energetics

• exothermic reaction transfers thermal energy to the surroundings leading to an increase in the temperature of the surroundings
• endothermic reaction takes in thermal energy from the surroundings leading to a decrease in the temperature of the surroundings
• the transfer of thermal energy during a reaction is called the enthalpy change, ∆H, of the reaction
• ∆H is negative for exothermic reactions and positive for endothermic reactions
• activation energy, Ea : the minimum energy that colliding particles must have to react
• bond breaking is an endothermic process and bond making is an exothermic process
• 1

  A) exothermic

  B) released

  C) increase

  
• examples of exothermic reactions

  • combustion
  • neutralisation
  • most oxidation
• 2

  A) endothermic

  B) absorbed

  
• 3

  A) reactants

  B) activation energy

  C) products

  D) energy

  E) progress of reaction

  
• Bond energy


  amount of energy required to break one mole of a particular covalent bond