Final answer:
The amount of SO₂ at equilibrium in the reaction 2SO₂(g) + O₂(g) = 2SO₃(g) increases when the volume of the system is increased, due to the shift in equilibrium towards the reactants side to counter the change.
Step-by-step explanation:
Considering the reaction:
2SO₂(g) + O₂(g) = 2SO₃(g) with a delta H_rxn of -198 kJ, we can analyze the effect of various changes on the equilibrium concentration of SO₂(g). Given that the reaction is exothermic (negative delta H_rxn), applying Le Chatelier's Principle allows us to predict the response of the system to different disturbances:
- (a) Temperature Decrease: Lowering the temperature favors the exothermic reaction, hence increasing the production of SO₃ and reducing the concentration of SO₂.
- (b) Adding Oxygen: More SO₃ will be formed, consuming more SO₂.
- (c) Removing SO₃: This shifts the equilibrium to the right, promoting the consumption of SO₂ and O₂ to form more SO₃.
- (d) Increasing Volume: This results in a decrease in the concentration of gases, favoring the direction with more gas molecules, which is the reverse reaction in this case, thus increasing the amount of SO₂.
Hence, the amount of SO₂ at equilibrium increases when the volume is increased.