Final topics

• Litmus


  • Blue
  • Red
• Phenolphthalein


  • Pink
  • Colourless
• Methyl Orange


  • Orange
  • Red
• pH ranges


  • Strong acids (0-3)
  • Weak acids (4-6)
  • Neutral (7)
  • Weak alkaline (8-10)
  • Strong alkaline (11-14)
• Universal indicator


  An indicator which changes colour when put in solutions of different pH. It goes red, orange, yellow, green, blue, purple, red being acidic purple being alkaline.
• Bases

  Metal oxides, metal hydroxides and ammonia can act as bases, and alkalis are just bases that are soluble in water.
• Reactions of bases


  1. Metal oxide + acid salt+ water

  2. Metal hydroxide + acid salt + water

  3. Metal carbonate + water salt + water + carbon dioxide

  4. Ammonia + acid Ammonium + metal
• Acids in aqueous solutions


  A source of hydrogen ions (H+ )
• Bases


  A source of hydroxide ions (OH- )
• Acid-metal reaction


  Acid + metal Salt+ hydrogen
• Acids


  • Sulfuric acid = sulphate
  • Hydrochloric acid= chloride
  • Nitric acid= nitrate
• Iron+ sulphuric acid Iron sulphate + hydrogen
• Hydrogen = squeaky pop test with lit split
• Oxygen= relighting glowing splint test
• Carbon dioxide = lime water test
• Bases


  Neutralise acids
• Acids and bases


  In terms of proton transfer
• Hydrogen is just 1 Proton and 1 electron, a H+ is just 1 proton, meaning acids produce protons and bases accept protons.
• Preparation of copper sulphate crystals


  1. Heat sulphuric acid in a beaker

  2. Add copper oxide in excess

  3. Filter the solution

  4. Gently heat the filtered solution to evaporate some water

  5. Leave to cool so crystals form
• Preparation of lead sulphate


  1. Mix similar volumes of lead nitrate and sodium Sulphate in a beaker

  2. A white precipitate of lead sulphate will form

  3. Filter the mixture

  4. Wash the residue with distilled water several times

  5. Leave the residue in a warm oven to dry
• Solvent


  Substance that dissolves a solute
• Solute


  Substance that dissolves in a solvent
• Solution


  Mixture formed by a solvent and solute
• Saturated solution


  Solution where no more solute can dissolve at a specified temperature
• Mass of solute that will saturate 100g of solvent at a stated temperature.
• Temperature


  The greater the temperature the more solute that can be dissolved by the solvent
• Point of crystallisation


  When crystals start to appear- indicating that the solution is saturated. May occur when a solution is cooled or when water is evaporated off.
• Crude oil is a mixture of hydrocarbons which are compounds made up of only hydrogen and carbon
• Industrial fractional distillation


  1. Heat the crude oil at the base of a fractionating column

  2. Different hydrocarbons have different boiling points and condense at different temperatures

  3. Separated into fractions which are tapped off and used for different purposes
• Main fractions obtained from crude oil


  • Refinery gas = Bottled gas
  • Gasoline=Fuel for cars
  • Kerosene=Fuel for aeroplanes
  • Diesel oil= Fuel for lorries
  • Fuel oil= fuel for ships
  • Bitumen= Road surfacing
• Small Alkanes


  Lower boiling points, higher flammability, burn with clean flame and less viscous
• Large Alkanes


  High boiling point, lower flammability, burn with dirty flame and more viscous
• Types of chemical formulas


  • Molecular formula
  • Empirical formula
  • Structural formula
  • Displayed formula
  • General formula
• Homologous series


  A group of chemicals with similar chemical properties. And have the same general formula
• Functional group


  An atom or a group of atoms that determine the chemical properties of a compound
• Isomers


  Molecules with the same molecular formula but with a different structure
• Alkanes


  Prefix= Meth, etc Suffix= ane
• Alkenes


  Prefix =Meth, etc Suffix= ene
• Branched alkanes/alkenes


  • If the branch has 1 carbon add methyl, with 2 carbons add ethyl e.g. methyl hexane
  • Add the point carbon the branch is coming of e.g. 2-methyl hexane
• General Formula for Alkanes = CnH2n+2