Bond enthalpy not given

[505095793]

If the bond enthalpy is not given how would we calculate the reaction enthalpy?

[Manya Bali 4E]

There are two other ways. One is that the enthalpy of the reaction equals the sum of the enthalpies of formations of the products minus the sum of the enthalpies of formation for the products. The other way is to use Hess's method and add together the enthalpies of different reactions if, together, the reactions form the reactants/products you want.

[LorenzoDuvergne3I]

It should be noted that the other two methods also require some sort of given information, either the enthalpies of formation or the enthalpies of each reaction, so which method you use depends on what information the problem gives you.

[Clarissa Cabil 1I]

If a certain bond enthalpy is not given, also note if the bond is between elemental molecules at their most natural state at standard conditions (E.g. O₂ (g), F₂ (g)) in which the bond enthalpy is assumed to be equal to 0.

Hope this helps!