Given the reaction: SO2(g) + NO2(g) = NO(g) + SO3(g) H = -42.6Kj
How will the concentration of SO3 at equilibrium be effected by the following:
a) Adding more NO2(g)
b) Removing some NO(g)
c) Increasing the temperature
Let me rewrite the equation to include the heat content instead of using two separate equations for that.
SO2(g) + NO2(g) = NO(g) + SO3(g) + heat
Now, the long explanation of Le Chatelier's Principle is that when a system in equilibrium is subjected to a stress, the reaction will shift in such a way as to relieve the stress. The shorter way, I think is better, and it says, a system in equilibrium will try to undo what we do to it. There are only three answers to these problems. (a) reaction shifts to the right.
(b) reaction shifts to the left.
(c) reaction doesn't shift at all.
a) if NO2 is added. The system will try to use up NO2. How can it do that. The reaction will shift to the right because that uses up NO2.
(b) removing NO. The system will try to add NO to replace what we've removed. How can it do that? By shifting to the right.
When shifting to the right, NO is increased, SO3 is increased, heat is increased, SO2 is decreased, and NO2 is decreased. I will leave the last one for you.
a) Adding more NO2(g): According to Le Chatelier's principle, if more NO2(g) is added, the system will try to counteract the change by shifting the equilibrium to the right to consume the excess NO2(g). Since SO3(g) is produced on the right side of the equation, increasing the concentration of NO2(g) will result in an increase in the concentration of SO3(g) at equilibrium.
b) Removing some NO(g): If some NO(g) is removed, the equilibrium will shift to the left to replace the lost NO(g). As a result, the concentration of SO3(g) will decrease since the forward reaction is no longer favored. So, removing some NO(g) will decrease the concentration of SO3(g) at equilibrium.
c) Increasing the temperature: According to Le Chatelier's principle, increasing the temperature will favor the endothermic reaction direction. In this case, the forward reaction is endothermic, meaning it consumes heat. Therefore, increasing the temperature will shift the equilibrium to the right to consume the excess heat. Since SO3(g) is produced on the right side of the equation, increasing the temperature will increase the concentration of SO3(g) at equilibrium.
To determine how the concentration of SO3 at equilibrium will be affected by different changes, we need to understand Le Chatelier's Principle. According to this principle, when a system at equilibrium is subjected to a change, the system will try to counteract the change to reach a new equilibrium.
a) Adding more NO2(g):
Increasing the concentration of NO2(g) will disturb the equilibrium because it is a reactant in the forward direction of the reaction. As a result, the system will try to decrease the added NO2(g) by consuming it. As per the reaction, SO2(g) + NO2(g) → NO(g) + SO3(g), the forward reaction will proceed to the right to consume the excess NO2(g). Consequently, the concentration of SO3(g) will increase at equilibrium.
b) Removing some NO(g):
Removing NO(g) affects the equilibrium by reducing the concentration of one of the products. Again, since the system aims to counteract this change, it will shift towards the side that produces more NO(g). In this case, the reverse reaction, NO(g) + SO3(g) → SO2(g) + NO2(g), will move forward to replenish the decreased NO(g). As a result, the concentration of SO3(g) will increase as the equilibrium is shifted to the right.
c) Increasing the temperature:
Raising the temperature is an energy-based change. In this exothermic reaction, lowering the temperature shifts the equilibrium to the right, favoring the formation of more products (NO(g) and SO3(g)). Hence, increasing the temperature will shift the equilibrium to the left, reducing the concentration of SO3(g) at equilibrium. This is because the system will try to counteract the increase in temperature by favoring the endothermic reaction, consuming NO(g) and SO3(g) to produce more reactants (SO2(g) and NO2(g)).
Keep in mind that these effects are general observations based on Le Chatelier's Principle. The actual quantitative impact on the concentration of SO3(g) will depend on the stoichiometry and equilibrium constant of the reaction.