Chemical changes

• Explain the reactivity series

  Metals can be placed in order of reactivity by their reactions with water and dilute acid. Hydrogen gas is given off when metals react with acid or water. The gas gives a squeaky pop with a lighted splint
• State the reactivity series

  Potassium

  Sodium

  Lithium

  Calcium

  Magnesium

  (Carbon)

  Zinc

  Iron

  (Hydrogen)

  Copper

  Silver

  Gold
• Describe how potassium reacts with water

  It melts, floats & moves around very quickly. It sets on fire with a lilac flame. Alkaline solution forms.
• How does potassium react with acid?

  Explodes
• How does sodium react with water?

  fizzes rapidly and melts to form a ball that moves around on the water surface. Alkaline solution forms.
• How does sodium react with acid?

  Explodes
• How does lithium react with water?

  Floats, does not melt, fizzes steadily, does not burst into flames. Becomes smaller. Alkaline solution forms.
• How does lithium react with acid?

  Explodes
• How does calcium react with water?

  It fizzes steadily leaving an alkaline solution
• How does calcium react with acid?

  Fizzes quickly with dilute acid
• How does magnesium react with water?

  very slowly
• How does magnesium react with acid?

  Fizzes quickly with dilute acid
• How does zinc react with water?

  Very slowly
• How does zinc react with acid?

  Bubbles slowly with dilute acid.
• How does iron react with water?

  very slow reaction
• How does iron react with acid?

  Very slow reaction with dilute acid.
• How does copper react with water?

  No reaction
• How does copper react with acid?

  no reaction
• How does silver react with water?

  No reaction
• How does silver react with acid?

  No reaction
• How does gold react with water?

  No reaction
• How does gold react with acid?

  No reaction
• What is a displacement reaction?


  A more reactive metal will displace the less reactive metal from a compound.

  E.g. Fe+CuSO4=FeSO4+Cu
• What is oxidation?

  Loss of electrons, gain of oxygen
• What is reduction?

  gain of electrons, loss of oxygen
• What is an acid?

  A chemical that dissolves in water to produce H+ ions.
• What is a base?

  A chemical that reacts with acids and neutralises them. E.g. metal oxides, metal hydroxides, metal carbonate.
• What is an alkali?

  a soluble base that produces OH- ions in a solution.
• What is neutralisation?


  When a neutral solution is formed from reacting an acid and alkali.

  E.g. H+ + OH-= H20
• What is PH?

  A scale to measure acidity or alkalinity. A decrease of one PH unit causes a 10X increase in conc of H+ ions.
• What are the strong acids?

  Strong acids are completely ionised in a solution. E.g. hydrochloric, nitric and sulfuric acids.
• What is a weak acid?

  A weak acid is only partially ionised in solution. Examples of weak acids are ethanoic, citric and carbonic acids.
• How do you extract very unreactive metals? E.g. silver and gold

  Found naturally in the ground. Extracted using mining.
• How do you extract metals less reactive than carbon? E.g. zinc, iron and & lead.

  Metals less reactive than carbon can be extracted from their ores by reduction using carbon, coke or charcoal.

  2PbO+C=2Pb+CO2. Carbon has displaces lead from its oxide because carbon is more reactive than lead. This extraction takes place in a blast furnace at high temperatures.
• How do you extract metals less reactive than hydrogen. E.g. tungsten?

  Metals less reactive than hydrogen can be extracted from their ores by reduction using hydrogen. Tungsten is obtained from its oxide by reduction using hydrogen.

  WO3+3H2=W+3H2O
• How do you extract metals more reactive than carbon e.g. Aluminium

  Extracted by electrolysis.
• What is electrolysis?


  the breakdown of a substance containing ions by electricity
• What is the neutralisation reaction with metal?

  Acid+ metal= salt+ hydrogen

  2HCl+Fe=FeCl2+H2
• What is the neutralisation reaction with an alkali?

  Acid+ Metal Hydroxide= Salt+ Water

  HCl+NaOH=NaCl+ H20
• What is the neutralisation reaction with a metal oxide?

  Acid+Metal oxide=Salt+ Water

  2HCl+MgO=MgCl2+ H2O