At 850 K, the equilibrium constant for the reaction 2 SO 2 ( g ) + O 2 ( g ) − ⇀ ↽ − 2 SO 3 ( g ) is K c = 15 . If the given concentrations of the three gases are mixed, predict in which direction the net reaction will proceed toward equilibrium.

[SO2] = 0.20 M

[O2] = 0.60 M

[SO3] = 0.60 M

Qc = 15

Qc = Kc, the reaction mixture is in equilibrium.

[SO2] = 0.14 M

[O2] = 0.20 M

[SO3] = 0.40 M

Qc = 40.8

Qc > Kc, the reaction will shift to the left.

[SO2] = 0.50 M

[O2] = 0.50 M

[SO3] = 0.10 M

Qc = 0.08

Qc < Kc, the reaction will shift to the right

Explanation:

At 850 K, the equilibrium constant for the reaction

2SO2 (g) + O2 (g)⇔ 2SO3 (g)

Kc = 15 . If the given concentrations of the three gases are mixed, predict in which direction the net reaction will proceed toward equilibrium.

[SO2] = 0.20 M

[O2] = 0.60 M

[SO3] = 0.60 M

[SO2] = 0.14 M

[O2] = 0.20 M

[SO3] = 0.40 M

[SO2] = 0.50 M

[O2] = 0.50 M

[SO3] = 0.10 M

Will each go to the left, right, or will there be no net reaction?

Step 1:

From the Law of Mass Action, the equilibrium constant for this reaction is defined as:

Kc = [SO3]² / [SO2]² [O2] = 15.0

If Qc = Kc, the reaction mixture is in equilibrium.

If Qc > Kc, the reaction will shift to the left.

If Qc < Kc, the reaction will shift to the right.

[SO2] = 0.20 M

[O2] = 0.60 M

[SO3] = 0.60 M

Qc = [SO3]² / [SO2]² [O2]

Qc = (0.60² )/(0.20² *0.60)

Qc = 15

Qc = Kc, the reaction mixture is in equilibrium.

[SO2] = 0.14 M

[O2] = 0.20 M

[SO3] = 0.40 M

Qc = [SO3]² / [SO2]² [O2]

Qc = (0.40² )/(0.14² *0.20)

Qc = 40.8

Qc > Kc, the reaction will shift to the left.

[SO2] = 0.50 M

[O2] = 0.50 M

[SO3] = 0.10 M

Qc = [SO3]² / [SO2]² [O2]

Qc = (0.10² )/(0.50² *0.50)

Qc = 0.08

Qc < Kc, the reaction will shift to the right