Chapter 12 & 13
States of Matter and Temperature
Vocabulary List
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Thermodynamics
Thermal Energy
Kinetic-molecular
Theory
Temperature
Absolute Zero
Thermometer
Conduction
Convection
Radiation
Specific Heat
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Calorimeter
Calorimetry
Melting Point
Boiling Point
Evaporation
Condensation
Sublimation
Deposition
Ionization
Deionization
Entropy
Standards
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SP3:
Students will evaluate the forms and
transformations of energy.
F - Analyze the relationship between
temperature, internal energy, and work
done in a physical system.
Journal #41
What makes an object hot or cold?
 What changes about that object might
be observed while it goes from cold to
hot?
 What are some ways to detect the
temperature of an object?
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Thermodynamics
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Thermodynamics – The study of heat
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Thermal Energy – the overall energy of
motion of the particles that make up an
object. Represented by the symbol Q and
measured in Joules
Kinetic-Molecular Theory
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States that atomic
particles of any matter
are always in motion
and that the faster those
particles move the
greater the kinetic
energy.
Temperature
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Temperature –the measure of an objects thermal
energy. SI Unit is Kelvin (K) and is scalar.
– It does NOT depend on the number of particles in the
object, only the average KE of those particles.
– There does not seem to be an upper limit to
temperature, but there is a definite lower limit to the
amount of thermal energy (it can’t be negative).
– When thermal energy reaches 0, an object is at absolute
zero and the particles have completely stopped moving.
Temperature
Thermometer – a device that measures
temperature usually by coming to a thermal
equilibrium with that object.
 Thermometers usually work based on the
rules of thermal expansion, that is, when
most objects are heated, they expand.
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Common Temps
Fahrenheit (F)
Celsius (C)
Kelvin (K)
Water
Freezes/Melts
32
0
273
Human Body
Temp
98.6
37
310
Water Boils
212
100
373
You are expected to memorize these temperatures
Journal #42
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Look at the photo. The
coil is made of 2 strips
of different metals that
are sandwiched
together. When there is
an increase in
temperature, the coil
expands and comes
into contact with the
circuit. Where do you
think you might find this
device in your house?
Bimetallic Strip Demo
Pay attention to the demonstration and
record your observations in your
notebook.
 Supplies used:
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– Bimetallic Strip
– Bunsen Burner
– Water Bath
Phases of Matter
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There are 4 phases of matter:
– Solid: atoms are packed tightly together and have
very limited movement
– Liquid: atoms are packed loosely together and can
flow freely next to each other
– Gas: atoms are not bound to each other allowing
them to spread in all directions (diffuse)
– Plasma: atoms are moving at such high speeds
that they are ripping themselves apart into ions
Change of Phase
Sublimation
SOLID
Deposition
LIQUID
GAS
PLASMA
Heat
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Heat – the thermal energy that flows between two
objects as a result of a difference in temperature.
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Heat can be transferred by 3 common methods:
– Conduction
– Convection
– Radiation
Conduction
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Conduction is the transfer of energy
through direct contact.
 Examples:
– Touching a hot pan with your skin
– Frying an egg on a hot skillet
– Putting ice directly on a burn to cool it
Convection
Convection – the transfer of energy through
currents of fluids. Hot fluids rise and cooler fluids
sink. The movement of the fluids creates
convection currents with a distinct pattern.
 Examples:
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– Smoke rising above a fire
– The way that water boils up then rolls outward
– Using an oven to heat the air around the food
Radiation
Radiation – the transfer of energy through
electromagnetic waves. This is the only type that
does not involve matter, meaning it can happen in
a vacuum.
 Examples:
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– The energy the Earth receives from the sun
– The heat you feel when you stand NEXT to a fire
– The focusing of light rays with a magnifying glass to
start a fire
Conductors and Insulators
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Heat travels best in substances we label
as conductors.
– Examples include most metals, which is
why we cook in metal pots and pans
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Heat travels poorly in substances we
label as insulators.
– Examples include anything that makes use
of empty space; Styrofoam, vacuums, etc.
Journal #43
Why do people wear dark colors in the
winter and light colors in the fall?
Explain this phenomenon with science
using what we have learned recently.
Specific Heat
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Some objects are easier to heat than
others… why?
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Think of the first day of summer vacation at
the pool. The sun may get the furniture and
concrete very warm, but the water in the
pool is still quite cool compared to the
surroundings.
Specific Heat
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When heat flows into an object, its thermal energy
increases, and so does its temperature.
 The amount of the increase depends on the mass
of the object and the material from which the
object is made.
 The specific heat (C) of a material is the amount
of energy that must be added to 1-kg of the
material to raise the temperature by 1 C (or 1
Kelvin).
 A chart of common specific heats is on P. 318.
