Solution Chemistry & Properties of Water Mixtures Review • Homogeneous – Solutions • Heterogeneous – Suspension - is a fluid containing solid particles that are sufficiently.
Download ReportTranscript Solution Chemistry & Properties of Water Mixtures Review • Homogeneous – Solutions • Heterogeneous – Suspension - is a fluid containing solid particles that are sufficiently.
Slide 1
Solution Chemistry &
Properties of Water
Slide 2
Mixtures Review
• Homogeneous
– Solutions
• Heterogeneous
– Suspension - is a fluid containing solid particles
that are sufficiently large enough to settle.
– Colloid - is a substance microscopically dispersed
evenly throughout another substance.
– Emulsion - is a mixture of two or more immiscible
(unblendable) liquids.
Slide 3
Characteristics of solutions
• Solution – homogeneous mixture
a) parts of a solution
i) solute – substance being dissolved
ii) solvent – substance doing dissolving
both can be either solid, liquid, or gas
Slide 4
Solubility
• Soluble – substance can dissolve in a
solvent
ex: salt in water
• Insoluble – substance cannot dissolve in a
solvent
ex: sand in water
Slide 5
Solvation In Aqueous Solutions
• Solvation – process of surrounding solute
particles with solvent particles
Why are some substances soluble in a
solvent and some others are not?
must be compatibility between solute and
solvent
Slide 6
“like dissolves like”
• Defn – rule used to determine if substance
will dissolve in another
- based on attractive forces between
solute and solvent
Slide 7
“like dissolves like”
• polar solvents – dissolve polar molecular
compounds and ionic compounds
ex: salt and water, alcohol and vinegar
• nonpolar solvents – dissolve nonpolar
compounds only
ex: oil and gasoline
Slide 8
Factors Affecting Rate of Solvation
• How can you dissolve something
faster???
a) increase temp of solvent
this accelerates particles creating more
particle collisions
Slide 9
Factors Affecting Rate of Solvation
b) agitate the solution
more particle collisions between solute
and solvent
c) Increase surface area of solute
breaking into smaller pieces allows more
solute to be in contact w/ solvent
Slide 10
Solubility
• Defn – max amt of solute that can
dissolve in a solvent at a specific temp
how much solute can be put into solvent?
Slide 11
Unsaturated Solution
• Defn – less than max amt of solute
dissolved
if I put sugar into water and all sugar is
dissolved, solution is unsaturated
Slide 12
Saturated Solution
• Defn – contains max amt of solute
dissolved
if I put sugar into water and not dissolves
(you can see the sugar), the solution is
saturated
Slide 13
Supersaturated Solution
• Defn – contains more solute than
saturated solution at the same conditions
a saturated solution made at high temp
cools slowly. Slow cooling allows excess
solute to remain dissolved in solution at
lower temperature
very unstable
Slide 14
Sum up Solubility
UNSATURATED
SOLUTION
more solute
dissolves
SATURATED
SOLUTION
no more solute
dissolves
concentration
SUPERSATURATED
SOLUTION
becomes unstable,
crystals form
Slide 15
Solubility
(g solute/ 100 g H2O)
Solubility Curve
Supersaturated
(above line)
Unsaturated
(below line)
Temperature
SaturatedLine
represents
max amount
solute that
will dissolve
at a given
temperature
Slide 16
Slide 17
How does temp affect solubility?
• The higher the temp, higher the solubility
(for most cases)
Slide 18
Solution Concentration
• Concentration – how much solute
dissolved in amount of solvent
what is difference between concentrated
and diluted?
Slide 19
Concentrated vs. Dilute
Slide 20
Concentration
• 3 different units of concentration
a) percent by mass
b) molarity (M)
c) molality (m)
Slide 21
Colligative Properties of Solutions
• Solutes affect the physical properties of
their solvents
• Colligative properties (defn) – properties
that depend only on the number of solute
particles present, not their identity
• Ex: boiling point, freezing point
Slide 22
Electrolytes
• Defn – substances that break up (ionize)
in water to produce ions; can conduct
electricity
- consist of acids, bases, ionic compounds
Ex: NaCl Na1+ + Cl1H2SO4 2 H+ + SO42-
Slide 23
Nonelectrolytes
• Defn – do not break up (ionize) in water,
they stay the same; doesn’t conduct
electricity
- usually molecular/covalent compounds
Ex: sugar
ethanol
C6H12O6 C6H12O6
C2H5OH C2H5OH
Slide 24
Acids & Bases
Slide 25
Properties
Electrolytes
Electrolytes
Sour Taste
Bitter taste
Turn Litmus Red
Turn Litmus Blue
React with Metals to
Slippery feel
Form Hydrogen gas
Ex. Ammonia,
Ex. Vinegar, milk, soda
lye, antacids,
Apples, citrus fruits
baking soda
ChemASAP
Slide 26
Strength of Acids & Bases
• Strong Acid/Base
–100% ionized in water, comes apart
completely in water
–Strong electrolyte, conducts electricity
–Strong Acids: HCl, HNO3, H2SO4
–Strong Bases: NaOH, KOH
Slide 27
Strength of Acids & Bases
Weak Acid/Base
• Does not ionize completely, does not
come apart completely in water
• Weak electrolyte, does not conduct
electricity well.
