Chapter 5, Problem 5.123AP

(a)

Interpretation Introduction

Interpretation: The given reactions are to be identified as exothermic and endothermic.

The value of $\Delta H_{\text{rxn}}^{\text{ο}}$ and the amount of energy absorbed or released is to be calculated for the given values. The $\Delta H_{\text{rxn}}^{\text{ο}}$ for the metabolism of $1$ mole of ${\text{CH}}_{\text{3}}\text{OH}\left(l\right)$ to give $1$ mole of formaldehyde is to be compared with $509.8\text{kJ}$.

Concept introduction: The reactions, in which heat energy is evolved, are termed as an exothermic process and if heat energy is absorbed then they are termed as an endothermic.

The standard enthalpy change $\left(\Delta H_{\text{rxn}}^{\text{ο}}\right)$ is the change in enthalpy when one mole of product is formed at standard condition.

The amount of energy released or absorbed $\left(q\right)$ is calculated by the formula,

$q=n\times \Delta H_{\text{rxn}}^{\text{ο}}$

To determine: The given reaction is to be identified as exothermic and endothermic.

(b)

Interpretation Introduction

To determine: The value of $\Delta H_{\text{rxn}}^{\text{ο}}$.

(c)

Interpretation Introduction

To determine: The amount of energy absorbed or released.

(d)

Interpretation Introduction

To determine: The comparison of $\Delta H_{\text{rxn}}^{\text{ο}}$ for the metabolism of $1$ mole of ${\text{CH}}_{\text{3}}\text{OH}\left(l\right)$ to give $1$ mole of formaldehyde with $509.8\text{kJ}$.