Mixtures & Seperation

• Mixture:

  Substance made by mixing other substances together classified by whether the substances in them are solids, liquids or gases
• Types of mixtures:

  Suspension

  → mixture of two substances that separate if mixture is not stirred

  (eg: sand mixed with water)

  Colloid

  → one substance is dispersed in another substance and cannot be separated easily

  (eg: whipped cream)

  Solution

  → solid dissolves in the liquid, making mixture clear or transparent

  Solvent

  → liquid in the solution (eg: water)

  Solute

  → the substance that is dissolved in a solvent (which means its soluble)

  (eg: sand, salt)
• Filtration:

  → Process of separating solid particles from a fluid or gas by passing it through a filter

  → Filtering separates a solid from a liquid (liquid and insoluble solid is being filtered)
• Parts of Bunsen burner and their functions:

  Hose - supplies gas to burner

  Barrel - lifts flame to useful height for heating

  Base - keeps the burner stable on a flat surface

  Collar with air hole - controls how much air mixes with the gas
• Rules of using Bunsen burner:

  • make sure the area is safe enough to work in (eg: flat surface, enough space to work, no books to close to the flame)
  • hair tied back
  • sleeves rolled up to the elbows
  • safety goggles
  • never leave flame unattended
  • switch on safe flame when not in use
  • light flame with air hole closed
  • check the tubing for any tears
  • use heat-proof mat
• Heat to dryness:

  Evaporating all the liquid from a solution to leave behind the solids that were dissolved in it 
• Evaporation:

  • the process of a liquid changing to a gas, especially by heating
• Separation techniques:

  • chromatography
  • filtration
  • evaporation
  • heating to dryness
• • mass of solution is the same as the mass of the dissolved substance + mass of liquid at the start
  • there is a limit to how much solute you put dissolve in a solvent, if you add more solute the extra will sink to the bottom and stay dissolved, this is called saturated
• The boiling point is the temperature where vapour pressure equals atmospheric pressure
• Distillation - based on different boiling points of liquids mixed together
• Distillation setup apparatus - flask, Liebig condenser, beaker, Bunsen burner, thermometer
• Filtration setup apparatus - conical flask, filter funnel, filter paper
• Heating to dryness setup apparatus - evaporating basin, tripod, wire gauze, Bunsen burner