• Weak Acids: HF, CH3COOH
• Weak Base: NH3
Slide 28
Neutralization Reactions
Strong acid + Strong base Salt + Water
Ex.
HCl(aq) + NaOH(aq) NaCl(aq)+ H2O
Slide 29
pH
Acids & Bases
Slide 30
The pH Scale
• The pH scale indicates the hydronium ion
concentration, [H3O+]
• In other words how many H3O+ ions are in a
solution. If there are a lot we assume it is an
acid, if there are very few it is a base.
Slide 31
The pH Scale
14
0
7
INCREASING
ACIDITY
NEUTRAL
INCREASING
BASICITY
Slide 32
The pH Scale
pH of Common Substances
Slide 33
Acid/Base Indicators
• An acid-base indicator is a weak acid or a
weak base.
• An Indicator changes color over a range of
hydrogen ion concentrations. This range is
expressed as a pH range.
• Some common indicators are: litmus
paper, cabbage juice, phenolphthalein
bromthymol blue etc.
Slide 34
Acid/Base Indicators -Litmus Paper
• Litmus paper is paper that has been
treated with a specific indicator
• Litmus paper turns red in acidic conditions
(pH < 7)
• Litmus paper turns blue under alkaline
conditions (pH > 7).
Slide 35
Properties of Water
Slide 36
Water is Polar
Water is polar because
oxygen is a “bully” and
does not share the
electrons.
Oxygen is negative with
more electrons and
Hydrogen is positive with
less electrons.
Slide 37
Cohesion
• Cohesion is the
•
attraction of the same
type of molecules to
each other.
Water molecules stick
together and “hold
hands” with hydrogen
bonds
Slide 38
Water is the Universal Solvent
Water is polar and can
dissolve both salts,
sugars, and other
molecules.
Slide 39
Adhesion
• Adhesion is the
•
attraction of
molecules between
two different
substances.
Example: The
attraction of water
molecules to a glass.
Slide 40
Adhesion
Adhesion causes the
water molecules to
stick to the sides of
the graduated
cylinder creating a
meniscus.
Adhesion causes water
to rise in a straw.
Slide 41
Water: Acids and Bases
Acid: pH 0-6.9
Property of water – a
H+ ions
water molecule can
split to form ions and
make acids and
bases.
Base: pH 7.1-14
OH- ions
Solution Chemistry &
Properties of Water
Slide 2
Mixtures Review
• Homogeneous
– Solutions
• Heterogeneous
– Suspension - is a fluid containing solid particles
that are sufficiently large enough to settle.
– Colloid - is a substance microscopically dispersed
evenly throughout another substance.
– Emulsion - is a mixture of two or more immiscible
(unblendable) liquids.
Slide 3
Characteristics of solutions
• Solution – homogeneous mixture
a) parts of a solution
i) solute – substance being dissolved
ii) solvent – substance doing dissolving
both can be either solid, liquid, or gas
Slide 4
Solubility
• Soluble – substance can dissolve in a
solvent
ex: salt in water
• Insoluble – substance cannot dissolve in a
solvent
ex: sand in water
Slide 5
Solvation In Aqueous Solutions
• Solvation – process of surrounding solute
particles with solvent particles
Why are some substances soluble in a
solvent and some others are not?
must be compatibility between solute and
solvent
Slide 6
“like dissolves like”
• Defn – rule used to determine if substance
will dissolve in another
- based on attractive forces between
solute and solvent
Slide 7
“like dissolves like”
• polar solvents – dissolve polar molecular
compounds and ionic compounds
ex: salt and water, alcohol and vinegar
• nonpolar solvents – dissolve nonpolar
compounds only
ex: oil and gasoline
Slide 8
Factors Affecting Rate of Solvation
• How can you dissolve something
faster???
a) increase temp of solvent
this accelerates particles creating more
particle collisions
Slide 9
Factors Affecting Rate of Solvation
b) agitate the solution
more particle collisions between solute
and solvent
c) Increase surface area of solute
breaking into smaller pieces allows more
solute to be in contact w/ solvent
Slide 10
Solubility
• Defn – max amt of solute that can
dissolve in a solvent at a specific temp
how much solute can be put into solvent?
