The solution would be like this for this specific problem:
First, we need to write out the balanced reaction equation for the problem:
"gaseous nitrogen with gaseous hydrogen to produce gaseous ammonia"
gaseous nitrogen + gaseous hydrogen = gaseous ammonia
gaseous nitrogen = N2(g)
gaseous hydrogen = H2(g)
gaseous ammonia = NH3(g)
In here, I’m going to show you how to balance this from start to finish:
N2(g) + H2(g) ↔ NH3(g) (basic, unbalanced equation that shows reactants and product)
N2(g) + H2(g) ↔ 2NH3(g) (balances the nitrogens)
N2(g) + 3H2(g) ↔ 2NH3(g) (balances the hydrogens) => Balanced Equation
Next, we write the Keq expression of the balanced reaction:
Keq = (∏[products]^n) /(∏[reactants]^n)
Keq = [NH3]^2 / [[N2][H2]]^3
Therefore, the correct equilibrium constant expression is Keq = (NH3)2 / (N2)(H2)3.