Chemical Equilibrium
12 terms
Effect of a Catalyst on Equilibrium
Chemical Equilibrium
Dimensionless
A catalyst changes how quickly equilibrium is reached but never where that equilibrium lies.
K unchanged
Effect of an Inert Gas
Chemical Equilibrium
Pa
The influence of adding a non-reacting gas on the position of a gaseous equilibrium.
Effect of Concentration Change
Chemical Equilibrium
mol/L
The shift in equilibrium position caused by adding or removing a reactant or product.
Q ≠ K → shift until Q = K
Effect of Pressure Change
Chemical Equilibrium
Pa
The shift in a gaseous equilibrium caused by changing the total pressure through a volume change.
shift towards fewer gas moles when p rises
Effect of Temperature Change
Chemical Equilibrium
K
The shift in equilibrium caused by heating or cooling, which uniquely also changes the equilibrium constant.
exothermic: K falls as T rises
Equilibrium Constant
Chemical Equilibrium
Various
The fixed ratio of product to reactant terms, each raised to its stoichiometric power, that characterises a reaction at a given temperature.
K = Π[products]^ν / Π[reactants]^ν
Equilibrium Constant of a Reversed Reaction
Chemical Equilibrium
Various
The constant obtained when a reaction is written in the opposite direction, equal to the reciprocal of the original.
K_reverse = 1 / K_forward
Equilibrium Constant of a Scaled Reaction
Chemical Equilibrium
Various
The constant obtained when every coefficient in an equation is multiplied by the same factor.
K_new = K_old^n
Equilibrium in Closed Systems
Chemical Equilibrium
Dimensionless
The requirement that no matter enters or leaves for a true chemical equilibrium to be established.
Equilibrium Position
Chemical Equilibrium
mol/L
The particular set of concentrations at which a system settles, describing how far the reaction has proceeded.
Equilibrium Yield
Chemical Equilibrium
Dimensionless
The proportion of reactant converted to product once equilibrium has been reached.
yield = n_product / n_theoretical
Extent of Reaction
Chemical Equilibrium
mol
A single variable measuring how far a reaction has progressed from pure reactants towards products.
ξ = (n_i − n_i°) / ν_i