Endo and exo

• Exothermic reaction


  Reaction that gives off energy to the surroundings, usually in the form of heat
• Endothermic reaction


  Reaction that takes in energy from the surroundings, usually in the form of heat
• Exothermic reactions


  • Fire giving off heat
  • Neutralization reactions between acids and alkalis
  • Reactions between water and calcium oxide
  • Respiration
• Detecting exothermic reactions


  Use a thermometer to see if the temperature increases
• Most chemical reactions are exothermic because heat is given out
• When something freezes (liquid to solid)


  It is exothermic because bonds need to be made, which gives out energy
• When condensation happens (gas to liquid)

  It is exothermic because bonds need to be made, which gives out energy
• In exothermic reactions


  The energy of the reactants is higher than the energy of the products
• Endothermic reactions


  • Electrolysis
  • Reaction between sodium carbonate and ethanoic acid
  • Photosynthesis
• When something melts (solid to liquid)

  It is endothermic because bonds need to be broken, which requires energy
• When boiling happens (liquid to gas)

  It is endothermic because bonds need to be broken, which requires energy
• In endothermic reactions


  The energy of the products is higher than the energy of the reactants
• Exothermic reactions are more common than endothermic reactions