Chapter 10, Problem 10.78QP

Interpretation Introduction

Interpretation: The average bond enthalpy has to be used to calculate the enthalpy of the reaction.

Concept Introduction:

Bond Enthalpy:

The measure of stability of molecule is bond enthalpy.  The change in enthalpy is related in breaking a specific bond of 1 mole of gaseous molecule. In solids and liquids bond enthalpies are affected by neighboring molecules.  There is possibility to predict the enthalpy of reaction using the average bond enthalpies. Energy is always needed for the breaking of chemical bonds and release of energy always takes place with the formation of chemical bonds.  The enthalpy of reaction is estimated by counting the total number of broken bonds and bonds formed in a reaction.

The enthalpy of reaction in gas phase is given by,

$\text{ΔH°=}{\displaystyle \sum {\text{BE}}_{\text{(reactants)}}}\text{-}{\displaystyle \sum {\text{BE}}_{\left(\text{products}\right)}}$

Where,

BE= Bond enthalpy and ${\displaystyle \sum \text{=}}$ summation

To calculate: The ${\text{ΔH}}_{\text{reaction}}$