Solutions
Chapter 8
Objectives
• Review key principles from previous
chapters
• Recognize how a solution differs from
other types of mixtures
• Name the different parts of a solution.
• Distinguish how properties of solutions
differ from properties of their original
components.
• Observe in an experiment how to separate
the components of a solution.
Things to Remember…
PHYSICAL
• A change in state is a ______________ change.
•
•
EX)
Chemical reactions REARRANGE
_____________ bonds
between atoms
Law of Conservation of mass states that the
ATOMS in the products must
number of ___________
equal the number of atoms in the
REACTANTS
_________________.
Things to Remember…
COMPOUND
• A ______________________
can be
created through covalent or ionic bonds. A
MOLECULE
________________
can only be created
through a covalent bond (EX. Water
Molecule).
• The temperature at which a liquid
becomes a solid is called its
FREEZING POINT
_____________________.
The
temperature at which a liquid rapidly
becomes a gas is called its
BOILING POINT
________________________.
A Solution is a Type of MIXTURE
1. A solution is actually a
HOMOGENOUS mixture because it
___________________
is the same throughout, but a solution
SEPARATED by physical
CAN be _________________
means. The substances in a mixture
REACT CHEMICALLY
DO NOT ____________
____________.
2. All proportions of a solution have the
SAME _____________.
PROPERTIES
_________
Solution or Not
Kool-Aid is a SOLUTION!!!!!
Water (by itself) is not a solution, but we can
use water to make different solutions.
Solute
SOLUTE
A. The ____________________
is a
substance that is dissolved to make a
solution. When it dissolves it separates
INDIVIDUAL
PARTICLES
into _______________
______________.
Solvents
SOLVENT
B. The __________________
is a
substance that dissolves a solute.
WATER
______________
is the most
commonly used solvent (We even
call it the “Universal Solvent”)
DID YOU KNOW????
• It is not possible to identify the
solute and solvent as different
substances when they form a
solution!!!
SOLUTES
DISSOLVE IN
SOLVENTS
Types of Solutions
4. Solutions can be SOILD, LIQIUD, or GAS.
• For example, Oxygen is a gas dissolved in
sea water.
• Page 240
Types of Solutions
• Some solutions are in the same
•
physical state.
For example: Vinegar is a
solution of acetic acid and
water.
A. If solutions are in the same state of matter
(EX. 2 Liquids), the substance present in the
greatest amount is considered to be the
SOLVENT
______________________.
Types of Solutions
• Do solutions ever exists as a solid???
• Yes, Bronze is a solid solution in which
tin is the solute and copper the solvent.
• Do solutions exists as gases???
• Of course, think about the air we
breathe!
Suspensions
• In a suspension , the
•
particles are larger
than those found in a
solution.
Instead of dissolving
they are suspended.
Solvent & Solute Particles Interact
• The parts of a solution—that is, the solute
and the solvent—can be physically
separated because they are not changed
into new substances.
• However, individual particles of solute and
solvent do interact.
• The solute particles become evenly
distributed throughout the solvent.
Interaction continued…
• The way compounds dissolve depends on
the type of bonds in the compound.
• Ionic compounds like table salt, split
into individual ions.
• Covalent compounds like table sugar,
dissolve and each molecule stays together
and is surrounded by solvent molecules.
Properties of Solvents
• In every solution, solutes change the
physical properties of a solvent:
LOWER
– They always ___________________
the
freezing point (Adding salt to roads during
snow storms)
RAISE
– They always___________________
the
boiling point (Adding antifreeze to your car)
Lowering the Freezing Point
• Page 243
Raising the Boiling Point
• Putting salt in water can
raise the boiling point.
• The amount of salt in the
water determines how
much the boiling point is
increased.
• Example for both lowering
and raising temperature:
Antifreeze!
• How do you think it
works?
Suspensions
SUSPENSION
7. In a ___________________,
the particles
are larger than those found in a solution.
EX) FLOUR IN WATER
SOLUTIONS
Suspensions are not ______________.
8.2 Objectives
• Explain how the
concentration of a solution
varies.
• Describe how a solute’s
solubility can be changed.
