Four Phases or states of Matter

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Four Phases or states of Matter

• Solid
• Liquid

• Gas
• Plasma

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Solids

• Constant volume
• Constant shape
• Atoms or molecules are well ordered into a
  crystal lattice for most materials
• Particles have VIBRATIONAL motion ONLY
• Exceptions
• Glass which is a very slow flowing liquid
• Amorphous solids have no crystal structure

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Liquids

• Constant volume
• Variable shape
• Incompressible
• Atoms or molecules loosely attracted to its
  neighbors, but in close proximity which allows
  fluid particles Translational (place to place)
  motion

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Gases

• Variable volume
• Variable shape
• VERY Compressible
• Atoms or molecules are widely separated and have
  little interaction with each other aside from
  collisions resulting from their Translational
  motion

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Water is strange! Water expands as it forms a
solid. This causes the density of ice to be less
than liquid water and, therefore, ice floats in
liquid water. Note the structure of liquid
water (left) and ice (right). Notice the
greater space in the organized crystalline ice
structure which is the cause of the expansion.
Germanium also does this.
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Plasma

• Temperature is so high that negative electrons
  are separated from their positively charged
  atomic nuclei
• No molecules exist
• Particles are electrically charged
• Found in Sun, stars, neon bulbs, lightning bolts
  and Fusion reactors.

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Direction of Heat Transfer

• Heat ALWAYS travels from a higher concentration
  of energy (high temperature) to a lower
  concentration of energy (low temperature).

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Changing Phases or States

• For elements, all four states are possible.
  Compounds can be only solids, liquids or gases
• PHASE CHANGES occur when energy content changes
• ENERGY PlasmagtGasgtLiquidgtSolid
• Energy content is the cause of the differences
  between states or phases at the particle level

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Molecular velocity determines TEMPERATURE and
STATE

• Slow moving molecules

• Fast moving molecules

• Means cooler material
• If cool enough, particle attractions overcome
  motion and they begin to stick together(freezing)

• Means warmer material
• If warm enough, particles have enough energy to
  leave the solid surface to liquid
  (melting) or the liquid surface to become
  gaseous (vaporizing)

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6 Phase Changes

• Freezing (liquid to solid)
• Melting(solid to liquid)
• Vaporization (evaporation or boiling)(liquid to
  gas)
• Condensation(gas to liquid)
• Sublimation(solid to gas- skip liquid)
• Deposition(gas to solid- skip liquid)

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Melting and Freezing

• Changes between liquid and solid
• Freezing is the opposite of melting
• Melting - Attractions between solid particles
  break when energy is added and vibrations
  increase until they escape into liquid state
• Freezing - Particles move slowly enough that
  attractions can pull particles together to form
  solid

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Vaporizing

• Liquid particles break the attractions of
  neighboring particles and travel up into the
  gaseous layer
• Evaporation- only particles near the surface have
  enough energy (traveling fast enough) to break
  the attractions
• Boiling particles throughout the liquid are
  traveling fast enough to form bubbles with higher
  pressure than outside conditions. Boiling Point

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Evaporation occurs only from
the surface
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Evaporation-surface particles only

• Only particles near the surface have enough
  energy to become a gas
• Liquid particles take energy from the liquid
  to enter gaseous state which cools the liquid
• The gas layer can also cool because of the influx
  of slower moving gas particles

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Boiling any particle in the sample has enough
energy to travel fast enough to exit the liquid
phase
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Evaporation (are you sure?)
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Condensation
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Condensation

• The opposite of evaporation
• Interaction of high energy particles with a
  cooler surface to form liquid
• Evaporation and Condensation occur usually on the
  SURFACE
• Gas particles release heat to rejoin the liquid
  (Exothermic)

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Sublimation

• Particles going directly from solid state to
  gaseous state.
• Dry Ice is a good example Dont touch, use
  gloves -78C - Sublimation point which is
  115colder than you
• Extended contact Frost bite
• Dry Ice NEVER melts
• Solids that smell usually do so because of
  Sublimation Chocolate particles enter your
  nose

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Deposition

• Hot gaseous atoms forming a layer of solid on a
  cooler surface manmade Diamonds are gaseous
  Carbon on a seed crystal
• Can be used to form a layer of thin expensive
  metal on cheap metal base

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Energy and Phase Change
Adding heat at a constant rate
T
Boiling
Melting
Time
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Viscosity is related to flow rate

• Low Viscosity material can flow rapidly
• Water and Alcohol have low viscosity
• High Viscosity material flows slowly
• Motor oil, lava, molasses, honey
• all have high viscosity

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Pressure

•  

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Boyles Law Pressure vs Volume Relationship

• P1 x V1 P2 x V2
• Original New
• Decrease the volume of a gas causes a higher
  pressure.
• Increase the Volume of a gas causes a lower
  pressure. Indirect Relationship

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Boyles Law Sample Problem

•  

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Charles Law Volume vs Temperature

•  

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Charles Law Sample problem

•  

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Graphing Reasons and Rules

• Purpose To find how variables relate
• X-axis Independent variable (manipulated)
• Y-axis Dependent variable (responding)
• Slope rise/run rate of change
• Use Predicting values that were previously
  unknown
• Graphs MUST have TITLES
• Graphs MUST have Labels
• X-axis Independent
• Y-axis Dependent

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Graphing Outcomes

• Directly proportional A is up B is up
• Indirectly proportional A is up but B is
  down
• Straight line graph varying at a constant rate
• Curved line graph varying at a changing rate