General orrganic and biological chemistry structures off liffe 5th CH9 solutions GOB structures 5th ed

Lecture Presentation

Chapter 9
Solutions

Karen C. Timberlake
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chapter 9 Solutions
A dialysis nurse informs
Michelle that
• her side effects are due to
her body’s inability to
regulate the amount of
water in her cells.
• the amount of water in her
body fluids is regulated by
the concentration of
electrolytes and the rate at
which waste products are
removed from her body.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Chapter 9 Readiness
Key Math Skills
• Calculating a Percentage (1.4C)
• Solving Equations (1.4D)
• Interpreting a Line Graph (1.4E)
Core Chemistry Skills
• Writing Conversion Factors from Conversion
Equalities (2.5)
• Using Conversion Factors (2.6)
• Identifying Attractive Forces (6.8)
• Using Mole–Mole Factors (7.6)
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


9.1 Solutions
Solutions
• are homogeneous mixtures of
two or more substances.
• form when there is sufficient
attraction between the solute and
solvent molecules.
• have two components: the
solvent, present in a larger
amount, and the solute, present
in a smaller amount.
Learning Goal Identify the solute and solvent in a solution;
describe the formation of a solution.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutes
Solutes
• may be a liquid, gas, or solid.
• are spread evenly throughout the solution.
• mix with solvents so the solute and solvent
have the same physical state.
• cannot be separated by filtration, but they can
be separated by evaporation.
• are not visible, but they can give a color to the
solution.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutes

A solution of copper(II) sulfate (CuSO4) forms as particles of
solute dissolve and become evenly dispersed among the solvent
(water) molecules.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Types of Solutes and Solvents

Solutes and solvents may be solids, liquids, or gases.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Water as a Solvent
Water
• is one of the most common solvents in nature.
• is a polar molecule due to polar O–H bonds.
• molecules form hydrogen bonds important in many biological
compounds.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Formation of Solutions
Solutions form when the
solute–solvent
interactions are large
enough to overcome the

solute–solute
interactions and the
solvent–solvent
interactions.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutions, Like Dissolves Like
Solutions will form when the solute and solvent have
similar polarities: “like dissolves like.”

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutions with Ionic Solutes
NaCl crystals undergo
hydration as water molecules
surround each ion and pull it
into solution.
H2O(l)

NaCl(s) → Na+(aq) + Cl–(aq)
solid

separate ions

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutions with Polar Solutes
A polar molecular compound such as methanol,
CH3—OH, is soluble in water because methanol has
a polar –OH group to form hydrogen bonds with water.
Polar solutes require polar solvents for a solution
to form.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutions with Nonpolar Solutes
Compounds containing nonpolar molecules, such as
iodine (I2), oil, or grease, do not dissolve in water
because there are essentially no attractions between
the particles of a nonpolar solute and the polar
solvent.
Nonpolar solutes require nonpolar solvents for a
solution to form.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check
Identify the solute in each of the following
solutions.
A. 2 g of sugar and 100 mL of water
B. 60.0 mL of ethyl alcohol and 30.0 mL of
methyl alcohol
C. 55.0 mL of water and 1.50 g of NaCl
D. Air: 200 mL of O2 and 800 mL of N2

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution
Identify the solute in each of the following solutions.
A. 2 g of sugar and 100 mL of water
The solute is sugar.
B. 60.0 mL of ethyl alcohol and 30.0 mL of methyl alcohol
The solute is methyl alcohol.
C. 55.0 mL of water and 1.50 g of NaCl
The solute is NaCl.

D. Air: 200 mL of O2 and 800 mL of N2
The solute is O2.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check
When solid LiCl is added to water it dissolves because
A. the Li+ ions are attracted to the
1) oxygen atom ( −) of water.
2) hydrogen atom ( +) of water.
B. the Cl− ions are attracted to the
1) oxygen atom ( −) of water.
2) hydrogen atom ( +) of water.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution
When solid LiCl is added to water it dissolves because
A. the Li+ ions are attracted to the
1) oxygen atom (σ −) of water.
B. the Cl− ions are attracted to the
2) hydrogen atom (σ +) of water.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check
Which of the following solutes will dissolve in water?
Why?
A. Na2SO4
B. gasoline (nonpolar)
C. I2
D. HCl

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution
Which of the following solutes will dissolve in water?
Why?
Water is a polar solvent that can dissolve ionic and polar
substances but not nonpolar solutes.
A. Na2SO4

will dissolve, ionic

B. gasoline (nonpolar)
C. I2
D. HCl

will not dissolve, nonpolar

will not dissolve, nonpolar
will dissolve, polar

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


9.2 Electrolytes and Nonelectrolytes
Electrolytes in the body
play an important role in
maintaining the proper
function of the cells and
organs.
Electrolytes such as
sodium, potassium,
chloride, bicarbonate

can be measured in a
blood test.
Learning Goal Identify solutes as electrolytes or
nonelectrolytes.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Strong Electrolytes
Strong electrolytes
• dissociate 100% in water,
producing positive and
negative ions.
• form solutions that conduct
an electric current strong
enough to light a bulb.
dissociation
H2O(l)

NaCl(s) → Na+(aq) + Cl–(aq)

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Weak Electrolytes

A weak electrolyte
• dissociates only slightly in
water.
• forms a solution with a few
ions and mostly undissociated
molecules.
dissociation

HF(aq)

HH22O(l)
O(l)

H+(aq) + F–(aq)

recombination

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Nonelectrolytes
Nonelectrolytes
• dissolve as molecules
in water.
• do not produce ions in
water.
• do not conduct an

electric current.
C12H22O11(s)
sucrose

H2O(l)

C12H22O11(aq)
solution of sucrose

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solutes in Aqueous Solutions

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.