States of Matter

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Chapter 3

• States of Matter

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Kinetic Theory of Matter

• 1) All matter is made up of atoms and molecules

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Kinetic Theory of Matter

• 2) These tiny particles are always in motion.
• State of matter depends on its molecular motion
  as measured by temperature
• ? temperature ? motion of particles
• ? temperature ? motion of particles

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Kinetic Theory of Matter

• 3) At the same temperature, the heavier particles
  move slower than the lighter particles.

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Temperature

• A measure of the average kinetic energy (K.E.) in
  a sample.

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Absolute Zero

• Temperature at which all molecular (particle)
  motion stops.
• 0 Kelvin ( -273 C -459 F)

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States of Matter

• Solid-
• Liquids-
• Gases-
• 4th state?
• What is plasma?
• 5th state?
• NOVA Bose Einstein Constant

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Solids

• Solids have a definite shape and a definite
  volume

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Liquids

• Molecules have room to slide over each other
• Have no definite shape, but have a definite
  volume.
• Not easily compressed

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Gases

• Molecules move freely to fill the container
• Have no definite volume or shape
• Easily compressed

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States of Matter

• Gases
• Particle Movement Examples

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• Plasma
• A plasma is a gaslike mixture of and charged
  particles
• A plasma is a very good conductor of electricity
• ex. Fluorescent lights, stars
• Plasma, like gases have an indefinite shape and
  an indefinite volume.
• Most common state of matter in the universe.

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• Plasma
• Particles
• The negatively charged electrons (yellow) are
  freely streaming through the positively charged
  ions (blue).

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More about gases..

• Gas pressure the force exerted by gas particles
  on their surroundings
• Vacuum- absence of particles- absence of pressure
  
• how a vacuum cleaner works
• vacuum assist brakes
• what happens to water in a vacuum?

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Variables that can affect gases..

• Four variables are generally used to describe a
  gas. The variables and their common units are
• pressure (P) in kilopascals
• volume (V) in liters
• temperature (T) in kelvins
• Amount of gas
• simulation

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Factors Affecting Gas Pressure

• Amount of Gas
• Increase the amount of gas increase pressure
• Ex If you inflate an air raft, the pressure
  inside the raft will increase.

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Factors Affecting Gas Pressure

• Volume
• volume then
  pressure
• volume then
  pressure
• Inversely Proportional !! When one goes up the
  other goes down!!

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Boyles Law

• Robert Boyle born in 1627
• Known for his works in mechanics, medicine,
  hydrodynamics and chemistry
• Published The Spring and the Weight of the Air in
  1662 which contained his pressure-volume inverse
  relationship

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Boyles Law Pressure and Volume

• Boyles law states that for a given mass of gas
  at constant temperature, the volume of the gas
  varies inversely with pressure.

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Practical Applications?

• Ear popping?
• Aerosol cans ?
• Hole in your pen?

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• http//www.mhhe.com/physsci/chemistry/essentialche
  mistry/flash/gasesv6.swf

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Factors Affecting Gas Pressure

• Temperature
• temp then pressure
• temp then pressure
• Directly proportional !!
• Why???
• Increase kinetic energy increase collision into
  walls of container
• increase pressure

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Charles Law

• Jacques Alexander Cesar Charles
• Born in France in 1746
• Chemist, physicist, aeronaut
• Formulated gas law in1787 which states that
  pressure and volume occupied by a fixed weight of
  gas is directly proportional to the absolute
  temperature

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Thermal Expansion

• Thermal expansion- matter expands as it gets
  hotter and contracts when it cools
• Exception- water actually expands when it freezes
  (due to locking of hydrogen bonds b/w water
  molecules)
• up
• Ex. Expansion joints on bridges, run hot water
  over jar lid to open it, gaps in sidewalk

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Charless Law Temperature and Volume

• As the temperature of the water increases, the
  volume of the balloon increases.

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Charless Law Temperature and Volume

• Charless law states that the volume of a fixed
  mass of gas is directly proportional to its
  Kelvin temperature if the pressure is kept
  constant.

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Review Concepts

• 1. What are 3 factors that affect gas pressure?
• 2. How does increasing the temperature affect the
  pressure of a contained gas?
• 3. What happens to the pressure of a gas if its
  volume is reduced?
• 4. How does increasing the particles of a
  contained gas affect its pressure?

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Why We Love Gas Laws

• Tapping on soda cans
• CO2 gas is dissolved in carbonated beverages
  at increased pressure. Shaking the can causes
  some of the CO2 to come out of solution and
  bubbles form on the sides of the can . Tapping
  the can can knock some of the bubbles back into
  solution.

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Phase changes
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Phase changes

• Phase change reversible physical change that
  occurs when a substance changes from one state of
  matter to another

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Phase Changes

• Melting/Freezing
• Boiling(vaporization)/ Condensing
• Sublimation/deposition

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Melting/Freezing Point

• Change from solid to liquid /liquid to solid.
• Freezing point and melting point are the same
  temp!
• if melting, particles are gaining energy if
  freezing, particles are losing energy.

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Melting/Freezing Continued

• During the phase change, the temp. remains the
  sameconstant. (flat/horizontal region on a phase
  diagram.)
• After all the sample has changed phase, the temp.
  will change.
• During the phase change, potential energy (P.E.)
  is changing, but K.E. is constant.

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Boiling/Condensation Point(Vaporization)

• Change from liquid to gas/ gas to liquid.
• Boiling temperature condensing
  temperature

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Boiling/Condensation Point(Vaporization)

• During the phase change, the temp. remains the
  same constant. (flat/horizontal region on a phase
  diagram.)
• After all the sample has changed phase, the temp.
  will change.
• During the phase change, potential energy (P.E.)
  is changing, but K.E. is constant.

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Sublimation/Deposition

• Changing directly from a solid to a gas/ changing
  from a gas to solid
• Skipping the liquid state.

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Evaporation

• Liquid to gas but not necessarily at the boiling
  point temperature.
• Some particles gain enough K.E. to overcome the
  attractions between molecules and become a gas.

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Energy and Phase Changes

• Energy is either absorbed or released during a
  phase change
• Endothermic- system absorbs energy from its
  surroundings
• Exothermic- system releases energy to its
  surroundings

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Review concepts

1. Name 6 common phase changes
2. What happens to the temperature of a substance
   during a phase change?
3. How does the energy of a system change during a
   phase change?
4. What is the difference between evaporation and
   boiling?