Chemistry 8

• Kinetic Particle Theory:

  • Matter can be classified as solid, liquid, or gas
  • All matter is made up of tiny particles with attractive forces between them
  • Particles are in constant random motion and undergo perfectly elastic collisions
  • Particles collide without losing kinetic energy
  • Kinetic energy is the energy of a particle in motion, higher speed means higher kinetic energy
  • Attractive forces hold particles together
• Solids:

  • Have fixed shapes and volumes
  • Particles are arranged in an orderly manner and closely packed
  • Held together by very strong attractive forces
  • Low kinetic energy limits movement to vibrations and rotations
  • Cannot move freely and stay beside each other
• Liquids:

  • Have a fixed volume but not fixed shapes
  • Particles are arranged in a less closely packed, disorderly manner compared to solids
  • Held together by weaker attractive forces than solid particles
  • Have more kinetic energy than solid particles of the same substance
  • Particles move more freely compared to solids
• Gases:

  • Do not have fixed shapes or volume
  • Particles are arranged in a very disordered manner and far apart from each other
  • Held together by weaker attractive forces compared to liquid particles
  • Have high kinetic energy
  • Particles can move freely and rapidly in any direction
• Phase Changes of Matter:

  • Phase changes like freezing and boiling are physical changes
  • Identity of the substance remains the same and can be reversed
  • Melting: solid to liquid
  • Freezing: liquid to solid
  • Evaporation: liquid to gas
  • Condensation: gas to liquid
  • Sublimation: solid to gas without liquid phase
  • Deposition: gas to solid without liquid phase
• Melting:

  • Substance changes from solid to liquid at its melting temperature
  • Particles absorb heat energy converted to kinetic energy
  • Vibrations increase with temperature, weakening attractive forces
  • Particles break away from fixed positions, substance becomes liquid
• Boiling:

  • Substance changes from liquid to gas at its boiling temperature
  • Particles absorb heat energy, increasing kinetic energy
  • Faster movement causes attractive forces between particles to break
  • Particles spread apart and move in different directions, turning into gas
• Sublimation:

  • Substance changes from solid to gas without passing the liquid state
  • Particles at the surface have enough kinetic energy to break attractive forces
  • Examples include solid carbon dioxide (dry ice)
• Evaporation:

  • Substance changes from liquid to gas at temperatures lower than boiling
  • Volatile liquids evaporate easily at room temperature
  • Examples include alcohols like ethanol
• Freezing:

  • Substance changes from liquid to solid
  • Particles lose heat energy and kinetic energy, moving more slowly
  • Particles settle and vibrate about fixed positions, becoming solid
• Condensation:

  • Substance changes from gas to liquid, reverse of evaporation
  • Particles lose heat energy, resulting in lower kinetic energy and slower movement
  • Gas changes into liquid as temperature decreases
• Deposition:

  • Substance changes from gas to solid without passing through the liquid state, reverse of sublimation
• Subatomic Particles:

  • Atoms are made of protons, electrons, and neutrons
  • Proton (p+): positive charge
  • Electron (e-): negative charge
  • Neutron (no): no net electric charge
  • Nucleus is at the center of the atom
  • Atomic number (Z) is the number of protons and electrons in a neutral atom
• Mass Number:

  • Total number of protons and neutrons in the atom (A)
  • Calculated by adding protons and neutrons
• Isotopes:

  • Atoms of the same element with the same number of protons and electrons but different number of neutrons
• Formulas:

  • p+ = Atomic #
  • e- = Atomic # - charge
  • no = Atomic Mass - Atomic #
  • A = Z + A
• Kinetic Particle Theory:

  • Matter can be classified as solid, liquid, or gas
  • All matter is made up of tiny particles with attractive forces between them
  • Particles are in constant random motion and undergo perfectly elastic collisions
  • Particles collide without losing kinetic energy
  • Kinetic energy is the energy of a particle in motion, higher speed means higher kinetic energy
  • Attractive forces hold particles together
• Solids:

  • Have fixed shapes and volumes
  • Particles are arranged in an orderly manner and closely packed
  • Held together by very strong attractive forces
  • Low kinetic energy limits movement to vibrations and rotations
  • Cannot move freely and stay beside each other
• Liquids:

  • Have a fixed volume but not fixed shapes
  • Particles are arranged in a less closely packed, disorderly manner compared to solids
  • Held together by weaker attractive forces than solid particles
  • Have more kinetic energy than solid particles of the same substance
  • Particles move more freely compared to solids
• Gases:

  • Do not have fixed shapes or volume
  • Particles are arranged in a very disordered manner and very far apart
  • Held together by weaker attractive forces compared to liquid particles
  • Have high kinetic energy
  • Particles can move freely and rapidly in any direction
• Phase Changes of Matter:

  • Phase changes like freezing and boiling are physical changes
  • Identity of the substance remains the same and the process can be reversed
  • Melting: solid to liquid
  • Freezing: liquid to solid
  • Evaporation: liquid to gas
  • Condensation: gas to liquid
  • Sublimation: solid to gas without passing the liquid phase
  • Deposition: gas to solid without passing the liquid phase
• Melting:

  • Substance changes from solid to liquid at its melting temperature
  • Particles absorb heat energy converted to kinetic energy
  • Vibrations increase with temperature, weakening attractive forces
  • Particles break away from fixed positions, substance becomes liquid
• Boiling:

  • Substance changes from liquid to gas at its boiling temperature
  • Particles absorb heat energy, increasing kinetic energy
  • Faster movement causes attractive forces between particles to break
  • Particles spread apart and move in different directions, turning into gas
• Evaporation:

  • Substance changes from liquid to gas at temperatures lower than boiling
  • Volatile liquids evaporate easily at room temperature
  • Examples include alcohols like ethanol
• Sublimation:

  • Substance changes from solid to gas without passing the liquid state
  • Particles at the surface have enough kinetic energy to break attractive forces and escape as gas particles
  • Examples include solid carbon dioxide (dry ice)
• Freezing:

  • Substance changes from liquid to solid
  • Particles lose heat energy and kinetic energy, moving more slowly
  • Particles settle and vibrate about fixed positions, becoming solid
• Condensation:

  • Substance changes from gas to liquid, reverse of evaporation
  • Particles lose heat energy, resulting in lower kinetic energy and slower movement
  • Gas changes into liquid as temperature decreases
• Deposition:

  • Substance changes from gas to solid without passing through the liquid state, reverse of sublimation
• Subatomic Particles:

  • Atoms are made of protons, electrons, and neutrons
  • Proton (p+): positive charge
  • Electron (e-): negative charge
  • Neutron (no): no net electric charge
  • Nucleus is at the center of the atom
  • Atomic number (Z) is the number of protons and electrons in a neutral atom
• Mass Number:

  • Total number of protons and neutrons in the atom, represented by symbol A
  • Calculated by adding protons and neutrons
• Isotopes:

  • Atoms of the same element with the same number of protons and electrons but different number of neutrons
• Formulas:

  • p+ = Atomic #
  • e- = Atomic # - charge
  • no = Atomic Mass - Atomic #
  • A = Z + A