Ammonia synthesis is represented by the balanced equation
N2(g)+3H2(g)⇌2NH3(g)
The numerical value of the equilibrium constant depends on whether it is expressed in terms of molar concentrations or partial pressures.
Parts below refer to this reaction at a fixed temperature of 500 K.
(a) Identify the value of Δn (the change in the number of moles of gaseous species) for the balanced equation above, and explain how the sign of Δn reflects the relative number of product and reactant gas molecules.
(b) Without performing any calculations, predict whether the numerical value of the equilibrium constant expressed in terms of partial pressures will be greater than, less than, or equal to the numerical value expressed in terms of molar concentrations at 500 K. Justify your prediction using particle-level reasoning.
(c) Some gas-phase reactions have Δn=0. Compare and contrast how the numerical values of the two expressions for the equilibrium constant behave for reactions in which Δn=0 versus reactions in which Δn=0. Include a discussion of the temperature dependence of the ratio of the two constants.