Chapter 7 : Model of Matter - Particulate Nature of Matter

• All matter, like air and water, consists of tiny particles

  All particles of matter are constantly moving in a random manner and this is know as Brownian Motion
• Brownian motion refers to air particles moving about randomly at all times
• Matter is anything that has mass and takes up space.

  The arrangement and movement of particles will be different when in different states
• All matter is made up of small discrete particles that are in constant random motion

  All particles of one pure substance are identical
• Solid

  Arrangement of particles : Have a fixed regular pattern and are packed very closely in an orderly manner

  Movement of particles : They vibrate about their fixed positions and are held together by very strong forces of attraction
• Liquid

  Arrangement of particles : Has no fixed regular pattern and are packed closely in a disorderly manner

  Movement of particles : They slide past one another freely and are held together by strong forces of attraction
• Gas

  Arrangement of particles : Have no fixed regular pattern and are far apart from one another

  Movement of particles : They move randomly and quickly and are held together by weak forces of attraction
• Expansions and Contractions of solids

  Expansions

  Upon heating, the (substance) particles gain energy and vibrate more vigorously making the particles move further apart from one another causing the volume to increase. As a result, the substance expands
• Expansions and Contractions of solids

  contractions

  Upon contraction, the (substance) particles lose energy and vibrate less vigorously making the particles move closer to one another causing the volume to decrease. As a result, the substance contracts
• Expansions and Contractions of liquids

  Expansions

  Upon heating, the (substance) particles gain energy and slide past one another more quickly making the particles move further apart from one another causing the volume to increase. As a result, the substance expands
• Expansions and Contractions of liquids

  contractions

  Upon contraction, the (substance) particles lose energy and slide past one another less quickly making the particles move closer to one another causing the volume to decrease. As a result, the substance contracts
• Expansions and Contractions of gasses

  Expansions

  Upon heating, the (substance) particles gain energy and move more quickly making the particles move further apart from one another causing the volume to increase. As a result, the substance expands
• Expansions and Contractions of gasses

  contractions

  Upon contraction, the (substance) particles lose energy and move past one another less quickly making the particles move closer to one another causing the volume to decrease. As a result, the substance contracts
• Melting

  • The process in which as solid changes into a liquid without a change in temperature
  • As the solid is heated, the particles will gain energy and vibrate faster about their fixed positions. When particles gain enough energy, they will overcome the very strong forces of attraction between one another
  • The solid will hence melt and become liquid
• Boiling

  • The process in which a liquid changes into a gas without a change in temperature
  • As they liquid is heated, the particles will gain energy and move faster and further apart from one another. When the particles gain enough energy, they will overcome the strong forces of attraction between one another
  • The liquid boils and becomes a gas
• Freezing

  • The process in which a liquid changes into a solid without a change in temperature.
  • As the liquid is cooled, the particles will lose energy and move slower. When the particles lose enough energy, they are pulled much closer to one another by forces of attraction between them.
  • The liquid freezes and becomes a solid
• Condensation

  • The process in which a gas changes into a liquid without a change in temperature
  • As the gas is cooled, the particles will lose energy and move slower. When the particles lose enough energy, they are pulled closer to one another by the forces of attraction between them
  • The gas condenses and becomes a liquid
• Diffusion

  Diffusion is the net movement of particles from a region of high concentration to a region of low concentration