Notes –
Properties of Water /Chemical
Reactions
v
v
Properties of Water
• Hydrogen Bonds –
Weak forces between
some covalently
bonded molecules
(polar molecules)
Properties of Water
• Properties of Water
• Cohesion – polar
molecules attract and
stick together
• Adhesion – water
molecules stick to
other molecules
• Examples
Surface tension,
capillary action, high
boiling point, water in
sphere droplets, high
heat capacity
(storage)
Fig. 3-3
Adhesion
Water-conducting
cells
Direction
of water
movement
Cohesion
150 µm
Fig. 3-4
Properties of Water
• Properties of Water
• Universal solvent –
More substances
dissolve in water than
any other molecule.
• Solvent – The
substance other
substances dissolve
in.
• Solute – The
substance being
dissolved
Properties of Water
Solutions - Mixtures in
which one or more
substances are
uniformly distributed in
another.
• A Solute is dissolved
in a solvent.
• Examples:
Aqueous solutions
(water solvent), blood
plasma, plant sap,
seawater.
Salt in Water
• Salt in water
dissolves and
becomes positive and
negative ions.
• Saltwater conducts
electricity
• Salt in water
dissolves and
becomes positive
and negative ions.
• Saltwater conducts
electricity
Salt in Water
• Salt in water
dissolves and lowers
the freezing point of
water.
– Ex: Applying salt on
icy roads causes ice to
melt
• Salt in water
dissolves and raises
the boiling point of
water
Salt in Water
• Salt in water dissolves and
lowers the freezing point of
water.
– Ex: Applying salt on icy
roads causes ice to melt
• Salt in water
dissolves and raises
the boiling point of
water
– Ex: Adding salt to
water makes water
boil hotter and cooks
food faster
Solubility – The maximum quantity of a
substance that will dissolve in a certain
quantity of water at a specified temperature
• Solubility curve –
Graphical
representation of the
amount of solute that
dissolves in a given
amount of solvent
Solubility – The maximum quantity of a
substance that will dissolve in a certain
quantity of water at a specified temperature
• Solubility curve –
Graphical
representation of the
amount of solute that
dissolves in a given
amount of solvent
Concentration – How much solute is
dissolved in a specific quantity of solvent or
solution
Solubility can be
measured in :
• per cent % - parts per
hundred
• ppm – parts per
million
• ppb – parts per billion
Solubility - concentrations depend
on the amount/type of solvent and
the temperature
• Saturated – solutions
holding the maximum
amount of solute
• Unsaturated –
solutions holding less
than the max. amount
• Supersaturated –
solutions holding
more than the max
amount of solute
Solubility - concentrations depend
on the amount/type of solvent and
the temperature
• Saturated – solutions
holding the maximum
amount of solute
• Unsaturated –
solutions holding less
than the max. amount
• Supersaturated –
solutions holding
more than the max
amount of solute
Solubility - concentrations depend on
the amount/type of solvent and the
temperature
• Saturated – solutions
holding the maximum
amount of solute
• Unsaturated –
solutions holding less
than the max. amount
• Supersaturated –
solutions holding
more than the max
amount of solute
Solubility
Solubility
• Substances that
dissolve in H2O are
soluble.
• If substances do not
dissolve in water they
are insoluble.
• Substances that
dissolve in water are
ionic compounds or
other polar molecules
Solubility
• Substances that
dissolve in H2O are
soluble.
• If substances do not
dissolve in water they
are insoluble.
• Substances that
dissolve in water are
ionic compounds or
other polar molecules
• Ex: Salts, Alcohol
Solubility
• Nonpolar substances
do not have partial
charges.
• They do not readily
dissolve in water
• Nonpolar substances
include oils,
petroleum products,
kerosene
Solubility
• Nonpolar substances
will dissolve in other
nonpolar substances.
• Ex: Paint thinner for
oil-based paints
• Like dissolves in like
• Soap breaks nonpolar
molecules into
smaller particles to
make them more
soluble in water
Solubility
• Nonpolar substances will
dissolve in other nonpolar
substances.
