The equilibrium position of a chemical reaction is determined by the free energy difference between the product and the reagent. Free energy is a state function, which means it depends on the state of the system only. In other words, the free energy difference between the product and the reagent will be the same regardless of whether the reaction is catalyzed.

Both thermodynamic issues and kinetic issues relate to the practicality of a reaction process. If equilibrium is not favorable or if the reaction rate is too slow, the reaction might not be feasible from a practical standpoint. Whether the barrier is thermodynamic or kinetic is an important consideration in laboratory problem solving. If the barrier is thermodynamic, for example, the chemist may seek to exploit LeChatelier's principle and adjust some condition (pressure, temperature, or concentration) to drive the equilibrium in the desired direction. If the barrier is the reaction rate, the chemist may seek a catalyst to increase the reaction rate.

The MCAT loves to present such a problem. From an MCAT writer's perspective, can you see how wonderfully kinetics vs. thermodynamic considerations can be made to fit into the multiple choice format? Look for it in your practice tests.