Chapter 7, Problem 21E

Interpretation Introduction

(a)

Interpretation:

The reaction between hydrogen gas and nitrogen gas is to be classified as combination, decomposition, single replacement, double replacement, or neutralization.

Concept introduction:

A chemical reaction is a process in which rearrangement of atom or ions takes place between two reacting species. A balanced chemical equation represents an equation in which all the reactants and products are written with their stoichiometric coefficient and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 21E

The combination reaction occurs between hydrogen gas and nitrogen gas is shown below.

Explanation of Solution

The unbalanced chemical equation for the reaction between hydrogen gas and nitrogen gas is shown below.

${\text{H}}_{\text{2}}\left(g\right)+{\text{N}}_{\text{2}}\left(g\right)\to {\text{NH}}_{\text{3}}\left(g\right)$

The numbers of atoms of elements on the left side of the reaction are not equal to the right side of the reaction. Therefore, the reaction is unbalanced.

A coefficient of $2$ is placed in front of ${\text{NH}}_{\text{3}}$ and a coefficient of $3$ is placed in front of ${\text{H}}_{\text{2}}$ to balance the chemical equation.

Therefore, the balanced chemical equation for the reaction between hydrogen gas and nitrogen gas is shown below.

${\text{3H}}_{\text{2}}\left(g\right)+{\text{N}}_{\text{2}}\left(g\right)\to 2{\text{NH}}_{\text{3}}\left(g\right)$

The numbers of atoms of each element on the left side of the reaction are equal to the right side of the reaction. Therefore, the reaction is balanced.

The balanced reaction represents that the product is the formed by the combination of reactants. Therefore, this is combination reaction.

Conclusion

The reaction between hydrogen gas and nitrogen gas is to be classified as combination reaction.

Interpretation Introduction

(b)

Interpretation:

The reaction of aluminum is to be classified as combination, decomposition, single replacement, double replacement, or neutralization.

Concept introduction:

A chemical reaction is a process in which rearrangement of atom or ions takes place between two reacting species. A balanced chemical equation represents an equation in which all the reactants and products are written with their stoichiometric coefficient and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 21E

Aluminum carbonate undergoes a decomposition reaction to produce aluminum oxide and carbon dioxide.

Explanation of Solution

The unbalanced chemical equation of the reaction of aluminum carbonate is shown below.

${\text{Al}}_{\text{2}}{\left({\text{CO}}_3\right)}_3\left(s\right)\to {\text{Al}}_{\text{2}}{\text{O}}_3\left(s\right)+{\text{CO}}_2\left(g\right)$

The numbers of atoms of elements on the left side of the reaction are not equal to the right side of the reaction. Therefore, the reaction is unbalanced.

A coefficient of $3$ is placed in front of ${\text{CO}}_2$ to balance the chemical equation.

Therefore, the balanced chemical equation of the reaction of aluminum carbonate is shown below.

${\text{Al}}_{\text{2}}{\left({\text{CO}}_3\right)}_3\left(s\right)\to {\text{Al}}_{\text{2}}{\text{O}}_3\left(s\right)+3{\text{CO}}_2\left(g\right)$

The numbers of atoms of each element on the left side of the reaction are equal to the right side of the reaction. Therefore, the reaction is balanced.

The balanced reaction represents that the products are formed after the decomposition of reactant. Therefore, it is decomposition reaction.

Conclusion

The reaction of aluminum carbonate is classified as decomposition reaction.

Interpretation Introduction

(c)

Interpretation:

The reaction between strontium metal and water is to be classified as combination, decomposition, single replacement, double replacement, or neutralization.

Concept introduction:

A chemical reaction is a process in which rearrangement of atom or ions takes place between two reacting species. A balanced chemical equation represents an equation in which all the reactants and products are written with their stoichiometric coefficient and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 21E

The single replacement reaction occurs between strontium metal and water.

Explanation of Solution

The unbalanced chemical equation for the reaction between strontium metal and water is shown below.

$\text{Sr}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{Sr}{\left(\text{OH}\right)}_{\text{2}}\left(aq\right)+{\text{H}}_2\left(g\right)$

The numbers of atoms of elements on the left side of the reaction are not equal to the right side of the reaction. Therefore, the reaction is unbalanced.

A coefficient of $2$ is placed in front of ${\text{H}}_{\text{2}}\text{O}$ to balance the chemical equation.

