Chemical reaction: 4PBr₃(g) → P₄(g) + 6Br₂<span>(g).
</span>Pressure equilibrium constant (Kp) express the relationship between product pressures and reactant pressures. The partial pressures of gases are used to calculate pressure equilibrium constant.
Kp = (p(P₄) · p(Br₂)⁶) ÷ p(PBr₃)⁴.
p(P₄) - partial pressure of phosphorus.
p(Br₂) - partial pressure of bromine.
