Solutions
Applied Chemistry 4.0
Background to Solutions

A solution is a homogenous mixture that has
different substances dissolved in it that cannot
be seen.
This results in a single physical state.

Parts of a solution
 Solute: substance that is dissolved
…present in smaller amount

Solvent: substance that does the
dissolving
…present in larger amount
Parts of a Solution
Solvent
Solute
Homogeneous
Mixture
SOLUTION
Properties of Solutions

Small particles

Evenly distributed particles (uniform)

Particles will not separate when at rest

The ability to dissolve (solubility)

Dissolving Salt Animation
Background (cont.)

Soluble means something can be dissolved
in something else.

Insoluble mean something cannot be
dissolved in something else.

Dissolving a solid in a liquid can affect the
boiling point and freezing point. This is
called a colligative property.
Types of Solutions
Solid Solutions

Solid solution – final phase is solid

Alloys: Solid solutions containing two or more
metals or a metal and a nonmetal

Advantages of alloys over pure metals:
 Stronger
 Cheaper
 More resistant to corrosion
 Lighter
 Harder
Examples of Alloys
Brass is an alloy of
copper and zinc.
Steel is an alloy of
carbon and iron.
Bronze is an alloy of
copper and tin.
A closer look at alloys
Types of Solutions
Gaseous and Liquid Solutions

Gaseous Solutions – final phase is gas
 Ex. Air

Liquid Solutions – final phase is liquid
 Miscible liquids: Can mix in all proportions
(ex. alcohol and water)

Immiscible liquids: Cannot mix in all
proportions (ex. oil and water)
Miscible Liquids
Immiscible Liquids
Types of Solutions
Aqueous Solutions

Solutions with water as the solvent.

Because water can dissolve so many
things, it is called the Universal
solvent.

Electrolyte – a solution that
conducts electricity.
Example of an electrolyte
Other types of solutions




Tincture: Solutions with alcohol as the
solvent (ex – herbal medicines)
A saline solution is a solution of salt and
water.
 The solute is salt.
 The solvent is water.
A dilute solution is a solution with little
solute.
A concentrated solution is a solution
with a lot of solute.
Concentration

A measure of the amount of solute in a
solution.

% Concentration = mass of solute x 100
mass of solution

Usually used for concentrated solutions.
Example: Salt water is prepared by
mixing 3g of salt with 97g of water.
Calculate % concentration.
3g

Mass of solute:

Mass of solvent:
97 g

Mass of solution:
(solvent + solute)
100 g
% Con:
3 x
100
(water)
= 3%
100
Dilution: to decrease the concentration by
adding more solvent
Parts per million (ppm)
-Usually used with dilute solutions.

One hundred
or
100

One hundredth
1000
or
1/100

One million
One millionth
1/1,000,000
1 ppm
One thousandth
1/1000
or
1,000,000

One thousand
One billion
1,000,000,000
or
One billionth
1/1,000,000,000
1 ppb
Parts per million

Sea water is a 3% solution.

Means: 3 grams of salt to 100 grams
of sea water or 3 parts salt to 100
parts sea water

Looks like: 3/100 dilution
(keep as a fraction)
ppm Examples

Food coloring is a 10% aqueous solution.

Means:10 grams of pigment to 100 grams of solution
or 10 parts pigment to 100 parts of solution

Looks like: 10/100 dilution or 1/10 dilution
Other examples of ppm & ppb




1 ppm is 1 second
in 12 days.
1 ppm is one
minute in two
years.
1 ppm means 1
penny in $10,000.
1 ppm means one
inch in 16 miles.




1 ppb is 1 second
in 11,574 days.
1 ppb is one
minute in 32
years.
1 ppm means 1
penny in
$10,000,000.
1 ppb means one
inch in 16,000
miles.
Solubility and the Dissolving Process

Solubility is a physical property that gives the
grams of solute that will dissolve in a solvent
(usually water) at a given temperature and pressure.

Saturated: A solution is saturated if it contains as
much solute as can possibly be dissolved under
existing conditions of temperature and pressure.

Unsaturated: Has less solute than the maximum
amount that can be dissolved.

Supersaturated: Has more solute than the
maximum amount that can be dissolved.
Solution Video
(G drive)
Unsaturated vs. Saturated
Solution
Supersaturated Solutions
Supersat
Video
Sodium
Thiosulfate
Sodium
Acetate
Supersat
Sodium Acetate
(on G drive)
Three Factors Affecting the Rate of
Dissolving

Surface Area – increases the number of
collisions between the solute and solvent


Stirring – increases the number of collisions
between the solute and solvent.


Sugar cube vs. sugar crystals
Stirring sugar in coffee/tea
Temperature – increases the energy of the
collisions between the solute and solvent.

Warm water vs. cold water
Solubility Graph for NaNO3
180
Saturated sol’n
170
160
90 g
What is the solubility at
70oC?
135 g/100 g water
What kind of solution is
formed when 90 g NaNO3 is
dissolved in 100 g water at
30oC?
unsaturated
What kind of solution is
formed when 120 g NaNO3
is dissolved in 100 g water
at 40oC?
supersaturated
Supersaturated
solution
150
140
130
120
Solubility ( g/100 g water )
At 20oC, a saturated
solution contains
how many grams of
NaNO3 in 100 g of
water?
110
100
90
80
Unsaturated solution
70
60
50
40
30
20
10
0
0
10
20
30
40
50
60
70
Temperature (deg C)
80
90
100
110
Solubility Graph for NaNO3
At 20°C, a saturated solution
contains how many grams of
NaNO3 in 100 g of water?
180
170
160
150
140
What is the solubility at 70oC?
130
What kind of solution is formed
when 90 g NaNO3 is dissolved in
100 g water at 30oC?
Solubility ( g/100 g water )
120
110
100
90
80
70
60
50
40
What kind of solution is formed
when 120 g NaNO3 is dissolved
in 100 g water at 40oC?
30
20
10
0
0
10
20
30
40
50
60
70
Temperature (deg C)
80
90
100
110