Chapter 11, Problem 70E

Interpretation Introduction

(a)

Interpretation:

The balanced chemical equation for the reaction between butanol and oxygen gas is to be stated.

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 coefficients and physical states. The number of atoms of an element on both sides of the equation is equal.

Answer to Problem 70E

The balanced chemical equation for the reaction between butanol and oxygen gas is shown below.

${\text{2C}}_{\text{4}}{\text{H}}_{\text{9}}\text{OH}\left(l\right)+12{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }8{\text{CO}}_{\text{2}}\left(g\right)+10{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Explanation of Solution

Alcohols react in the presence of oxygen to give carbon dioxide and water. This reaction is known as combustion reaction. Butanol reacts with oxygen to form carbon dioxide and water

The unbalanced chemical equation for the reaction between butanol and oxygen gas is as shown below.

${\text{C}}_{\text{4}}{\text{H}}_{\text{9}}\text{OH}\left(l\right)+{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }{\text{CO}}_{\text{2}}\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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.

Butanol is multiplied by the coefficient two, oxygen gas by twelve. On the right side, carbon dioxide is multiplied by eight and water is multiplied by ten.

Therefore, the balanced chemical equation for the reaction between butanol and oxygen is shown below.

${\text{2C}}_{\text{4}}{\text{H}}_{\text{9}}\text{OH}\left(l\right)+12{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }8{\text{CO}}_{\text{2}}\left(g\right)+10{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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.

Conclusion

The balanced chemical equation for the reaction between butanol and oxygen gas has been stated.

Interpretation Introduction

(b)

Interpretation:

The balanced chemical equation for the heating of $\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is to be stated.

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 70E

The balanced chemical equation for the heating of $\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is shown below.

$\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\left(s\right)+12{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Explanation of Solution

A hydrated salt on heating evaporates water molecules to form anhydrous salt. Therefore, Potassium aluminium sulphate dodecahydrate on heating gives anhydrous potassium aluminium sulphate and water vapour.

The completed chemical equation of the reaction for the heating of $\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is shown below.

$\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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.

Water molecule is multiplied by twelve for balancing the equation.

Therefore, the balanced chemical equation for the reaction for the heating of $\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is shown below.

$\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\left(s\right)+12{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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.

Conclusion

The balanced chemical equation of the reaction for heating of $\text{KAl}{\left({\text{SO}}_{\text{4}}\right)}_2\cdot 12{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is stated above.

Interpretation Introduction

(c)

Interpretation:

The balanced chemical equation for the reaction between phosphoric acid and sodium hydroxide is to be stated.

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 70E

The balanced chemical equation for the reaction between phosphoric acid and sodium hydroxide is shown below.

${\text{H}}_3{\text{PO}}_{\text{4}}\left(aq\right)+3\text{NaOH}\left(aq\right)\to {\text{Na}}_{\text{3}}{\text{PO}}_{\text{4}}\left(aq\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)$

Explanation of Solution

An acid and base reacts to form salt and water. Phosphoric acid reacts with sodium hydroxide to give sodium phosphate(salt) and water.

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

${\text{H}}_3{\text{PO}}_{\text{4}}\left(aq\right)+\text{NaOH}\left(aq\right)\to {\text{Na}}_{\text{3}}{\text{PO}}_{\text{4}}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)$

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 $3$ is placed in front of $\text{NaOH}$ a coefficient of $3$ 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 phosphoric acid and sodium hydroxide is shown below.

${\text{H}}_3{\text{PO}}_{\text{4}}\left(aq\right)+3\text{NaOH}\left(aq\right)\to {\text{Na}}_{\text{3}}{\text{PO}}_{\text{4}}\left(aq\right)+3{\text{H}}_{\text{2}}\text{O}\left(l\right)$

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.

Conclusion

The balanced chemical equation for the reaction between phosphoric acid and sodium hydroxide is stated above.