C7 ENDO AND EXOTHERMIC REACTIONS

• exothermic reaction : energy moves from reacting chemicals to their surroundings
• exothermic reactions mean temperature of surroundings increase
• endothermic : energy moves from surroundings to reacting chemicals
• endothermic reactions mean temperature of surroundings deacrease
• respiration is exothermic and photosynthesis is endothermic
• complete combustion is exothermic
• thermal decomposition is endothermic
• exothermic changes can be used in hand warmers and self heating cans
• endothermic changes can be used in instant cold packs for sports injuries
• reaction profile examples

  A) exothermic

  B) endothermic

  C) reactants

  D) products

  E) reaction progress

  F) potential energy

  G) activation energy

  H) overall energy change

  I) reactants

  J) products

  
• breaking bonds absorbs energy (endothermic)
• forming bonds releases energy (exothermic)
• reatants - products = overall energy change