Topic 4 - Chemical Changes

• Which ion makes a solution acidic?

  H+
• What is the ionic equation of neutralisation?

  H+ + OH- ==> H2O
• What colour does universal indicator turn in neutral solutions?

  Green
• What is an alkali?


  A soluble base that can neutralise acids
• What is a base?

  A substance that can neutralise acids
• When the concentration of OH- ions increases, what happens to pH?

  The pH increases
• When the concentration of OH- ions decreases, what happens to pH?

  The pH decreases
• What are the products when a base or alkali reacts with an acid?

  Salt + water
• Which ion makes a solution alkaline?

  OH-
• What colour does universal indicator turn in acidic solutions?


  Red
• What colour does universal indicator turn in alkaline solutions?


  Blue/Purple
• What is an acid?


  A substance that can neutralise bases
• When the concentration of H+ ions increases, what happens to pH?

  The pH decreases
• When the concentration of H+ ions decreases, what happens to pH?

  The pH increases
• What are the products when a metal reacts with an acid?

  Salt + Hydrogen
• What are the products when a metal carbonate (base) reacts with an acid?

  Salt + water + carbon dioxide
• In the soluble salts practical, why is filtration required?

  To remove excess base
• On which side of the equation do you find alkalis in a neutralisation reaction?

  Left hand side (reactants)
• On which side of the equation do you find salts in a neutralisation reaction?

  Right hand side (products)
• What is the definition of a weak acid?

  An acid that partially ionises in solution
• What is meant by reduction, in terms of oxygen?

  Loss of oxygen
• What is meant by reduction, in terms of electrons?

  Gain of electrons
• Sulfate


  Salts produced using sulfuric acid have what ending to their name?
• Chloride


  Salts produced using hydrochloric acid have what ending to their name?
• In the soluble salts practical, why is the base added in excess?

  To ensure all the acid is fully neutralised
• On which side of the equation do you find bases in a neutralisation reaction?

  Left hand side (reactants)
• On which side of the equation do you find acids in a neutralisation reaction?

  Left hand side (reactants)
• What is the definition of a strong acid?

  An acid that completely/fully ionises in solution
• What is meant by oxidation, in terms of oxygen?

  Gain of oxygen
• What is meant by oxidation, in terms of electrons?

  Loss of electrons
• What is the name for the type of reaction where oxidation and reduction occur at the same time?


  Redox
• Nitrate


  Salts produced using nitric acid have what ending to their name?