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Calculating Equilibrium Concentrations

Calculating Equilibrium Concentrations.

Consider the reaction SO2(g) + NO2(g) = NO(g) + SO3(g) at 460 C. What are the equilibrium concentrations of all reactants and products if the initial concentrations are [SO2]o = [NO2]o = 3.00 x 10-3 M and [NO]o = [SO3]o = 4.00 x 10-2 M? The value of the equilibrium constant for the reaction is 85.0 at 460 C.

Solution This solution is FREE courtesy of BrainMass!

Set up table with initial, change, and equilibrium expressions:

SO2(g) + NO2(g) = NO(g) + SO3(g)

I 3x10-3 3x10-3 4x10-2 4x10-2

C -x -x +x +x

E 3x10-3 -x 3x10-3 -x 4x10-2 +x 4x10-2 +x

Keq = [NO][SO3]/[SO2][NO2] = (3x10-3 -x)^2 / (4x10-2 +x)^2 = 85.0

Solve this equation for x... Hint: take the square root of both sides first

Then plug in your value of x into the table above for the equilibrium row (E) and solve for all the equilibrium concentrations.

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