The question below, i was wondering if it decrease because the N2 is on the right and so to add to left it would be too much so it gets rid of it by decreases and doing to the right? because the left side is (+) endothermic? sorry im a little confused.
if the number was negative would it make a difference?
Consider the following reaction at equilibrium:
2NH3 (g)<-> N2 (g) + 3H2 (g) ΔH° = +92.4 kJ
Le Cha^telier's principle predicts that adding N2 (g) to the system at equilibrium will result in
__________.
A) an increase in the value of the equilibrium constant
B) a decrease in the concentration of H2 (g)
C) removal of all of the H2 (g)
D) a lower partial pressure of N2
E) a decrease in the concentration of NH3 (g)
I think you are a little confused. Le Chatelier's Principle says that what we do to a rxn at equilibrium, the reaction shifts so as to undo what we did. So we added N2, the reaction shifts to try to get rid of the N2; therefore, it shifts to the left. That means NH3 will increase, H2 will decrease, N2 is the agent causing the "problem" so we don't worry about it too much. In reality, and we can calculate to what extent it occurs, N2 gets larger (because we've added to it), the reaction shifts and SOME of the excess is used up but the original amount we had PLUS the amount we added still will be more than we started with but less than the sum of the two. From this analysis, you should pick B as the correct answer.
A. The equilibrium constant changes ONLY with a change in temperature.
C. No, removal of some of the hydrogen but not ALL of it. We hardly ever get ALL of anything.
D. If we ADD N2, the partial pressure will increase.
E. A shift to the left means more NH3, not less NH3.
A shift to the left also means that some heat is generated since it is an endothermic reaction AND we are shifting to the heat side.
To determine the effect of adding N2 to the system at equilibrium, we need to understand Le Chatelier's principle and how it applies to this reaction.
Le Chatelier's principle states that if a system at equilibrium is subjected to a change, it will respond by shifting in a way that minimizes the effect of the change and restores equilibrium. In this case, adding N2 to the system will disturb the equilibrium.
In the given reaction, 2NH3 (g) ↔ N2 (g) + 3H2 (g), N2 is on the right-hand side of the equation, and it is a product of the reaction. According to Le Chatelier's principle, adding more N2 to the reaction will cause the equilibrium to shift in the reverse direction to minimize the effect of the increase in N2 concentration.
As a result, the equilibrium will shift to the left, favoring the reactants and decreasing the concentration of NH3 and H2. However, since the reaction is endothermic (ΔH° = +92.4 kJ), decreasing the reactant concentrations will help restore equilibrium by consuming some of the excess heat.
Now, let's evaluate the answer choices:
A) an increase in the value of the equilibrium constant - Adding N2 would cause a decrease, not an increase, in the value of the equilibrium constant. So, this option is incorrect.
B) a decrease in the concentration of H2 (g) - Adding N2 would indeed reduce the concentration of H2 because the equilibrium will shift toward the reactants. This option is a plausible answer.
C) removal of all of the H2 (g) - While adding N2 will reduce the concentration of H2, it won't remove all of it. Therefore, this option is incorrect.
D) a lower partial pressure of N2 - Adding N2 would actually increase the partial pressure of N2 since it is added to the system. So, this option is incorrect.
E) a decrease in the concentration of NH3 (g) - Adding N2 will cause a decrease in the concentration of NH3 because the equilibrium will shift to the left. Therefore, this option is a plausible answer.
To summarize, based on Le Chatelier's principle, adding N2 to the system will result in a decrease in the concentration of H2 (B) and a decrease in the concentration of NH3 (E).
Based on Le Châtelier's principle, adding N2 gas to the system at equilibrium will shift the reaction to the left in order to minimize the disturbance and restore equilibrium.
Let's break it down step-by-step:
1. The reaction equation is: 2NH3 (g) <-> N2 (g) + 3H2 (g)
2. According to Le Châtelier's principle, when you add N2 (g) to the system at equilibrium, it will try to counteract this disturbance.
3. To restore equilibrium, the system will shift to the left, meaning the reaction will produce more reactants (NH3) and consume more products (N2 and H2).
4. As a result, the concentration of NH3 (g) will increase, while the concentrations of N2 (g) and H2 (g) will decrease.
5. Therefore, the answer to the question is E) a decrease in the concentration of NH3 (g).
Now, regarding your second question about the sign of the number, the value of ΔH° (+92.4 kJ) does not directly affect the direction of the shift. It only indicates whether the reaction is endothermic (positive ΔH°) or exothermic (negative ΔH°). In this case, the reaction is endothermic, but it doesn't impact the direction of the shift when N2 is added at equilibrium.