Glossary
Common Ion
An ion that is already present in a solution from one source and is also produced by the dissolution of a sparingly soluble salt.
Example:
In a solution containing calcium sulfate and sodium sulfate, the sulfate ion () is the common ion.
Common Ion Effect
The decrease in the solubility of a sparingly soluble salt when a soluble salt containing a common ion is added to the solution.
Example:
Adding sodium chloride to a saturated silver chloride solution will cause more solid silver chloride to precipitate, demonstrating the common ion effect.
Equilibrium
A state in which opposing forces or influences are balanced, resulting in no net change in the system's macroscopic properties.
Example:
In a closed bottle of soda, the rate at which CO2 gas dissolves into the liquid is equal to the rate at which it escapes, establishing a dynamic equilibrium.
ICE Table
An acronym for Initial, Change, Equilibrium, a tabular method used to organize and solve equilibrium problems by tracking the concentrations of reactants and products.
Example:
When calculating the equilibrium concentrations for a weak acid dissociation, setting up an ICE table helps systematically determine the unknown values.
Le Chatelier's Principle
A principle stating that if a change of condition is applied to a system in equilibrium, the system will shift in a direction that relieves the stress.
Example:
If you increase the pressure on a gaseous equilibrium, the reaction will shift to the side with fewer moles of gas to relieve that stress, as predicted by Le Chatelier's Principle.
Molar Solubility
The number of moles of a solute that can dissolve per liter of solution before the solution becomes saturated.
Example:
If 1.3 x 10^-5 moles of AgCl dissolve in 1 liter of water, then its molar solubility is 1.3 x 10^-5 M.
Solubility Equilibria
The dynamic state where the rate of dissolution of a solid equals the rate of precipitation, resulting in a saturated solution.
Example:
When you add sugar to hot tea until no more dissolves, you've reached a state of solubility equilibria where the undissolved sugar is in balance with the dissolved sugar.
Solubility Product (Ksp)
The equilibrium constant for the dissolution of a sparingly soluble ionic compound, representing the product of the concentrations of its ions in a saturated solution, each raised to the power of its stoichiometric coefficient.
Example:
For calcium fluoride, , the Ksp expression is .