Therefore, the balanced chemical equation for the reaction between strontium metal and water is shown below.

$\text{Sr}\left(s\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)\to \text{Sr}{\left(\text{OH}\right)}_{\text{2}}\left(aq\right)+{\text{H}}_2\left(g\right)$

The numbers of atoms of each element on the left side of the reaction are equal to the right side of the reaction. Therefore, the reaction is balanced.

The hydrogen atom is replaced by strontium atom in the above balanced reaction. Therefore, it is single replacement reaction.

Conclusion

The reaction between strontium metal and water is single replacement reaction.

Interpretation Introduction

(d)

Interpretation:

The reaction between potassium sulfate and barium hydroxide is to be classified as combination, decomposition, single replacement, double replacement, or neutralization.

Concept introduction:

A chemical reaction is a process in which rearrangement of atom or ions takes place between two reacting species. A balanced chemical equation represents an equation in which all the reactants and products are written with their stoichiometric coefficient and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 21E

The double replacement reaction occurs between potassium sulfate and barium hydroxide.

Explanation of Solution

The unbalanced chemical equation for the reaction between potassium sulfate and barium hydroxide is shown below.

${\text{K}}_2{\text{SO}}_4\left(aq\right)+\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\left(aq\right)\to {\text{BaSO}}_{\text{4}}\left(s\right)+\text{KOH}\left(aq\right)$

The numbers of atoms of elements on the left side of the reaction are not equal to the right side of the reaction. Therefore, the reaction is unbalanced.

A coefficient of $2$ is placed in front of $\text{KOH}$ to balance the chemical equation.

Therefore, the balanced chemical equation for the reaction between potassium sulfate and barium hydroxide is shown below.

${\text{K}}_2{\text{SO}}_4\left(aq\right)+\text{Ba}{\left(\text{OH}\right)}_{\text{2}}\left(aq\right)\to {\text{BaSO}}_{\text{4}}\left(s\right)+2\text{KOH}\left(aq\right)$

The numbers of atoms of each element on the left side of the reaction are equal to the right side of the reaction. Therefore, the reaction is balanced.

The ions of the reactants are rearranged in the above reaction. Therefore, it is a double replacement reaction.

Conclusion

The reaction between potassium sulfate and barium hydroxide is double replacement.

Interpretation Introduction

(e)

Interpretation:

The reaction between phosphoric acid and manganese hydroxide is to be classified as combination, decomposition, single replacement, double replacement, or neutralization.

Concept introduction:

A chemical reaction is a process in which rearrangement of atom or ions takes place between two reacting species. A balanced chemical equation represents an equation in which all the reactants and products are written with their stoichiometric coefficient and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 21E

The neutralization reaction occurs between phosphoric acid and manganese hydroxide.

Explanation of Solution

The unbalanced chemical equation for the reaction between phosphoric acid and manganese hydroxide is shown below.

${\text{H}}_3{\text{PO}}_4\left(aq\right)+\text{Mn}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)\to {\text{Mn}}_3{\left({\text{PO}}_{\text{4}}\right)}_2\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)$

The numbers of atoms of elements on the left side of the reaction are not equal to the right side of the reaction. Therefore, the reaction is unbalanced.

A coefficient of $2$ is placed in front of ${\text{H}}_3{\text{PO}}_4$, a coefficient of $3$ is placed in front of $\text{Mn}{\left(\text{OH}\right)}_{\text{2}}$ and a coefficient of $6$ is placed in front of ${\text{H}}_{\text{2}}\text{O}$ to balance the reaction.

Therefore, the balanced chemical equation for the reaction between phosphoric acid and manganese hydroxide is shown below.

${\text{2H}}_3{\text{PO}}_4\left(aq\right)+3\text{Mn}{\left(\text{OH}\right)}_{\text{2}}\left(s\right)\to {\text{Mn}}_3{\left({\text{PO}}_{\text{4}}\right)}_2\left(s\right)+6{\text{H}}_{\text{2}}\text{O}\left(l\right)$

The numbers of atoms of each element on the left side of the reaction are equal to the right side of the reaction. Therefore, the reaction is balanced.

An acid and base reacted in the above reaction. Therefore, it is neutralization reaction.

Conclusion

The reaction between phosphoric acid and manganese hydroxide is neutralization.