The equilibrium constant is given by the concentraton of products over the concentration of reactants. If it lies to the right, it means that it favors the forward reaction, and thus the reaction is "more complete" or closer to completion.

When writing the equilibrium expression for an insoluble salt, remember that pure solids and liquids are not included in the expression. Also, the coefficients for the compounds in the balanced reaction become the exponents for the compounds in the equilibrium expression.

Given a generalized chemical reaction, we can determine the equilibrium constant expression.

In our reaction, the reactant is a pure solid and is not included in the equilibrium calculation.

The only factor that changes the equilibrium constant is temperature. Changes in concentration of reactants or products by any means (whether addition, taking away solvent, or adding a chemical that will cause side reactions) will remove the system from equilibrium, but will not change the equilibrium constant.

The only factor that changes the equilibrium constant is temperature. Changes in concentration of reactants or products by any means (whether addition, taking away solvent, or adding a chemical that will cause side reactions) will remove the system from equilibrium, but will not change the equilibrium constant.

By placing these initial concentrations in the equilibrium expression, we can compare the reaction quotient, , to the equilibrium constant, . 

The reaction quotient for this reaction is:

Note that the reactant is a pure solid, and will not be included in this expression. By setting this equal to the equilibrium constant, we can see whether  or is larger in value.

We can predict how a solution will change based on the value of . When  is less than , the reaction will shift to the right. If  is greater than , the reaction will shift to the left. If  is equal to , the solution is at equilibrium.

Since the value for  is greater than the equilibrium constant in this instance, the reaction will shift to the left.

The reaction quotient, or Q, of the above reaction is equal to the products over the reactants. Q is calculated in the same manner as K_eq, but does not require that the reaction be at equilibrium.

Le Chatelier's principle states that changes in pressure are attributable to changes in volume. If we increase the volume, the reaction will shift toward the side that has more moles of gas. If we decrease the volume, the reaction will shift toward the side that has less moles of gas. Since the product side has only two moles of gas, compared to the reactant side with four moles, the reaction would shift toward the product side, and more NH₃ would form.

Chemical equilibrium is defined as a state when the rates of the forward and reverse reactions are equal. Different reactions will have different concentrations of products are reactants, and concentration can vary depending on the process. Chemical equilibrium, however, is always the point at which there is no bias towards creating products or reactants.

If the forward reaction rate and reverse reaction rate are equal, then there is no net change in concentration of the reactants or products. This makes them appear to be stable.

When a reaction is at equilibrium, the concentrations of reactants and products are no longer increasing or decreasing; however, this does not mean that the forward and reverse reactions have stopped taking place. They are simply taking place at the same rate so that the concentrations of products and reactants do not change. Equilibrium is a dynamic process. Reactions are still taking place, but they offset one another in terms of rate. Essentially, every product that is created is immediately converted back to reactant by the reverse process, making the concentration of reactants and products appear constant.

Le Chatelier's principle states that a system will shift in a particular direction in order to reduce introduced stress to the system. In other words, if something is added to one side of the equation, the other side will consequently increase in order to restore equilibrium.

When gases are involved in the reaction, pressure increases on the side of the reaction with more moles of gas. Adding an additional amount of pressure will push the reaction toward the side with fewer moles of gas. This helps lower the pressure inside the container.

There are four moles of gas on the reactants side, and two moles on the products side. If pressure is increased, the system will shift to the right in order to adjust to the new pressure.