chapter 4

• acids release H+ ions into a solution. A strong acid completely dissociates in an aqueous solution and all its H+ ions are released, whereas a weak acid only partially dissociated and releases a portion of its H+ ions.
• a base neutralises acids to form salts. an alkali is a base that dissolves in water to release hydroxide ions into the solution
• neutralisation is when a acid and base react to form a salt and water.

  acids with metal oxides and hydroxides form a salt and water

  acids with a carbonate form a salt, water and carbon dioxide
• a titration is a technique that is used to measure the volume of one solution that reacts with another solution. Its used to find the concentration of a solution
• to prepare a standard solution, a volumetric flask should be used, which are typically 250cm3. A pipette and burette should be used for titrations as well
• you should calculate the mean titre by using concordant results, so they have to be within 0.1cm of each other
• oxidation numbers are used when writing formulae. the oxidation numbers for elements are always zero, and always have the sign placed before the number. special cases when oxidation number changes

  • H in metal hydrides ( NaH) = -1
  • Oxygen in peroxides= -1
  • Oxygen bonded to F2O is 2+
• oxidation is loss of electrons whereas reduction is gain of electrons. Redox reactions involve oxidation and reduction