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Mixtures and Solutions
Section 14.1 Types of Mixtures
Section 14.2 Solution
Concentration
Section 14.3 Factors Affecting
Solvation
Section 14.4 Colligative Properties
of Solutions
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Section 14.1 Types of Mixtures
• Compare the properties solute: a substance
of suspensions, colloids, dissolved in a solution
and solutions.
• Identify types of colloids suspension
and types of solutions.
colloid
• Describe the electrostatic Brownian motion
forces in colloids.
Tyndall effect
soluble
Mixtures can be either miscible
heterogeneous or insoluble
homogeneous.
immiscible
Heterogeneous Mixtures
• A heterogeneous mixture is a mixture that
does not have a uniform composition and
in which the individual substances remain
distinct.
• Suspensions are mixtures containing
particles that settle out if left undisturbed.
(Like dirty water)
Heterogeneous Mixtures (cont.)
• Colloids are heterogeneous mixtures of
intermediate sized particles (between 1 nm
and 1000 nm) and do not settle out.
• Colloids are categorized
according to the phases of
their particles.
Heterogeneous Mixtures (cont.)
Heterogeneous Mixtures (cont.)
• The Tyndall effect is when dispersed colloid
particles scatter light.
• Both suspensions and solutions display this.
• Tyndall effect
Homogeneous Mixtures
• Solutions are homogeneous mixtures that
contain two or more substances called the
solute and solvent.
• Most solutions are liquids, but gaseous and
solid solutions exist.
Homogeneous Mixtures (cont.)
Homogeneous Mixtures (cont.)
• A substance that dissolves in a solvent is
soluble.
• Two liquids that are soluble in each other in
any proportion are miscible.
• A substance that does not dissolve in a
solvent is insoluble.
• Two liquids that can be mixed but separate
shortly after are immiscible.
Section 14.1 Assessment
Miscible substances are:
A. two liquids that are not soluble in
each other
B. solids that dissolve in liquids
C. solids that do not dissolve in A. A
liquids
B. B
D. two liquids that are soluble in C. C
each other 0% 0% 0% 0%
D. D
A
B
C
D
Section 14.1 Assessment
The jerky, random movement of particles
in a liquid colloid is known as ____.
A. Brownian motion
B. Tyndall effect
C. Charles’s Law A. A
D. kinetic energy B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
• Self check quizzes
Section 14.2 Solution Concentration
• Describe concentration solvent: the substance
using different units. that dissolves a solute to
form a solution
• Determine the
concentrations of
solutions.
concentration
• Calculate the molarity of molarity
a solution.
molality
mole fraction
Concentration can be expressed in
terms of percent or in terms of moles.
Expressing Concentration
• The concentration of a solution is a
measure of how much solute is dissolved
in a specific amount of solvent or solution.
• Concentration can be described as
concentrated or dilute.
• Many ways to express this
• % by mass or volume
• like D5W which is a 5% sugar solution or
normal saline which is 0.9% sodium
chloride (table salt) in IV solutions
• A volume example is 70% isopropyl
(rubbing) alcohol
Expressing Concentration (cont.)
Expressing Concentration (cont.)
• The equation is
• Mass (or volume) of solute ÷ mass (or
volume) of solution x 100
• How would you make up a normal saline
solution?
• .9 g of NaCl up to 100 mL of water
• Do problems 9-11 page 481
• Check your answers on 1000 10)54.3 g
• Do problems 13,14 page 482 14) 2.1%
Expressing Concentration (cont.)
• Molarity is the number of moles of solute
dissolved per liter of solution.
• Molarity ( M)is a more precise way to do
concentration as it goes by particles not
mass
• Moles of solute ÷ liters (dm3) of solution
• M = mole/liter
• What is the molarity of a normal saline
solution 0.9 g in 100 mL of water solution?
• 0.9 / 58.5 g/mol = 0.0154 100ml
/1000= .1
• 0.154 M
• What is the molarity of a D5W solution 5 g of
dextrose (mm 180) in 100 mL of water ?
