Chapter 4, Problem 4.156P

(1)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when copper metal reacts with aqueous bromine to produce a green-blue solution is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

The molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction, the useful ions that participate in the reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as a precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The balanced chemical equation of the reaction is as follows:

$\text{Cu}\left(s\right)+{\text{Br}}_{\text{2}}\left(aq\right)\to {\text{CuBr}}_{\text{2}}\left(aq\right)$

The net ionic equation for the given reaction is as follows:

$\text{Cu}\left(s\right)+{\text{Br}}_{\text{2}}\left(aq\right)\to {\text{Cu}}^{2+}\left(aq\right)+2{\text{Br}}^{-}\left(aq\right)$

Explanation of Solution

Copper reacts with bromine molecule to form copper bromide $\left({\text{CuBr}}_{\text{2}}\right)$. This reaction is an example of combination reaction. The balanced chemical equation of the reaction is as follows:

$\text{Cu}\left(s\right)+{\text{Br}}_{\text{2}}\left(aq\right)\to {\text{CuBr}}_{\text{2}}\left(aq\right)$

The net ionic equation for the given reaction is as follows:

$\text{Cu}\left(s\right)+{\text{Br}}_{\text{2}}\left(aq\right)\to {\text{Cu}}^{2+}\left(aq\right)+2{\text{Br}}^{-}\left(aq\right)$

Conclusion

The reaction that involves the combination of reactant to form the product is known as a combination reaction. $\text{Cu}$ combine with ${\text{Br}}_{\text{2}}$ to form ${\text{CuBr}}_{\text{2}}$ therefore it is a combination reaction.

(2)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when aqueous sodium hydroxide is added to copper bromide to form a blue precipitate is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

The molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction, the useful ions that participate in the reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as a precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The balanced chemical equation of the reaction is as follows:

${\text{CuBr}}_{\text{2}}\left(aq\right)+2\text{NaOH}\left(aq\right)\to \text{Cu}{\left(\text{OH}\right)}_2\left(s\right)+2\text{NaBr}\left(aq\right)$

The net ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Cu}{\left(\text{OH}\right)}_2\left(s\right)$

Explanation of Solution

Copper bromide reacts with aqueous bromide to form copper hydroxide. According to the solubility rules, all the common hydroxide are insoluble so the reaction is the precipitation reaction. The balanced chemical equation of the reaction is as follows:

${\text{CuBr}}_{\text{2}}\left(aq\right)+2\text{NaOH}\left(aq\right)\to \text{Cu}{\left(\text{OH}\right)}_2\left(s\right)+2\text{NaBr}\left(aq\right)$

The total ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+2{\text{Br}}^{-}\left(aq\right)+2{\text{Na}}^{+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Cu}{\left(\text{OH}\right)}_2\left(s\right)+2{\text{Na}}^{+}\left(aq\right)+2{\text{Br}}^{-}\left(aq\right)$

${\text{Na}}^{+}$ and ${\text{Br}}^{-}$ are the spectator ions that are present in the reaction mixture. Spectator ions are not present in the net ionic equation.

The net ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+2{\text{OH}}^{-}\left(aq\right)\to \text{Cu}{\left(\text{OH}\right)}_2\left(s\right)$

Conclusion

$\text{Cu}{\left(\text{OH}\right)}_2$ is the solid insoluble substance that is formed in the reaction. ${\text{Na}}^{+}$ and ${\text{Br}}^{-}$ are the spectator ions that are present in the reaction mixture. These ions are present in total ionic equation but are absent in net ionic equation.

(3)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when copper hydroxide precipitate is heated to form black product is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

Molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction the useful ions that participate in reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The balanced chemical equation of the reaction is as follows:

$\text{Cu}{\left(\text{OH}\right)}_2\left(s\right)\to \text{CuO}\left(s\right)+{\text{H}}_2\text{O}\left(l\right)$

The net ionic equation for the given reaction is as follows:

$\text{Cu}{\left(\text{OH}\right)}_2\left(s\right)\to \text{CuO}\left(s\right)+{\text{H}}_2\text{O}\left(l\right)$

Explanation of Solution

Copper hydroxide decomposes to form copper oxide and water. Copper oxide forms black precipitate and this reaction is an example of decomposition reaction. The balanced chemical equation of the reaction is as follows:

$\text{Cu}{\left(\text{OH}\right)}_2\left(s\right)\to \text{CuO}\left(s\right)+{\text{H}}_2\text{O}\left(l\right)$

The net ionic equation for the given reaction is as follows:

$\text{Cu}{\left(\text{OH}\right)}_2\left(s\right)\to \text{CuO}\left(s\right)+{\text{H}}_2\text{O}\left(l\right)$

Conclusion

The reaction that involves the decomposition of the compound to form the product is known as a decomposition reaction. $\text{Cu}{\left(\text{OH}\right)}_2$ breaks to form $\text{CuO}$ and ${\text{H}}_2\text{O}$ molecule, therefore, it is a decomposition reaction.

