Consider the following sequence of reversible reactions carried out at a fixed…
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
Consider the following sequence of reversible reactions carried out at a fixed temperature:
(1) Derive an expression for the equilibrium constant, Koverall, for the single-step transformation X(g)⇌Z(g) in terms of K1 and K2. Then compute its numerical value.
(2) Classify the overall equilibrium X(g)⇌Z(g) as product-favored, reactant-favored, or neither, based on the value obtained in part (a).
(3) Provide a detailed explanation of how a large K1 value can be effectively "counterbalanced" by a small K2 value to yield the overall equilibrium position you found. In your discussion, connect the mathematical relationship among the constants to the relative concentrations of X, Y, and Z at equilibrium.
(4) If a catalyst were added that speeds both elementary reactions equally without changing their equilibrium constants, discuss qualitatively how (if at all) it would affect the overall equilibrium constant and the composition of the equilibrium mixture. Justify your response.