Final answer:
Negative delta G indicates that a chemical reaction is exergonic and spontaneous, meaning it releases energy and the products have less free energy than the reactants. This does not necessarily mean the reaction is fast, as exemplified by the rusting of iron.
Step-by-step explanation:
When negative delta G occurs in a reaction, it means that the reaction releases energy, and the products have less free energy than the reactants. This indicates that the reaction is exergonic (energy exiting the system) and is considered spontaneous; however, it does not necessarily happen quickly, as seen in the slow rusting of iron. Furthermore, a negative delta G implies directionality in reactions; in the forward direction, if delta G is negative, the equilibrium constant (K) is greater than 1, indicating that the reaction favors the formation of products. It's important to note that during glycolysis, which is a spontaneous cellular process, the actual free energy change (ΔG') is even more negative than the standard free energy change (ΔG°), indicating a highly favorable reaction in the context of a living cell. The Gibbs free energy change (ΔG) can be calculated using the equation ΔG = ΔH - TΔS, where ΔH represents the enthalpy change, T the absolute temperature in Kelvin, and ΔS the change in entropy. If the value of ΔG is negative, the process is energetically favorable and will frequently occur under given conditions.