At a certain temperature, 0.660 mol of SO3 is placed in a 3.00-L container.

2SO3 (g) 2SO2 + O2 (g)

At equilibrium, 0.160 mol of O2 is present. Calculate Kc.

When this equilibrium shifts to the right, forming "X" mol of O2

2SO3 (g) - - - > 2SO2 (g) + O2 (g) 0.660 - 2X - - > - - > 2X & X since X = 0.130 this becomes 0.400 0.260 & 0.130 find moles / litre: (0.400) / 4.5L - - > - - > 0.260 / 4.5L & 0.130 / 4.5 L which gives these molarities: 2SO3 (g) - - - > 2SO2 (g) + 1 O2 (g) [0.08889] - - > [0.05778] & [0.02889] Kc = [SO2]^2 [O2] / [SO3]^2 Kc = [0.05778]^2 [0.02889] / [0.08889]^2 Kc = (0.003338) [0.02889] / [ (0.007901) Kc = 0.0122