Chapter 4, Problem 4.122EP

(a)

Interpretation Introduction

Interpretation:

The name of the ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is to be written.

Concept Introduction:

Chemical formulas and names for ionic compounds containing polyatomic ions:

Ionic compounds containing positive and negative charges present must add to zero.

If more than one polyatomic ion is present in a compound, the chemical formula can be written as a polyatomic ion is enclose in parentheses and a subscript, placed outside of the parentheses.  Example- ${\text{Fe(OH)}}_{\text{3}}$.

Sometimes same element is present in two different locations.  For example, ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}$- in this chemical formula “N” is present in two different locations as ${\text{NH}}_{\text{4}}^{\text{+}}{\text{ and NO}}_{\text{3}}^{\text{-}}$ ions.

Answer to Problem 4.122EP

The name of the ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is Calcium phosphate.

Explanation of Solution

The given name of the compound has ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ ions.

Calcium ion has $\text{+2}$ charge and phosphate ion has $\text{-3}$ charge.  So, $\text{3:2}$ ratio of calcium and phosphate ion produces a chemical formula ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ with zero total charge.

Hence, the chemical formula of the compound is ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$.

The metal atom is calcium cation and polyatomic anion is phosphate ion.

Hence, the name of the compound ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ is calcium phosphate.

(b)

Interpretation Introduction

Interpretation:

The chemical formula of the ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is to be written.

Concept Introduction:

Chemical formulas and names for ionic compounds containing polyatomic ions:

Ionic compounds containing positive and negative charges present must add to zero.

If more than one polyatomic ion is present in a compound, the chemical formula can be written as a polyatomic ion is enclose in parentheses and a subscript, placed outside of the parentheses.  Example- ${\text{Fe(OH)}}_{\text{3}}$.

Sometimes same element is present in two different locations.  For example, ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}$- in this chemical formula “N” is present in two different locations as ${\text{NH}}_{\text{4}}^{\text{+}}{\text{ and NO}}_{\text{3}}^{\text{-}}$ ions.

Answer to Problem 4.122EP

The chemical formula of ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$.

Explanation of Solution

The given name of the compound has ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ ions.

Calcium ion has $\text{+2}$ charge and phosphate ion has $\text{-3}$ charge.  So, $\text{3:2}$ ratio of calcium and phosphate ion produces a chemical formula ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ with zero total charge.

Hence, the chemical formula of the compound is ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$.

(c)

Interpretation Introduction

Interpretation:

The number of polyatomic ions present in one formula unit of ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is to be identified.

Concept Introduction:

Chemical formulas and names for ionic compounds containing polyatomic ions:

Ionic compounds containing positive and negative charges present must add to zero.

If more than one polyatomic ion is present in a compound, the chemical formula can be written as a polyatomic ion is enclose in parentheses and a subscript, placed outside of the parentheses.  Example- ${\text{Fe(OH)}}_{\text{3}}$.

Sometimes same element is present in two different locations.  For example, ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}$- in this chemical formula “N” is present in two different locations as ${\text{NH}}_{\text{4}}^{\text{+}}{\text{ and NO}}_{\text{3}}^{\text{-}}$ ions.

Answer to Problem 4.122EP

Two polyatomic ions are present in one formula unit of ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$.

Explanation of Solution

The given name of the compound has ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ ions.

Calcium ion has $\text{+2}$ charge and phosphate ion has $\text{-3}$ charge.  So, $\text{3:2}$ ratio of calcium and phosphate ion produces a chemical formula ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ with zero total charge.

The chemical formula of the compound is ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$.

Dissociation of ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ is as follows.

    ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}\to {\text{ 3Ca}}^{\text{2+}}{\text{+ 2PO}}_{\text{4}}^{\text{3-}}$

From the above reaction, one formula unit of calcium phosphate (${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$) produce three monoatomic ions (${\text{Ca}}^{\text{2+}}$) and two polyatomic ions (${\text{PO}}_{\text{4}}^{\text{3-}}$).

Hence, two polyatomic ions are present in the ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$.

(d)

Interpretation Introduction

Interpretation:

The number of monoatomic ions present in the one formula unit of ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ is to be identified.

Concept Introduction:

Chemical formulas and names for ionic compounds containing polyatomic ions:

Ionic compounds containing positive and negative charges present must add to zero.

If more than one polyatomic ion is present in a compound, the chemical formula can be written as a polyatomic ion is enclose in parentheses and a subscript, placed outside of the parentheses.  Example- ${\text{Fe(OH)}}_{\text{3}}$.

Sometimes same element is present in two different locations.  For example, ${\text{NH}}_{\text{4}}{\text{NO}}_{\text{3}}$- in this chemical formula “N” is present in two different locations as ${\text{NH}}_{\text{4}}^{\text{+}}{\text{ and NO}}_{\text{3}}^{\text{-}}$ ions.

Answer to Problem 4.122EP

Three monoatomic ions are present in the one formula unit of ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$.

Explanation of Solution

The given name of the compound has ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$ ions.

Calcium ion has $\text{+2}$ charge and phosphate ion has $\text{-3}$ charge.  So, $\text{3:2}$ ratio of calcium and phosphate ion produces a chemical formula ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ with zero total charge.

The chemical formula of the compound is ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$.

Dissociation of ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$ is as follows.

    ${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}\to {\text{ 3Ca}}^{\text{2+}}{\text{+ 2PO}}_{\text{4}}^{\text{3-}}$

From the above reaction, one formula unit of calcium phosphate (${\text{Ca}}_{\text{3}}{{\text{(PO}}_{\text{4}}\text{)}}_{\text{2}}$) produces three monoatomic ions (${\text{Ca}}^{\text{2+}}$) and two polyatomic ions (${\text{PO}}_{\text{4}}^{\text{3-}}$).

Hence, three monoatomic ions present in the ionic compound formed from the ions ${\text{Ca}}^{\text{2+}}$ and ${\text{PO}}_{\text{4}}^{\text{3-}}$.