Two reversible reactions in the sequence:

A+B <=> 2C <=> D+E

The rate constants for the reactions are as follows, where ‘1’ and ‘2’ refer to the first and second reaction, respectively:

k1,f = 0.04M−1 ·s−1 k1,r = 0.01M−1 ·s−1

k2,f = 0.10M−1 ·s−1 k2,r = 0.10M−1 ·s−1

(a) If a solution initially contains 60 mmol/L of A, 40 mmol/L of B, and no C, D, or E, what will the distribution of species be at equilibrium? (Hint: the equilibrium solution composition comprises five unknowns [the concentrations of the five species], which can be determined by writing and solving five independent equations involving those unknowns. The available equations include mass balances that characterize the stoichiometry of the reactions, and equilibrium constant expressions. Try to write and solve five independent equations that characterize the system.)

(b) What is the equilibrium constant for the reaction 0.5A+0.5B <=> C?