Kinetic Theory

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Kinetic Theory
Chapter 16 Lesson 1

• States of Matter
• Kinetic Molecular Theory
• Four States of Matter
• Thermal Expansion

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Kinetic Molecular Theory

• KMT
• Tiny, constantly moving particles make up all
  matter.
• The kinetic energy (motion) of these particles
  increases as temperature increases.
• These particles are colliding with each other and
  the walls of their container.

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Four States of Matter

• Solids
• low KE - particles vibrate but cant move around
• atoms held tightly into place
• definite shape volume

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Four States of Matter

• Liquids
• higher KE - particles can move around but are
  still close together
• indefinite shape
• definite volume

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Four States of Matter

• Gases
• high KE - particles can separate and move
  throughout container
• indefinite shape volume
• move more quickly than particles that make up
  solids

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Four States of Matter

• Plasma
• very high KE - particles collide with enough
  energy to break into charged particles (/-)
• gas-like, indefiniteshape volume
• stars, fluorescentlight bulbs, TV tubes

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Phase Changes

• Heat of fusion-melting
• solid to liquid.
• energy required to change a substance from the
  solid phase to the liquid phase at its melting
  point is known as the
• some attractive forces are broken
• Freezing
• liquid to solid
• melting point freezing point

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Phase Changes

• Heat of vaporization
• energy required for the liquid at its boiling
  point to become a gas.
• all attractive forces are broken
• EX steam burns, sweating, and the drinking bird

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Heating Curves

• Evaporation
• liquid to gas below the boiling point
• Condensation
• gas to liquid

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Heating Curves
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Phase Changes

• Sublimation
• solid to gas
• EX dry ice, freeze drying, iodine

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Phase Changes
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Thermal Expansion

• Most matter expands when heated contracts when
  cooled.
• ? Temp causes ? KE. Particles collide with more
  force spread out.
• EX thermostats (bimetallic strip)

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Heating Curves

• Kinetic Energy
• motion of particles
• related to temperature
• Potential Energy
• space between particles
• related to phase changes

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Solid or a Liquid?

• Amorphous solids and liquid crystals
• two classes of materials dont react as expected
  when changing states.
• solids soften and gradually turn into a liquid
  over a temperature range
• lack the highly ordered structure found in
  crystals
• are typically long, chainlike structures that can
  get jumbled and twisted

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The Strange Behavior of Water

• Water molecules
• unusual in that they have highly positive and
  highly negative areas
• charged regions affect its behavior
• as the temp drops the particles move closer
  together

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The Strange Behavior of Water

• Freezing water molecules
• unlike charges are attracted to each other and
  line up so that only positive and negative zones
  are near each other.
• water molecules orient themselves according to
  charge, empty spaces occur in the structure.
• these empty spaces are larger in ice than in
  liquid water, so water expands when going from a
  liquid to a solid state.

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Liquid Crystals

• LCD
• flow during the melting phase similar to a
  liquid, but they do not lose their ordered
  arrangement completely.
• placed in classes depending upon the type of
  order they maintain when they liquefy
• are highly responsive to temperature changes and
  electric fields.
• ex televisions, watches, clocks, and calculators