For the gas–phase equilibrium

CHEMISTRY · Single correct · AP · Chemistry · Equilibrium · Equilibrium

Problem

\text{N}_2\text{O}_4(g) \rightleftharpoons 2\text{NO}_2(g)

, the equilibrium constant at a certain temperature is

K_c = 0.36

. A mixture is prepared with

[\text{N}_2\text{O}_4] = 0.40\,\text{M}

and

[\text{NO}_2] = 0.60\,\text{M}

. Which statement correctly describes how the system will respond as it approaches equilibrium? (a) The reaction will shift toward products because

Q > K

. (b) The mixture is already at equilibrium because

Q = K

. (c) The reaction will shift toward reactants because

Q > K

. (d) The direction cannot be determined without knowing

K_p

and the total pressure.