Answer to Question #323340 in General Chemistry for Wellen

Question

Dinitrogentetraoxide partially decomposes according to the following equilibrium: N₂O_4(g) ⇌ 2NO_2(g). A 1.00-L flask is charged with 0.04000 mol of N₂O₄. At equilibrium at 373 K, 0.0055 mol of N₂O₄ remains. Determine the K_eq for this reaction.

Answer 1

N₂O_4(g) ⇌ 2NO_2(g)

Set up an ICE chart

Initial:

N₂O₄ = 0.400 M

NO₂ = 0 M

Change:

NO₂ = +2x

N₂O₄ = -x

Equilibrium:

NO₂ = 2x

N₂O₄ = 0.400 - x = 0.0055

[N₂O₄] = x = 0.3945 M

[NO₂] = 2x = 2 × 0.3945 = 0.789 M

K_eq = [NO₂]² / [N₂O₄] = (0.789)² / 0.3945 = 1.578