DO NOW
What is a solution?
AGENDA
 Introduction to
solutions
 Solutions vocabulary
REMINDERS

What do the following pictures
have in common?
Air
Salt water
Bronze
(copper + tin)
They are all “solutions…” A solution is a homogeneous
mixture in a single phase…
Review
 Element—substance that cannot be broken
down into simpler substances (periodic
table)
 Compound—a substance made of atoms of
more than one element bound together
(H2O, CO2, NaCl)
 Mixture—a combination of more than one
pure substance (Salt water, Powerade,
Salad)
Mixture Review
 Mixture—a physical blend of two or more
substances
 Heterogeneous mixture—one that is not
uniform in composition
 Homogeneous mixture—one that has a
completely uniform composition
Homogenous Mixture
 Homogeneous mixture—one that has a
completely uniform composition

Alloy – uniform mixture of two metals

Amalgam (silver + mercury), steel (iron + carbon)
Mixture Review
Mixture REVIEW
 You can separate mixtures by PHYSICAL
means



Distillation
Separation
Chromatography
Polarity
 Polar molecules

one end of a molecule is slightly positive
and the other end is slightly negative
Unequal sharing of electrons
 Nonpolar molecules

charges are equal and cancel out each
other
Equal sharing of electrons
Water
 Water is a polar molecule!
p. 398
summary
Solutions
Colloid
Type
Particle
size
Settle
Tyndall
upon
effect
standing (Scatter
light)
Homogeneous
0.01-1 nm
No (cannot no
Heterogeneous
1-1000 nm No (cannot Yes
Suspension Heterogeneous
be filtered)
be filtered)
Greater
than 1000
nm
Yes (can be sometimes
filtered)
Solution Chemistry
 Solution—a homogeneous mixture


1. Solute—dissolved particles in a solution
2. Solvent—the dissolving medium in a
solution (usually water, the universal solvent)
Kool-Aid Solution
 Kool-Aid Juice is the SOLUTION
 Kool-Aid powder and Sugar are the
SOLUTES
 Water is the SOLVENT
Solutions are homogeneous mixtures
that could be solid, liquid, or gaseous
solute solvent
Gas
Gas
Gas
Liquid CO2 in water
Liquid Gas
Oxygen in nitrogen
Water in air
Liquid Liquid Alcohol in water
Liquid Solid
Solid
Mercury in silver and
tin (dental amalgam)
Liquid Sugar in water
Solid
Solid
Copper in nickel
(alloys)
Soluble vs. Insoluble
 Soluble—dissolves completely so that
solution looks transparent (free of any
floating particles
 Insoluble—does not dissolve completely;
solution is cloudy
How does dissolving takes place?
 What happens when salt is dissolved in
water?
NaCl  Na+ + Cl-
Complete the dissociation of the
following salts:
 KCl 
 MgCl2
 AlCl3
 MgF2
*
Complete the dissociation of the
following acids:
 HCl 
 HBr
 HC2H3O2
 HNO3
*
Solution Chemistry
 Electrolytes—compounds that conduct an
electric current

ALL ionic compounds; NaCl, CuSO4, NaOH
 Nonelectrolytes—Compounds that do not
conduct an electric current in either aqueous
solution or the molten state

Many molecular (covalent) compounds; carbon,
sugar, alcohol
Electrolytes vs. Nonelectrolytes
Electrolytes vs. Nonelectrolytes
 Weak Electrolyte—only a fraction of the
solute exists as ions; partially dissociate
 Strong Electrolyte—almost all the solute
exists as separate ions; completely
dissociate
Strong electrolyte
in solution.
Weak Electrolyte in
solution.
Electrolytes vs. Nonelectrolytes
 STRONG ELECTROLYTES
 Strong acids (HCl, H2SO4, HNO3, HBr, HI,
HClO4)
 Strong bases (NaOH, KOH, etc.)
 WEAK ELECTROLYTES
 Weak acids (Vinegar, acetic acid, CH3COOH)
 Weak bases (Ammonia, NH3)
 NONELECTROLYTES
 Molecular compounds
 Nonmetal bonded to nonmetal
Electrolytes vs. Nonelectrolytes
 More moles of ions in solutions, the more
conductivity
 Which salt would give more ions: NaCl or
MgCl2?
 So, which will conduct electricity more/be a
better electrolyte?
 Look back at the dissociation reactions and
determine the better electrolyte.
Solubility
 Solubility—the amount that dissolves in a
given quantity of a solvent at a given
temperature to produce a saturated solution.

