8.2 ENDOTHERMIC REACTIONS

• Endothermic Reactions


  When the temperature at the end of the reaction is lower than at the start of the reaction.

  some chemical reactions absorb thermal energy from their surroundings and change it to chemical energy stored in chemical bonds.

  energy is absorbed from the surroundings and stored in chemical bonds, so the surroundings have a lower temp and the sunstance feels cooler.
• Endothermic Processes

  • when potassium dissolving in water, thermal energy is absorbed from the surroundings so the beaker feels cold.
  • ice melting is another because the particles absorb thermal energy from the surroundings and vibrate faster. the ice begins to melt and can move and overcome the forces holding them in place. particles slide past each other till a liquid is presented.
  • no new substances are formed like in a reaction
• Exothermic or Endothermic


  exo -> thermal enegry is given out eg. a self-heating can

  endo -> thermal energy is taken in eg. a chemical ice pack treating an injury