Solutions
I. What is a solution?
A solution is a
homogeneous
mixture of 2 or more
substances in a single
phase.
One constituent is
usually regarded as the
SOLVENT and the
others as SOLUTES.
solute
solvent
Parts of a Solution
 SOLUTE – the part of a solution that is being
dissolved (usually the lesser amount)
 SOLVENT – the part of a solution that dissolves the
solute (usually the greater amount)
 Solute + Solvent = Solution
Solution
Solvent
Solute
Soluble/Insoluble vs. Miscible/Immiscible
 SOLUBLE – a substance
that can be dissolved.
 INSOLUBLE – a substance
that CANNOT be dissolved
 MISCIBLE – a liquid
substance that is soluble in
Immiscible
another liquid.
 IMMISCIBLE – a liquid
substance that is insoluble
in another liquid.
Miscible
Types of Solutions
1. Gaseous solutions
2. Liquid solutions
3. Solid solutions--alloys
Types of Solutions
Examples
Gas in a Gas
Gas in a Liquid
Liquid in a Liquid
Solid in a Liquid
Solids in Solids





Air
Soda
Gasoline
Sea Water
Brass
Non-Examples
salad
soil
water
Which solution has the greatest,
the least and no concentration of
solute?
Nature of Solutes in Solutions
 Spread evenly throughout the solution
 Cannot be separated by filtration
 Can be separated by evaporation
 Not visible, solution appears transparent
 May give a color to the solution
8
Water is the universal solvent
because more substances dissolve
in water than in any other
chemical.
This has to do with the polarity of
each water molecule.
Molecular Polarity
Nonpolar molecules:
-- e– are shared equally
e.g., fats and oils
Polar molecules:
-- e– NOT shared equally
e.g., water
H
H–C–H
H–C–H
H–C–H
H–C–H
H
H
H
O
Water Molecules
 Are polar because O is more
electronegative than H
 Gives O a partial negative
charge.
 Form strong intermolecular
hydrogen bonds.
 Water molecules are
attracted to one another
better than other molecules
its size.
Hydrogen bonding
animation
Hydrogen bonding
occurs because of
polarity
One water molecule
bonds to another.
12
What is, or is not, soluble in H20?
Like Dissolves Like
 “Polar solvents dissolve ionic compounds and polar
molecules
 Water is polar therefore it can dissolve
NaCl
 Copper (II) sulfate
 NaOH
 Nonpolar solvents dissolve nonpolar compounds
 Oil is nonpolar, which is why oil and water separate

Which of these sugar cubes will
dissolve the fastest and how do
you know?
Animations of the Solvation
(Animation of a Solute Dissolving)
While you watch each video clip, record your
observations on your notes.
Animation of Salt Dissolving in Water
Animation of Sugar Dissolving in Water
Aqueous Solutions
How do we know ions are
present in aqueous solutions?
The solutions can
electricity
conduct
They are called
ELECTROLYTES
Examples:
HCl, MgCl2, and NaCl
Types of solutes
high conductivity
Strong Electrolyte 100% dissociation,
all ions in solution
Na+
Cl-
Types of solutes
slight conductivity
Weak Electrolyte partial dissociation,
molecules and ions in
solution
CH3COOH
H+
CH3COO-
Types of solutes
no conductivity
Non-electrolyte No dissociation,
all molecules in
solution
sugar
Electrolyte vs. Non-Electrolyte
Salt
(Ionic Solids)
Broke apart into
ions
Was able to light
the light bulb
an electrolyte
Can Conduct an
Electric Current
Sugar
(Covalent Solids)
Both
Water is
the solvent.
Forms a
solution
Broke apart into
whole molecules
Did not light the
light bulb
a non-electrolyte
Can’t Conduct an
Electric Current
1. Break apart into whole molecules or Breaks apart into ions.
2. Able to light the bulb or Not able to light the bulb
3. Is a non-electrolyte or Is an electrolyte
4. Cannot conduct electricity or Can conduct electricity.
Electrolyte vs. Non-Electrolyte
An electrolyte is a substance when dissolved in water can
conduct an electric current.
A non-electrolyte is a substance when dissolved in water can’t
conduct an electric current.
Rate of Solution = How Fast
Exploration
1) To an empty 250mL beaker, add approximately
100mL of warm-hot water from a hot plate.
2) To an empty 250mL beaker, add approximately
100mL of ice water. Be sure to leave the ice behind!

