The dimer–monomer equilibrium of dinitrogen tetroxide and nitrogen dioxide is…
CHEMISTRY · Multi-part · A Level · Chemistry · Chemical equilibria (Le Chatelier’s principle and Kc) · Chemical equilibria (Le Chatelier’s principle and Kc)
Problem
The dimer–monomer equilibrium of dinitrogen tetroxide and nitrogen dioxide is represented by the balanced equation
N2O4(g)⇌2NO2(g)
At 298 K the equilibrium constant Kp=0.36. Four sealed containers of equal volume (labeled D1–D4) each hold a total of 26 nitrogen-containing particles at 298 K. Assume the partial pressure of each species is directly proportional to its particle count in the diagram.
Container descriptions:
• D1: 12 N2O4 molecules and 6 NO2 molecules
• D2: 8 N2O4 molecules and 16 NO2 molecules
• D3: 5 N2O4 molecules and 20 NO2 molecules
• D4: 14 N2O4 molecules and 2 NO2 molecules
(a) For each container, calculate the ratio P(N2O4)[P(NO2)]2 using the particle counts as proxies for partial pressures. Present your results to two significant figures.
(b) Identify which container is closest to equilibrium at 298 K. Justify your selection quantitatively by comparing your calculated ratios with Kp.
(c) For one container that is not at equilibrium, predict the direction (toward products or toward reactant) in which the reaction will proceed to reach equilibrium. Support your prediction with numerical reasoning.