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.
Evaporation happens when a liquid substance becomes a gas. When water is heated, it evaporates. The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor.