Chapter 2, Problem 2.29E

Interpretation Introduction

(a)

Interpretation:

The molecular weight of the given molecule in $\text{u}$ is to be stated.

Concept introduction:

The total number of protons and neutron which are present in an atom is collectively known as atomic mass of that atom. The total number of protons present in the nucleus of an atom is known as atomic number of that atom.

Answer to Problem 2.29E

The molecular weight of the given molecule, fluorine in $\text{u}$ is $\text{38}\text{.00}\text{u}$.

Explanation of Solution

The given molecule is fluorine, ${\text{F}}_{\text{2}}$. It is a diatomic molecule and possesses two atoms of fluorine.

According to the periodic table, the atomic weight of one fluorine atom is $19.00\text{u}$. Thus, the molecular weight of fluorine molecule is calculated as,

$\text{Molecular}\text{weight}\text{of}{\text{F}}_{\text{2}}=2\times \left(\text{atomic}\text{weight}\text{of}\text{F}\right)$

Substitute the value of atomic weight of one fluorine atom in the above expression.

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{F}}_{\text{2}}& =& 2\times \left(19.00\text{u}\right)\\ & =& \text{38}\text{.00}\text{u}\end{array}$

Thus, the molecular weight of the given molecule, fluorine in $\text{u}$ is $\text{38}\text{.00}\text{u}$.

Conclusion

The molecular weight of the given molecule, fluorine in $\text{u}$ is $\text{38}\text{.00}\text{u}$.

Interpretation Introduction

(b)

Interpretation:

The molecular weight of the given molecule in $\text{u}$ is to be stated.

Concept introduction:

The total number of protons and neutron which are present in an atom is collectively known as atomic mass of that atom. The total number of protons present in the nucleus of an atom is known as atomic number of that atom.

Answer to Problem 2.29E

The molecular weight of the given molecule, carbon disulfide in $\text{u}$ is $76.13\text{u}$.

Explanation of Solution

The given molecule is carbon disulfide, ${\text{CS}}_{\text{2}}$. The molecule of carbon disulfide contains one carbon and two sulfur atoms.

According to the periodic table, the atomic weight of one carbon atom is $12.01\text{u}$ and the atomic weight of one sulfur atom is $32.06\text{u}$. Thus, the molecular weight of carbon disulfide molecule is calculated as,

$\text{Molecular}\text{weight}\text{of}{\text{CS}}_{\text{2}}=\left(\text{atomic}\text{weight}\text{of}\text{C}\right)+\left(2\times \text{atomic}\text{weight}\text{of}\text{S}\right)$

Substitute the value of atomic weights of carbon and sulfur atoms in the above expression.

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{CS}}_{\text{2}}& =& \left(12.01\text{u}\right)+\left(2\times 32.06\text{u}\right)\\ & =& 76.13\text{u}\end{array}$

Thus, the molecular weight of the given molecule, carbon disulfide in $\text{u}$ is $76.13\text{u}$.

Conclusion

The molecular weight of the given molecule, carbon disulfide in $\text{u}$ is $76.13\text{u}$.

Interpretation Introduction

(c)

Interpretation:

The molecular weight of the given molecule in $\text{u}$ is to be stated.

Concept introduction:

The total number of protons and neutron which are present in an atom is collectively known as atomic mass of that atom. The total number of protons present in the nucleus of an atom is known as atomic number of that atom.

Answer to Problem 2.29E

The molecular weight of the given molecule, sulfurous acid in $\text{u}$ is $82.076\text{u}$.

Explanation of Solution

The given molecule is sulfurous acid, ${\text{H}}_2{\text{SO}}_3$. The molecule of sulfurous acid contains two hydrogen atoms, one sulfur atom and three oxygen atoms.

According to the periodic table, the atomic weight of one hydrogen atom is $1.008\text{u}$, the atomic weight of one oxygen atom is $16.00\text{u}$ and the atomic weight of one sulfur atom is $32.06\text{u}$. Thus, the molecular weight of sulfurous acid molecule is calculated as,

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{H}}_2{\text{SO}}_{\text{3}}& =& \left(2\times \text{atomic}\text{weight}\text{of}\text{H}\right)+\left(\text{atomic}\text{weight}\text{of}\text{S}\right)\\ +\left(3\times \text{atomic}\text{weight}\text{of}\text{O}\right)\end{array}$

Substitute the value of atomic weights of hydrogen, oxygen and sulfur atoms in the above expression.

