Chapter 11, Problem 69E

Interpretation Introduction

(a)

Interpretation:

The balanced chemical equation for the reaction between propanol 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 69E

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

${\text{2C}}_{\text{3}}{\text{H}}_{\text{7}}\text{OH}\left(l\right)+9{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }6{\text{CO}}_{\text{2}}\left(g\right)+8{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Explanation of Solution

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

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

${\text{C}}_{\text{3}}{\text{H}}_{\text{7}}\text{OH}\left(l\right)+{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }{\text{CO}}_{\text{2}}\left(g\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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.

Propanol is multiplied by the coefficient two, oxygen gas by nine. On the right side, carbon dioxide is multiplied by six and water is multiplied by eight.

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

${\text{2C}}_{\text{3}}{\text{H}}_{\text{7}}\text{OH}\left(l\right)+9{\text{O}}_2\left(g\right)\stackrel{\text{spark}}{\to }6{\text{CO}}_{\text{2}}\left(g\right)+8{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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 propanol and oxygen gas has been stated.

Interpretation Introduction

(b)

Interpretation:

The balanced chemical equation for the heating of $\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)$ 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 69E

The balanced chemical equation for the heating of $\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is shown below.

$\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(s\right)+4{\text{H}}_{\text{2}}\text{O}\left(g\right)$

Explanation of Solution

A hydrated salt on heating evaporates water molecules to form anhydrous salt. Therefore, Calcium nitrate tetrahydrate on heating gives anhydrous calcium acetate and water vapour.

The completed chemical equation of the reaction for the heating of $\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is shown below.

$\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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 four for balancing the equation.

Therefore, the balanced chemical equation for the reaction for the heating of hydrated salt of sodium dichromate is shown below.

$\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)\stackrel{\Delta }{\to }\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\left(s\right)+{\text{H}}_{\text{2}}\text{O}\left(g\right)$

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 $\text{Ca}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}\cdot 4{\text{H}}_{\text{2}}\text{O}\left(s\right)$ is stated above.

Interpretation Introduction

(c)

Interpretation:

The balanced chemical equation for the reaction between carbonic acid and potassium 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 69E

The balanced chemical equation for the reaction between carbonic acid and potassium hydroxide is shown below.

${\text{H}}_{\text{2}}{\text{CO}}_3\left(aq\right)+2\text{KOH}\left(aq\right)\to {\text{K}}_2{\text{CO}}_{\text{3}}\left(aq\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)$

Explanation of Solution

An acid and base reacts to form salt and water. Carbonic acid reacts with potassium hydroxide to give potassium carbonate(salt) and water.

The unbalanced chemical equation for the reaction between nitric acid and barium hydroxide is shown below.

${\text{H}}_{\text{2}}{\text{CO}}_3\left(aq\right)+\text{KOH}\left(aq\right)\to {\text{K}}_2{\text{CO}}_{\text{3}}\left(aq\right)+{\text{H}}_{\text{2}}\text{O}\left(l\right)$

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 $2$ is placed in front of $\text{KOH}$ 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 carbonic acid and potassium hydroxide is shown below.

${\text{H}}_{\text{2}}{\text{CO}}_3\left(aq\right)+2\text{KOH}\left(aq\right)\to {\text{K}}_2{\text{CO}}_{\text{3}}\left(aq\right)+2{\text{H}}_{\text{2}}\text{O}\left(l\right)$

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 carbonic acid and potassium hydroxide is stated above.