mean bond enthalpies

• what is mean bond enthalpy?

  average energy required to separate completely the atoms in one mole of covalent bond in gas phase
• what type of reaction is it to break the bonds of the reactants?

  endothermic
• what type of reaction is it to form the bonds of the products?

  exothermic
• what is the mean bond enthalpy calculation?

  H= sum of bonds broken (reactants) - sum of bonds formed (products)