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{H}}_2{\text{SO}}_{\text{3}}& =& \left(2\times 1.008\text{u}\right)+\left(32.06\text{u}\right)+\left(3\times 16.00\text{u}\right)\\ & =& 82.076\text{u}\end{array}$

Thus, the molecular weight of the given molecule, sulfurous acid in $\text{u}$ is $82.076\text{u}$.

Conclusion

The molecular weight of the given molecule, sulfurous acid in $\text{u}$ is $82.076\text{u}$.

Interpretation Introduction

(d)

Interpretation:

The molecular weight of the given molecule in $\text{u}$ is to be stated.

Concept introduction:

The total number of protons and neutron which are present in an atom is collectively known as atomic mass of that atom. The total number of protons present in the nucleus of an atom is known as atomic number of that atom.

Answer to Problem 2.29E

The molecular weight of the given molecule, ethyl alcohol in $\text{u}$ is $46.068\text{u}$.

Explanation of Solution

The given molecule is ethyl alcohol, ${\text{C}}_2{\text{H}}_6\text{O}$. The molecule of ethyl alcohol contains two carbon atoms, six hydrogen atoms and one oxygen atom.

According to the periodic table, the atomic weight of one hydrogen atom is $1.008\text{u}$, the atomic weight of one oxygen atom is $16.00\text{u}$ and the atomic weight of one carbon atom is $12.01\text{u}$. Thus, the molecular weight of ethyl alcohol molecule is calculated as,

$\text{Molecular}\text{weight}\text{of}{\text{C}}_2{\text{H}}_6\text{O}=\left[\begin{array}{c}\left(2\times \text{atomic}\text{weight}\text{of}\text{C}\right)+\left(6\times \text{atomic}\text{weight}\text{of}\text{H}\right)+\\ \left(\text{atomic}\text{weight}\text{of}\text{O}\right)\end{array}\right]$

Substitute the value of atomic weights of hydrogen, oxygen and carbon atoms in the above expression.

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{C}}_2{\text{H}}_6\text{O}& =& \left[\begin{array}{c}\left(2\times 12.01\text{u}\right)+\left(6\times 1.008\text{u}\right)+\\ \left(16.00\text{u}\right)\end{array}\right]\\ =46.068\text{u}\end{array}$

Thus, the molecular weight of the given molecule, ethyl alcohol in $\text{u}$ is $46.068\text{u}$.

Conclusion

The molecular weight of the given molecule, ethyl alcohol in $\text{u}$ is $46.068\text{u}$.

Interpretation Introduction

(e)

Interpretation:

The molecular weight of the given molecule in $\text{u}$ is to be stated.

Concept introduction:

The total number of protons and neutron which are present in an atom is collectively known as atomic mass of that atom. The total number of protons present in the nucleus of an atom is known as atomic number of that atom.

Answer to Problem 2.29E

The molecular weight of the given molecule, ethane in $\text{u}$ is $30.068\text{u}$.

Explanation of Solution

The given molecule is ethane, ${\text{C}}_2{\text{H}}_6$. This molecule of ethane contains two carbon atoms, and six hydrogen atoms.

According to the periodic table, the atomic weight of one hydrogen atom is $1.008\text{u}$ and the atomic weight of one carbon atom is $12.01\text{u}$. Thus, the molecular weight of ethane molecule is calculated as,

$\text{Molecular}\text{weight}\text{of}{\text{C}}_2{\text{H}}_6=\left(2\times \text{atomic}\text{weight}\text{of}\text{C}\right)+\left(6\times \text{atomic}\text{weight}\text{of}\text{H}\right)$

Substitute the value of atomic weights of hydrogen, oxygen and carbon atoms in the above expression.

$\begin{array}{rll}\text{Molecular}\text{weight}\text{of}{\text{C}}_2{\text{H}}_6\text{O}& =& \left(2\times 12.01\text{u}\right)+\left(6\times 1.008\text{u}\right)\\ & =& 30.068\text{u}\end{array}$

Thus, the molecular weight of the given molecule, ethane in $\text{u}$ is $30.068\text{u}$.

Conclusion

The molecular weight of the given molecule, ethane in $\text{u}$ is $30.068\text{u}$.