8.2 Solubility and Concentration
Fresh lemonade is a
solution of water, lemon
juice, and sugar.
There is a limit to the
amount of sugar that
can dissolve in a given
amount of water. Once
that limit is reached, you
cannot make the
solution taste any
sweeter.
8.2 Solubility and Concentration
Solubility
Solutions are described as saturated, unsaturated,
or supersaturated, depending on the amount of
solute in solution.
The maximum amount of a solute that dissolves in a
given amount of solvent at a constant temperature is
called ________________.
Solubilities are usually expressed in grams of solute
per ____ grams of solvent at a specified temperature.
8.2 Solubility and Concentration
Solubility
At a given temperature, different substances have
different solubilities in __________.
8.2 Solubility and Concentration
Solubility
Saturated Solutions
A saturated solution is one that contains as much
solute as the solvent can hold at a given _________.
At 20°C, 203.9 grams of table sugar will dissolve in
100 grams of water. If you add more sugar, it will not
dissolve.
8.2 Solubility and Concentration
Solubility
Unsaturated Solutions
A solution that has____than the maximum amount of
solute that can be dissolved is called an unsaturated
solution.
As long as the amount of solute is less than the
solubility at that temperature, the solution is
unsaturated.
8.2 Solubility and Concentration
Solubility
Supersaturated Solutions
A supersaturated solution is one that contains ____
solute than it can normally hold at a given
temperature.
A solvent can sometimes dissolve more solute than
you might expect, based on its solubility.
If you _______ a solution, more solute may dissolve.
Carefully cool the solution without jarring it and the
extra solute in solution remains.
8.2 Solubility and Concentration
Solubility
Supersaturated solutions are very unstable. When a
single crystal of sodium acetate is added to a
supersaturated solution of sodium acetate in water, the
excess solute rapidly crystallizes.
8.2 Solubility and Concentration
Solubility
Three factors that affect the solubility of a solute are
the polarity of the solvent, temperature, and
pressure.
Polar and Nonpolar Solvents
Oil does not dissolve in water because oil molecules
are _________and water molecules are _______.
Solutions are more likely to form when the solute and
solvent are either ______ polar or ______ nonpolar.
A soap molecule has a polar end, which attracts
water molecules, and a nonpolar end, which attracts
oil.
8.2 Solubility and Concentration
Solubility
Generally, a solute is more likely to dissolve in a “like”
solvent than an “unlike” solvent.
8.2 Solubility and Concentration
Solubility
Soaps and detergents are used to remove
grease and oil stains.
8.2 Solubility and Concentration
Solubility
Temperature
In general, the solubility of _______ increases as the
solvent temperature increases.
In general, gases become ______ soluble as the
temperature of the solvent increases.
8.2 Solubility and Concentration
Solubility
Pressure
Increasing the pressure on a gas _____________ its
solubility in a liquid.
The pressure of CO2 in a sealed 12-ounce can of
soda at room temperature can be ___________times
atmospheric pressure.
8.2 Solubility and Concentration
Concentration of Solutions
The _______________ of a solution is the amount of
solute dissolved in a specified amount of solution.
Concentration can be expressed as percent by
volume, percent by mass, and molarity.
8.2 Solubility and Concentration
Concentration of Solutions
Percent by Volume
Most bottled or canned juices are
made by adding water to natural
fruit juices. These solutions are
less concentrated than natural
fruit juices.
Percent by volume is a way to
measure the concentration of one
_________ dissolved in another.
8.2 Solubility and Concentration
Concentration of Solutions
Percent by Mass
Concentration expressed as a percent by mass is
more useful when the solute is a _______.
Percent by mass is the percent of a solution’s total
mass that is accounted for by solute.
Ex: sugar in water
8.2 Solubility and Concentration
Concentration of Solutions
Molarity
To compare the number of solute particles in
solutions, chemists often use moles to measure
concentration.
Molarity is the number of _____ of a solute dissolved
per liter of solution.
A _______ is the amount of a substance that contains
approximately 6.02 X 1023 particles.