(4)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when is $\text{CuO}$ dissolves in nitric acid to give a blue solution is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

Molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction the useful ions that participate in reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The balanced chemical equation of the reaction is as follows:

$\text{CuO}\left(s\right)+2{\text{HNO}}_3\left(aq\right)\to \text{Cu}{\left({\text{NO}}_3\right)}_2\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)$

The net ionic equation for the given reaction is as follows:

$\text{CuO}\left(s\right)+2{\text{H}}^{+}\left(aq\right)\to {\text{Cu}}^{2+}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)$

Explanation of Solution

Copper oxide $\left(\text{CuO}\right)$ reacts with nitric acid to form copper nitrate and water molecule. This reaction is an example of acid-base reaction. The balanced chemical equation of the reaction is as follows:

$\text{CuO}\left(s\right)+2{\text{HNO}}_3\left(aq\right)\to \text{Cu}{\left({\text{NO}}_3\right)}_2\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)$

The total ionic equation for the given reaction is as follows:

$\text{CuO}\left(s\right)+2{\text{H}}^{+}\left(aq\right)+2{\text{NO}}_3^{-}\left(aq\right)\to {\text{Cu}}^{2+}\left(aq\right)+2{\text{NO}}_3^{-}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)$

${\text{NO}}_3^{-}$ is the spectator ions that is present in the reaction mixture. Spectator ions are not present in the net ionic equation.

The net ionic equation for the given reaction is as follows:

$\text{CuO}\left(s\right)+2{\text{H}}^{+}\left(aq\right)\to {\text{Cu}}^{2+}\left(aq\right)+{\text{H}}_2\text{O}\left(l\right)$

Conclusion

$\text{CuO}$ is a base and ${\text{HNO}}_3$ is an acid and both react to form copper nitrate and water. Therefore, this reaction is an example of acid-base reaction.

(5)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when aqueous sodium phosphate is added to copper nitrate to form a green precipitate is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

Molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction the useful ions that participate in reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The balanced chemical equation of the reaction is as follows:

$\text{3Cu}{\left({\text{NO}}_3\right)}_2\left(aq\right)+2{\text{Na}}_{\text{3}}{\text{PO}}_4\left(aq\right)\to {\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{NaNO}}_3\left(aq\right)$

The net ionic equation for the given reaction is as follows:

${\text{3Cu}}^{2+}\left(aq\right)+2{\text{PO}}_4^{3-}\left(aq\right)\to {\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)$

Explanation of Solution

Copper nitrate reacts with aqueous sodium phosphate to form copper phosphate and sodium nitrate. According to the solubility rules, all the common phosphate are insoluble so the reaction is the precipitation reaction. The balanced chemical equation of the reaction is as follows:

$\text{3Cu}{\left({\text{NO}}_3\right)}_2\left(aq\right)+2{\text{Na}}_{\text{3}}{\text{PO}}_4\left(aq\right)\to {\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{NaNO}}_3\left(aq\right)$

The total ionic equation for the given reaction is as follows:

$\begin{array}{c}{\text{3Cu}}^{2+}\left(aq\right)+6{\text{NO}}_3^{-}\left(aq\right)+6{\text{Na}}^{+}\left(aq\right)+2{\text{PO}}_4^{3-}\left(aq\right)\to {\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{Na}}^{+}\left(aq\right)\\ +6{\text{NO}}_3^{-}\left(aq\right)\end{array}$

${\text{Na}}^{+}$ and ${\text{NO}}_3^{-}$ are the spectator ions that are present in the reaction mixture. Spectator ions are not present in the net ionic equation.

The net ionic equation for the given reaction is as follows:

${\text{3Cu}}^{2+}\left(aq\right)+2{\text{PO}}_4^{3-}\left(aq\right)\to {\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)$

Conclusion

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2$ is the solid insoluble substance that is formed in the reaction. ${\text{Na}}^{+}$ and ${\text{NO}}_3^{-}$ are the spectator ions that are present in the reaction mixture. These ions are present in total ionic equation but are absent in net ionic equation.

