Final answer:
The 'hump' in a Gibbs free energy graph signifies the activation energy barrier that must be overcome for a chemical reaction to proceed from reactants to products.
Step-by-step explanation:
The "hump" in a Gibbs free energy graph represents the activation energy needed for a chemical reaction to proceed. The Gibbs energy, denoted by G, is defined as G=H-TS, where H is the enthalpy, T is the temperature in Kelvin, and S is the entropy. The hump shows where the energy of the system is at its highest point before the reaction proceeds to form products. This energy barrier must be overcome for the reaction to take place.
According to the Gibbs free energy equation, ΔG = ΔH - TΔS, a negative ΔG indicates a spontaneous process, while a positive ΔG indicates a non-spontaneous process. If ΔG is zero, the system is at equilibrium. Therefore, the area under the "hump" can be associated with the activation energy that must be surpassed for the reactants to be converted into products, which then allows the reaction to proceed towards equilibrium, relying on the principle that the Gibbs energy of the system decreases in a spontaneous process.