Chapter 11.2, Problem 11PP

(a)

Interpretation Introduction

Interpretation:

A chemical equation has to be balanced.

Concept introduction:

The substances that undergo chemical reaction are defined as reactants and the substances thus formed are known as products.

Answer to Problem 11PP

The balanced chemical equation is shown below:

${\text{2CH}}_4\left(g\right)+{\text{S}}_8\left(s\right)\to 2{\text{CS}}_{\text{2}}\left(l\right)+4{\text{H}}_{\text{2}}\text{S}\left(g\right)$

Explanation of Solution

The given chemical equation is shown below:

${\text{CH}}_4\left(g\right)+{\text{S}}_8\left(s\right)\to {\text{CS}}_{\text{2}}\left(l\right)+{\text{H}}_{\text{2}}\text{S}\left(g\right)$

The coefficient of two is multiplied with methane and carbon disulfide and the coefficient of four is multiplied with hydrogen sulfide to balance the chemical equation.

${\text{2CH}}_4\left(g\right)+{\text{S}}_8\left(s\right)\to 2{\text{CS}}_{\text{2}}\left(l\right)+4{\text{H}}_{\text{2}}\text{S}\left(g\right)$

(b)

Interpretation Introduction

Interpretation:

The $\text{1}\text{.50}\text{mol}$ of ${\text{S}}_{\text{8}}$ is used to produce carbon disulfide. The number of moles of carbon disulfide produced is to be calculated.

Concept introduction:

According to law of conservation of mass it is not possible to form the mass or to destroy the mass. The mass always remains conserved.

The number of moles is calculated as shown below:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ (1)

Answer to Problem 11PP

The number of moles of carbon disulfide produced is $3\text{mol}$.

Explanation of Solution

The balanced chemical equation is shown below:

${\text{2CH}}_4\left(g\right)+{\text{S}}_8\left(s\right)\to 2{\text{CS}}_{\text{2}}\left(l\right)+4{\text{H}}_{\text{2}}\text{S}\left(g\right)$

The above equation shows that two moles of methane reacts with one mole of octasulfur to form two moles of carbon disulfide and four moles of hydrogen sulfide.

Therefore, the number of moles of carbon disulfide produced is,

$\begin{array}{c}\text{1}\text{mol}\text{of}{\text{S}}_8=\text{2}\text{mol}\text{of}{\text{CS}}_{\text{2}}\\ 1.5\text{mol}\text{of}{\text{S}}_8=\text{2}\times \text{1}\text{.5}\text{mol}\text{of}{\text{CS}}_{\text{2}}\\ =3\text{mol}\text{of}{\text{CS}}_{\text{2}}\end{array}$

(c)

Interpretation Introduction

Interpretation:

The number of moles of hydrogen sulfide produced is to be calculated.

Concept introduction:

According to law of conservation of mass it is not possible to form the mass or to destroy the mass. The mass always remains conserved.

Answer to Problem 11PP

The number of moles of hydrogen sulfide produced is $6\text{mol}$.

Explanation of Solution

The balanced chemical equation is shown below:

${\text{2CH}}_4\left(g\right)+{\text{S}}_8\left(s\right)\to 2{\text{CS}}_{\text{2}}\left(l\right)+4{\text{H}}_{\text{2}}\text{S}\left(g\right)$

The above equation shows that two moles of methane reacts with one mole of octasulfur to form two moles of carbon disulfide and four moles of hydrogen sulfide.

Therefore, the number of moles of hydrogen sulfide produced for $1.50\text{mol}$ of ${\text{S}}_{\text{8}}$ is,

$\begin{array}{c}\text{1}\text{mol}\text{of}{\text{S}}_8=4\text{mol}\text{of}{\text{H}}_2\text{S}\\ 1.5\text{mol}\text{of}{\text{S}}_8=4\times \text{1}\text{.5}\text{mol}\text{of}{\text{H}}_2\text{S}\\ =6\text{mol}\text{of}{\text{H}}_2\text{S}\end{array}$