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Matter and Energy Chapter 3 Omit Section #3.1

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Matter and Energy Chapter 3 Omit Section #3.1
Chapter 3
Matter and Energy
Omit Section #3.1
Summary of the States of Matter (Page 62)
2
Changes of Matter . . . . Section 3.2 Page 62
We can change matter in either of 2 ways. A change can be Physical
or Chemical
In a physical change, the substance itself is not changed, only
its appearance, or its size, or its physical state is changed.
For example . . . Freezing water to ice is a physical change.
In a chemical change, the substance itself is changed.
For example burning gasoline is a chemical change.
Burning anything is a chemical change.
Do Problems #3.11 & #3.12 on Page 64
Temperature
Section #3.3
Page 64
Temperature Scales (Page 65)
Temperature Scales
are Fahrenheit,
Celsius, and
Kelvin.
These are the
reference points
for the boiling
and freezing
points of water.
Copyright © 2009 by Pearson Education, Inc.
6
Temperature Conversions
Use the conversion formulas
given on Pages 65 - 66
Example #1 What is the temperature in Kelvin
of 176 degrees Fahrenheit ?
To convert from Celsius to Fahrenheit: (Page 65)
oF
= 1.8(oC) + 32
To convert from Fahrenheit to Celsius: (Page 65)
oC
= (oF – 32)/1.8
To convert from Celsius to Kelvin: (Page 66)
K = oC + 273
Example: What is the
temperature in Kelvin of
176 degrees Fahrenheit ?
Two steps required.
First convert Fahrenheit to Celsius,
then add 273 to C to get Kelvin
C = (F – 32)/1.8 (given in Sample
problem 2.5 --- Step 3
C = (176 – 32)/1.8 = 80
Then, K = 80 + 273
K = 353 ans.
Recommended problems for
temperature conversions:
Chapter #3
Page 67 --- #3.17 a through e
and, #3.18 a through e
Section 3.4 Page 68
ENERGY is defined as the ability to do work.
All matter possesses energy.
Energy is classified as either kinetic or
potential.
Energy can be converted from one form
to another.
When matter undergoes a chemical or
physical change, the amount of energy in
the matter changes as well.
Recommended Problems: Page 69 --- #3.23 & 3.24
Potential Energy (Page 68)
Potential energy is
stored energy.
Examples are:
1. water behind a dam.
2. a compressed spring.
3. chemical bonds in gasoline,
coal, or food.
Copyright © 2009 by Pearson Education, Inc.
13
Kinetic Energy
Kinetic energy is the
energy of motion.
Examples are:
1. swimming.
2. water flowing over a dam.
3. working out.
Copyright © 2009 by Pearson Education, Inc.
4. burning gasoline.
14
Learning Check
Identify the energy as potential or kinetic.
A.
B.
C.
D.
Rollerblading
a peanut butter and jelly sandwich
mowing the lawn
gasoline in the gas tank
15
(Page 68)
HEAT is defined as the motion of particles in a substance.
The higher the temperature of a substance, the faster the
particles in that substance are moving.
The lower the temperature of a substance, the slower the
particles in that substance are moving.
Global Warming - - - Page 70
Sun
N2 and O2 (gas)
Also CO2
Earth’s Atmosphere
Sun
N2 and O2 (gas)
Also CO2
Earth’s Atmosphere
Eventually, the heat needs to
escape, but large amounts of
carbon dioxide will create a heat
shield (greenhouse effect) and
prevent some of the heat from
escaping.
Increasing amounts of CO2 are
mainly due to:
Sun
N2 and O2 (gas)
Also CO2
Earth’s Atmosphere
Increasing amounts of CO2 are mainly due to:
burning of fossil fuels (gasoline, oil, wood,
etc.) and urban sprawl (expansion of human
settlements).
As the temperature of the earth increases,
the polar ice will melt at an alarming rate
and raise the ocean levels.
Plant life,
especially trees,
absorb carbon
dioxide !
Omit Sections #3.5 and #3.6
Changes of State of Matter (Page 75)
Section #3.7
•
•
•
•
Matter can exist in any of the three physical states.
Matter can exist as a solid, a liquid, or a gas.
Matter can never be created or destroyed.
However, can always be converted from one physical state
to another.
• These processes are called “Changes of State”.
• Changes of State almost always involves energy changes.
• The energy changes almost always requires heating or
cooling.
21
A substance •is melting while it changes from a solid to
a liquid.
•is freezing while it changes from a liquid
to a solid.
•such as water has a freezing (melting)
point of 0 °C.
See Page 75
Evaporation and Condensation
Water
• evaporates when
molecules on the surface
gain sufficient energy to
form a gas.
• condenses when gas
molecules lose energy
and form a liquid.
See Page 78
Copyright © 2009 by Pearson Education, Inc.
23
Sublimation
Sublimation
• occurs when particles
change directly from solid
to a gas.
• is typical of dry ice, which
sublimes at -78 C.
• takes place in frost-free
refrigerators.
• is used to prepare freezedried foods for long-term
storage.
See Page 78
24
Omit Pages 79-83
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