•
• 0.278 M
• Do 16-19 page 483
• Answers on page 1000 16) 0.148 M
18) 0.128 M
• How do you make up 500 mL of a 0.25
molar NaCl solution?
• 0.25 mol/L x 0.5 L = 0.125 mol
• 0.125 mol x mm(58.5 g/mol) = 7.31 g of
NaCl
• Put 7.31 g in a volumetric flask and dilute
to 500 mL
• Do problems 20-22 page 484
• Check you answers on page 1000
20) 11g 22) 30. g
•
How many grams of NaCl are dissolved in
500.0 mL of a 0.05M solution of NaCl?
A)0.05 g B)0.29 g C)1.46 g D)2.92 g
• Prepare 500 mL of a 0.1 M HCl solution
using a 12 M stock solution
• M1V1 = M2V2
• 12 M x V1 = 0.1 M x 0.500 L
• V1 = (0.1M x 0.500 L) ÷ 12 M
• Use 0.00417 L or 4.17 mL and
dilute to 500 mL
• Do 24 and 25 page 486
• Answers on page 1000 24) 125 mL
• To avoid the change in volume due to
temperature a unit using mass is used
• m = mol of solute / kg of solvent
• 9.00 grams of NaCl is added to (not
diluted to)500 g of water. What is its
molality
• 9/58.5 mol ÷0.500 kg = 0.171 m
Expressing Concentration (cont.)
• Molality is the ratio of moles of solute
dissolved in 1 kg of solvent.
• Do 27 and 28 page 487 28) 171g answers
on page 1000
Expressing Concentration (cont.)
• Mole fraction is the ratio of the number of
moles of solute in solution to the total
number of moles of solute and solvent.
where XA and XB represent mole fractions of
each substance
We will not test on this
Section 14.2 Assessment
Which is NOT a quantitative measure of
concentration?
A. molarity
B. molality
C. percent by mass A. A
D. dilute B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Section 14.2 Assessment
The number of moles of solute divided by
liters of solvution is called ____.
A. molarity
B. molality
C. percent by volume A. A
D. percent by mass B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
• Self check quizzes
Section 14.3 Factors Affecting Solvation
• Describe how exothermic: a chemical
intermolecular forces reaction in which more
affect solvation. energy is released than
is required to break
• Define solubility. bonds in the initial
reactants
• Understand what
factors affect solubility.
Section 14.3 Factors Affecting Solvation (cont.)
solvation
heat of solution
unsaturated solution
saturated solution
supersaturated solution
Henry’s law
Factors such as temperature, pressure,
and polarity affect the formation of
solutions.
The Solvation Process
• Solvation is the process of surrounding
solute particles with solvent particles to
form a solution.
• Solvation in water is called hydration.
• The attraction between dipoles of a water
molecule and the ions of a crystal are greater
than the attraction among ions of a crystal.
The Solvation Process (cont.)
The Solvation Process (cont.)
• Sucrose molecules have several O–H
bonds, which become sites for hydrogen
bonding with water molecules.
• Oil does not form a
solution with water
because there is
little attraction
between polar
water molecules
and nonpolar oil
molecules.
The Solvation Process (cont.)
• During solvation, the solute must separate
into particles and move apart, which
requires energy.
• The overall energy change that occurs during
solution formation is called the heat of
solution.
Factors That Affect Solvation
• Stirring or shaking moves dissolved
particles away from the contact surfaces
more quickly and allows new collisions to
occur.
• Breaking the solute into small pieces
increases surface area and allows more
collisions to occur.
• As temperature increases, rate of solvation
increases.
Solubility
• Solubility depends on the nature of the
solute and solvent.
• Unsaturated solutions are solutions that
contain less dissolved solute for a given
temperature and pressure than a saturated
solution.
Solubility (cont.)
• Saturated solutions contain the maximum
amount of dissolved solute for a given
amount of solute at a specific temperature
and pressure.
