Question

A mixture initially contains A, B, and C in the following concentrations: [A] = 0.700 M , [B] = 0.700 M , and [C] = 0.550 M . The following reaction occurs and equilibrium is established: A+2B⇌C At equilibrium, [A] = 0.540 M and [C] = 0.710 M . Calculate the value of the equilibrium constant, Kc.

Answer 1

A    +     2B   <-------------> C

0.7        0.7                       0.55   ----------------> initial

0.7 - x    0.7 - 2x                 0.55 + x   ------------> equilibrium

At equilibrium :

[A] = 0.7 - x = 0.540

x = 0.160

[B] = 0.7 - 2x = 0.7 - 2 x 0.16

[B] = 0.38 M

Kc = [C] / [A][B]^2

    = 0.710 / 0.540 x 0.38^2

   = 9.11

equilibrium constant, Kc = 9.11