Chapter 12, Problem 12.141MP

Interpretation Introduction

(a)

Interpretation:

The value of $x$ in the formula ${\text{Fe}}_x\text{O}$ is to be determined.

Concept introduction:

The density of the crystal is defined as the mass of the crystal divided by the volume of the crystal.

The formula to calculate the density of the crystal is as follows:

$d=\frac{ZM}{N_{\text{A}}{a}^3}$

Where,

• $d$ is the density of the crystal.
• $Z$ is the number of atoms in the crystal.
• $M$ is the atomic mass.
• $a$ is the edge length of the crystal.
• $N_{\text{A}}$ is the Avogadro’s number.

Interpretation Introduction

(b)

Interpretation:

The average oxidation state of $\text{Fe}$ is to be determined.

Concept introduction:

The positive or negative number that is used to denote the net charge on any atom or element is called oxidation state.

Interpretation Introduction

(c)

Interpretation:

The percent of $\text{Fe}$ atoms in $+3$ oxidation state is to be determined.

Concept introduction:

The positive or negative number that is used to denote the net charge on any atom or element is called oxidation state.

d)

Interpretation Introduction

Interpretation:

The angle for the third-order diffraction is to be determined.

Concept introduction:

Electrons have properties of matter as well as waves. These can undergo diffraction by the crystals.

The Bragg equation is as follows:

$\text{nλ}=2\text{dsinθ}$

Where,

• $\text{n}$ is the order of diffraction.
• $\text{λ}$ is the wavelength of electrons.
• $\text{d}$ is the spacing of the crystal planes.
• $\text{θ}$ is the angle of incidence.

Interpretation Introduction

(e)

Interpretation:

Whether wustite is a $n$ -type or a $p$ -type semiconductor should be determined.

Concept introduction:

Semiconductors are the substances or materials that have conductivity in between that of conductors and insulators. The $n$ -type or a $p$ -type semiconductors are formed by the process of doping or addition of impurities in the normal pure crystal. If the impurity added or the doped material is a trivalent atom, $p$ -type semiconductors are formed. In this type of semiconductor, holes are the majority charge carriers. But if the added impurity is a pentavalent atom, $n$ -type semiconductors are produced. In this type of semiconductor, electrons are the majority charge carriers.