Question

At a particular temperature, K = 3.11 for the reaction

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

If all four gases had initial concentrations of 0.800 M, calculate the equilibrium concentrations of the gases.

[SO2]= ___________M

[NO2]= ___________M

[SO3]= ___________M

[NO]= ____________M

Answer 1

The equilibrium concentration will be calculated from the equation,

K = [SO3][NO] / [[SO2][NO2]

Let x be the change in concenration then,

equilibrium concentration of the gases would be,

[SO2] = (0.8-x)

[NO2] = (0.8-x)

[SO3] = (0.8+x)

[NO] = (0.8+x)

Feed the values,

3.11 = (0.8+x)(0.8+x)/(0.8-x)(0.8-x)

thus their is no much change at equilibrium for the gases

solving the quadratic equation for x,

x = 0.797 M

Thus, concentration of all the gases at equilibrium would be,

[SO2] = (0.8-0.797) = 0.003 M

[NO2] = (0.8-x) = 0.003 M

[SO3] = (0.8+x) = 1.597 M

[NO] = (0.8+x) = 1.597 M

Or, the answer could also be not much change in concentration at euilibrium occures. Choose the best of the two solutions.