The equilibrium
2 SO2(g) + O2(g) ⇌ 2 SO3(g)
is studied at a temperature where Kp = 4.0. A different student draws a particulate representation of a 1.0 L container by including exactly 10 yellow spheres labeled SO2, 10 blue spheres labeled O2, and 10 green spheres labeled SO3. Assume ideal-gas behavior so that the count of each particle type is directly proportional to its partial pressure.
(1) Determine whether the particle counts in the student’s diagram are consistent with the system being at equilibrium. Justify your answer using appropriate reasoning based on stoichiometry and partial pressures.
(2) Using the student’s particle counts, calculate the reaction quotient Qp. Show your reasoning clearly.
(3) Keeping the total number of particles fixed at 30 and maintaining the ideal-gas assumption, propose a new set of particle counts that would better represent a mixture at equilibrium with Kp = 4.0. Justify how your proposed counts satisfy the equilibrium expression.
(4) Explain the conceptual error a student might make by assuming that “equal numbers of particles for each species” must imply that the system is at equilibrium.