Mixtures

• Element


  A substance that is made up of only one kind of atom
• Mixture


  Two or more substances not chemically bonded
• Compound


  A substance made up of two or more elements chemically bonded together (compound can be split into their elements)
• Rules for mixtures


  • They can be separated by physical methods
  • They have the properties of the things in the mixture
  • No chemical change occurs when making a mixture
• Filtration


  1. Separate an insoluble solid from a pure liquid or solution

  2. The insoluble solid cannot pass through the filter paper but the liquid can

  3. The solid stays on the surface of the filter paper as a residue

  4. The liquid passes through the filter paper forming the filtrate
• Evaporation


  1. Separate a solute from a solution

  2. The solvent (e.g. water) evaporates leaving the solute (e.g. salt) behind as a condensate
• Distillation


  1. Boiling

  2. Condensing

  3. Collecting
• Simple distillation


  • Separate the solvent (e.g. water) from a solution (e.g. salt water)
  • Works because the solvent has a much lower boiling point than the solute
• Fractional distillation


  1. Separate 2 or more liquids with different boiling points

  2. Mixture is boiled in a fractionating column

  3. Liquids with lower boiling points evaporate first and condense at the top

  4. Liquids with higher boiling points evaporate later and condense lower down
• Crude oil


  • A mixture of hydrocarbon molecules
  • Hydrocarbons are molecules containing only hydrogen and carbon
  • Crude oil is separated into fractions with different boiling points
• Gases in air


  • Oxygen
  • Carbon Dioxide
  • Nitrogen
  • Argon
• Separating gases in air

  1. Cool air to -200oC to liquefy it

  2. Allow it to slowly warm up and collect each gas as it boils off

  3. Carbon dioxide and water are removed as solids

  4. Nitrogen boils off at -196oC

  5. Oxygen boils off at -185oC
• Uses of gases from air

  • Nitrogen - make ammonia, cool things, food packaging
  • Argon - light bulbs
  • Oxygen - hospitals, welding
  • Carbon Dioxide - cooling, dry ice
• A mixture is made up of two or more substances that are not chemically combined.
• Mixtures can be separated using techniques like filtration, decanting, crystallisation, chromatography, distillation, centrifugation, magnetism, and electrolysis.
• Chromatography separates mixtures based on their ability to dissolve in a particular solvent.
• Filtration involves pouring the liquid through a filter paper to separate solid particles.
• Pure substances have uniform composition and properties throughout their structure, while mixtures do not.
• The components of a mixture can be identified by physical properties such as melting point, density, colour, odour, etc.
• Distillation involves heating the mixture until one component evaporates and then condensing it back into liquid form.
• Distillation uses heat to evaporate one component of a mixture and then condense it back into a liquid.
• Separation methods include filtration, evaporation, fractional distillation, and chromatography.
• Evaporation is used when there are two liquids with different boiling points that need to be separated.
• Fractional distillation separates a mixture based on its boiling point range.
• Filtration separates solids from liquids using a filter paper or cloth.
• Evaporation removes water from a solution by heating it.
• Chromatography is used to separate mixtures based on their solubility in a mobile phase.
• Distillation involves the separation of components of a liquid mixture based on differences in boiling points.
• A solute is a substance that can be dissolved into a solution by a solvent. 
• Fractional distillation is used to seperate a mixture of liquids