Chemical Equilibrium Constant Expression (Pressure)

Formula: For a gas - phase reversible reaction aA(g) + bB(g) ightleftharpoons cC(g) + dD(g), the equilibrium constant expressed with partial pressures is K p = ((p C)^c (p D)^d)/((p A)^a (p B)^b) Applicable Conditions: Reactions involving ideal gases. K p is constant at a given temperature. Explanation: The ratio of the product of the equilibrium partial pressures of the products to that of the reactants, each raised to the power of its stoichiometric coefficient. The relationship between K p and K c is K p = K c (RT)^(Δ n), where Δ n = (c + d) - (a + b).