Answer
(a) Temperature must be low in order to favor $SO_3$ production.
Higher pressure.
(b) $O_2$ is a reactant, so its addition decreases Q.
The K is not affected by concentrations.
(c) Since the temperature is low, the rate of the reaction is probably low, which means a slow reaction. The catalyst is used in order to accelerate the reaction.
Work Step by Step
(a) The reaction is exothermic (negative delta H), therefore, heat is a product, and temperature must be low in order to favor $SO_3$ production.
Reactants: 1.5 mol of gas; Products: 1 mol of gas.
In order to favor products, the volume must be low, which means a high pressure.
(b) $O_2$ is a reactant, so its addition decreases Q. The K is not affected by concentrations.
(c) Since the temperature is low, the rate of the reaction is probably low, which means a slow reaction. The catalyst is used in order to accelerate the reaction.
