Video Transcript
At what point does a solution
become saturated?
A solution is a homogeneous mixture
consisting of one or more solutes dissolved in a solvent. There is a maximum amount of solute
that can be dissolved in a solvent to create a solution. This depends on the properties of
the solute and solvent as well as the temperature. We can qualitatively describe the
amount of solute dissolved in a solvent using the terms unsaturated, saturated, and
supersaturated.
To help us better understand these
terms, let’s consider a beaker that contains 100 grams of water at 26 degrees
Celsius. To the beaker, we’ll add 10 grams
of potassium chloride. After adding the potassium chloride
and stirring, we’ll find that all 10 grams dissolve in the water. If we continue to add potassium
chloride to this solution, we’ll notice that more potassium chloride can dissolve in
the water. So, we haven’t yet added the
maximum amount of potassium chloride that can dissolve in 100 grams of water at this
temperature. We can describe this solution as
unsaturated, a solution that contains less than the maximum amount of solute
dissolved in a solvent at a given temperature.
As we continue to add potassium
chloride to the water, we’ll eventually reach a point where no more potassium
chloride will dissolve. At this point, we’ve created a
saturated solution, a solution that contains the maximum amount of solute dissolved
in a solvent at a given temperature.
The maximum amount of solute that
can dissolve in the solvent is dependent on the temperature. So, if we increase the temperature
of this solution, we can increase the amount of potassium chloride that will
dissolve in the water. If the solution is then slowly
cooled, it is possible to create a solution in which more than the maximum amount of
solute that should be able to dissolve is dissolved in the solvent at the cooler
temperature. This type of solution is a
supersaturated solution.
To answer the question, we want to
know at what point does a solution become saturated. We know that a saturated solution
contains the maximum amount of solute dissolved in a solvent at a given
temperature. And this type of solution is
reached when no more solute dissolves in the solvent. So, the point at which a solution
becomes saturated is when the maximum amount of solute has been dissolved. And therefore, no more solute will
dissolve in the solution.
