Chapter 9, Problem 9.93QP

Interpretation Introduction

Interpretation:

Bond enthalpy of $F_2$ has to be compared with energy change of given process.  The preferred dissociation for $F_2$ has to be identified.

Concept Introduction:

$\Delta H°$ refers to change in enthalpy.  Change in enthalpy in a reaction and bond energy (BE) are related as,

    $\text{ΔH°}\text{=}\text{ΣBE(reactants)-ΣBE(products)}$

Hess’s law is applied to calculate the enthalpy changes in a reaction.  According to Hess’s law – “The overall enthalpy change of a reaction is equal to the sum of the enthalpy changes involving in each and every individual steps in the reaction.”  Thus if a reaction involves ‘n’ steps then enthalpy change $\Delta H°$ of the reaction is,

  $\Delta H°=\Delta {\text{H}}_1^{°}+\Delta {\text{H}}_2^{°}+\Delta {\text{H}}_3^{°}\mathrm{....}+\Delta {\text{H}}_n^{°}$