Heat of Reaction

  1. The Heat of Reaction is the heat absorbed in a reaction at standard state condition between the numbers of moles of reactants shown in the equation for the reaction. 
  2. The Heat of reaction is represented by the symbol ∆H. 
  3. The unit of ∆H is kJmol-1
  4. If the reaction is exothernic, ∆H shows a value of negative. If the reaction is endothernic, ∆H shows a value of positive.
  5. The 4 heat of reaction that you need to know in the syllabus
    1. Heat of Precipitation
      The heat of precipitation of a substance is the heat change when 1 mole of precipitate formed from its solution of ion under standard state condition.
    2. Heat of Displacement
      The Heat of Displacement of an element is the heat change when 1 mole of the element was displaced from its compound under standard state condition.
    3. Heat of Neutralisation
      Heat of neutralisation is the heat change when 1 mol of water is formed by the neutralisation of hydrogen ions by hydroxide ions with measurements made under standard conditions.
    4. Heat of Combustion
      The Heat of Combustion of a substance is the heat energy evolved when 1 mole of the substance is completely burnt in oxygen.