Chemical Changes

• what is produced when a metal reacts with oxygen

  metal oxide
• what is oxidation

  gain of oxygen
• what is reduction

  loss of oxygen
• what is the reactivity series

  metals arranged in order of their reactivity
• how are metals ordered in the reactivity series

  the tendency of the metal to lose electrons and form positive ions
• what experiments can be done to put metals in their reactivity series

  how they react with water and acids
• why would you not use acids to predict the reactivity of sodium and potassium

  as very reactive would be too dangerous
• what are the products when a metal reacts with water

  metal hydroxide and hydrogen
• what are the products when a metal reacts with an acid

  salt and hydrogen
• what two non-metals are placed in the reactivity series

  carbon and hydrogen
• what is displacement reaction

  when a more reactive metal can displace a less reactive metal from a compound
• how are unreactive (native) metals found in the earth

  as the metal itself
• how are metals which are more reactive than carbon extracted from their oxides

  by electrolysis
• what is oxidation in terms of electron (HT only)

  loss of electrons
• what is reduction in terms of electrons (HT only)

  gain of electrons
• what is an oxidising agent

  a substance that causes another chemical to gain oxygen
• what is a reducing agent

  a substance that causes another chemical to lose oxygen
• what is the pH scale

  a scale of how acidic or alkaline a substance is
• what pH are acids

  less than 7 (red/orange/yellow)
• what pH are alkalis

  more than 7 (blue/purple)
• what pH is neutral

  7 (green)
• what can be used to measure pH

  universal indicator or a pH probe
• what is an alkali

  a metal hydroxide, a base that is soluble (e.g. Na2O can dissolve to make NaOH)
• what ion is in all acids

  H+ (hydrogen ion)
• what ion is in all alkalis

  OH- (hydroxide ions)
• what is the general equation for neutralisation?

  acid + base --> salt + water
• what is the ionic equation for neutralisation

  H+(aq) + OH-(aq) --> H2O(l)
• what is made when an acid reacts with an alkalis/bases

  salt and water
• what is made when a metal carbonate reacts with an acid

  salt, water and carbon dioxide
• what is the formula for hydrochloric acid


  HCl
• what is the formula of sulphuric acid


  H2SO4
• what is the formula of nitric acid


  HNO3
• what salt is made from hydrochloric acid

  chloride
• what salt is made from sulphuric acid

  sulphate
• what salt is made from nitric acid

  nitrate
• how can you make a soluble salt

  by reacting a metal, metal hydroxide or metal oxide with an acid.
• how can you make sure all of the acid used up when making a soluble salt

  keep adding the metal etc. until no more reacts
• how can you remove the metal/metal oxide or metal hydroxide that hasn't reacted when making a soluble salt

  filter it off
• what is the process called when a solid salt is obtained from a salt solution

  crystallisation
• what is a strong acid (HT only)

  an acid that is completely ionised in aqueous solution

  (e.g. hydrochloric, sulphuric and nitric)