chemical changes

• What is oxidation in terms of oxygen gain?

  When a substance gains oxygen
• What is reduction in terms of oxygen loss?

  When a substance loses oxygen
• What does the reactivity series of metals indicate?

  It shows metals in order of reactivity
• What happens to metals above hydrogen in the reactivity series when reacting with acids?

  They react to produce hydrogen gas
• How does the reactivity of metals with acids change?

  The more reactive, the quicker and more violent reaction
• Which metals do not react with acids?

  Metals below hydrogen
• Which metals primarily react with water?

  Mostly Group I and II metals
• What is a displacement reaction?

  A reaction where a more reactive metal displaces a less reactive metal
• How are unreactive metals found in Earth?

  In their natural state
• How can metals less reactive than carbon be extracted?

  By reduction with carbon
• What happens during the reduction with carbon?

  Carbon displaces the metal in a metal oxide
• How are metals more reactive than carbon extracted?

  By electrolysis
• How are oxidation and reduction defined in terms of electron transfer?

  Oxidation is loss of electrons; reduction is gain
• What is the general equation for a reaction between metals and acids?

  Metal + acid → salt + hydrogen
• What type of reaction is the reaction between metals and acids?

  It is a redox and displacement reaction
• Which metals in the reactivity series will react with acid?

  Those above hydrogen
• What is the general equation for a neutralisation reaction?

  Base + acid → salt + water
• What is the general equation for the reaction between metal carbonate and acid?

  Metal carbonate + acid → salt + water + carbon dioxide
• What is the general equation for the reaction between metal oxides and acids?

  Metal oxide + acid → salt + water
• What is a redox reaction?

  A reaction where both oxidation and reduction occurs
• In the reaction of magnesium with hydrochloric acid, which species is oxidised?

  Magnesium is oxidised (loses electrons)
• In the reaction of magnesium with hydrochloric acid, which species is reduced?

  Hydrogen in HCl is reduced (gains electrons)
• How is a soluble salt formed?

  React excess acid with insoluble chemical
• What do acids produce in aqueous solutions?

  Acids produce hydrogen ions
• What do alkalis produce in aqueous solutions?

  Alkalis produce hydroxide ions
• What are bases, acids, and alkalis?

  Bases neutralise acids; acids produce H+ ions
• What does a pH of 7 indicate?

  It indicates a neutral solution
• What is the short ionic equation for a neutralisation reaction?

  H+ + OH− → H2O
• What is a strong acid?

  Completely ionised in aqueous solution
• What is a weak acid?

  Partially ionised in aqueous solution
• What happens to pH as the concentration of H+ increases?

  pH decreases as H+ concentration increases
• What is the general equation for a neutralisation reaction in ionic form?

  H+ + OH− → H2O
• What defines a strong acid?

  Completely ionised in aqueous solution
• What defines a weak acid?

  Partially ionised in aqueous solution
• What happens to pH as the concentration of H+ increases?

  The pH decreases
• What is the difference between concentrated and dilute acids?

  • Concentrated acid has more moles per unit volume
  • Dilute acid has low concentrations
  • Concentration is not the same as strength
  • Strength refers to ionisation in water
• What change occurs in hydrogen ion concentration when pH decreases by one unit?

  Increases by a factor of 10
• Name the following salts: LiNO3, K2CO3, MgBr2, BaSO4.

  • Lithium nitrate
  • Potassium carbonate
  • Magnesium bromide
  • Barium sulfate
• What is electrolysis?

  Passing electric current through ionic substances
• What is an electrolyte?

  The liquid/solution which conducts electricity