• Recognize that solubility
depends on molecular
structure.
Concentration
A solution’s
CONCENTRATION
depends on the amount of
solute dissolved in a solvent
at a particular temperature.
EX) “Orange Juice
Concentration” simply
means how much juice is
dissolved into water.
Concentration Can Vary
• A DILUTE solution has a low
concentration of solutes (It has a
higher level of solvents)
• A SATURATED solution has a high
concentration of solutes (It has a lower
level of solvents)
• You can raise the concentration by
adding more SOLUTES or decrease
the concentration by adding more
SOLVENTS.
• A SUPER SATURATED solution
contains more solutes than is normally
possible.
SOLUBILITY
9. The SOLUBILITY of a substance is the
amount of the substance that will dissolve in
a certain amount of a solvent at a given
temperature
– If the solute is highly soluble, a saturated
solution will be very CONCENTRATED.
– If a solute has a low solubility, the saturated
solution will be DILUTE.
Changing Solubility
• We can change the solubility of
a solute. There are two
different ways:
– To dissolve more solid into a
liquid, we simply raise the
TEMPERATURE. The solid will
dissolve quicker and more of it
will dissolve in a given solvent.
– To dissolve more gases into a
liquid, we must increase the
PRESSURE. Increasing the
temperature of a gas will actually
make it less soluble.
Temperature
• Increase in
Temperature:
– Solutes dissolves
more quickly
– Greater amount of
solid dissolves in a
given amount of
solvent.
– Page 249
Temperature & Gases
The opposite is true for gases—an increase in
temperature makes a gas less soluble in
water.
Pressure & Solubility
• Cokes add CO2 gas at
•
a pressure slightly
greater than normal
air pressure.
When you open the
can, the pressure
decreases and the
Carbon dioxide
bubbles out of
solution with a fizz!
• Scuba tanks include
•
79% N. People
breathe like this all the
time without any
problem, but the
pressure underwater is
much greater than on
Earth’s surface.
The higher pressure
increases the solubility
of N in the diver’s
blood.
Divers
• When a diver heads up to the surface too
fast, the pressure decreases, and so does
the solubility of N.
• The N comes out of solution and into the
diver’s blood. These bubbles can cause
painful and sometimes fatal condition
called the “bends.”
To Prevent The Bend’s
• Divers can rise to the surface slowly, so
bubbles stay small.
• They can breathe a different mixture of
gases, which contains only 66% of N.
Temperature and Solubility
Solute
Increased
Decreased
Temperature Temperature
Solid
Increase is
Solubility
Decrease in
Solubility
Gas
Decrease in
Solubility
Increase in
Solubility
This is how we make
SUPER SATURATED
solutions!
Supersaturated Solutions
Concentration
• A solution’s concentration depends on the
amount of solute dissolved in a solvent at
a particular temperature.
• Is it easier to make lemonade with or hot
or cold water?
Solubility Depends on Molecular
Structure
• When a substance dissolves, the molecules
•
•
•
separate from one another and become evenly
mixed
A POLAR substance attracts a POLAR substance
to form solutions.
“Like dissolves like”
PAGE 251
What Would Happen????
• What would happen if I mixed water, oil
and corn syrup in the same bottle?
Do Oil and Water Mix?
Review
• Why will a nonpolar substance not dissolve
in a polar substance?
– Nonpolar solutes do not have a charged
regions that would be attracted to charged
regions of polar solvents.
• How does pressure affect the solubility of
solids? Of gases?
– Solid and liquid solutes are not affected by
pressure. An increase in pressure increases
solubility of gases.
Review
• What effect does temperature have on most
solid solutes? On gases solutes?
– Increase in temp increases the solubility of most solid
solutes. Increase in temp decreases the solubility of
gases.
What do these terms mean: dilute and
saturated?
Dilute- low concentration
Saturated- Contains maximum amount of solute
Acids, bases and salts
Section 3
Chapter 8
Our learning goals for this section:
•To learn about acids and
bases
•To learn how to determine if
a solution is acidic or basic
•To learn how acids and
bases react with each other
Acids & Bases Basics
12. Acids and Bases are formed when solutions are
dissolved in WATER. When they dissolve they
produce an ION, or charged particle.
