Chemical Equilibrium — Formula Sheet

Irreversible reactions proceed in one direction until reactants are exhausted (C + O₂ → CO₂)

Reversible reactions occur in both forward and backward directions simultaneously (H₂ + I₂ ⇌ 2HI)

Law of Mass Action

rate ∝ product of concentration terms raised to their stoichiometric coefficients

Homogeneous equilibrium

all species in same phase (2HI(g) ⇌ H₂(g) + I₂(g))

Heterogeneous equilibrium

species in different phases (CaCO₃(s) ⇌ CaO(s) + CO₂(g))

For reaction aA + bB ⇌ cC + dD, the equilibrium constant Kc = [C]ᶜ[D]ᵈ/[A]ᵃ[B]ᵇ.

Homogeneous equilibrium involves all species in same phase (H₂(g) + I₂(g) ⇌ 2HI(g)).