Chapter 10, Problem 10.82P

(a)

Interpretation Introduction

Interpretation:

The unusual characteristic about the electronic structure of $\text{OH}$ is to be determined.

Concept introduction:

Lewis structure is generally considered as a simplified structure of any molecule or atom. Lewis structure for any atom or molecule depicts the valence electrons as dots around the element’s symbol present in the molecule along with the bonds that connect them. Every element tries to complete an octet except the hydrogen atom. Every element in the Lewis structure tries to attain eight electrons in its valence shell by transfer or share of electrons. This rule is known as the octet rule.

(b)

Interpretation Introduction

Interpretation:

The $\text{O}-\text{H}$ bond energy in $\text{OH}\left(g\right)$ is to be calculated.

Concept introduction:

The heat of the reaction $\left(\Delta H_{\text{rxn}}^{°}\right)$ is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. $\Delta H_{\text{rxn}}^{°}$ is negative for exothermic reaction and $\Delta H_{\text{rxn}}^{°}$ is positive for an endothermic reaction.

The formula to calculate $\Delta H_{\text{rxn}}^{°}$ of reaction is as follows:

  $\Delta H_{\text{rxn}}^{°}=\sum \Delta H_{\text{reactant bond broken}}^{°}+\sum \Delta H_{\text{product bond formed}}^{°}$

Or,

  $\Delta H_{\text{rxn}}^{°}=\sum {\text{BE}}_{\text{reactant bond broken}}-\sum {\text{BE}}_{\text{product bond formed}}$

The bond energy of reactants is positive and the bond energy of products is negative.

(c)

Interpretation Introduction

Interpretation:

The energy needed to break the first $\text{O}-\text{H}$ bond in water is to be calculated.

Concept introduction:

The heat of the reaction $\left(\Delta H_{\text{rxn}}^{°}\right)$ is defined as the heat released or absorbed during a chemical reaction as a result of the difference in the bond energies (BE) of reactant and product in the reaction. $\Delta H_{\text{rxn}}^{°}$ is negative for exothermic reaction and $\Delta H_{\text{rxn}}^{°}$ is positive for an endothermic reaction.