******EX) If a hydrogen atoms loses its electron,
it becomes positive (it’s actually just a PROTON.)
13. Acids and bases are classified based on their
ability to either accept or donate these hydrogen
ions (or PROTONS)
How do we measure acids & bases
• pH scale (pg 258)
Properties
Acids
Bases
Does it donate or accept
hydrogen ions?
Donates hydrogen ions
Accepts hydrogen ions
0-6
8-14
Sour
Bitter
Burning/Itching
Slippery
pH
Taste
Touch
Example
HCl-Hydrochloric
Acid
NaOH-Sodium
Hydroxide
It is all about the IONS…..
• Remember an ion is a charged particle.
And if a hydrogen atom loses an electron
it becomes a hydrogen ion. Which is
simply a proton and has a positive charge.
• An acid is defined as a substance that can
donate a hydrogen ion (a proton) to
H Osubstance.
another
2
HCl →
+
H
+
Cl
IONS CONT.
• A base is a substance that can accept a
hydrogen ion from another substance.
H2O
NaOH →
Na+ +
OH-
• So just generally speaking the difference
between an acid and a base is that acids
donate protons and bases accept protons.
• A~D
• B~A…………….bases
Characteristics of acids
• Tastes sour
• Strong acids are corrosive and
poison
• Hydronium ions in all acids
• Variety of changes to
indicators
Characteristics of bases
•Tastes bitter
•Feels slippery
•Strong bases can be
corrosive and poison
•OH- ion present in all bases
Not all acids and bases are alike.
They can vary in STRENGETH.
-When a STRONG ACID is dissolved in water, it
separates almost completely into ions (H+).
-When a WEAK ACID is dissolved in water, it does
not form many ions.
-When a STRONG BASE is dissolved in water, it
separates almost completely into ions (OH-)
-When a WEAK BASE is dissolved in water, it does
not form many ions.
**PAGE 256 for examples
Strong acid and weak acid
Strong base and weak base
Neutralization
16. Acids & Bases will NEUTRALIZE
each other. The neutral pH is 7.
***The H+ collides with the OH- to
create H2O!!!
*** Other atoms will create the salts!
The neutralization process
• When you have an upset tummy your
stomach is producing too much HCl. The
pH is about 1.5. You take an antacid that
contains a base and the base reacts with
the acid to produce a salt and water.
• So an acid + base gives a salt + water.
• Two very harmful things come together to
produce two very harmless things.
• This is called the neutralization process.
Explore acids and bases
• What are some observations we can make
about this cup of vinegar?
• What happens when we add 2 crushed
alka seltzer tablets?
At the start of the demo looked like water but had a strong smell. After the addition
of the alka seltzers the mixture fizzed and bubbles were produced. The vinegar odor
was not as strong. So when you have a tummy ache you take an antacid to neutralize
the acid being produced by the lining in your stomach.
8.4 Objectives
You will learn
-How metal alloys are made
-How a variety of alloys are used in modern
society
-Why different alloys have different
properties
What is an alloy?
• An alloy is a mixture of a metal and
one or more other elements, usually
metals as well.
Making Alloys
• First, we melt
the metals
• Then, mix them
together
• Finally, we allow
them to cool to a
solid
• EX) Steel
Alloy Properties
• Alloys have different
•
•
properties than the elements
that make them up.
The alloy BRONZE is harder
than either copper or tin alone
Nitinol (nickel & titanium) has
the ability to form to a
particular shape, be moved to
another shape, and then
reform to its original shape
How Do We Use Alloys?
• Steel makes up many
•
•
•
of our large buildings
Steel makes up many
of the ships we use
(including cruise
liners)
Most vehicles are
built with many types
of alloys
Medical Equipment is
made of stainless
steel
Alloys are also used in
Space Flight
• They allow airplanes to be
•
•
lightweight, yet strong
Research on the space
station has allowed scientist
to make alloys in a
microgravity environment
The alloy research could lead
to new innovations in robotics
& creating artificial organs for
humans