Chapter 6, Problem 2PE

(a)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{S}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{S}$ is ${\text{Al}}_{\text{2}}{\text{S}}_{\text{3}}\text{.}$

Explanation of Solution

Aluminum forms ${\text{Al}}^{\text{3+}}$ and sulfur forms sulfide ${\text{S}}^{\text{2-}\text{.}}.$  The formula of the ions are ${\text{Al}}^{\text{3+}}$ and ${\text{S}}^{\text{2-}}.$  The smallest number of ${\text{Al}}^{\text{3+}}$ and ${\text{S}}^{\text{2-}\text{.}}$ are combined to give the sum of charges equal to zero.  The lowest common multiple is six.

  $\begin{array}{l}\text{2}\left({\text{Al}}^{\text{3+}}\right)\text{+3}\left({\text{S}}^{\text{2-}}\right)\text{=0}\\ \text{2}\left(\text{3+}\right)\text{+3}\left(\text{2-}\right)\text{=0}\end{array}$

The formula is ${\text{Al}}_{\text{2}}{\text{S}}_{\text{3}}\text{.}$

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{S}$ is ${\text{Al}}_{\text{2}}{\text{S}}_{\text{3}}\text{.}$

(b)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{H}$ and $\text{F}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{H}$ and $\text{F}$ is $\text{HF}\text{.}$

Explanation of Solution

Hydrogen forms ${\text{H}}^{\text{+}}$ and fluorine forms ${\text{F}}^{\text{-}}\text{.}$  The formula of the ions are ${\text{H}}^{\text{+}}$ and ${\text{F}}^{\text{-}}\text{.}$  The smallest number of ${\text{H}}^{\text{+}}$ and ${\text{F}}^{\text{-}}$ are combined to give the sum of charges equal to zero.

  $\begin{array}{l}\left({\text{H}}^{\text{+}}\right)\text{+}\left({\text{F}}^{\text{-}}\right)\text{=0}\\ \left(\text{1+}\right)\text{+}\left(\text{1-}\right)\text{=0}\end{array}$

The formula is $\text{HF}\text{.}$

The chemical formula of the compound formed from elements $\text{H}$ and $\text{F}$ is $\text{HF}\text{.}$

(c)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{K}$ and $\text{N}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{K}$ and $\text{N}$ is ${\text{K}}_{\text{3}}\text{N}\text{.}$

Explanation of Solution

Potassium forms ${\text{K}}^{\text{+}}$ and nitrogen forms ${\text{N}}^{\text{3-}}\text{.}$  The formula of the ions are ${\text{K}}^{\text{+}}$ and ${\text{N}}^{\text{3-}}\text{.}$  The smallest number of ${\text{K}}^{\text{+}}$ and ${\text{N}}^{\text{3-}}$ are combined to give the sum of charges equal to zero.  The lowest common multiple is three.

  $\begin{array}{l}\text{3}\left({\text{K}}^{\text{+}}\right)\text{+1}\left({\text{N}}^{\text{3-}}\right)\text{=0}\\ \text{3}\left(\text{1+}\right)\text{+1}\left(\text{3-}\right)\text{=0}\end{array}$

The formula is ${\text{K}}_{\text{3}}\text{N}\text{.}$

The chemical formula of the compound formed from elements $\text{K}$ and $\text{N}$ is ${\text{K}}_{\text{3}}\text{N}\text{.}$

(d)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{Sr}$ and $\text{O}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{Sr}$ and $\text{O}$ is $\text{SrO}\text{.}$

Explanation of Solution

Strontium forms ${\text{Sr}}^{\text{2+}}$ and oxygen forms ${\text{O}}^{\text{2-}}\text{.}$  The formula of the ions are ${\text{Sr}}^{\text{2+}}$ and ${\text{O}}^{\text{2-}}\text{.}$  The smallest number of ${\text{Sr}}^{\text{2+}}$ and ${\text{O}}^{\text{2-}}$ are combined to give the sum of charges equal to zero.

  $\begin{array}{l}\left({\text{Sr}}^{\text{2+}}\right)\text{+}\left({\text{O}}^{\text{2-}}\right)\text{=0}\\ \left(\text{2+}\right)\text{+}\left(\text{2-}\right)\text{=0}\end{array}$

The formula is $\text{SrO}\text{.}$

The chemical formula of the compound formed from elements $\text{Sr}$ and $\text{O}$ is $\text{SrO}\text{.}$

(e)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{Cs}$ and $\text{P}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{Cs}$ and $\text{P}$ is ${\text{Cs}}_{\text{3}}\text{P}\text{.}$

Explanation of Solution

Cesium forms ${\text{Cs}}^{\text{+}}$ and phosphorus forms ${\text{P}}^{\text{3-}}\text{.}$  The formula of the ions are ${\text{Cs}}^{\text{+}}$ and ${\text{P}}^{\text{3-}}\text{.}$  The smallest number of ${\text{Cs}}^{\text{+}}$ and ${\text{P}}^{\text{3-}}$ are combined to give the sum of charges equal to zero.  The lowest common multiple of the charges is three.

  $\begin{array}{l}\text{3}\left({\text{Cs}}^{\text{+}}\right)\text{+1}\left({\text{P}}^{\text{3-}}\right)\text{=0}\\ \text{3}\left(\text{1+}\right)\text{+1}\left(\text{3-}\right)\text{=0}\end{array}$

The formula is ${\text{Cs}}_{\text{3}}\text{P}\text{.}$

The chemical formula of the compound formed from elements $\text{Cs}$ and $\text{P}$ is ${\text{Cs}}_{\text{3}}\text{P}\text{.}$

(f)

Interpretation Introduction

Interpretation:

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{Cl}$ has to be written.

Answer to Problem 2PE

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{Cl}$ is ${\text{AlCl}}_{\text{3}}\text{.}$

Explanation of Solution

Aluminum forms ${\text{Al}}^{\text{3+}}$ and chlorine forms ${\text{Cl}}^{\text{-}}\text{.}$  The formula of the ions are ${\text{Al}}^{\text{3+}}$ and ${\text{Cl}}^{\text{-}}\text{.}$  The smallest number of ${\text{Al}}^{\text{3+}}$ and ${\text{Cl}}^{\text{-}}$ are combined to give the sum of charges equal to zero.  The lowest common multiple is $\text{3}\text{.}$

  $\begin{array}{l}\text{1}\left({\text{Al}}^{\text{3+}}\right)\text{+3}\left({\text{Cl}}^{\text{-}}\right)\text{=0}\\ \text{1}\left(\text{3+}\right)\text{+3}\left(\text{1-}\right)\text{=0}\end{array}$

The formula is ${\text{AlCl}}_{\text{3}}\text{.}$

The chemical formula of the compound formed from elements $\text{Al}$ and $\text{Cl}$ is ${\text{AlCl}}_{\text{3}}\text{.}$