3) Add a sugar cube to each of the 250mL beakers.
Observe what happens.
4) Record your observations on your notes.
5) List other ways that you believe that you could make
a solute dissolve more quickly.
Electrolytes in the Body
 Carry messages to
and from the brain as
electrical signals
 Maintain cellular
function with the
correct
concentrations
electrolytes
Make your own
50-70 g sugar
One liter of warm water
Pinch of salt
200ml of sugar free fruit
squash
Mix, cool and drink
Rate of Solution
What are ways that you make a solute dissolve
faster in water?
1) Increase the temperature.
2) Crush or use smaller size solute particles.
3) Stir the solutions.
Solubility = How Much
Type of Solute
Temperature
Pressure
Solid Solute
Solubility generally
increases as
temperature increases.
Pressure has no effect
on the solubility of a
solid.
Gaseous Solute
Solubility generally
decreases as
temperature increases.
Solubility generally
increases as pressure
increases.
Gases and Solubility
 Effect of pressure on
gas solubility.
 Sudden release of
pressure from a
carbonated beverage.
Types of Solutions
There are three ways to classify a
solution.
1) Unsaturated Solutions
2) Saturated Solutions
3) Supersaturated Solutions
Types of Solutions
Type of Solution
Description
Picture
Relation to
Solubility Curve
Unsaturated
A solution in which
more solute can
dissolve
Below the
Line
Saturated
A solution in which
contains the
maximum amount
of solute
On the
Line
Supersaturated
A solution in which
contains more than
the maximum
amount of solute
Above the
Line
Supersaturated
 The solution is holding more solute than it should be
able to. This is achieved by heating the solution and
then cooling it slowly.
 Examples: rock candy, southern style sweet tea,
chemical heat packs
 Supersaturated solutions are unstable. The
supersaturation is only temporary
Supersaturated
Solubility Curves
Solubility indicates the amount
of solute that will dissolve in a
given amount of solvent at a
specific temperature.
For this curve,
 X-Axis
 Temperature
 Y-Axis
 How Much Solute Dissolves in 100g of
Water
 Various Lines
 Each line represents a different solute.
Solubility Curves
Supersaturated
Saturated
CO2
Unsaturated
Using an available solubility
curve, classify as
unsaturated, saturated,
or supersaturated.
1. 80 g NaNO3 @ 30oC
unsaturated
per 100 g H2O
2. 45 g KCl @ 60oC
saturated
3. 30 g KClO3 @ 30oC
supersaturated
4. 70 g Pb(NO3)2 @ 60oC
unsaturated
Describe each situation below.
5.
Per 100 g H2O,
100 g NaNO3 @ 50oC.
unsaturated;
all solute dissolves;
clear solution.
6. Cool solution (A) very
slowly to 10oC.
supersaturated;
extra solute remains
in solution; still clear
7. Quench solution (A) in
an ice bath to 10oC.
saturated; extra solute (20 g)
can’t remain in solution and becomes visible
How to use a solubility graph?
A.
IDENTIFYING A SUBSTANCE ( given the
solubility in g/100 cm3 of water and the temperature)
• Look for the intersection of the
solubility and temperature.
Using Solubility Curves
8. How much KNO3 would dissolve in
100g of water at 50oC?
84g
9. How much NH4Cl would dissolve in
200g of water at 70oC?
120g
10. At what temperature would 22g
of KCl be able to dissolve in 50g of
water?
68oC
11. Which is more soluble (has a
higher solubility) at 40oC?


NH3
KClO3
Learning Check :
12. What
substance has a
solubility of 90
g/100 cm3 in water
at a temperature
of 25ºC ?
Learning Check :
13. What substance
has a solubility of
200 g/100 cm3 of
water at a
temperature of
90ºC ?
Look for the temperature or solubility
•Locate the solubility curve needed and
see for a given temperature, which
solubility it lines up with and visa versa.
Learning Check:
14. What is the
solubility of
potassium
nitrate at 80ºC ?
• 14. What is the
solubility of
potassium
nitrate at 80ºC ?
Learning Check :
15. At what
temperature will
sodium nitrate have
a solubility of 95
g/100 cm3 ?
Learning Check:
15. At what
temperature will
sodium nitrate have
a solubility of 95
g/100 cm3 ?
Learning Check:
16. At what
temperature will
potassium iodide
have a solubility of
230 g/100 cm3 ?
Learning Check:
17. At what
temperature will
potassium iodide
have a solubility of
130 g/100 cm3 ?
Using Solubility
Curves:
18. What is the
solubility of sodium
chloride at 25ºC in 100
cm3 of water ?
From the solubility
graph we see that
sodium chlorides
solubility is 36 g.
SOLUBLE OR INSOLUBLE?
 Soluble:
 able to be dissolved
 Insoluble:
 does not dissolve in solution (or water)
 Precipitate:
 an insoluble solid formed when two
solutions are mixed
Soluble compounds contain…
Insoluble compounds contain…
For these compounds, common exceptions are
INSOLUBLE.
For these compounds, common exceptions are
SOLUBLE.
Double Replacement reactions
AB + CD  AD + CB
NaCl + AgNO3  NaNO3 + AgCl
Concentration of Solute
The amount of solute in a solution is given by
its concentration.
Molarity
(M)
=
moles solute
liters of solution
PROBLEM: Dissolve 5.00 g of NiCl2•6 H2O in enough water
to make 250 mL of solution. Calculate the Molarity.
Known
Mass=5 g
Volume = 0.250 L
Unknown
Molarity of
NiCl2•6 H2O ?
Analysis
molar mass = 237.7 g
M= n/ V;
Step 1: Calculate moles of NiCl2•6H2O
5.00 g •
1 mol
= 0.0210 mol
237.7 g
Step 2: Calculate Molarity
0.0210 mol
= 0.0841 M
0.250 L
[NiCl2•6 H2O ] = 0.0841 M
MOLARITY PROBLEM
What mass of oxalic acid, H2C2O4, is required to make
250. mL of a 0.0500 M solution?
Known
Volume = 0.250 L
M = 0.0500 moles/L
Unknown
g of H2C2O4,?
Analysis
molar mass = 90.00 g
M= mol/ V;
Step 1: Calculate moles of H2C2O4
(0.0500 mol/L) x (0.250 L) = 0.0125 moles
Step 2: Convert moles to grams
0.0125 mol H2C2O4 x (90.00 g/mol) = 1.13 g H2C2O4
1 mol H2C2O4
Learning Check
How many grams of NaOH are required
to prepare 400. mL of 3.0 M NaOH
solution?
1) 12 g
2) 48 g
3) 300 g