Structure 1.1 - Introduction to particular nature of matter

• All matter is made from small particles.
• Elements are the primary constituents of matter, which cannot be chemically broken down into simpler substances.
• An element is a pure chemical substance composed of the same type of atoms.
• Compounds consist of atoms of different elements chemically bonded together in a fixed ratio.
• Mixtures are made from particles of one substance interspersed between particles of at least one other substance.
• Mixtures contain more than one element or compound in no fixed ratio, which are not chemically bonded and so can be separated by physical methods.
• If the mixing is uniform, it is homogenous, if not uniform then heterogenous.
• List the properties of elements

  • Pure substance
  • Basic unit of matter
  • Can’t be broken down 
• List the properties of compounds

  • Pure substance
  • Formed by a combination of two or more elements
  • Elements are combined in a fixed ratio
  • Can be broken down into its elements by chemical means
• List the properties of mixtures

  • Impure substance
  • Formed by combining two or more elements, compounds, or both
  • Substances are mixed together in any ratio
• Define solvation

  Solvation involves the separation of a heterogeneous mixture of two solids based on differences in solubility if one of the substances is soluble in a solvent, but the other solid is insoluble. 
• Define filtration

  Filtration involves the separation of an insoluble solid from a liquid or solution.
• Define recrystallization

  Recrystallisation is a separation technique used to remove impurities that are mixed in with a solid. This technique uses the varied solubilities of solids at different temperatures to separate them. 
• Define evaporation

  Evaporation is used to separate a mixture which has a solute dissolved in a solvent which is usually water. 
• Define distillation

  Distillation involves the separation of a liquid mixture based on the difference in volatility or boiling points between the components of the mixture. 
• Define paper chromatography

  Paper chromatography is used to separate a mixture of solutes in a solvent. 
• Define characteristics of solids

  • Particles are in fixed positions but vibrate around a fixed point
  • Cannot be compressed because the particles are so close together
  • Cannot flow as they have a fixed shape and volume due to their strong forces of attraction
• Define characteristics of liquids

  • Particles are more spread in a random arrangement out but are still attracted to each other
  • Cannot be compressed as the particles are still close together
  • Can flow as it doesn't have a fixed shape because the forces of attraction are weaker than in a solid BUT will only take the shape of the bottom of the container
• Define characteristics of gases

  • The particles are very spread out and randomly in straight lines
  • Can be compressed as the particles have a lot of space between them
  • Can flow as it doesn't have a fixed shape or volume because the forces of attraction between the particles are very weak will take the shape of the whole container
• Changes of state require energy changes as energy is required to separate particles and is released when particles come together.
• Define the kinetic molecular theory

  • All matter is made up of small particles
  • These particles all have kinetic energy which mean they constantly move
  • The amount of KE is proportional to the temperature because at higher temp the particles have greater motion (straight line motion)
  • And lesser motion at lower temperatures (vibrational motion)
  • Collisions between the particles are elastic (no kinetic energy is lost)
• Melting

  Solid -> liquid
• Freezing

  Liquid -> solid
• Evaporation

  Liquid -> gas
• Condensation

  gas -> liquid
• Sublimation

  solid -> gas
• deposition

  gas -> solid
• The temperature, T, in Kelvin (K) is a measure of average kinetic energy (Ek) of particles.
• Kelvin (K) is the SI unit of temperature
• 0⁰C = 273K