1. Concentration:
* Molarity (M): moles of solute per liter of solution (mol/L).
* Molality (m): moles of solute per kilogram of solvent (mol/kg).
* Mass percentage (%): grams of solute per 100 grams of solution (g/100g).
* Parts per million (ppm): milligrams of solute per liter of solution (mg/L), or milligrams of solute per kilogram of solution (mg/kg).
* Parts per billion (ppb): micrograms of solute per liter of solution (µg/L), or micrograms of solute per kilogram of solution (µg/kg).
2. Saturation:
* Saturated: The solution contains the maximum amount of solute that can dissolve at that temperature.
* Unsaturated: The solution contains less than the maximum amount of solute that can dissolve at that temperature.
* Supersaturated: The solution contains more than the maximum amount of solute that can dissolve at that temperature (unstable, prone to precipitation).
3. Solubility Product Constant (Ksp):
* Applies to sparingly soluble ionic compounds.
* Represents the equilibrium constant for the dissolution reaction of the ionic compound.
* A higher Ksp value indicates greater solubility.
The most common way to express solubility is by concentration, specifically molarity or mass percentage. However, the best way to express solubility depends on the specific application and the nature of the substance.
