Chemical changes 4

• Equation for a metal produce solid salt


  Metal + Acid= Salt +hydrogen
• Equation for a metal produce a metal hydroxide


  Metal + water= metal hydroxide +hydrogen
• OIL RIG


  Oxidation

  Is

  Lost

  Reduction

  Is

  Gained
• Equation when metals are gaining oxygen


  Metal + oxygen = metal oxide
• Reduction


  gain of electrons
• oxidation


  the loss of electrons
• Acids


  Substances that will produce hydrogen ions in aqueous solutions
• Bases


  Substances that will produce hydroxide ions in aqueous solutions
• 0-6 pH scale


  acidic

  e.g stomach, vinegar and milk
• 7 pH scale


  neutral

  e.g water
• 8-14 pH scale


  Basic

  e.g blood, ammonia and bleach
• strong acids


  typically made up of ionic compounds
• weak acids


  typically made from organic compounds
• neutralisation


  acids and alkalis will react together
• Equation for neutralisation


  Acid + Base = salt +water
• Reactivity Series:


  P otassium

  S odium

  c alcium

  M agnesium

  A luminium

  Car bon

  Z inc

  I ron

  T in

  L ead

  H ydrogen

  Copper

  S ilver

  Gold
• Molten (l) In electrolysis


  (no water)
• Solution (aq) In electrolysis:

  water is produced (H+ and OH-)
• Rule 1 in electrolysis:

  Lowest reactive metal goes to the cathode (- electrode)
• Rule 2 In electrolysis:

  If it contains a halogen then goes to the anode (+ electrode)
• Rule 3 in electrolysis:

  If NOT then OH- (oxygen) goes to either (anode/ cathode)
• Equation if no halogen is present: (oxygen)


  4OH- -> 2H20 + 02 + 4e-
• Aluminium Electrolysis:


  Electrolyte = Al203- Aluminum oxide

  Carbon dioxide is produced by the carbon and oxygen in the anode

  Cathode- aluminium
• What is a cryolite?

  Lowers the melting point (uses less electricity= cheaper)
• What's is a displacement reaction?

  occurs when a more reactive metal displaces a less reactive metal from a compound.
• Titration Practical:

  • use a burette to measure volume of acid/ alkali
  • measure 50cm^3 of alkali of known conc using glass pipette, put in conical flask with indicator (methyl orange)
  • acid in. burette
  • once it goes pink/red stop swirl
  • use moles to calculate unknown conc