Slide 11
Unsaturated Solution
• Defn – less than max amt of solute
dissolved
if I put sugar into water and all sugar is
dissolved, solution is unsaturated
Slide 12
Saturated Solution
• Defn – contains max amt of solute
dissolved
if I put sugar into water and not dissolves
(you can see the sugar), the solution is
saturated
Slide 13
Supersaturated Solution
• Defn – contains more solute than
saturated solution at the same conditions
a saturated solution made at high temp
cools slowly. Slow cooling allows excess
solute to remain dissolved in solution at
lower temperature
very unstable
Slide 14
Sum up Solubility
UNSATURATED
SOLUTION
more solute
dissolves
SATURATED
SOLUTION
no more solute
dissolves
concentration
SUPERSATURATED
SOLUTION
becomes unstable,
crystals form
Slide 15
Solubility
(g solute/ 100 g H2O)
Solubility Curve
Supersaturated
(above line)
Unsaturated
(below line)
Temperature
SaturatedLine
represents
max amount
solute that
will dissolve
at a given
temperature
Slide 16
Slide 17
How does temp affect solubility?
• The higher the temp, higher the solubility
(for most cases)
Slide 18
Solution Concentration
• Concentration – how much solute
dissolved in amount of solvent
what is difference between concentrated
and diluted?
Slide 19
Concentrated vs. Dilute
Slide 20
Concentration
• 3 different units of concentration
a) percent by mass
b) molarity (M)
c) molality (m)
Slide 21
Colligative Properties of Solutions
• Solutes affect the physical properties of
their solvents
• Colligative properties (defn) – properties
that depend only on the number of solute
particles present, not their identity
• Ex: boiling point, freezing point
Slide 22
Electrolytes
• Defn – substances that break up (ionize)
in water to produce ions; can conduct
electricity
- consist of acids, bases, ionic compounds
Ex: NaCl Na1+ + Cl1H2SO4 2 H+ + SO42-
Slide 23
Nonelectrolytes
• Defn – do not break up (ionize) in water,
they stay the same; doesn’t conduct
electricity
- usually molecular/covalent compounds
Ex: sugar
ethanol
C6H12O6 C6H12O6
C2H5OH C2H5OH
Slide 24
Acids & Bases
Slide 25
Properties
Electrolytes
Electrolytes
Sour Taste
Bitter taste
Turn Litmus Red
Turn Litmus Blue
React with Metals to
Slippery feel
Form Hydrogen gas
Ex. Ammonia,
Ex. Vinegar, milk, soda
lye, antacids,
Apples, citrus fruits
baking soda
ChemASAP
Slide 26
Strength of Acids & Bases
• Strong Acid/Base
–100% ionized in water, comes apart
completely in water
–Strong electrolyte, conducts electricity
–Strong Acids: HCl, HNO3, H2SO4
–Strong Bases: NaOH, KOH
Slide 27
Strength of Acids & Bases
Weak Acid/Base
• Does not ionize completely, does not
come apart completely in water
• Weak electrolyte, does not conduct
electricity well.
• Weak Acids: HF, CH3COOH
• Weak Base: NH3
Slide 28
Neutralization Reactions
Strong acid + Strong base Salt + Water
Ex.
HCl(aq) + NaOH(aq) NaCl(aq)+ H2O
Slide 29
pH
Acids & Bases
Slide 30
The pH Scale
• The pH scale indicates the hydronium ion
concentration, [H3O+]
• In other words how many H3O+ ions are in a
solution. If there are a lot we assume it is an
acid, if there are very few it is a base.
Slide 31
The pH Scale
14
0
7
INCREASING
ACIDITY
NEUTRAL
INCREASING
BASICITY
Slide 32
The pH Scale
pH of Common Substances
Slide 33
Acid/Base Indicators
• An acid-base indicator is a weak acid or a
weak base.
• An Indicator changes color over a range of
hydrogen ion concentrations. This range is
expressed as a pH range.
• Some common indicators are: litmus
paper, cabbage juice, phenolphthalein
bromthymol blue etc.
Slide 34
Acid/Base Indicators -Litmus Paper
• Litmus paper is paper that has been
treated with a specific indicator
• Litmus paper turns red in acidic conditions
(pH < 7)
• Litmus paper turns blue under alkaline
conditions (pH > 7).
Slide 35
Properties of Water
Slide 36
Water is Polar
Water is polar because
oxygen is a “bully” and
does not share the
electrons.
Oxygen is negative with
more electrons and
Hydrogen is positive with
less electrons.
Slide 37
Cohesion
• Cohesion is the
•
attraction of the same
type of molecules to
each other.
Water molecules stick
together and “hold
hands” with hydrogen
bonds
Slide 38
Water is the Universal Solvent
Water is polar and can
dissolve both salts,
sugars, and other
molecules.
Slide 39
Adhesion
• Adhesion is the
•
attraction of
molecules between
two different
substances.
Example: The
attraction of water
molecules to a glass.
Slide 40
Adhesion
Adhesion causes the
water molecules to
stick to the sides of
the graduated
cylinder creating a
meniscus.
Adhesion causes water
to rise in a straw.
Slide 41
Water: Acids and Bases
Acid: pH 0-6.9
Property of water – a
H+ ions
water molecule can
split to form ions and
make acids and
bases.
Base: pH 7.1-14
OH- ions