What is "equal" at equilibrium?

When you disrupt or "stress" an equilibrium system by "adding" reactant, the system will attempt to do the "opposite" action in order to relieve the stress.

What action would be the opposite of "adding a reactant"?

The stress of "adding" more reactant disrupts the equilibrium system. In order to re-establish equilibrium, the system will favor the forward reaction to relieve the stress of adding a reactant.

Why must the forward reaction be favored to re-establish equilibrium, after adding a reactant?

Consider the equilibrium system illustrated in the image.

Removing the product NH₃ is the "stressor".

To counter-act the stress, the system must do the opposite of "removing product".

How will our equilibrium system react to the stress of REMOVING the PRODUCT ammonia?

Adding H₂, "stresses" or disturbs the equilibrium system.

The system will respond by favoring the reaction that will counter-act or partially undo the stress.

The opposite of adding the reactant is removing reactant.

Which reaction (forward or reverse) will be favored to remove some of the extra reactant that was added?

Consider the concentration profile (actually a partial pressure vs time curve) in the image provide with this question.

The profile shows that the system is initially at equilibrium, before the system is disturbed.

What feature of the concentration profile indicates that the system is initially at equilibrium?

Consider the image provided describing our equilibrium system: N₂ (g) + H₂ (g) ⇌ 2NH₃ (g)

After the addition of hydrogen, the system shifts to favor the forward reaction. How has the hydrogen concentration changed once equilibrium is established?

Answer the question in the image (be careful, and review the explanation to the previous question if you are "stuck"

Consider the equilibrium system:

CaCO₃ (s) ⇌ CaO (s) + CO₂ (g)

Which of the following options is the law of mass action for this process?

Answer the question in the image (careful!).