A 5.00 L rigid steel cylinder at 298 K contains only dinitrogen tetroxide at an initial pressure of 1.00 atm. The gas is allowed to reach equilibrium according to
N2O4(g)⇌2NO2(g).
At 298 K the total pressure in the cylinder is found experimentally to be 1.45 atm.
Answer the following questions. Show all reasoning and include units with calculated values.
(a) Write the equilibrium-constant expression, Kp, for this reaction.
(b) Determine the equilibrium partial pressures of N2O4(g) and NO2(g) in the cylinder.
(c) Calculate the numerical value of Kp at 298 K for this equilibrium.
(d) If 0.20 atm of argon is now injected into the still-rigid cylinder at constant temperature, qualitatively predict whether the value of Kp will change and whether the equilibrium partial pressure of NO2(g) will increase, decrease, or remain the same. Justify each prediction.