Reactions of acids

• What is an acid in terms of pH?


  A solution with a pH of less than 7
• What is a neutral solution in terms of pH?


  A solution with a pH of 7
• In terms of H+ ions, what is an acid? 


  A substance that releases H+ ions when dissolved in water
• How is the amount of H+ ions in a solution related to its pH?


  The more H+ ions, the lower the pH
• What are the names and formulae of three main acids?

  Hydrochloric acid (HCl), sulfuric acid (H2SO4), nitric acid (HNO3)
• How do you measure the pH of a substance?

  Using a universal indicator or pH probe
• What is a strong acid?


  An acid where the molecules or ions completely ionise in water
• What is a weak acid?


  An acid where the molecules or ions partially ionise in water
• What is a salt?

  A compound formed when a metal ion takes the place of a hydrogen ion in an acid
• Which type of salts do sulfuric acid, hydrochloric acid, and nitric acid form?

  Sulfates, chlorides, nitrates
• What are the products of a reaction between a metal and an acid?


  Salt and hydrogen
• What are the products of a reaction between a metal hydroxide and an acid?


  Salt and water
• What are the products of a reaction between a metal oxide and an acid?


  Salt and water
• What are the products of a reaction between a metal carbonate and an acid?


  Salt, water, and carbon dioxide
• What is a base?


  A substance that reacts with acids in neutralisation reactions
• What is an alkali?


  A substance that dissolves in water to form a solution above pH 7
• What is a neutralisation reaction?


  A reaction between an acid and a base to produce water
• What is the ionic equation for a reaction between an acid and an alkali?


  H+(aq) + OH–(aq) → H2O(l)
• How can you obtain a solid salt from a solution?

  By crystallisation
• When an acid reacts with a metal, which species is oxidised?


  The metal
• When an acid reacts with a metal, which species is reduced?

  Hydrogen