Acids

• Solubility of ionic compounds in water


  • Soluble: sodium, potassium, ammonium, nitrates
  • Insoluble: silver chloride, lead chloride, lead sulfate, barium sulfate, calcium sulfate
  • Sodium, potassium, ammonium carbonates and hydroxides are soluble except...
• Acids


  Donate protons (H+)
• Bases


  Accept protons
• Acid


  Proton donor
• Base


  Proton acceptor
• Reactions of hydrochloric acid, sulfuric acid and nitric acid


  1. With metals

  2. With bases

  3. With metal carbonates
• Acid + base → salt + water
• Acid + metal → salt + hydrogen
• 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
• Example of ammonia as a base


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


  1. Add excess insoluble base to the acid

  2. Filter to remove unreacted base

  3. Heat the solution to evaporate water and leave salt crystals
• Preparing a pure, dry sample of a soluble salt from an acid and alkali


  1. Use titration to find exact volumes

  2. Mix the exact volumes of acid and base

  3. Warm solution to evaporate water and leave salt crystals
• Preparing a pure, dry sample of an insoluble salt from two soluble reactants


  1. Mix solutions of 2 soluble reactants

  2. Filter mixture to collect insoluble salt

  3. Wash salt with distilled water

  4. Leave salt to dry
• Copper (II) oxide is an insoluble base, so follow steps in 2.39 to prepare copper (II) sulfate
• Lead (II) sulfate is insoluble, so follow steps in 2.41 to prepare it
• 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 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
• Example of ammonia as a base


  • HCl + NH3 → NH4Cl
• Experiment to prepare 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
• Experiment to prepare 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
• Experiment to prepare 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