Chapter 9, Problem 75A

Interpretation Introduction

(a)

Interpretation:

The chemical equation for the combustion of solid naphthalene needs to be determined.

Concept introduction:

In a chemical reaction, the reactants are written on the left side of the equation and the product is written on the right side. The product and the reactants contain an arrow between them showing the proceeding of the reaction from the reactants to the products. A chemical equation is balanced by balancing the number of moles of each element on the reactants and on the products.

Answer to Problem 75A

The chemical equation for the reaction is,

${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}\left(\text{s}\right){\text{+12O}}_{\text{2}}\left(\text{g}\right)\to {\text{10CO}}_{\text{2}}\left(\text{g}\right){\text{+4H}}_{\text{2}}\text{O}\left(\text{l}\right)$

Explanation of Solution

To determine the chemical reaction, we must know the chemical symbols of elements and compounds.

The formula of naphthalene, oxygen and water is, ${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}$, ${\text{O}}_{\text{2}}$ and ${\text{H}}_{\text{2}}\text{O}$ respectively.

So, the skeleton equation for the reaction for the burning of solid naphthalene in air, to yield gaseous carbon dioxide and liquid water is,

${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}\left(\text{s}\right)\text{+}{\text{O}}_{\text{2}}\left(\text{g}\right)\to {\text{CO}}_{\text{2}}\left(\text{g}\right)\text{+}{\text{H}}_{\text{2}}\text{O}\left(\text{l}\right)$

The above equation is not a balanced chemical equation.

To balance the equation, give coefficient 10 to CO₂, 4 to H₂O and 12 to O₂.

Thus, the balanced chemical equation will be:

${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}\left(\text{s}\right){\text{+12O}}_{\text{2}}\left(\text{g}\right)\to {\text{10CO}}_{\text{2}}\left(\text{g}\right){\text{+4H}}_{\text{2}}\text{O}\left(\text{l}\right)$

(b)

Interpretation Introduction

Interpretation:

The chemical equation for the given reaction needs to be written.

Concept introduction:

In a chemical reaction, the reactants are written on the left side of the equation and the product is written on the right side. The product and the reactants contain an arrow between them showing the proceeding of the reaction from the reactants to the products.

A chemical equation is balanced by balancing the number of moles of each element on the reactants and on the products.

Answer to Problem 75A

The chemical equation for the reaction is,

${\text{H}}_{\text{2}}\text{S}\left(\text{g}\right)\text{+}{\text{MnCl}}_{\text{2}}\left(\text{aq}\right)\to \text{MnS}\left(\text{s}\right)\text{+}\text{2HCl}\left(\text{aq}\right)$

Explanation of Solution

To determine the chemical reaction, one must know the chemical symbols of elements and compounds.

The formula of hydrogen sulfide, manganese, chlorine, hydrochloric acid and manganese sulfide is ${\text{H}}_{\text{2}}\text{S}$, ${\text{MnCl}}_{\text{2}}$, $\text{HCl}$ and $\text{MnS}$ respectively.

So, the skeleton equation for the reaction will be:

${\text{H}}_{\text{2}}\text{S}\left(\text{g}\right)\text{+}{\text{MnCl}}_{\text{2}}\left(\text{aq}\right)\to \text{MnS}\left(\text{s}\right)\text{+}\text{HCl}\left(\text{aq}\right)$

The above equation is not a balanced chemical equation. So, the balanced chemical equation is,

${\text{H}}_{\text{2}}\text{S}\left(\text{g}\right)\text{+}{\text{MnCl}}_{\text{2}}\left(\text{aq}\right)\to \text{MnS}\left(\text{s}\right)\text{+}\text{2HCl}\left(\text{aq}\right)$

(c)

Interpretation Introduction

Interpretation:

The chemical equation for the reaction of solid magnesium and nitrogen gas to produce solid magnesium nitride needs to be written.

Concept introduction:

In a chemical reaction, the reactants are written on the left side of the equation and the product is written on the right side. The product and the reactants contain an arrow between them showing the proceeding of the reaction from the reactants to the products.

A chemical equation is balanced by balancing the number of moles of each element on the reactants and on the product side.

Answer to Problem 75A

The chemical equation for the reaction is,

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

Explanation of Solution

To determine the chemical reaction, one must know the chemical symbols of elements and compounds.

The formula of magnesium and nitrogen is Mg and ${\text{N}}_{\text{2}}$ respectively.

So, the skeleton equation for the reaction will be:

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

The above equation is not a balanced chemical equation. So, the balanced chemical equation is,

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

(d)

Interpretation Introduction

Interpretation:

The chemical equation for the reaction of heating oxygen difluoride gas to produce oxygen gas and fluorine gas needs to be written.

Concept introduction:

In a chemical reaction, the reactants are written on the left side of the equation and the product is written on the right side. The product and the reactants contain an arrow between them showing the proceeding of the reaction from the reactants to the products.

A chemical equation is balanced by balancing the number of moles of each element on the reactants and on the products.

Answer to Problem 75A

The chemical equation for the reaction is,

${\text{2OF}}_{\text{2}}\left(\text{g}\right)\to {\text{O}}_{\text{2}}\left(\text{g}\right)\text{+}{\text{2F}}_{\text{2}}\left(\text{g}\right)$

Explanation of Solution

To determine the chemical reaction, one must know the chemical symbols of elements and compounds.

The formula of oxygen and fluorine gas is ${\text{O}}_{\text{2}}$ and F₂ respectively.

So, the skeleton equation for the reaction will be:

${\text{OF}}_{\text{2}}\left(\text{g}\right)\to {\text{O}}_{\text{2}}\left(\text{g}\right)\text{+}{\text{F}}_{\text{2}}\left(\text{g}\right)$

The above equation is not a balanced chemical equation. So, the balanced chemical equation is,

${\text{2OF}}_{\text{2}}\left(\text{g}\right)\to {\text{O}}_{\text{2}}\left(\text{g}\right)\text{+}{\text{2F}}_{\text{2}}\left(\text{g}\right)$