Write the equilibrium-constant expression for the reaction shown in terms of [A], [B], [C], and [D]:
A(g) + B(g) ⇌ 2 C(g) + D(g)
Note that Kc, which is sometimes symbolized as K or Keq, denotes that the equilibrium constant is expressed using molar concentrations. For this question, Kc means the same thing as K and Keq.
Kc = [C]^2[D] / [A][B]