Transcript Science League Competition

States of Matter Grid
Kinetic Energy: Energy of Motion
Kinetic Theory: ALL MATTER is in constant motion.
Solids
Liquids
Attractive
Forces
Very Strong
Moderate
Molecular
Packing
Very tight, close
Molecular
Motion
Vibrate, spin in
place
Shape of
Matter
definite
indefinite
Volume of
Matter
definite
definite
Compressibility of
Molecules
Mass of
Matter
Flow of
Molecules
Moderate
Slide past each
other
Gases
NONE
99% empty space
Rapid, random
straight line
indefinite
indefinite
incompressible
incompressible
compressible
definite
definite
definite
flows
flows
Does not flow
STATES OF MATTER: Solid,
Liquid, Gas, Plasma
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SOLIDS:
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Most solids are crystalline –
Atoms, ions or molecules arranged in an
orderly, repeating 3-D pattern called a…
(CRYSTAL LATTICE).
Unit cellSmallest group of particles that keep the
shape of the crystal.
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•Allotropes2 or more forms of the same element in
the same physical state
 Example:
Solid Carbon
 GRAPHITE DIAMOND
BUCKEY BALL
PENCIL
Widely spaced,
linked, hexagon.
Weak bonds soft
Each
CARBON
atom is
strongly
bonded to 4
other carbons
hard
60 carbons
attached
together like a
soccer ball.
Really flexible
Carbon Allotropes
So far, it is just of theoretical interest. It is not used in any
products or manufacturing processes. One process
developed in the Chemistry Division at Argonne National
Lab produces smooth thin films of diamond from bucky
balls. These films are smoother than those produced by
any other method. This some day may be useful in
making wear-resistant coatings on things like machine
parts.
Amorphous solids
 Solids
that lack an orderly internal
structure. Atoms are randomly arranged.
 Examples:
rubber, asphalt, plastics
 Glasses:
 Amorphous
solids; super cooled liquids
 Cooled to a rigid state without crystallizing.
Does not melt at a definite temperature but
gradually softens. When broken it forms
jagged irregular edges.
GASES:
 KINETIC
THEORY OF GASES
 1. There are no attractive forces between
gas molecules.
 2. Gases are in constant rapid random
straight line motion.
 3. All collisions between gas particles are
perfectly elastic. NO ENERGY LOST just
transferred from one particle to another.
Plasma
Gases heated to very high temperatures.
 1. KE becomes great enough to break
molecules into atoms.
 2. As the temp. increases the electrons are
stripped off the gaseous atoms.
 3. What results are + ions and free electrons.
This is known as plasma.
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COLD PLASMA – 50,000K to 1,000,000K
 HOT PLASMA- “stars” 10,000,000 to
1,000,000,000K
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Bose-Einstein
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A Bose–Einstein condensate (BEC) is a state of matter of bosons
confined in an external potential and cooled to temperatures very
near to absolute zero (0 K or -273.15 °C). Under such supercooled
conditions, a large fraction of the atoms collapse into the lowest
quantum state of the external potential, at which point quantum
effects become apparent on a macroscopic scale.
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This state of matter was first predicted by Satyendra Nath Bose in
1925. Bose submitted a paper to the Zeitschrift für Physik but was
turned down by the peer review. Bose then took his work to
Einstein who recognized its merit and had it published under the
names Bose and Einstein hence the acronymn.