(6)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when copper phosphate forms a blue solution in sulfuric acid is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

Molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction the useful ions that participate in reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The chemical equation of the reaction is as follows:

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+3{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)\to 3{\text{CuSO}}_{\text{4}}\left(aq\right)+2{\text{H}}_3{\text{PO}}_4\left(aq\right)$

The net ionic equation for the given reaction is as follows:

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{H}}^{+}\left(aq\right)\to 3{\text{Cu}}^{2+}\left(aq\right)+2{\text{H}}_3{\text{PO}}_4\left(aq\right)$

Explanation of Solution

Copper phosphate reacts with sulfuric acid to form copper sulfate and phosphoric acid. The chemical equation of the reaction is as follows:

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+3{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\left(aq\right)\to 3{\text{CuSO}}_{\text{4}}\left(aq\right)+2{\text{H}}_3{\text{PO}}_4\left(aq\right)$

The total ionic equation for the given reaction is as follows:

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{H}}^{+}\left(aq\right)+3{\text{SO}}_4^{2-}\left(aq\right)\to 3{\text{Cu}}^{2+}\left(aq\right)+3{\text{SO}}_4^{2-}\left(aq\right)+2{\text{H}}_3{\text{PO}}_4\left(aq\right)$

${\text{SO}}_4^{2-}$ is the spectator ions that is present in the reaction mixture. Spectator ions are not present in the net ionic equation.

The net ionic equation for the given reaction is as follows:

${\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)+6{\text{H}}^{+}\left(aq\right)\to 3{\text{Cu}}^{2+}\left(aq\right)+2{\text{H}}_3{\text{PO}}_4\left(aq\right)$

Conclusion

Copper phosphate $\left({\text{Cu}}_3{\left({\text{PO}}_4\right)}_2\right)$ reacts with sulfuric acid $\left({\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\right)$ to form copper sulfate and phosphoric acid $\left({\text{H}}_{\text{3}}{\text{PO}}_4\right)$. Copper displaces hydrogen ions from sulfuric acid to form copper sulphate.

(7)

Interpretation Introduction

Interpretation:

The balanced and net ionic equation when zinc is added to the blue solution to recover copper is to be determined.

Concept introduction:

There are three types of equations that are utilized to represent an ionic reaction:

1. Molecular equation

2. Total ionic equation

3. Net ionic equation

Molecular equation represents the reactants and products of the ionic reaction in undissociated form. In total ionic reaction, all the dissociated ions that are present in the reaction mixture are represented and in net ionic reaction the useful ions that participate in reaction are represented.

Precipitation reaction involves the reaction of two soluble ionic compounds to form an insoluble product. The insoluble product is known as precipitate.

A redox reaction is a type of reaction that involves the change in oxidation number of a molecule, atom or ion changes due to the transfer of an electron from one species to another.

The redox reaction can be classified into three types depending upon the number of reactants and products as follows:

1. Combination redox reaction

2. Decomposition redox reaction

3. Displacement redox reactions

Answer to Problem 4.156P

The total ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+{\text{SO}}_4^{2-}\left(aq\right)+\text{Zn}\left(s\right)\to {\text{Zn}}^{2+}\left(aq\right)+{\text{SO}}_4^{2-}\left(aq\right)+\text{Cu}\left(s\right)$

The net ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+\text{Zn}\left(s\right)\to {\text{Zn}}^{2+}\left(aq\right)+\text{Cu}\left(s\right)$

Explanation of Solution

Zinc displaces copper from copper sulfate from and form zinc sulphate and copper. this reaction is an example of displacement reaction. The chemical equation of the reaction is as follows:

${\text{CuSO}}_{\text{4}}\left(aq\right)+\text{Zn}\left(s\right)\to {\text{ZnSO}}_{\text{4}}\left(aq\right)+\text{Cu}\left(s\right)$

The total ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+{\text{SO}}_4^{2-}\left(aq\right)+\text{Zn}\left(s\right)\to {\text{Zn}}^{2+}\left(aq\right)+{\text{SO}}_4^{2-}\left(aq\right)+\text{Cu}\left(s\right)$

${\text{SO}}_4^{2-}$ is the spectator ions that is present in the reaction mixture. Spectator ions are not present in the net ionic equation.

The net ionic equation for the given reaction is as follows:

${\text{Cu}}^{2+}\left(aq\right)+\text{Zn}\left(s\right)\to {\text{Zn}}^{2+}\left(aq\right)+\text{Cu}\left(s\right)$

Conclusion

The reaction that involves the displacement of an atom by another atom is known as displacement reaction. Zinc replaces copper atom from copper sulfate, therefore, it is a displacement reaction.