chap 6 - kinetic particle model of matter

• properties of solid, liquid and gas

  • solid

  - fixed shape and volume

  - high density

  - not compressible
• properties of solid, liquid and gas

  • liquid

  - fixed volume but no fixed shape

  - high density compared to gas

  - not compressible
• properties of solid, liquid and gas

  • gas

  - no fixed volume and shape

  - low density

  - compressible
• kinetic particles model of matter

  • all matter are made up of tiny particles called atoms or molecules (atoms joined together)
  • tiny particles that make up matter are always in continuous motion

  > solid - closely packed

  > liquid - slightly further apart

  -relatively high density

  > gas - moving very fast

  - very far apart

  - low density
• molecular structure

  • solid

  - vibrate about fixed position

  - very strong attraction force

  - regular pattern -- arrangement

  - closely packed
• molecular structure

  • liquid

  - particles are free to move about at high speed

  - strong attraction force

  - random pattern -- arrangement

  - close together
• molecular structure

  • gas

  - move freely and quickly in all direction

  - weak forces of attraction

  - random arrangement

  - far apart
• why can gases be compressed easily but not liquid or solid?

  • gas have large intermolecular spaces between the molecules
  • as a result, the intermolecular forces of attraction is very weak
• effect of temp. on the motion of particles

  • what happenes to the motion of particles when temp. changes?

  - when temp. increase, particles gain kinetic energy stored and thus move faster --> thermal energy is being transferred

  - when temp. decrease, particles move more slowly

  - particle movement remains random and continuous regardless if the temp. increase or decrease
• internal energy

  • energy stored that is made up of the total kinetic energy stored (with random motion if particles) and total potential energy stored (between particles)
  • when is transferred to kinetic energy store, it will move faster and therefore temp. change
  • .when transferred to potential energy store, particles move further apart, the state changes
• changing state of matter

  • when thermal energy is added to a substance, its temp. changes from solid to liquid or liquid to gas
  • they can weaken or break their bonds and experience change of state which is caused by simple conservation of energy and energy transfers

  > solid --> liquid = melting

  > liquid --> gas = vaporization

  > gas --> solid = deposition

  > solid --> gas = sublimation

  > liquid --> solid = freezing

  > gas --> liquid = condensation
• why temp. remain constant when substance changes its state?

  • the energy that is added during changes of state is used to break the attractions between particles
  • therefore, the temp. does not change until the change of state is complete
• brownian motion

  • refers to the random, irregular and jerky motion of smoke particles in the air
  • the smoke particles are continuously bombarded unevenly on different sides by air molecules = irregular movement