Gaseous ammonia was introduced into a sealed container and heated to a certain temperature:
2NH3(g) ⇔ N2(g) + 3H2(g)
At equilibrium, [NH3] = 0.0406 M, [N2] = 0.126 M, and [H2] = 0.208 M.
Calculate Keq for the reaction at this temperature.

Question

Gaseous ammonia was introduced into a sealed container and heated to a certain temperature: 
2NH3(g) ⇔ N2(g) + 3H2(g) 
At equilibrium, [NH3] = 0.0406 M, [N2] = 0.126 M, and [H2] = 0.208 M. 
Calculate Keq for the reaction at this temperature.

anonymous · Answer

do you know how to write the Keq in terms of the equilibrium concentrations for this equilibrium?

anonymous · Answer

no, i do not.

anonymous · Answer

Let's take an example: A2 --> 2A

then in terms of the equil. concentrations:

 Keq = [A]^2 / [A2]

do you get what i am doing?

anonymous · Answer

Yes! I got the answer.. should be .6878!

anonymous · Answer

i have .688 (3 sig figs not 4)

anonymous · Answer

so you didn't need to ask me after all...awesome.