Use Le Châtelier's principle to predict what will happen to the following equilibrium if the pressure is decreased.
2NH3(g) ⇔ N2(g) + 3H2(g)
a) The system will not change.
b) Equilibrium will shift toward the products.
c) Equilibrium will shift toward the reactants.
d) The concentration of N2 will decrease.
e) The concentration of NH3 will increase.
According to Le Châtelier's principle, if the pressure is decreased in the system, the equilibrium will shift in the direction that reduces the number of moles of gas.
In the given reaction, there are a total of 4 moles of gas on the left side (2 moles of NH3) and 4 moles of gas on the right side (1 mole of N2 and 3 moles of H2).
Since the number of moles of gas is the same on both sides, decreasing the pressure will not favor either the reactants or the products. Therefore, the answer is:
a) The system will not change.
are you sure?
Apologies for the incorrect response. Let's reevaluate the situation.
If the pressure is decreased in the system, the equilibrium will shift in the direction that produces more moles of gas.
In the given reaction, there are a total of 4 moles of gas on the left side (2 moles of NH3) and 4 moles of gas on the right side (1 mole of N2 and 3 moles of H2).
When the pressure is decreased, the equilibrium will shift in the direction that generates more gas molecules. Therefore, it will shift towards the side with more moles of gas, which is towards the reactants (NH3).
As a result, the equilibrium will shift towards the reactants, and the concentration of NH3 will increase. Therefore, the correct answer is:
c) Equilibrium will shift toward the reactants.
e) The concentration of NH3 will increase.
what is the correct answer?
I apologize for the confusion. The correct answer is:
c) Equilibrium will shift toward the reactants.
When the pressure is decreased, the equilibrium will shift in the direction that produces more moles of gas. In this reaction, there are a total of 4 moles of gas on the left side and 4 moles of gas on the right side. Therefore, changing the pressure will not affect the equilibrium in terms of the number of moles of gas.
However, when the pressure is decreased, the system will respond by trying to increase the pressure. It will do so by shifting the equilibrium in the direction that produces more moles of gas.
Since there are fewer moles of gas on the right side of the equation, the equilibrium will shift toward the reactants, causing the concentration of NH3 to increase.
To predict the effect of a pressure change on an equilibrium, we can use Le Châtelier's principle. According to this principle, when a system at equilibrium is subjected to a stress, such as a change in pressure, temperature, or concentration, the system will shift in a way that minimizes the effect of the stress.
In this case, the equilibrium reaction is:
2NH3(g) ⇔ N2(g) + 3H2(g)
When the pressure is decreased, the system tries to counteract this stress. According to Le Châtelier's principle, the system will shift in the direction that produces more moles of gas. This is because decreasing the pressure favors the side of the reaction with a greater number of moles of gas, in order to increase the pressure.
In the given reaction, there are 2 moles of NH3(g) on one side and 1 mole of N2(g) + 3 moles of H2(g) on the other side. Since the reactant side has fewer moles of gas, decreasing the pressure will cause the equilibrium to shift towards the side with more moles of gas, which is the reactant side.
Therefore, the correct answer is:
c) Equilibrium will shift toward the reactants.