P. 318
Specific Heat
Good conductors have LOW specific
heats
 Good insulators have HIGH specific
heats
 The “best” insulator is a vacuum b/c it
does not allow conduction or convection
to occur.
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Calculating Thermal Energy
Q mCT
Q is Thermal Energy and measured in
Joules
 m is mass and measured in kg
 C is specific heat and will be given to
you in a chart or in the question
 T is the change in temperature and
can be in either Celsius or Kelvin
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Example 1
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Suppose that you are camping in the
mountains. You need to heat 1.50 kg of
water at 10.0º C to 70.0º C to make hot
cocoa. How much heat will be needed?
Q?
m  1.50kg
C  4180 (from chart )
T  Tf  Ti  7010  60
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Example 1 Answer
Q?
m  1.50kg
C  4180 (from chart )
T  Tf  Ti  7010  60
Q  m CT
Q  1.50 4180 60
Q  3.7610 J
5
Example 2
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A 5.10-kg cast-iron skillet is heated on
the stove from 295 K to 450 K. How
much heat had to be transferred to the
iron?
Q?
m  5.10kg
C  450 (from chart)
T  Tf  Ti  450 295 155
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Example 2 Answer
Q?
m  5.10kg
C  450 (from chart)
T  Tf  Ti  450 295 155
Q  m CT
Q  5.10 450155
Q  3.5610 J
5
Homework
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We will review in class on Wednesday
– P. 319 #3
– P. 336 #52, 53
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You are expected to do a left-hand lineup and convert to SI units at minimum.
Journal #44
1kg of copper, aluminum, and iron,
which have been heated to 450K, are
dropped into three pails that contain the
same amount of water at room
temperature.
 How will the temperature of the water in
the three pails compare when they
reach thermal equilibrium? Why?
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Journal #44 Explanation
Copper
C=385
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Aluminum
C=897
Iron
C=450
Each pail will have a different final
temperature. If mass and initial temperature
are controls, then only the specific heat of the
material will cause a difference. Aluminum
takes more energy to heat than iron or
copper, so it would have the highest final
temperature and copper would have the
lowest.
Pre-Lab Info (part of notes)
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Upon completion, you should know the
answers to these questions:
– What is specific heat?
– How can it be determined experimentally?
– What does it mean if a substance has a
high or low specific heat?
Answers to HW
P. 319 #3 - 5.3x104 J
 P. 336 #52 - 1.64x104 J
 P. 336 #53 - 1.00x103 J/kg*K
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Journal #45
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How much heat must be added to a
250.0g aluminum pan to raise its
temperature from 20.0 to 85.0 degrees
Celsius? (CAL=897 J/kg*K)
Journal #45 Explanation
Q?
m  250.0 g  0.2500kg
C  897
T  T f  Ti  85.0  20.0  65.0
Q  mC T
Q  0.2500  897  65
Q  1.46 10 J
4
Journal #46
What is the coldest that water can be?
(trick question?)
 What is the hottest that water can be?
(trick question?)
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Energy of a phase change
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When a substance undergoes a phase
change, special calculations must be
done to account for the energy that is
absorbed or released.
– From a solid to a liquid (or vice versa), this
energy is called the heat of fusion.
– From a liquid to a gas (or vice versa), this
energy is called the heat of vaporization.
Phase Change Graph
P. 323
The positive slopes from A to B, C to D, and beyond E all
indicate an increase in temperature.
The zero slopes from B to C and D to E indicate that a phase
change is occuring, but temp does not change.
Journal #47
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In terms of physics, what makes one
object “hotter” than another?
Calorimetry
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If two objects have different temperatures and
are brought into contact with each other,
there will be a transfer of energy from one to
the other until they reach a thermal
equilibrium, meaning that they have the
same temperature.
 For this to be possible, the heat lost by one
object is gained by the other.
 The mathematical process used to find the
solution to this type of question is called
calorimetry.
Diagram of Calorimeter
Calorimetry
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It is possible to calculate the final temperature
of two substances after they are mixed if you
know the amount of thermal energy they
possess before they are mixed.
 This follows the rules of conservation of
energy because energy will be transferred
from the warmer to the cooler object.
 The final temperature MUST fall between the
two original temperatures. If not, you have
made an error.
1st Law of Thermodynamics
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A restatement of the conservation of energy,
states that the total increase in the thermal
energy of a system is the sum of the work
done on it or the heat added to it.
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Basically, energy can’t be created, it must
be transferred from some other place.
2nd Law of Thermodynamics
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States that natural processes go in a direction that
maintains or increases the total entropy of the
universe. That is, all things will become more and
more disordered unless some action is taken to
keep the ordered.
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Entropy – a measure of the disorder of a system
Entropy
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Examples of Entropy
– You clean your bedroom and within days it is
messy again.
– An abandoned house will slowly have paint
fade and peal, shingles warp, weeds grow, etc.
– You light a match and the smoke (and smell)
spread out through the entire room.