atoms, elements, compounds and mixtures

• describe atom

  smallest part of element that can exist
• describe element

  substance only containing one type of atom
• describe a compound

  two or more elements chemically combined together
• describe a mixture

  two or more elements not chemically combined together
• describe an isotope

  different forms of the same element with same number of protons and different number of neutrons
• give methods of separation

  filtration, crystallisation, evaporation and distillation
• describe filtration

  separates insoluble solids from liquids
• describe crystallisation

  separates solutes from solutions
• describe process of crystillisation

  1. heat solution
  2. heat until crystals start to form
  3. remove from heat and allow to cool
  4. filter and dry crystals
• describe evaporation

  separate solutes from solution
• describe process of evaporation

  1. heat solution
  2. heat until crystals left behind
• describe chromatography

  separate substances from solutions
• describe distillation

  separate solvents from solution
• describe process of simple distillation

  1. heat solution
  2. solvent of lowest boiling point evaporates
  3. vapour cool and condense
• describe process of fractional distillation

  1. heat solution
  2. multiple solvents with evaporates
  3. vapour of lowest boiling point cools, condenses and collected
  4. other vapours cool and condense back to flask before collection