• Solubility is affected by increasing the
temperature of the solvent because the
kinetic energy of the particles increases.
At what temperature is KCl saturated with 46 g? What is the
general trend for solubilities of solids in water?
Solubility (cont.)
• A supersaturated solution contains more
dissolved solute than a saturated solution
at the same temperature.
• To form a supersaturated solution, a
saturated solution is formed at high
temperature and then slowly cooled.
• Supersaturated solutions are unstable.
Solubility (cont.)
Solubility (cont.)
• Gases are less soluble in liquid solvents at
high temperatures.
• Solubility of gases increases as its external
pressure is increased.
• Henry’s law (not tested on this) states that at
a given temperature, the solubility (S) of a gas
in liquid is directly proportional to the
pressure (P).
• Why do pop bottles foam over when they
are warm and you shake them up?
Section 14.3 Assessment
For a given amount, which type of
solution contains the LEAST amount of
solute?
A. solvated
B. saturated
A. A
C. supersaturated
B. B
D. unsaturated C. C
0% 0% 0% 0%
D. D
A
B
C
D
Section 14.3 Assessment
At a given temperature, the solubility of a
gas is directly proportional to what?
A. volume
B. mass
C. molarity A. A
D. pressure B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
• Section quiz
Section 14.4 Colligative Properties of
Solutions
• Describe colligative ion: an atom that is
properties. electrically charged
• Identify four colligative
properties of solutions.
• Determine the boiling
point elevation and
freezing point depression
of a solution.
Section 14.4 Colligative Properties of
Solutions (cont.)
colligative property
vapor pressure lowering
boiling point elevation
freezing point depression
osmosis
osmotic pressure
Colligative properties depend on the
number of solute particles in a
solution.
Electrolytes and Colligative Properties
• Colligative properties are physical
properties of solutions that are affected by
the number of particles but not by the
identity of dissolved solute particles.
• Ionic compounds are electrolytes because
they dissociate in water to form a solution that
conducts electricity.
• Some molecular compounds are also
electrolytes.
Electrolytes and Colligative Properties (cont.)
• Electrolytes that produce many ions in
solution are strong electrolytes.
Vapor Pressure Lowering
• Adding a nonvolatile solute to a solvent
lowers the solvent’s vapor pressure.
• When a solute is present, a mixture of solvent
and solute occupies the surface area, and
fewer particles enter the gaseous state.
• The greater the number of solute particles,
the lower the vapor pressure.
Vapor Pressure Lowering (cont.)
• Vapor pressure lowering is due to the
number of solute particles in solution and is
a colligative property of solutions.
Boiling Point Elevation
• When a nonvolatile solute lowers the vapor
pressure of a solvent, the boiling point is
also affected. (elevated)
• More heat is needed to supply additional
kinetic energy to raise the vapor pressure to
atmospheric pressure.
Freezing Point Depression
• At a solvent's freezing point temperature,
particles no longer have sufficient kinetic
energy to overcome interparticle attractive
forces.
• The freezing point
of a solution is
always lower than
that of the pure
solvent.
Freezing Point Depression (cont.)
• Solute particles interfere with the attractive
forces among solvent particles.
• A solution's freezing point depression is the
difference in temperature between its freezing
point and the freezing point of the pure
solvent.
Osmotic Pressure
• Osmosis is the diffusion of a solvent
through a semipermeable membrane.
Osmotic Pressure (cont.)
• Osmotic pressure is the amount of
additional pressure caused by water
molecules that moved that moved into the
concentrated solution.
Section 14.4 Assessment
Nonvolatile solutes ____ the vapor
pressure of a solution.
A. increase
B. decrease
C. do not change A. A
D. unpredictably change B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Section 14.4 Assessment
Colligative properties of a solution
depend on:
A. the type of solute
B. the type of solvent
C. the vapor pressure of the A. A
solvent
B. B
D. the number of particles of C. C
solute 0% 0% 0% 0%
D. D
A
B
C
D
• Section 4 quiz
Chemistry Online
Study Guide
Chapter Assessment
Standardized Test Practice
Image Bank
Concepts in Motion
Chemistry Online
Study Guide
Chapter Assessment
Standardized Test Practice
Image Bank
Concepts in Motion
Section 14.1 Types of Mixtures
Key Concepts
• The individual substances in a heterogeneous
mixture remain distinct.
