mixtures

• Pure substance:

  • A substance with identical particles that cannot be separated into other materials
  • Divided into elements (e.g. silver, gold, copper) and compounds
  • Example: silver, gold, copper, noble gases
• The Particle Theory of Matter:

  • All matter is made up of particles that are too small to see with the human eye
  • Particles can be individual atoms or groups of atoms known as molecules
  • All particles are in constant motion, which can be observed in the states of matter (solid particles vibrate, liquid particles flow, gas particles fly around each other)
• Mixture:

  • Made up of two or more different substances that have not been chemically bonded
  • Substances are physically mixed and keep their individual properties
  • Example: cereal and milk
• Dissolving:

  • Process of substances being fully mixed together to create homogeneous mixtures
  • Example: mixing sugar and tea
• Heterogeneous mixture:

  • Mixture where different parts have not dissolved and are visible
  • Components are larger than in homogeneous mixtures, making separation easier
  • Example: salad
• Disadvantage of water's ability to dissolve substances:

  • Can dissolve contaminants that can harm life
• Concentrated solution:

  • Contains a lot of dissolved solute
  • Example: frozen orange juice concentrate
• Diluted solution:

  • Small amount of dissolved solute
  • Can be achieved by adding water to a concentrated solution
• Unsaturated solution:

  • Contains less solute that can be dissolved
  • More solute can be dissolved
• Saturated solution:

  • Solvent can no longer dissolve the solute
  • Remaining solutes sink to the bottom
• Supersaturated solution:

  • Contains more solute than a standard solution
  • Heat is used to produce a supersaturated solution
• Sifting:

  • Technique for sorting solids based on sizes by shaking materials through a mesh or screen
• Homogeneous mixture:

  • Mixture where different parts have dissolved and are not visible
  • Components retain their properties and can be separated through physical means
  • Example: sugar, water, lemon juice mixture
• Filtration:

  • Mechanical separation of solids from liquids or gases using filters (e.g. paper, sand, carbon)
• Solution:

  • Mixture of one or more solutes and a solvent
  • Solvent dissolves the solute
  • Example: water (solvent) and instant coffee grounds (solute) to make a coffee solution
• Water as the "universal solvent":

  • Dissolves more particles than any other liquid
  • Important for transporting chemicals, minerals, and nutrients
• Distillation:

  • Technique for separating a mixture of different pure substances by vaporising and condensing the liquid components
• Evaporation:

  • Used to separate homogeneous mixtures with dissolved solids by heating and evaporating the liquid components
• Magnets:

  • Attract iron and steel, allowing separation from non-magnetic materials
• Sorting:

  • Separates objects based on appearance (e.g. colour, size, composition)
  • Common in recycling centres