Solubility is often expressed in grams of solute
per 100g of solvent
Water and Solubility?
 REMEMBER water is a POLAR molecule

Polar means electrons are not spread evenly
throughout the molecule
 Polar molecules dissolve polar molecules

Water can dissolve ammonia
 Nonpolar molecules dissolve nonpolar
molecules

Octane (gasoline) can dissolve CO2
 LIKE DISSOLVES LIKE!!!!
Solution Concentration
 Concentration—the quantity of solute
dissolved in a given quantity of solution

Three ways to describe a solution
Unsaturated solution
 Saturated solution
 Supersaturated solution

Solubility
 Unsaturated—a solution that contains less
solute than solvent
 Saturated—a solution that contains the
maximum amount of solute for a given
amount of solvent at a constant temperature
 Supersaturated—a solution that contains
more solute than it can theoretically hold at a
given temperature; crystals form
Solubility
 Two liquids are said to be MISCIBLE if they
dissolve in each other

Water and ethanol dissolve in each other
 Liquids that are insoluble in each other are
IMMISCIBLE.

Oil and water do not dissolve in each other
MISCIBLE
Water and alcohol
IMMISCIBLE
Water and oil
Gas Solubility
 Henry’s Law—as the pressure of the gas
above the liquid increases, solubility of the
gas increases and vice versa
Gas Solubility
 Henry’s Law
S1
P1
=
S2
P2
 S = solubility
 P = Pressure
Gas Solubility and temperature
 As temperature increases, the solubility of a
gas tends to decreases.
Factors Affecting Rate of
Dissolving of solid solutes
 SURFACE AREA

Solutes with larger surface area dissolves faster

Smaller pieces = larger surface area
 Smaller pieces dissolve faster than larger pieces
Factors Affecting Rate of
Dissolving of solid solutes
 STIRRING

Stirring or shaking a solution helps the solute
dissolve faster

Stirring or shaking moves dissolved sugar away from
undissolved sugar crystals
Factors Affecting Rate of
Dissolving of solid solutes
 TEMPERATURE

Solid solutes dissolve faster when the solvent is
hot (except gases !)

When substance is heated, particles move faster
causing more collisions between particles
Solubility Curves
 Solubility curves (graphs) give the solubility
and temperature of a saturated solution.
 Solubility is on y-axis
 Temperature (°C) is on x-axis
Solubility Curve
Solubility Curves
 SATURATED solution is ON line or curve
 UNSATURATED solution is BELOW line
or curve
 SUPERSATURATED solution is above line
or curve
Colligative Properties
 Properties that depend on the solution
concentration of solute particles but NOT
their identity… i.e. the addition of ANY
solute will affect the property (ionic
compounds usually more of an effect than
molecular)
Colligative Properties examples
Vapor Pressure – pressure caused by molecules
that have escaped the liquid phase;
nonvolatile solutes will lower the vapor
pressure; the addition of a solute prevents as
many water molecules from leaving
Vapor Pressure, cont’d
 Volatile Substances will increase vapor
pressure (volatile means that it evaporates
easily – volatile substances like acetone will
increase vapor pressure when mixed with
water)
Freezing Point Depression
 Adding a solute to water will LOWER the
freezing point –
 The ocean freezes at -2.2oC because of the
added salt
 Antifreeze is added to car radiators in the
winter to prevent from freezing
 Electrolytes have more of an impact than
non-electrolytes do
Boiling Point Elevation
 The boiling point is raised when a solute is
added to water
 Again, electrolytes will affect this more than
non-electrolytes do
Precipitation Reactions
 Double Replacement reaction in which an
insoluble product is formed
 AC + BD  AD(s) + BC(aq)