• Ex: Paint thinner for oil-based
paints
• Like dissolves in like
• Soap breaks nonpolar
molecules into
smaller particles to
make them more
soluble in water
Measuring Solubility
Water Dissociation –
Self Ionization
• Water can break down into
ionized particles
H20 (l) = H+ (aq) + OH- (aq)
H20
+
H+ =
H30 +
Hydronium ion
ACID / BASE
• Acid/Base – Special
compounds containing
excess :
• Hydrogen (H+) (H30+ )
(hydronium) (acids)
or
• Hydroxide (OH-) ions
(charged particles)
dissolved in water
(base)
ACID / BASE
• Acid/Base – Special
compounds
containing excess :
• Hydrogen (H+) (H30+ )
(hydronium) (acids)or
• Hydroxide (OH-) ions
(charged particles)
dissolved in water
(base)
ACID / BASE
• Acid/Base – Special
compounds
containing excess :
• Hydrogen (H+) (H30+ )
(hydronium) (acids)or
• Hydroxide (OH-) ions
(charged particles)
dissolved in water
(base)
• pH = Scale to
measure H+
concentration (-log)
• pH 1= 1/10=1/101 H+
• pH 2 = 1/100=1/102
• pH 3 = 1/1000= 1/103
•
•
pH 1 = highest H+
pH 14= lowest H+
ACID / BASE
•
• Acid/Base – Special
•
compounds
•
•
containing excess :
• Hydrogen (H+) (H30+ ) •
(hydronium) (acids)or •
• Hydroxide (OH-) ions
(charged particles)
dissolved in water
(base)
pH = Scale to measure H+
concentration (-log)
pH 1= 1/10=1/101 H+
pH 2 = 1/100=1/102
pH 3 = 1/1000= 1/103
pH 1 = highest H+
pH 14= lowest H+
ACID / BASE
•
• Acid/Base – Special
compounds
containing excess :
• Hydrogen (H+)
(hydronium) (acids)or
• Hydroxide (OH-) ions
(charged particles)
dissolved in water
(base)
•
•
•
•
•
pH = Scale to measure H+
concentration (-log)
pH 1= 1/10=1/101 H+
pH 2 = 1/100=1/102
pH 3 = 1/1000= 1/103
pH 1 = highest H+
pH 14= lowest H+
Acids
• Made up of molecules
including one or more
hydrogen (H+) (H30+ )
atoms that can be
easily released in
water solutions
• Substances in
common have a sour
taste
• Ex: Lemons, vinegar
Acids
• Made up of molecules
including one or more
hydrogen (H+) (H30+ )
atoms that can be
easily released in
water solutions
• Substances in
common have a sour
taste
• Ex: Lemons, vinegar
• Acids contain (H+)
ions and compounds
are renamed as acids
• Example:
• HCl =
Hydrogen
Chloride
renamed:
Hydrochloric Acid
Acids
Formula name
Acid Name
HCl =
HCl =
H2CO3 =
H2CO3 =
HC2H3O2 =
HC2H3O2 =
HNO3 =
HNO3 =
H3PO4 =
H3PO4 =
H2SO4 =
H2SO4 =
Acids
Formula name
Acid Name
HCl = Hydrogen Chloride
HCl =
Hydrochloric Acid
H2CO3 = Hydrogen Carbonate
H2CO3 = Carbonic Acid
HC2H3O2 = Hydrogen Acetate
HC2H3O2 = Acetic Acid
HNO3 = Hydrogen Nitrate
HNO3 = Nitric Acid
H3PO4 = Hydrogen Phosphate
H3PO4 = Phosphoric Acid
H2SO4 = Hydrogen Sulfate
H2SO4 = Sulfuric acid
Acid / Base
• Acid (H+) (H30+ ) =
Hydronium ion
• pH 1-6
• 1 is strongest , 6 is
weakest
Bases
• Ionic substances that
include (OH-)
hydroxide ions or
generate (OH-) ions
in solution
• In common
substances have a
bitter taste and
slippery feel
• Ex: soap, peppers
Bases
• Ionic substances that
include (OH-)
hydroxide ions or
generate (OH-) ions
in solution
• In common
substances have a
bitter taste and
slippery feel
• Ex: soap, peppers
• Bases keep their
original compound
name
• Ca(OH)2 =
• Mg(OH)2 =
• KOH =
• NaOH =
Bases
• Ionic substances that
include (OH-)
hydroxide ions or
generate (OH-) ions
in solution
• In common
substances have a
bitter taste and
slippery feel
• Ex: soap, peppers
• Bases keep their
original compound
name
• Ca(OH)2 = Calcium Hydroxide
• Mg(OH)2 =
Magnesium
Hydroxide
• KOH = Potassium Hydroxide
• NaOH = Sodium Hydroxide
• Base (OH-) =
Hydroxide ion
• pH 8-14
• 14 is strongest, 8 is
weakest
Acid / Base
• Acid (H+) =
Hydronium ion
• pH 1-6
• 1 is strongest , 6 is
weakest
• Base (OH-) =
Hydroxide ion
• pH 8-14
• 14 is strongest, 8 is
weakest
Neutral pH
• pH 7
• H+ = (OH)- = neutral
H+ + (OH)- =HOH=H2O
Ex: Distilled water
pH indicators
Indicators – show pH
with color changes.
H+ or (OH)concentrations
Ex: Litmus paper,
phenolphthalein
Acid / Base
•
•
•
•
•
Neutralization Equation
Reactants
Products
HCl + NaOH = NaCl + H2O
Acid Base Salt Water
pH1 pH14 pH7 pH7
• Buffer – Baking Soda (HCO3-)
prevents pH change
Acid / Base
• Neutralization Equation
• Reactants
Products
• 1M HCl + 1M NaOH =
1M NaCl + 1M H2O
• Acid + Base = Salt + Water
• pH1 pH14 pH7 pH7
• Buffer – Baking Soda (HCO3-)
prevents pH change
• Titration – adding known quantities
of acids and/or bases together to
determine M or pH quantities