Chapter 2, Problem 2.40P

Interpretation Introduction

(a)

Interpretation:

Given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is nonpolar.

Explanation of Solution

The electrostatic potential map shows the molecule with a negative charge concentrated at the center, with positive charge distributed symmetrically around the center. This shows that the individual bond dipoles are all of equal magnitude, and they all point toward the center. The vector addition of these dipoles will be zero because of their symmetric distribution. Therefore, the molecule is nonpolar.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.

Interpretation Introduction

(b)

Interpretation:

Given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is nonpolar.

Explanation of Solution

The electrostatic potential map shows a molecule with a negative charge concentrated at the center, with positive charge distributed symmetrically around the center. This shows that the individual bond dipoles are all of equal magnitude, and they all point toward the center. The vector addition of these dipoles will be zero because of their symmetric distribution. Therefore, the molecule is nonpolar.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.

Interpretation Introduction

(c)

Interpretation:

The given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is polar.

The direction of the net molecular dipole is downward as shown below.

Explanation of Solution

The electrostatic potential map shows a molecule with an asymmetric charge distribution. The positive charge is concentrated on the atom at the top, while the negative charge is distributed on three atoms at the bottom. The individual bond dipoles will therefore not cancel completely. Therefore, the molecule is polar.

The direction of the molecular dipole will be downward, as shown below by the black arrow.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.

Interpretation Introduction

(d)

Interpretation:

The given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is polar.

The direction of the net molecular dipole is upward, as shown below.

Explanation of Solution

The electrostatic potential map shows a molecule with a negative charge distributed on two atoms at the top and the positive charge distributed on two atoms at the bottom. This shows that the individual bond dipoles both point approximately upward and slightly away from the center line. The vector addition of these dipoles will be nonzero. Therefore, the molecule is polar.

The direction of the net dipole moment will be upward as shown below.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.

Interpretation Introduction

(e)

Interpretation:

The given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is polar.

The direction of the net molecular dipole is upward as shown below.

Explanation of Solution

The electrostatic potential map shows a molecule with a negative charge concentrated on the atom at the top center, with positive charge distributed over atoms on the side and at the bottom. This shows that the individual bond dipoles are not symmetrically distributed and will not cancel out completely. Therefore, the molecule is polar.

The direction of the net molecular dipole will be upward because of the concentration of negative charge at the top and a symmetrical distribution of the positive charge in the rest of the molecule.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.

Interpretation Introduction

(f)

Interpretation:

The given uncharged molecule is to be identified as polar or nonpolar, using its electrostatic potential map. If the molecule is polar, the direction of its net molecular dipole moment it to be determined.

Concept introduction:

A polar bond is one in which the bond pair is unequally shared by the two atoms.

A partial positive charge is developed on the less electronegative atom while and an equal but negative partial charge is developed on the more electronegative atom.

Molecules that contain more than one polar bond may or may not have a net dipole moment. The dipole moment is a vector quantity. The net molecular dipole moment is the result of the vector addition of all the individual dipole moments. Depending on the symmetry of the molecule, the individual bond dipoles can partly or completely cancel or reinforce each other.

A bond dipole or a molecular dipole is represented by an arrow pointing from the atom or region with a partial positive charge toward an atom or region with a partial negative charge.

Electrostatic potential maps of molecules show the distribution of electron density in different parts of the molecule. The electron density is represented by different colors, ranging from blue to red. Blue color indicates a low electron density, an atom or region with a partial positive charge. Red color indicates high electron density, an atom or region with a partial negative charge.

Answer to Problem 2.40P

The electrostatic potential map shows that the molecule is nonpolar.

Explanation of Solution

The electrostatic potential map shows a charge distribution that is symmetric about the center of the molecule with two negative regions opposite each other across the center as well as two positive regions across the center. The individual bond dipoles will therefore cancel out completely. Therefore, the net dipole moment will be zero, and the molecule will be nonpolar.

Conclusion

The net dipole moment of a molecule is the vector sum of the individual bond dipoles.