A reversible gas-phase reaction is allowed to reach equilibrium in a sealed
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
A reversible gas-phase reaction is allowed to reach equilibrium in a sealed, rigid container at constant temperature. A finely powdered heterogeneous catalyst is then introduced into the vessel.
(a) Describe the immediate effect, if any, of adding the catalyst on the numerical value of the reaction quotient Q.
(b) Explain whether the position of equilibrium (i.e., the equilibrium concentrations of the reacting species) will change after the catalyst is added, and justify your answer in terms of Q and K.
(c) Despite your answer to part (b), experimental observation shows that the time required for the system to attain equilibrium after a disturbance is reduced when the catalyst is present. Explain why this is consistent with the role of a catalyst.