states of matter

• fixed


  particles can't move from place to place
• matter - energy levels

  1. gas (highest)
  2. liquid (greater)
  3. solid (lowest)
• evaporation

  1. particles leave a liquid (from only its surface)
  2. bubbles of gas form throughout the liquid
  3. they rise to the surface and escape to the surroundings, forming a gas
• how a solid heats

  1. the particles gain energy and vibrate faster
  2. the particles have so much energy that they can overcome the forces holding them together
  3. the substance melts into a liquid
• liquid being heated

  1. as heat is applied to a liquid the particles gain kinetic energy and move faster and boil into a gas
  2. with enough energy they can break the forces of attraction between the molecules
  3. the liquid would boil into a gas
• gas being heated

  1. the particles gain kinetic energy and move faster
• melting point


  the temperature at which a solid converts into a liquid
• boiling point


  the temperature at which a liquid converts into a gas
• in a closed system changes in state won't change the mass, because the number of particles remain the same
• densities - states of matter

  1. solids (highest)
  2. liquids (greater)
  3. gases (lowest)
• changes of state (energy and forces of attraction)

  • during changes of state particles gain energy (which is used to break some of the bonds between particles) and overcome the remaining forces of attraction
  • the amount of energy needed to change state, depends on the strength of the forces between the particles of a substance
  • the stronger the forces of attraction, the more energy is required to change its state (higher melting and boiling points)
• working out a gas, solid or liquid

  • if the given temperature is less than its melting point, it will be a solid
  • if the given temperature is between melting and boiling points, it will be a liquid
  • if the given temperature is greater than its boiling point, it will be a gas
• gases

  • state of matter
  • particles have enough energy to overcome the forces of attraction between them, so they spread out randomly
  • flow and completely fill the container (because their particles can move quickly in all directions)
  • can be compressed, as their particles are far apart and have space to move into
  • highest energy
• solids

  • state of matter
  • strong attractive forces hold the particles in place so that they can only vibrate in a fixed position and can't flow
  • can't be compressed, because their particles are close together and have no space to move into
  • when a solid is heated, energy is transferred to the kinetic energy stores (causing them to vibrate faster)
  • low energy
• liquids

  • state of matter
  • weak forces of attraction allow them to flow closely together and be randomly arranged
  • take the shape of their container, because their particles can move around each other
  • greater (medium) energy
  • can't be compressed, as their particles are close together and have no space to move into
• limitations of the particle model

  • assumes that particles are made up of solid spheres with no forces operating between them
  • particles can vary in size and shape (since the interactions between neighbouring particles can distort their shape)
  • atoms are mostly empty space, so real particles aren't solid
• changes of state


  • melting - solid to liquid
  • freezing - liquid to solid
  • evaporation/boiling - liquid to gas
  • condensation - gas to liquid
  • sublimation - solid to gas
  • deposition - gas to solid

  A) melting

  B) freezing

  C) evaporation/boiling

  D) condensing