Question

Define ΔGO, ΔGO’, ΔG, and ΔG‡

Answer 1

The following equation relates the standard-state free energy of reaction with the free energy of reaction at any moment in time during a reaction

ΔG∘=−RTlnK

ΔG=ΔG∘+RTlnQ

ΔG∘ is the value predicted by the standard free energies. It tells whether a reaction is spontaneous under standard conditions

ΔG is just the actual value. It tells whether the reaction is spontaneous, under the conditions that you actually have right now.

ΔG0′ - In biochemistry contexts, we often sees ΔG₀′ rather than the normal standard free energy change . The prime usually denotes a standard free energy that corresponds to an apparent equilibrium constant where the concentration (or activity) of one or more constituents is held constant. However, if the pH is held constant then [H+][HX+] is no longer a free variable and the apparent equilibrium constant is K′=[A−][H⁺] /[HA]

The corresponding standard free energy change is ΔG′∘=−RTln(K′)

So ΔG′∘=−RTln(K/[H+])

ΔG′∘=−RTln(K/[HX+])

ΔG‡ -A quantitative measure of the favorability of a given reaction at constant temperature and pressure is the change ΔG in Gibbs free energy that is caused by the reaction.