How are bond energies related to change in enthalpy of a reaction?

Asked by SAHANA Hebsur | 26th Oct, 2013, 03:09: PM

Expert Answer:

The net enthalpy change of a reaction is the amount of energy required to break all the bonds in the reactant molecules minus the amount of energy required to break all the bonds in the product molecules.

Enthalpy of a reaction = (Sum of bond enthalpies of reactants) - (Sum of bond enthalpies of products)

(i) Since H and S both are increasing so, their values will be positive hence the reaction will be feasible only if TS > H.

(ii) Since H and S both are decreasing so, their values will be negative hence the reaction will be feasible only if H > TS.

Answered by  | 28th Oct, 2013, 02:39: PM

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