Question

At 33K, N₂O₄ is fifty percent dissociated. Calculate the standard free energy change at this temperature and at one atmosphere.

Answer 1

Given T = 33 K

\[\ce{N2O4 ⇌ 2NO2}\]

Initial concentration: 100% and 0

Concentration dissociated: 50%

Concentration remaining at equilibrium: 50% and 100%

K_eq = `100/50` = 2

∆G⁰ = −2.303 RT log K_eq

∆G⁰= −2.303 × 8.314 × 33 × log 2

∆G⁰ = −190.18 J mol⁻¹