Chapter 12, Problem 12.68P

(a)

Interpretation Introduction

Interpretation:

Whether the same amount of heat is needed to melt $12.0\text{ g}$ of ${\text{CH}}_4$ or $12.0\text{ g}$ of $\text{Hg}$ is to be determined.

Concept introduction:

Heat $\left(q\right)$ is the energy transferred as a consequence of the difference of the temperature between the system and surrounding. The formula to calculate heat released or absorbed by a compound is as follows:

$q=n\left(\Delta H\right)$ (1)

Here,

$q$ is the heat released or absorbed.

$n$ is the number of moles.

$\Delta H$ is the enthalpy change.

(b)

Interpretation Introduction

Interpretation:

Whether the same amount of heat is needed to vaporize $12.0\text{ g}$ of ${\text{CH}}_4$ or $12.0\text{ g}$ of $\text{Hg}$ is to be determined.

Concept introduction:

Heat $\left(q\right)$ is the energy transferred as a consequence of the difference of the temperature between the system and surrounding. The formula to calculate heat released or absorbed by a compound is as follows:

$q=n\left(\Delta H\right)$ (1)

Here,

$q$ is the heat released or absorbed.

$n$ is the number of moles.

$\Delta H$ is the enthalpy change.

(c)

Interpretation Introduction

Interpretation:

The principal intermolecular force in $\text{Hg}$ and ${\text{CH}}_4$ is to be determined.

Concept introduction:

Intermolecular forces operate between the molecules so changes with change in the phase and effects with physical properties of the substance. In intermolecular forces, the bond is formed between two molecules with partial charges that are present relatively far away from each other. Dispersion forces are the type of intermolecular force.

In dispersion forces, a temporary dipole is generated on one molecule that further induces a temporary dipole on the molecule adjacent to it. The temporary dipole results in the attraction between opposite charges and dispersion forces exist in the molecule. All the atoms and molecules exhibit dispersion forces.

Metallic bonds are formed between metals. A metallic bond is formed between positively charged ions in a sea of delocalized electrons. The electrons in metals are delocalized over the entire metal.