Chemistry 3

• Acid-alkali titration procedure

  1. Place the acid (or alkali) into a burette

  2. Place some alkali (or acid) into a conical flask using a pipette

  3. Add a suitable indicator (you are likely to need to name this)

  4. Add acid (or alkali) to the flask until the colour changes. Do this drop wise near the end point

  5. Note the final reading

  6. Repeat
• Inert electrons

  Electrodes that do not decompose in the electrolyte (carbon/platinum closing)
• Non-inert electrons

  Electrodes that do decompose in the electrolyte
• Cation rule


  Less reactive elements form at the cathode
• Anion rule


  If halide ions are present eg. Cl-, then these will form at the anode. If no halide ions are present, oxygen will form at the anode
• H+ ions


  Present in acids
• OH- ions


  Present in alkalis
• Electrolysis

  Splitting of a substance using electricity
• Anode

  Positive electrode, attracts anions because opposite attract
• Cathode

  Negative electrode, attracts cations because opposites attract
• Anions

  Always negative ions
• Cations

  Always positive ions
• Reduction (in terms of electrolysis)

  Gaining electrons
• Oxidation (in terms of electrolysis)

  Losing electrons
• Oxidation (in terms of redox)

  Addition of oxygen
• Reduction (in terms of redox)

  Removal of oxygen
• Oxidising agent


  Gives oxygen to another substance
• Reducing agent


  Gains oxygen from another substance
• pH scale

  Numbers from 0 to 14
• Strong acid

  0 to 3
• Weak acid

  4 to 6
• Neutral

  pH 7
• Weak base

  8 to 10
• Strong base

  10 to 14
• Neutralisation

  Reaction between an acid and a base to produce a salt and water
• Acid


  Produces hydrogen ions in water
• Alkaline

  Soluble base that produces hydroxide ions in water
• Ionic equation

  [H+]+[OH-]—> [H2O]
• Generalised formula for acids and metals

  acid+metal—> salt+ Hydrogen
• Acid + metal carbonate

  —> salt + Water + Carbon dioxide
• Test for carbon dioxide


  Lime water test
• Neutralisation occurs


  In the vertical section of the graph, which is the end point
• Concentration


  Number of acid particles in a specific volume
• Dilute

  Few particles in a specific volume
• Concentrated

  Lot of particles in a specific volume
• Strength

  Number of acid particles that ionise
• Ionise

  Split into ions
• Strong acids


  Fully ionise in water with a pH of 0-2
• Weak acids


  Partially ionise in water with a pH of 2–6
• The ion that all acids release in water is H+