases energy, while a Keq less than 1 suggests an endergonic reaction that requires energy input. Exergonic and endergonic reactions also differ in Gibbs free energy change, with the former characterized by ΔG < 0 and the latter by ΔG > 0.
Step-by-step explanation:
The equilibrium constant (Keq) is a number that provides us with a snapshot of where the equilibrium lies in a chemical reaction--whether the reactants or products are favored. A Keq greater than 1 indicates that the products of the reaction are favored over the reactants and that the reaction is likely exergonic, meaning it releases energy. Accordingly, a Keq number less than 1 would indicate that the reactants are favored over the products, suggesting an endergonic reaction that requires energy input to proceed.
Exergonic reactions have a negative Gibbs free energy change (ΔG < 0), indicating spontaneity and the release of free energy. On the other hand, endergonic reactions result in a positive Gibbs free energy change (ΔG > 0), meaning they are non-spontaneous under standard conditions and require the input of energy.
It is important to note that an endergonic reaction can become spontaneous under certain conditions if it is coupled with another exergonic reaction, which then makes the overall process exergonic. This concept is particularly important in biological systems where reactions are often coupled to facilitate processes that otherwise would not occur spontaneously.