Dinitrogen tetraoxide is formed from nitrogen dioxide by the reversible reaction
2NO2(g)⇌N2O4(g)
A laboratory handbook reports the standard Gibbs free energy change for this reaction at 298 K as ΔG∘=−5.40kJ mol−1. Assume that ΔG∘ remains constant over the temperature range considered.
(a) Determine the numerical value of the equilibrium constant K298 at 298 K.
(b) Calculate the equilibrium constant K400 at 400 K under the stated assumption.
(c) Evaluate the ratio K400/K298 and interpret what this ratio implies about how the position of equilibrium shifts with increasing temperature.
(d) Discuss two reasons, grounded in thermodynamic principles, why treating ΔG∘ as temperature‐independent may introduce error when extending the calculation from 298 K to 400 K.