Chapter 13, Problem 60E

(a)

Interpretation Introduction

Interpretation: The bond energy of S-F bond needs to be determined with the help of given enthalpies of formation.

  $\begin{array}{l}{\text{ΔH for S}}_{\text{(g)}}\text{= +278}\text{.8kJ/mol}\\ {\text{ΔH for F}}_{\text{(g)}}\text{= +79}\text{.0 kJ/mol}\\ {\text{ΔH for SF}}_{\text{4}}{}_{\text{(g)}}\text{= -775 kJ/mol }\\ {\text{ΔH for SF}}_6{}_{\text{(g)}}\text{= -1209 kJ/mol }\end{array}$

Concept Introduction:

A chemical compound can be formed by either ionic bond or covalent bond between bonded atoms. The ionic compound is formed by opposite charge ions; cations and anions. The covalent compound is formed by sharing of electrons between bonded atoms.

The bond energy of a chemical bond can be defined as the energy required to break that chemical bond. The bond energy that is needed to break the bonds in reactant molecule and the energy released to form chemical bonds in product can be used to calculate the $\Delta \text{H}$ of the chemical reaction.

  $\Delta \text{H=}\sum {\text{BE}}_{\text{reactant }}\text{- }\sum {\text{BE}}_{\text{product }}$

  $\Delta \text{H}$ of reaction can also be calculated with the help of standard heat of formation of reactant and product.

  $\Delta \text{H =}\sum \Delta {\text{H}}_{\text{product }}\text{- }\sum \Delta {\text{H}}_{\text{reactant }}$

(b)

Interpretation Introduction

Interpretation: The calculated bond energy of S-F bond needs to be compared with the standard bond energy of the S-F bond.

Concept Introduction:

A chemical compound can be formed by either ionic bond or covalent bond between bonded atoms. The ionic compound is formed by opposite charge ions; cations and anions. The covalent compound is formed by sharing of electrons between bonded atoms.

The bond energy of a chemical bond can be defined as the energy required to break that chemical bond. The bond energy that is needed to break the bonds in reactant molecule and the energy released to form chemical bonds in product can be used to calculate the $\Delta \text{H}$ of the chemical reaction.

  $\Delta \text{H=}\sum {\text{BE}}_{\text{reactant }}\text{- }\sum {\text{BE}}_{\text{product }}$

  $\Delta \text{H}$ of reaction can also be calculated with the help of standard heat of formation of reactant and product.

  $\Delta \text{H =}\sum \Delta {\text{H}}_{\text{product }}\text{- }\sum \Delta {\text{H}}_{\text{reactant }}$

(c)

Interpretation Introduction

Interpretation: The reason of non-zero value of ${\text{ΔH}}_{\text{f}}^{\text{0}}$ for ${\text{S}}_{\text{(g)}}$ and ${\text{F}}_{\text{(g)}}$ although both are elemental states needs to be explained.

Concept Introduction:

A chemical compound can be formed by either ionic bond or covalent bond between bonded atoms. The ionic compound is formed by opposite charge ions; cations and anions. The covalent compound is formed by sharing of electrons between bonded atoms.

The bond energy of a chemical bond can be defined as the energy required to break that chemical bond. The bond energy that is needed to break the bonds in reactant molecule and the energy released to form chemical bonds in product can be used to calculate the $\Delta \text{H}$ of the chemical reaction.

  $\Delta \text{H=}\sum {\text{BE}}_{\text{reactant }}\text{- }\sum {\text{BE}}_{\text{product }}$

  $\Delta \text{H}$ of reaction can also be calculated with the help of standard heat of formation of reactant and product.

  $\Delta \text{H =}\sum \Delta {\text{H}}_{\text{product }}\text{- }\sum \Delta {\text{H}}_{\text{reactant }}$