Chapter 9, Problem 9.89QP

Interpretation Introduction

Interpretation:

For a given set of reactions based on energy considerations the reaction which occurs more readily 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,

$\Delta H_{rxn}^{°}\text{=}\text{ΣBE(reactants)-ΣBE(products)}$

A reaction is exothermic reaction when heat is released during the reaction.  A reaction is endothermic reaction when heat is absorbed during the reaction.

Endothermic reaction has $\Delta H°$ value in positive sign.

Exothermic reaction has $\Delta H°$ value in negative sign.