Using the Le Chatelier's principle, predict the direction of the net reaction in each of the following equilibrium systems, as a result of increasing the pressure at constant temperature.
a)N2(g) + O2(g) ==> 2NO(g)
<==
b)PCl5 ==> PCl3(g) + Cl2(g)
<==
c)CO(g) + Cl2(g) ==> COCl2(g)
<==
The reaction will shift to the side with fewer moles when the pressure is increased. For a there is no change. b is correct; c will go to the right.
To predict the direction of the net reaction in each equilibrium system when the pressure is increased at constant temperature, we can use Le Chatelier's Principle. This principle states that if a system at equilibrium is subjected to a stress, it will shift in a way that minimizes the effect of the stress.
In the case of increasing the pressure, the system will shift in the direction that reduces the number of gas molecules. This is because increasing the pressure will effectively increase the concentration of the gas molecules, and the system will try to counteract this increase by favoring the reaction that produces fewer gas molecules.
Now let's analyze each equilibrium system:
a) N2(g) + O2(g) ⇌ 2NO(g)
This reaction involves a total of three moles of gas on the left side and two moles of gas on the right side. Therefore, increasing the pressure will favor the side with fewer gas molecules. In this case, the reaction will shift to the right, producing more NO(g) and consuming N2(g) and O2(g).
b) PCl5 ⇌ PCl3(g) + Cl2(g)
Here, the reaction involves one mole of gas on the left side and two moles of gas on the right side. Therefore, increasing the pressure will favor the side with fewer gas molecules. In this case, the reaction will shift to the left, consuming PCl3(g) and Cl2(g) to produce more PCl5.
c) CO(g) + Cl2(g) ⇌ COCl2(g)
In this reaction, there are two moles of gas on the left side and one mole of gas on the right side. Increasing the pressure will favor the side with fewer gas molecules. Therefore, the reaction will shift to the right, producing more COCl2(g) and consuming CO(g) and Cl2(g).
In summary, when the pressure is increased at constant temperature, the equilibrium systems will shift in a way that reduces the number of gas molecules to minimize the effect of the pressure increase.