Chapter 4, Problem 4.40QP

For each of the following, write molecular and net ionic equations for any precipitation reaction that occurs. If no reaction occurs, indicate this.

1. a Zinc chloride and sodium sulfide are dissolved in water.
2. b Sodium sulfide and calcium chloride are dissolved in water.
3. c Magnesium sulfate and potassium bromide are dissolved in water.
4. d Magnesium sulfate and potassium carbonate are dissolved in water.

Interpretation Introduction

Interpretation:

To write the molecular equation and net ionic equations for the given set of reactions.

Concept introduction:

A chemical equation is the figurative representation of chemical reaction.  In a chemical equation the reactants are in the left side and the products are in the right side.  A balanced chemical equation serves as an easy tool for understanding a chemical reaction.  There are mainly three types of chemical equations, molecular equations, complete ionic equation and net ionic equation.

In molecular equations the reactants and products are represented as molecular substances, even though they exist as ions in solution phase.  The molecular equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ in solution phase is given below.

${\text{Ca(OH)}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{CO}}_{\text{3(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2NaOH}}_{\text{(aq)}}$

This equation is helpful in understanding the reactants and products involved in the reaction.

In complete ionic equations the electrolytes are represented as its ions.  Soluble compounds exist as ions in solution.  Complete ionic equation is helpful in understanding the reaction at ionic level.  The complete ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}$

The solid ${\text{CaCO}}_{\text{3}}$ is insoluble and it exist as solid in solution.

In net ionic equations the ions that are common in the reactant and product sides( Spectator ions) are cancelled.  These spectator ions are not participating in the chemical reactions.  The net ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.  As hydroxide ions and sodium ions are common in both the side it is neglected from the equation.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}\text{+}{\text{CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}$

Answer to Problem 4.40QP

Molecular equation

${\text{ZnCl}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{S}}_{\text{(aq)}}\stackrel{}{\to }{\text{ZnS}}_{\text{(s)}}{\text{+2NaCl}}_{\text{(aq)}}$

The net ionic equation

${\text{Zn}}^{2+}{}_{\text{(aq)}}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{ZnS}}_{\text{(s)}}$

Explanation of Solution

The molecular equation for the reaction between ${\text{ZnCl}}_{\text{2}}$ and ${\text{Na}}_{\text{2}}\text{S}$ is given below.

${\text{ZnCl}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{S}}_{\text{(aq)}}\stackrel{}{\to }{\text{ZnS}}_{\text{(s)}}{\text{+2NaCl}}_{\text{(aq)}}$

In complete ionic equation the electrolytes are represented as its ions.  The complete ionic equation for the reaction is given below.

${\text{Zn}}^{2+}{}_{\text{(aq)}}{\text{+2Cl}}^{-}{}_{\text{(aq)}}{\text{+2Na}}^{+}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{ZnS}}_{\text{(s)}}{\text{+2Na}}^{+}{\text{+2Cl}}^{-}{}_{\text{(aq)}}$

The ions common in the reactant and the product side are cancelled from the total ionic equation to get net ionic equation.

${\text{Zn}}^{2+}{}_{\text{(aq)}}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{ZnS}}_{\text{(s)}}$

Interpretation Introduction

Interpretation:

To write the molecular equation and net ionic equations for the given set of reactions.

Concept introduction:

A chemical equation is the figurative representation of chemical reaction.  In a chemical equation the reactants are in the left side and the products are in the right side.  A balanced chemical equation serves as an easy tool for understanding a chemical reaction.  There are mainly three types of chemical equations, molecular equations, complete ionic equation and net ionic equation.

In molecular equations the reactants and products are represented as molecular substances, even though they exist as ions in solution phase.  The molecular equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ in solution phase is given below.

${\text{Ca(OH)}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{CO}}_{\text{3(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2NaOH}}_{\text{(aq)}}$

This equation is helpful in understanding the reactants and products involved in the reaction.

In complete ionic equations the electrolytes are represented as its ions.  Soluble compounds exist as ions in solution.  Complete ionic equation is helpful in understanding the reaction at ionic level.  The complete ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}$

The solid ${\text{CaCO}}_{\text{3}}$ is insoluble and it exist as solid in solution.

In net ionic equations the ions that are common in the reactant and product sides( Spectator ions) are cancelled.  These spectator ions are not participating in the chemical reactions.  The net ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.  As hydroxide ions and sodium ions are common in both the side it is neglected from the equation.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}\text{+}{\text{CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}$

Answer to Problem 4.40QP

Molecular equation

${\text{CaCl}}_2{}_{\text{(aq)}}{\text{+Na}}_{\text{2}}{\text{S}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaS}}_{\text{(s)}}{\text{+2NaCl}}_{\text{(aq)}}$

The net ionic equation

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{CaS}}_{\text{(s)}}$

Explanation of Solution

The molecular equation for the reaction between ${\text{CaCl}}_{\text{2}}$ and ${\text{Na}}_{\text{2}}\text{S}$ are given below.

${\text{CaCl}}_2{}_{\text{(aq)}}{\text{+Na}}_{\text{2}}{\text{S}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaS}}_{\text{(s)}}{\text{+2NaCl}}_{\text{(aq)}}$

In complete ionic equation the electrolytes are represented as its ions.  The complete ionic equation for the reaction is given below.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+2Cl}}^{-}{}_{\text{(aq)}}{\text{+2Na}}^{+}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{CaS}}_{\text{(s)}}{\text{+2Na}}^{+}{\text{+2Cl}}^{-}{}_{\text{(aq)}}$

The ions common in the reactant and the product side are cancelled from the total ionic equation to get net ionic equation.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+S}}^{2-}{}_{\text{(aq)}}\stackrel{}{\to }{\text{CaS}}_{\text{(s)}}$

Interpretation Introduction

Interpretation:

To write the molecular equation and net ionic equations for the given set of reactions.