• Two types of heterogeneous mixtures are suspensions
and colloids.
• Brownian motion is the erratic movement of colloid
particles.
• Colloids exhibit the Tyndall effect.
• A solution can exist as a gas, a liquid, or a solid,
depending on the solvent.
• Solutes in a solution can be gases, liquids,
or solids.
Section 14.2 Solution Concentration
Key Concepts
• Concentrations can be measured qualitatively and
quantitatively.
• Molarity is the number of moles of solute dissolved per
liter of solution.
• Molality is the ratio of the number of moles of solute
dissolved in 1 kg of solvent.
Section 14.2 Solution Concentration
(cont.)
Key Concepts
• The number of moles of solute does not change during a
dilution.
M1V1 = M2V2
Section 14.3 Factors Affecting
Solvation
Key Concepts
• The process of solvation involves solute particles
surrounded by solvent particles.
• Solutions can be unsaturated, saturated, or
supersaturated.
• Henry’s law states that at a given temperature, the
solubility (S) of a gas in a liquid is directly proportional
to the pressure (P) of the gas above the liquid.
Section 14.4 Colligative Properties
of Solutions
Key Concepts
• Nonvolatile solutes lower the vapor pressure of a
solution.
• Boiling point elevation is directly related to the
solution’s molality.
∆Tb = Kbm
• A solution’s freezing point depression is always lower
than that of the pure solvent.
∆Tf = Kfm
• Osmotic pressure depends on the number of solute
particles in a given volume.
When dispersed solids in a colloid scatter
light, it is known as ____.
A. Tyndall effect
B. Brownian motion
C. Henry’s law A. A
D. Charles’s law B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Molality is:
A. the number of moles of solute divided
by liters of solution
B. the volume of solute divided by
liters of solution
A. A
C. the volume of solute divided
by the volume of solution
B. B
C. C
D. the number of moles of solute 0% 0% 0% 0%
divided by kg of solvent D. D
A
B
C
D
Which is NOT a type of solution?
A. saturated
B. unsaturated
C. polyunsaturated
A. A
D. supersaturated
B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
The addition of a nonvolatile solute to a
solution:
A. increases the freezing point
of the solution
B. increases the vapor pressure
of the solution A. A
C. lowers the boiling point of
B. B
the solution C. C
0% 0% 0% 0%
D. decreases vapor pressure of D. D
A
B
C
D
the solution
Solutes in a solution can be:
A. liquids only
B. liquids and solids only
C. gases and solids only
A. A
D. gases, liquids, or solids
B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Which is NOT an intensive physical
property?
A. volume
B. hardness
C. density A. A
D. mass B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Cl2(g) + 2NO(g) → 2NOCl is what type of
reaction?
A. dehydration
B. synthesis
C. fusion A. A
D. replacement B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
If 8 mol of H2 is used, how many moles of
Fe will be produced?
Fe3O4(s) + 4H2 →3Fe(s) + 4H2O(l)
A. 2
B. 3 A. A
C. 4 B. B
D. 6 C. C
0% 0% 0% 0%
D. D
A
B
C
D
Which is NOT a colligative property?
A. heat of solution
B. boiling point elevation
C. vapor pressure lowering
A. A
D. freezing point depression
B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Nonvolatile solutes _____ the boiling
point of a solution.
A. increase
B. decrease
C. do not change A. A
D. unpredictably change B. B
C. C
0% 0% 0% 0%
D. D
A
B
C
D
Click on an image to enlarge.
Table 14.2 Types and Examples of Solutions
Figure 14.10 Dissolution of Compounds
Figure 14.19 Strong, Weak, and Non-Electrolytes
Figure 14.23 Osmosis
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