At 298 K, the gas-phase equilibrium
2 NO2(g) ⇌ 2 NO(g) + O2(g)
has an equilibrium constant Kp=4.60. A 1.00 L reaction flask at 298 K initially contains the following concentrations: [NO2] = 0.050 M, [NO] = 0.010 M, and [O2] = 0.0050 M.
(1) Calculate the value of the equilibrium constant Kc at 298 K for the reaction. Show your work, including any necessary relationships between Kp and Kc.
(2) Compute the reaction quotient Qc for the initial mixture.
(3) Compare Qc with Kc and predict the direction in which the system will move to reach equilibrium. Provide a quantitative justification.
(4) Immediately after the initial mixture is prepared, the volume of the flask is abruptly doubled at constant temperature. Qualitatively describe how this sudden change affects the numerical value of Qc (increase, decrease, or unchanged) and predict the direction of the subsequent shift in the composition of the system. Explain your reasoning without performing additional calculations.