Concept introduction:

A chemical equation is the figurative representation of chemical reaction.  In a chemical equation the reactants are in the left side and the products are in the right side.  A balanced chemical equation serves as an easy tool for understanding a chemical reaction.  There are mainly three types of chemical equations, molecular equations, complete ionic equation and net ionic equation.

In molecular equations the reactants and products are represented as molecular substances, even though they exist as ions in solution phase.  The molecular equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ in solution phase is given below.

${\text{Ca(OH)}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{CO}}_{\text{3(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2NaOH}}_{\text{(aq)}}$

This equation is helpful in understanding the reactants and products involved in the reaction.

In complete ionic equations the electrolytes are represented as its ions.  Soluble compounds exist as ions in solution.  Complete ionic equation is helpful in understanding the reaction at ionic level.  The complete ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}$

The solid ${\text{CaCO}}_{\text{3}}$ is insoluble and it exist as solid in solution.

In net ionic equations the ions that are common in the reactant and product sides (Spectator ions) are cancelled.  These spectator ions are not participating in the chemical reactions.  The net ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.  As hydroxide ions and sodium ions are common in both the side it is neglected from the equation.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}\text{+}{\text{CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}$

Answer to Problem 4.40QP

No precipitation reaction occurs

Explanation of Solution

When ${\text{MgSO}}_{\text{4}}$ and $\text{KBr}$ are treated together there will not be any precipitation reaction occurring.  Ions exist in solution as such.

${\text{MgSO}}_{\text{4}}{}_{\text{(aq)}}{\text{+KBr}}_{\text{(aq)}}\stackrel{}{\to }\text{ NR}$

Interpretation Introduction

Interpretation:

To write the molecular equation and net ionic equations for the given set of reactions.

Concept introduction:

A chemical equation is the figurative representation of chemical reaction.  In a chemical equation the reactants are in the left side and the products are in the right side.  A balanced chemical equation serves as an easy tool for understanding a chemical reaction.  There are mainly three types of chemical equations, molecular equations, complete ionic equation and net ionic equation.

In molecular equations the reactants and products are represented as molecular substances, even though they exist as ions in solution phase.  The molecular equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ in solution phase is given below.

${\text{Ca(OH)}}_{\text{2(aq)}}{\text{+Na}}_{\text{2}}{\text{CO}}_{\text{3(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2NaOH}}_{\text{(aq)}}$

This equation is helpful in understanding the reactants and products involved in the reaction.

In complete ionic equations the electrolytes are represented as its ions.  Soluble compounds exist as ions in solution.  Complete ionic equation is helpful in understanding the reaction at ionic level.  The complete ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}{\text{+2Na}}^{\text{+}}{}_{\text{(aq)}}{\text{+2OH}}^{\text{-}}{}_{\text{(aq)}}$

The solid ${\text{CaCO}}_{\text{3}}$ is insoluble and it exist as solid in solution.

In net ionic equations the ions that are common in the reactant and product sides( Spectator ions) are cancelled.  These spectator ions are not participating in the chemical reactions.  The net ionic equation for the reaction between $\text{Ca}{\left(\text{OH}\right)}_{\text{2}}$ and ${\text{Na}}_{\text{2}}{\text{CO}}_{\text{3}}$ is given below.  As hydroxide ions and sodium ions are common in both the side it is neglected from the equation.

${\text{Ca}}^{\text{2+}}{}_{\text{(aq)}}\text{+}{\text{CO}}_{\text{3}}{{}^{\text{2-}}}_{\text{(aq)}}\stackrel{}{\to }{\text{CaCO}}_{\text{3(s)}}$

Answer to Problem 4.40QP

Molecular equation

${\text{MgSO}}_{\text{4}}{}_{\text{(aq)}}{\text{+K}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\text{(aq)}}\stackrel{}{\to }{\text{ MgCO}}_{\text{3(s)}}{\text{+K}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\text{(aq)}}$

The net ionic equation

${\text{Mg}}^{2+}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{2-}}_{\text{(aq)}}\stackrel{}{\to }{\text{ MgCO}}_{\text{3(s)}}$

Explanation of Solution

The molecular equation for the reaction between ${\text{MgSO}}_{\text{4}}$ and ${\text{K}}_{\text{2}}{\text{CO}}_{\text{3}}$ are given below.

${\text{MgSO}}_{\text{4}}{}_{\text{(aq)}}{\text{+K}}_{\text{2}}{\text{CO}}_{\text{3}}{}_{\text{(aq)}}\stackrel{}{\to }{\text{ MgCO}}_{\text{3(s)}}{\text{+K}}_{\text{2}}{\text{SO}}_{\text{4}}{}_{\text{(aq)}}$

In complete ionic equation the electrolytes are represented as its ions.  The complete ionic equation for the reaction is given below.

${\text{Mg}}^{2+}{}_{\text{(aq)}}{\text{+SO}}_{\text{4}}{{}^{2-}}_{\text{(aq)}}{\text{+2K}}^{+}{}_{(aq)}{\text{+CO}}_{\text{3}}{{}^{2-}}_{\text{(aq)}}\stackrel{}{\to }{\text{ MgCO}}_{\text{3(s)}}{\text{+SO}}_{\text{4}}{{}^{2-}}_{\text{(aq)}}{\text{+2K}}^{+}{}_{\text{(aq)}}$

The ions common in the reactant and the product side are cancelled from the total ionic equation to get net ionic equation.

${\text{Mg}}^{2+}{}_{\text{(aq)}}{\text{+CO}}_{\text{3}}{{}^{2-}}_{\text{(aq)}}\stackrel{}{\to }{\text{ MgCO}}_{\text{3(s)}}$