Seventy years later, the first such condensate was produced by
Eric Cornell and Carl Wieman in 1995 at the University of Colorado
at Boulder NIST-JILA lab, using a gas of rubidium atoms cooled to
170 nanokelvin (nK)[1] (0.000000170 K or -273.14999983 °C). Eric
Cornell, Carl Wieman and Wolfgang Ketterle at MIT were awarded
the 2001 Nobel Prize in Physics in Stockholm, Sweden[2].
 When a system of atoms is cooled rather than bosons, the BoseEinstein condensate is then sometimes called a Super Atom.[3]
B. TEMPERATURE
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TEMPERATURE AND ENERGY ARE NOT THE
SAME THING!!!
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Temperature is a measure of
AVERAGE Kinetic Energy
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The higher the temperature, the _(Greater)_, avg.
kinetic energy of the molecules.
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Energy is the ability to do work or supply heat.
Units: calorie or Joule
Oven analogy
KELVIN TEMPERATURE SCALE
 Based
on Absolute Zero.
 Used when doing Gas Law
calculations because there are no
neg. Numbers.
 Absolute Zero –
 Temperature at which
motion stops!
 0(K) or -273ºC
all molecular
Temperature Scale Comparison
Celcius
Thirty is hot
Twenty is nice
Ten is cool
Zero is ice
Temperature Scale Conversions
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Temperature conversions between the three
temperature scales:
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kelvin / ºCelsius conversions (exact):
kelvin = º Celsius + 273
ºCelsius = kelvin - 273
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ºFahrenheit / º Celsius conversions (exact):
º F = º C x 1.8 + 32.
º C = (º F - 32.) / 1.8
Temperature Scale Continued
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The Kelvin temperature of a substance is a
 Direct reading of the average kinetic energy of
the molecules!
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If you increase the Kelvin temperature of a
substance from 100K to 300K the average
speed of the molecules will
 TRIPLE (3x greater)
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Although the numbers are different on the
Celsius and Kelvin scales, each 1 increment on
the two scales is
 The same! 1ºC = 1 K
CHANGES OF STATE – PHASE CHANGES
(Solid Liquid Gas)
(Solid Liquid Gas)
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PHASE CHANGES ALWAYS INVOLVE ENERGY
CHANGES.
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Heat flows from
___(HOT)____ to ______(COLD)_____! ALWAYS
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Average Kinetic Energy (speed) =
KELVIN TEMPERATURE
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Is it possible for one water molecule to be at absolute zero
in a pot of boiling water?
YES
Explain: Temperature measures AVERAGE KE. Some
mc’s are much hotter and some much colder. As they
collide their individual KE’s (temperatures) change.
Melting and Freezing
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Melting
Phase change from solid to liquid.
Melting Point ( MP )
Temperature at which a solid becomes a liquid. Temp. remains constant during change.
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Freezing
Phase change from liquid to solid.
Freezing Point ( FP )
Temperature at which a liquid becomes a solid. Temp. remains constant during change.
energy in melts (endothermic)
solid
liquid
energy out freezes (exothermic)

MP = FP
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Ionic Solids:
Have high MP because they have very strong attractive forces. NaCl melts @ >801°C

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Molecular Solids:
Low MP because they have 2 forces. The bond that makes the molecule is strong and does
not break but the weak attractive forces between 2 different molecules does break. Ex. HCl
melts @ -112°C


Not all solids Melt!
Many organic solids like wood and animals decompose.
Ionic and Molecular Solids
+
-
+
-
-
+
-
+
+
-
+
-
Strong ionic bonds holding
positive and negative ions
together. MELTING!!
Ionic Compounds
Strong covalent bonds between H & O,
make up the water molecules.
NOT MELTING!
Weak attractive forces between
different water molecules. MELTING!!
Molecular Compounds
Boiling and Condensation
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Boiling
Phase change from a liquid to a vapor. (gas)
Boiling Point ( BP )
Temp. at which a liquid becomes a vapor (gas). Temp. remains
constant during the change!
Condensation
Phase change from a vapor to a liquid.
Condensation Point ( CP )
Temp. at which a vapor becomes a liquid. Temp. remains constant.
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BP = CP
energy in boils (endothermic)
liquid
gas
energy out condensed (exothermic)
Evaporation and Boiling are phase changes from a
Liquid to a vapor.
Evaporation and Boiling

Evaporation and Boiling are...
Cooling Processes.

Analyze Evaporation in terms of Kinetic Energy.

When liquid molecules evaporate the
FAST molecules escape.
Therefore, the
SLOW molecules are left behind.
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If Average Kinetic Energy = Temperature what can you determine
about the temperature of the liquid?
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SLOWER MC”S are COOLER!
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This is why evaporation is a
COOLING PROCESS.
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BOILING

Analyze Boiling in terms of Kinetic Energy.
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The____________under the pot ____________
FLAME
HEATS
the water, but the boiling takes away the
FAST MOLECULES so the actual boiling process
COOLS the water.
To take energy away means you are
COOLING.
This is why boiling is also a
COOLING PROCESS
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EVAPORATION VS BOILING
Evaporation is a
SURFACE phenomenon
whereas boiling occurs
Throughout the whole liquid.
How can you make something evaporate quickly without heating it?
SPREAD IT OUT. Surface mc’s get enough KE to escape.
Condensation
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Condensation is a phase change from a
VAPOR to a LIQUID.
Condensation is a
WARMING process.
When vapor hits a surface it gives up
ENERGY and makes what it hits
WARMER.
Which molecules are more prone to condense, the fast
or slow?
SLOW
Why? (FLY & FLY PAPER) Slow mc’s have little KE and
are attracted to other liquid mc’s on the surface.
Explain why it gets warmer outside just before it snows.
Snow is condensation. When you condensate you loose
energy. That released energy makes the surrounding air
warmer.
Sublimation
 Phase
change from a solid directly to a
gas without turning into a liquid.
 The
solid has a very high VAPOR
PRESSURE.
 Examples:
solid air fresheners, moth
balls, dry ice, iodine.
PHASE CHANGES ALWAYS
INVOLVE ENERGY CHANGES.
Energy In = Endothermic process = Cooling Process
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SOLID
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Energy out = Exothermic Process = Warming process

