Chemical Equilibrium 1A Post Module 31

[MichelleTran3I]

With respect to equilibrium constants what does it mean when the “equilibrium is shifted to the left”?


Also the module asks two different questions, one with "shifted to the left" and "lies to the left". Is there any difference between the two phrases? Thanks!

[Naveed Zaman 1C]

Whenever you put a stress onto a system at equilibrium, the concentrations of each reactant or product will change to reestablish equilibrium (remember that equilibrium is essentially a glorified ratio of products over reactants). When you say that the reaction "equilibrium has shifted to the left", this might mean you added more products, removed reactants, or changed the pressure somehow to mess up a system at equilibrium. This causes the reverse reaction (formation of reactants from products) to be favored, which will eventually get the system back to equilibrium.

To answer your second question, they both mean the same thing, but Dr. Lavelle noted that he prefers "lies to the left" to "shifts to the left." The reason this is the case is that when you say "shift to the left", you are making it sound like you are somehow changing the value of the equilibrium constant, which is NOT the case. You are simply moving from right to left from the perspective of the chemical equation to determine whether reactants/products are being formed.