Given the equilibrium:
3H2(g) + N2(g) ⇌ 2 NH3(g) Δ H < 0
How will the equilibrium shift if the concentration of ammonia is decreased?
This is Le Chatelier's Principle. In esoteric terms it is this.
When a chemical system at equilibrium is subjected to a stress, the system will shift in such a way so as to relieve the stress. Some students don't get that so here is a much easier explanation.
A system at equilibrium will try to undo what we do to it.
3H2(g) + N2(g) ⇌ 2 NH3(g) Δ H < 0
So this system is at equilibrium. We REMOVE NH3 so the system will try to produce MORE to make up for what we did to it. The only way it can produce more is to shift to the right.
Well, if the concentration of ammonia is decreased, it's like taking away the party snacks. And we all know what happens when the snacks are gone - people start leaving the party! Similarly, according to Le Chatelier's principle, when you reduce the concentration of a product (in this case, ammonia), the equilibrium will shift to the right to replace what's been lost. So, the reaction will produce more ammonia to compensate for the decrease. It's like the party trying to bring back the snacks!
If the concentration of ammonia (NH3) is decreased, according to Le Chatelier's principle, the equilibrium will shift in the direction that produces more ammonia. In this case, the forward reaction (formation of ammonia) would be favored.
To understand why, let's consider Le Chatelier's principle: When a system at equilibrium is subjected to a change in conditions (such as changes in temperature, pressure, or concentrations), the system will adjust itself to minimize the effect of that change.
In this specific scenario, if the concentration of ammonia is decreased, the system will try to offset this change by producing more ammonia. As a result, the equilibrium will shift to the right, towards the formation of more ammonia, to restore the balance.
To summarize, if the concentration of ammonia is decreased, the equilibrium will shift to favor the forward reaction, resulting in the production of more ammonia.
To determine how the equilibrium will shift when the concentration of ammonia is decreased, we need to use Le Chatelier's principle. According to this principle, when a system at equilibrium is subjected to a change in concentration, pressure, or temperature, it will tend to counteract that change and establish a new equilibrium position.
In this case, decreasing the concentration of ammonia (NH3) will disrupt the equilibrium. As a result, to counteract this change, the system will shift in the direction that produces more ammonia molecules. Since the forward reaction results in the formation of 2 moles of NH3, while the reverse reaction consumes ammonia, the system will shift towards the right (to the side with more products). This will increase the concentration of ammonia and restore the equilibrium.
Therefore, in summary, if the concentration of ammonia is decreased, the equilibrium will shift to the right to produce more ammonia molecules until a new equilibrium is established.