The following phase changes are cooling processes
MELTING, BOILING, EVAPORATING
Because they absorb energy leaving the surroundings cooler. (High
KE mc’s leave and the slower cooler mc’s are left behind.
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LIQUID
GAS
The following phase changes are warming processes
Freezing and Condensing
Because they release energy making the surroundings warmer (KE
is absorbed which adds energy and makes the surroundings
warmer.
Phase Diagram
 Shows
the relationship between solid, liquid
and vapor phases in a sealed container.
Each sections shows a pure phase.
Equilibrium
2 phases existing at the same time at
a certain temp & pressure. (line
separating 2 regions.)
Triple Point
Only condition that allows all 3
phases to exist at the same time.
(where lines intersect)
Gas Pressure
pressure –
 Due to the collisions of air mc’s on an
object.
 Collisions of gas molecules are
 Perfectly elastic which means
 No energy is lost (just transferred)
 Atmospheric
Measuring air pressure –Barometers
760mmHg
Eudiometer
Below sea level
Cave (2atm)
At sea level (1atm)
Higher than sea level
on Moon (0atm)
Pressure Unit Equalities
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1 atm (atmosphere)
= 760 mm Hg
= 30 “ Hg
= 14.7 psi (pounds per square inch)
= 101,3 kPA (kilo Pascal) metric unit
Using these equalities, it is possible to convert
from one unit of pressure to another.
Examples of Unit Conversions
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Convert 92.5 “ Hg to mm Hg
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Equality: 760 mm Hg = 30 ” Hg
92.5 “ Hg
760 mmHg
=
1
30”Hg
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Convert 2.25 atm to psi
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Equality: 1 atm = 14.7psi
2.25atm
14.7psi
1
1atm
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Convert 5.25 atm to kPA
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Equality: 1atm = 101.3 kPA
5.25 atm
101.3 kPA
=
1
1 atm
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Convert 222.2 kPA to mmHg
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Equality: 101.3 kPA = 760 mmHg
222.2 kPA
760 mmHg
= 1667.05
1
101.3 kPA
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2343 = 2340mmHg
= 33.075 = 33.1psi
531.825 = 532 kPA
= 1667mmHg
Factors involved in Boiling
 Boiling
is affected by 2 factors:
 Temperature
 Pressure
 vapor pressure Is the pressure above a liquid in a
SEALED CONTAINER!
 boiling point –
 Temp. at which the vapor pressure of a
liquid = external atmospheric pressure.
Diagram/Explanation of a pot of water trying to boil.
1atm
Air pressure
pushing down
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1 atm
Air pressure
pushing down
1 atm
Air pressure
pushing down
1. @ 70ºC air pressure greater than vapor pressure of liquid.
No Boiling = No Cooling Water continues to heat up.
2. @ 98ºC air pressure still greater than the vapor pressure of liquid.
No Boiling = No Cooling Water continues to heat up.
3. @ 100ºC air pressure = vapor pressure.
Boiling occurs. Water Cools. Temperature remains constant!
Why does a pressure cooker cook
your food faster?
 Sealed
lid!
 As water heats up and KE increases the
air pressure inside pushing down on the
liquid increases.
 More air pressure means liquid can not
boil at 100ºC. No Boiling = No cooling
 Water must heat up to a temp. > 100ºC in
order for the air pressure = vapor pressure
 Higher temp. boiling cooks food faster!
How Can You Make Water Boil at
Room Temperature?
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Boiling at room temp. demo.
The vacuum pump removes air mc’s.
No air mc’s = no collisions.
No collisions = no air pressure.
Therefore the temperature at which the temp. of
the water = external pressure is much lower than
100ºC.
Because boiling is a cooling process the temp.
of the water decreases as the water boils in a
vacuum.
Boiling Water on a Mountain
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Less air mc’s =
Less collisions =
Less air pressure =
Lower temp. for vapor pressure = air pressure
Boil water at lower temperature!
Will your food cook faster or slower?
Slower
Boiling is a cooling process it’s the heat (temp.) that’s
cooking the food.
Lower Temperature = Longer Cooking Time!
How does Pressure and Temperature
change in a Closed Container as Ice is
heated, Melts and turns to Steam.
5.
3.
2.
4.
1.
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1. Ice @ 0ºC. Temp. remains constant as ice melts. Pressure inside
container ↑.
2. Ice and Water at 0ºC. Remains constant until completely liquid.
Pressure inside container ↑.
3. Water only. Temperature ↑ until vapor pressure of the liquid = air
pressure that has built up in the sealed container. Pressure inside
container ↑.
4. Water and Steam at 100ºC. Remains Constant until completely
steam. Pressure inside container ↑.
5. Steam only. Temperature ↑ and Pressure inside container ↑until
pressure builds up so much container explodes!
The End!