Question

Consider the following reaction:  2 A + 3 B2 ⇌ A2B6 The initial concentrations of A and B2 are 0.340 M and 0.470 M, respectively, with no A2B6 initially present. When the reaction comes to equilibrium, the concentration of A2B6 is found to be 8.00×10−2 M.

Answer 1

2A     + 3 B2 <---------------------->A2 B6

0.340         0.470                               0       -----------------> initial

0.340-2x    0.470-3x                         x -------------------> equilibrium

but x = 8.00×10−2 M. given

equilibrium concentrations:

[A] = 0.340-2x   = 0.18 M

[B2] = .470 -3x = 0.23 M

[A2B6] = x = 8.00×10−2 M.

equilibrium constant :

Keq = [A2B6]/[A]^2 [B2]^2

Keq = (8.00×10−2 ) / (0.18)^2 (0.23)^3

Keq = 202.9