1. CONCENTRATIONS OF
SOLUTIONS
•Behavior of solutions depend on compound itself
and on how much is present, i.e. on the
concentration.
•Two solutions can contain the same compounds
but behave quite different because the
proportions of those compounds are different.
2. In general, a concentrated solution is
one where the amount of solute in a given
volume of solvent is great. A dilute
solution is one where the amount of
solute in a given volume of solvent is
relatively small.
3. Types of Concentrated
Solutions
Saturated
Solvent holds as
much solute as is
possible at that
temperature.
Dissolved solute is
in dynamic
equilibrium with
solid solute
particles.
4. Types of Solutions
Unsaturated
Less than the
maximum amount
of solute for that
temperature is
dissolved in the
solvent.
5. Types of Solutions
Supersaturated
Solvent holds more solute than is normally
possible at that temperature.
These solutions are unstable; crystallization
can usually be stimulated by adding a “seed
crystal” or scratching the side of the flask.
6. Solubility and the Solution
ProcessPresentation
of Lecture
Outlines, 12–6
– Many factors affect solubility, such as
temperature and, in some cases,
pressure.
– There is a limit as to how much of a
given solute will dissolve at a given
temperature.
– A saturated solution is one holding as
much solute as is allowed at a stated
The amount of a substance that will
dissolve in a solvent is referred to as its
solubility.
7. Solubility: Saturated Solutions
Presentation
of Lecture
Outlines, 12–7
Sometimes it is possible to obtain a
supersaturated solution, that is, one that
contains more solute than is allowed at a
given temperature.
– Supersaturated solutions are
unstable.
– If a small crystal of the solute is
added to a supersaturated solution,
the excess immediately crystallizes
out.
8. Effects of Temperature and
Pressure on SolubilityPresentation
of Lecture
Outlines, 12–8
The solubility of solutes is very
temperature dependent.
– For gases dissolved in liquids, as
temperature increases, solubility
decreases.
– On the other hand, for most solids
dissolved in liquids, solubility increases
as temperature increases.
