acids and bases

• General rules for predicting the solubility of ionic compounds in water

  • Soluble: sodium, potassium, ammonium, nitrates
  • Insoluble: silver chloride, lead chloride, lead sulfate, barium sulfate, calcium sulfate
  • Soluble carbonates: sodium, potassium, ammonium
  • Insoluble carbonates: all except sodium, potassium, ammonium
  • Soluble hydroxides: sodium, potassium, ammonium
  • Insoluble hydroxides: all except sodium, potassium, ammonium
• Acids


  Donate protons (H+)
• Bases


  Accept protons
• Acids are proton donors, bases are proton acceptors
• Reactions of hydrochloric acid, sulfuric acid and nitric acid


  1. Acid + base → salt + water

  2. Acid + metal → salt + hydrogen

  3. Acid + metal carbonate → salt + water + carbon dioxide
• To form the formula of the salt


  • Take the metal ion in the base/metal/carbonate
  • Take the ion part of the acid which isn't hydrogen
  • Balance the charges
• Reactions to form salts

  • H2SO4 + MgO → MgSO4 + H2O
  • HNO3 + NaOH → NaNO3 + H2O
  • 2HCl + 2Na → 2NaCl + H2
  • H2SO4 + Na2CO3 → Na2SO4 + H2O + CO2
• Metal oxides, metal hydroxides and ammonia


  Can act as bases
• Alkalis


  Bases that are soluble in water
• Use of ammonia as a base

  • HCl + NH3 → NH4Cl
• Preparing a pure, dry sample of a soluble salt starting from an insoluble reactant


  1. Add excess insoluble base to the acid

  2. Filter to remove unreacted base

  3. Heat the solution so that water evaporates and crystals of the salt remain
• Preparing a pure, dry sample of a soluble salt starting from an acid and alkali


  1. Use a titration to find the exact volume of the alkali that reacts with the acid

  2. Mix the exact volumes of the acid and base

  3. Warm solution so that water evaporates and crystals of the salt remain
• Preparing a pure, dry sample of an insoluble salt starting from two soluble reactants


  1. Mix solutions of 2 soluble reactants

  2. Filter mixture (insoluble salt will remain on filter paper)

  3. Wash salt with distilled water

  4. Leave salt to dry
• Practical: Prepare a sample of pure, dry hydrated copper (II) sulfate crystals starting from copper (II) oxide
• Practical: Prepare a sample of pure, dry lead (II) sulfate