A 1.00-L flask was filled with 2.00 moles of gaseous and 2.00 moles of gaseous and heated. After equilibrium was reached, it was found that 1.21 moles of gaseous was present. Assume that the reaction

SO2 + NO2 ⇌ SO3 + NO

occurs under these conditions. Calculate the value of the equilibrium constant, K, for this reaction.

A 1.00-L flask was filled with 2.00 moles of gaseous SO₂ and 2.00 moles of gaseous NO₂ and heated. After equilibrium was reached, it was found that 1.21 moles of gaseous NO was present. Assume that the reaction

SO₂ + NO₂ ⇌ SO₃ + NO

occurs under these conditions. Calculate the value of the equilibrium constant, K, for this reaction.

Step 1: Calculate the molar concentrations

Since the reaction takes place in a 1.00 L flask, the molar concentrations are:

[SO₂]i = 2.00 M

[NO₂]i = 2.00 M

[NO]eq = 1.21 M

Step 2: Make an ICE chart

SO₂ + NO₂ ⇌ SO₃ + NO

I 2.00 2.00 0 0

C -x -x +x +x

E 2.00-x 2.00-x x x

Step 3: Calculate the concentrations at equilibrium

The concentration of NO at equilibrium is 1.21 M. Then, x = 1.21.

[SO₂]eq = 2.00-1.21 = 0.79 M

[NO₂]eq = 2.00-1.21 = 0.79 M

[SO₃]eq = x = 1.21 M

[NO]eq = x = 1.21 M

Step 4: Calculate the value of the equilibrium constant, K, for this reaction

K = [SO₃] × [NO]/[SO₂] × [NO₂]

K = 1.21²/0.79² = 2.35