Chapter 6, Problem 6.15P

(a)

Interpretation Introduction

Interpretation: To write a balanced equation and draw an approximate enthalpy diagram for formation of 1 mol of sodium chloride.

Concept Introduction: An exothermic reaction releases heat and results in a decrease in enthalpy of the system. For exothermic reaction

  $\begin{array}{l}\Delta H_{\text{products}}>\Delta H_{\text{reactants}}\\ \Delta H<0\end{array}$

(b)

Interpretation Introduction

Interpretation: To write a balanced equation and draw an approximate enthalpy diagram for vaporization of liquid benzene.

Concept Introduction: An endothermic process absorbs heat as a result enthalpy of the system increase. For endothermic reaction

  $\begin{array}{l}\Delta H_{\text{products}}>\Delta H_{\text{reactants}}\\ \Delta H>0\end{array}$