Practice Problem 7
Predict the effect of the following changes on the reaction in which SO3 decomposes to form SO2 and O2.
2 SO3(g) 2 SO2 (g) + O2 (g) Ho = 197.78 kJ
(a) Increasing the temperature of the reaction.
(b) Increasing the pressure on the reaction.
(c) Adding more O2 when the reaction is at equilibrium.
(d) Removing O2 from the system when the reaction is at equilibrium.
(a) Because this is an endothermic reaction, which absorbs heat from its surroundings, an increase in the temperature of the reaction leads to an increase in the equilibrium constant and therefore a shift in the position of the equilibrium toward the products.
(b) There is a net increase in the number of molecules in the system as the reactants are converted into products, which leads to an increase in the pressure of the system. The system can minimize the effect of an increase in pressure by shifting the position of the equilibrium toward the reactants, thereby converting some of the SO2 and O2 into SO3.
(c) Adding more O2 to the system will shift the position of the equilibrium toward the reactants.
(d) Removing O2 from the system has the opposite effect; it shifts the equilibrium toward the products of the reaction.