Using LeChatelier's principle, predict the direction of the net reaction in each of the following system as a result of decreasing the volume of the chamber for the reaction mixture. Where does the direction shifts?

a.) N2(g)+ O2(g)= 2NO(g)
b.) PCl5(g)=PCl3(g)+Cl2(g)
c.) CO(g)+Cl(2)=COCl2(g)

right

left
right

I disagree with answer for a by Sabrina. I agree with b and c.

The answer for a is neither. Decreasing volume means increasing pressure so the reaction will shift to the side with the fewer moles of gas. There are two mols of gas on the left and two mols gas on the right; therefore, no shift.

To predict the direction of the net reaction using Le Chatelier's principle, we consider how the equilibrium position of a reaction system responds to changes in concentration, pressure, and temperature. In this case, we are specifically looking at the effect of decreasing the volume of the reaction chamber.

When the volume of the reaction chamber is decreased, the pressure of the system increases. Assuming the temperature remains constant, we can determine the direction of the net reaction by considering how the system responds to this change in pressure.

Now let's analyze each reaction system individually:

a.) N2(g) + O2(g) ⇌ 2NO(g)
In this reaction, the number of moles of gas on the left side of the equation (N2 and O2) is equal to the number of moles of gas on the right side of the equation (2NO).

- If we decrease the volume of the chamber, the pressure will increase. According to Le Chatelier's principle, the system will shift in the direction that reduces the pressure.
- Since there are the same number of moles of gas on both sides of the equation, changing the pressure will not affect the equilibrium position.

Hence, the direction of the net reaction remains unchanged.

b.) PCl5(g) ⇌ PCl3(g) + Cl2(g)
In this reaction, there is a decrease in the number of moles of gas when PCl5 decomposes into PCl3 and Cl2.

- If we decrease the volume of the chamber, the pressure will increase. According to Le Chatelier's principle, the system will shift in the direction that reduces the pressure.
- In this case, the side with fewer moles of gas (the right side) has a lower pressure. Therefore, the system will shift to the right to reduce the pressure.

Hence, the direction of the net reaction shifts to the right.

c.) CO(g) + Cl2(g) ⇌ COCl2(g)
In this reaction, the number of moles of gas remains the same on both sides of the equation.

- If we decrease the volume of the chamber, the pressure will increase. According to Le Chatelier's principle, the system will shift in the direction that reduces the pressure.
- Since the number of moles of gas is the same on both sides of the equation, changing the pressure will not affect the equilibrium position.

Hence, the direction of the net reaction remains unchanged.