Chemistry help please!!!?

Question

The first step in industrial nitric acid production is the catalyzed oxidation of ammonia. Without a catalyst, a different reaction predominates:

4NH3(g) + 3O2(g) <=> 2N2(g) + 6H2O(g)

When 0.0150 mol NH3(g) and 0.0280 mol O2(g) are placed in a 1.00 L container at a certain temperature, the N2 concentration at equilibrium is 1.40×10-3 M. Calculate Kc for the reaction at this temperature.

Answer 1

[N2]^2[H2O]^6/([NH3]^4[O2]^3]) = 3.24