energy changes

• What is the conservation of energy principle?


  The amount of energy in the universe at the end of a chemical reaction is the same as before the reaction takes place.
• Energy cannot be created or made.
• What is an exothermic reaction?


  When energy is transferred to surroundings and the surroundings temperature increases.
• Give examples of an exothermic reaction.


  • Oxidation.

  • Neutralisation.

  • Combustion.
• What is an endothermic reaction?


  When energy is taken in from the surroundings so the surroundings temperature decreases.
• Give examples of an endothermic reaction.


  • Thermal decomposition.

  • Self Heating Cans.
• What is activation energy?


  The minimum amount of energy needed for particles to react.