Matter

• Why does a substance flows in its gas state and completely fills its container?

  Due to the particles being spread far apart and moving randomly in all directions with no fixed shape or volume
• What are the three states of matter?

  The three states of matter are solid, liquid, and gas.
• Changes of state

  1. Melting

  2. Boiling

  3. Evaporation

  4. Freezing

  5. Condensation
• Change of state

  When a substance changes state (solid, liquid, gas) the particles stay the same, but their arrangement changes
• Heating

  Particles gain energy
• Cooling

  Particles lose energy
• Melting

  1. Solid changes into a liquid

  2. Occurs at a specific temperature called the melting point

  3. Particles vibrate more and break away from fixed positions
• Boiling

  1. Liquid changes into a gas

  2. Occurs at a specific temperature called the boiling point

  3. Particles gain enough energy to break free from each other
• Evaporation

  1. Occurs at the surface of liquids where high energy particles can escape

  2. No heat required, occurs over a range of temperatures

  3. Larger surface area and warmer temperature increases rate
• The state of a substance at a given temperature can be predicted if its melting point and boiling point are known
• Freezing

  1. Liquid changes into a solid

  2. Occurs at the same temperature as melting
• Condensation

  Gas changes into a liquid, usually on cooling
• Sublimation

  Solid changes directly into a gas
• Gaseous particles

  In constant and random motion
• Gaseous particles

  • Higher temperature = more kinetic energy
  • Lower temperature = less kinetic energy and slower motion
• Pressure of a gas

  Produced by gaseous particles hitting the inside walls of the container
• Boyle's Law

  1. Volume of a given amount of gas held at constant temperature varies inversely with pressure

  2. Increase volume = decrease pressure (less collisions)

  3. Decrease volume = increase pressure (more collisions)
• Gas pressure

  Result of collisions between gas particles and an object
• Particles

  • Atoms
  • Molecules
  • Ions
• Atom

  Smallest particle of an element, with a nucleus containing protons and neutrons, and electrons in outer shells
• Ion

  Charged particle formed when an atom loses or gains electrons
• Molecules are?

  Particles made up of two or more atoms joined together (e.g. by covalent bonds)
• The forces are strongest in solids because the particles are closer together