Chapter 5, Problem 5.86AP

(a)

Interpretation Introduction

Interpretation:

In the given equation the energy is released or absorbed has to be given using the enthalpy value.

The given equation is,

  ${\text{3H}}_{\text{2}}\left(\text{g}\right){\text{+N}}_{\text{2}}\left(\text{g}\right)\stackrel{}{\to }{\text{2NH}}_{\text{3}}\left(\text{g}\right)\text{ΔH=-20}\text{kcal/mol}$

Concept introduction:

Enthalpy:

The energy absorbed or released in any reaction is called the heat of reaction or the enthalpy change $\left(\text{ΔH}\right).$

If energy is absorbed by the reaction is said to be endothermic and $\text{ΔH}$ is positive and more energy is needed to break the bonds and the reactants are lower in energy than the products.

If energy is released by the reaction is said to be exothermic and $\text{ΔH}$ is negative and more energy is released while forming bonds and the energy of the product is lower than the reactants.

(b)

Interpretation Introduction

Interpretation:

In the given equation the energy of reactants or products is lower has to be analyzed using the enthalpy value.

The given equation is,

  ${\text{3H}}_{\text{2}}\left(\text{g}\right){\text{+N}}_{\text{2}}\left(\text{g}\right)\stackrel{}{\to }{\text{2NH}}_{\text{3}}\left(\text{g}\right)\text{ΔH=-20}\text{kcal/mol}$

Concept introduction:

Refer to part (a).

(c)

Interpretation Introduction

Interpretation:

The given reaction is exothermic and endothermic has to be given.

The given equation is,

  ${\text{3H}}_{\text{2}}\left(\text{g}\right){\text{+N}}_{\text{2}}\left(\text{g}\right)\stackrel{}{\to }{\text{2NH}}_{\text{3}}\left(\text{g}\right)\text{ΔH=-20}\text{kcal/mol}$

Concept introduction:

Refer to part (a).