Chapter 3 States of Matter

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Chapter 3States of Matter

• Chemistry 1

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Solids, Liquids, and Gases 3.1
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Describe the States of Matter 3.1

• Use shape and volume as clues to which state
• Solids Definite shape and volume
• Liquids- Definite volume, no definite shape
• Gases No definite shape or volume
• Other States
• 99 of matter in the universe is plasma
• Found on the sun and stars
• Extremely high temperatures
• Bose-Einstein Condensate (BEC) 5th state of
  matter that exists at extremely low temperature
  where atoms behave as a single particle
  predicted by Bose in 1920s and Einstein decades
  before
• 1st produced at CU in 1995

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• Amorphous Solids
• Solid or liquid??
• Do not have crystals!
• Can and will flow over time.
• Example glass, wax, plastic
• Small temperature changes affect these (plastic
  on a cold day)
• Officially, these are liquids!!!

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Kinetic Theory 3.1

• Energy an object has due to its motion
• An object that moves has ke
• The faster object moves, the greater the ke
• All particles of matter are in constant motion

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Explaining the Behavior of Gases 3.1

• Motion in Gases
• Particles never at rest
• Average speed of particles is 1600 km/hr
• Atoms moves in straight line until collides with
  something
• Collision 1 atom loses ke and slows down other
  atom gains ke and speeds up

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Kinetic Theory of Gases 3.1

1. Particles in a gas are in constant, random motion
2. Motion of 1 particle, unaffected unless particles
   collide
3. Forces of attraction ignored under normally
   conditions

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Explaining the Behavior of Liquids 3.1

• Particles always moving
• Move slower than a gas particle
• Greater mass slower speed
• More closely packed particles
• Force of attraction to keep particles close
  together

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Explaining the Behavior of Solids 3.1

• Particles vibrate around a fixed location
• Strong attraction among particles

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The Gas Laws 3.2
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Pressure 3.2

• The result of a force distributed ovan an area
• SI unit force/area
• Force Newtons (N)
• Area square meters (m2)
• N/m2 Pascal (Pa)

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Factors that Affect Gas Pressure 3.2

• Temperature
• Increase in temp? ke increases ? particles
  collide more ? increase in pressure
• Think of tires in a car
• Volume
• Reducing volume, increases pressure
• Think of your lungs
• Number of particles
• Increasing particles, increases pressure

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Charless Law 3.2

• Jacques Charles (1746-1823)
• Investigated gases
• Absolute Zero 0 K
• No scientist has produced a temp of 0K
• Volume of gas directly proportional to temp in K
  if pressure and particles are constant
• TEMP MUST BE IN KELVIN
• V1/T1 V2/T2

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Boyles Law

• Robert Boyle Ireland
• 1st to describe relationship of pressure and
  volume of gas
• Volume of a gas is inversely proportional to its
  pressure if the temp and the number of particles
  are constant
• P1V1P2V2

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Combined Gas Law 3.2

• (P1V1)/T1(P2V2)/T2

http//www.nclark.net/GasLaws
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Phase Changes 3.3
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Characteristics of Phase Changes 3.3

• Reversible physical change that occurs when a
  substance changes from 1 state of matter to
  another
• 6 common phase changes melting freezing,
  vaporization condensation, sublimation, and
  deposition

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Temperature and Phase Changes 3.3

• The temp of substance does not change during a
  phase change

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Energy and Phase Changes 3.3

• Energy absorbed or released during a phase change
• Endothermic system absorbs energy
• Ex melting
• Heat of Fusion amount of energy absorbed from a
  substance
• Fusion melting
• Exothermic Releases energy
• Ex freezing

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Melting and Freezing 3.3

• Molecules become less orderly when substance
  melts and more orderly when substance freezes
• Melting heat flows from air to ice, ice gains
  energy, molecules vibrate more quickly ?
  molecules gain enough energy to move from fixed
  position
• Increases average ke
• Freezing energy flows from water to air, water
  cools, average ke decreases, molecules drawn to
  an orderly position
• Decreases average ke

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Vaporization and Condensation 3.3

• Vaporization liquid to a gas
• Endothermic process (substance must absorb
  energy)
• Heat of Vaporization Amount of energy it takes
  to change from a liquid to a gas
• 2 process boiling and evaporation
• Evaporation Liquid to a gas at temp below
  boiling point
• Molecules at the surface moving fast enough to
  escape the liquid
• The greater the surface area, the faster the
  water evaporates
• Vapor Pressure pressure caused by the
  collisions of this vapor and the walls of the
  container occurs in a closed container
• Increases as the temp increases

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• Boiling
• Vapor pressure and temp increases
• When vapor pressure atmospheric pressure, water
  boils
• Water molecules move faster when heated, bubbles
  (boiling) are water vapor
• Water vapor is less dense so bubbles rise
• Bubbles burst and releases water vapor into the
  air
• Boiling point depends on the atmospheric pressure
• At high elevations, the atmospheric pressure is
  lower so boiling point is lower so food takes
  longer to cook at this lower temp!

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• Condensation
• Phase change in which a substance changes from a
  gas or vapor to a liquid
• Exothermic process
• Morning dew
• Foggy glass after a shower

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Sublimation and Deposition 3.3

• Sublimation substance changes from a solid to a
  gas or vapor
• Endothermic change
• Ex dry ice (form of carbon dioxide)
• Deposition gas or vapor changes directly into a
  solid
• Exothermic change
• Ex frost to form on windows