Bond Energies

• Mexican Ben

  Making bonds is exothermic

  Breaking bonds is endothermic
• In endothermic reactions, the energy used to break bonds is more than the energy released after the reaction
• In exothermic reactions, the energy required for the reaction to happen is less than the energy released after the reaction
• Every chemical bond e.g. C-O has a bond energy to break the bond
• Equation to measure energy change using bond energies:

  Overall energy change = energy required to break bonds - energy released when forming bonds
• Positive energy change = endothermic reaction

  Negative energy change = exothermic reaction