Topic 8 and 17 – Equilibrium
Closed system: A system in which neither matter nor energy can be lost or gained. An equilibrium can never occur in a system that is not closed.
Contact process: The synthesis of sulphuric acid, where V2O5 is used as a catalyst.
Equilibrium constant: For a reaction aA + bB cC + dD, where the small letters are coefficients and capital letters are the reactants, the equilibrium constant is [C]c[D]d/[A]a[B]b. Variable units.
Equilibrium, dynamic: An equilibrium in which the rates of the forward and reverse reactions are the same.
Haber process: The synthesis of ammonia, where Fe is used as a catalyst.
Optimum temperature: For exothermic reactions such as the Haber process, the optimum temperature is the best compromise between yield and rate.
Homogeneous reaction: A reaction in which all the species involved are in the same phase.
Le Chatelier’s principle: If an equilibrium is subjected to a stress, the equilibrium will shift to minimize the effect of the stress.
Phase equilibrium: When the rate of vaporization is equal to the rate of condensation.
Vapor pressure: The partial pressure of a vapor. Boiling occurs when a liquid’s vapor pressure equals the external pressure. The stronger the intermolecular forces the lower the vapor pressure at a particular temperature.